Progress 05/14/13 to 03/11/18
Outputs
Progress Report Objectives (from AD-416): Objective 1: Identify gaps and acquire new wild species to fill gaps or deficiencies in the sunflower germplasm collection. Objective 2: Identify insect pests and pathogens of sunflower, develop effective screening methods to optimize assessment of resistance to sunflower pathogens, determine mechanisms of plant resistance, phenotype germplasm for resistance to major insect pests and pathogens, and introgress insect and disease resistance genes from the wild species into diverse cultivated germplasm. Subobjective 2A: Identify and monitor pathogens. Subobjective 2B: Develop effective screening procedures for Phomopsis and insect damage. Subobjective 2C: Identify and assess mechanisms of insect resistance. Subobjective 2D: Transfer disease resistance, insect resistance, and other agronomic traits from wild Helianthus species into cultivated sunflower and improve methods for interspecific hybridization and release of pre-breeding germplasm. Subobjective 2E: Characterize and map resistance to pathogens and insect pests, and other agronomic traits. Objective 3: Develop sunflower germplasm with high yield, high oil content, and desirable fatty acid concentrations, as well as novel resistance genes for diseases and insects. Subobjective 3A: Develop new inbred lines with novel fatty acid compositions, such as low saturated fatty acids, and high oleic acid. Subobjective 3B: Pyramid disease and insect resistance genes with high yield and oil content in a common germplasm. Approach (from AD-416): Currently, there are a number of factors that reduce sunflower yield including a host of insects and diseases that require careful and costly management practices, reducing profitability. Research is proposed to reduce the input costs by developing durable pest resistance, herbicide resistance, oil content and quality increasing the oil per acre yield of sunflower. Specifically, we will collect wild sunflower relatives to broaden the crop�s genetic base. This germplasm will be phenotyped for resistance to major insect pests and pathogens, cytoplasmic male sterility, and fertility restoration. Methods for improving interspecific hybridization will focus on techniques to detect introgressed alien chromosome segments in interspecific crosses using the genomic fluorescence in situ hybridization technique. Interspecific gene transfer will be evaluated using molecular markers for desirable agronomic traits such as resistance genes to rust and downy mildew. Interspecific germplasm with useful genes will be introgressed into cultivated sunflower and released as enhanced pre-breeding germplasm. Current diseases will be monitored for shifts in virulence and races, and for newly emerged diseases. A field test will be developed to reliably test for the newly emerged Phomopsis stem canker pathogen. An efficient non- destructive screening method will be developed for detecting damage of banded sunflower moth, sunflower moth, red sunflower seed weevil, and sunflower stem weevil. Insect resistance mechanisms will be identified and assessed for sunflower moth. Resistance genes for pathogens and insects, and other agronomic traits will be characterized and mapped. DNA markers for selected traits will be developed and used for marker- assisted breeding. Enhanced sunflower germplasm with high yield, high oil content, and desirable fatty acids concentration, as well as novel resistance genes for diseases and insects will be developed and released. Accomplishing these objectives will provide producers with improved sunflower that will provide a stable supply of high quality oil and confectionery sunflower, improving on-farm profitability and providing the consumer with a reliable domestic supply of a healthy oil, a staple in the American diet. This is the final report for project 3060-21000-039-00D which ended in March 2018. This work is continued in project 3060-21000-043-00D, �Genetic Enhancement of Sunflower Yield and Tolerance to Biotic Stress�. Objective 1: Identify gaps and acquire new wild species to fill gaps or deficiencies in the sunflower germplasm collection. Explorations to fill gaps in the National Plant Germplasm System crop wild relatives� collection were undertaken annually. Five explorations covered four western and southwestern, two southeastern, and parts of two upper Mid- west states covering 9,500 miles driven with the collection of 96 populations of 18 Helianthus species. Unique among these populations were the first collections of a newly discovered species, perennial H. winteri collected in California. The first of two collecting trips for 2017-2018 also is complete, and this trip added six accessions of Helianthus maximiliani from North Dakota and Minnesota. These new populations make additional unique material available as sources of useful traits for cultivated sunflower improvement. Subobjective 2A: Identify and monitor pathogens. Pathogen survey work was not conducted for three years due to a critical vacancy. However, results provide a contrast between observed long-term trends and annual variation. Over many years, Sclerotinia head rot and basal stalk rot have been slowly declining, while Phomopsis has become much more common (from <2% to 10�15% prevalence). For the 2017 field season, low precipitation led to a decrease in disease prevalence for most sunflower pathogens. Data also show Phomopsis and downy mildew have considerable species- and race- level diversity, respectively, suggesting that continued work to map resistance genes and understand pathogen virulence is needed to support genetic resistance of sunflower hybrids. Subobjective 2B: Develop effective screening procedures for Phomopsis and insect damage. Artificial infestation methods have been tested and validated for Phomopsis and may be used if locations with consistent natural infestations are unavailable in the future. The use of X-ray imaging for insect damage assessments on stems and seeds has substantially improved accuracy of insect research and survey data, and also reduced labor costs. All current and future insect damage assessments will use this method. Subobjective 2C: Identify and assess mechanisms of insect resistance. Results over five years provided two key insights on seed feeding by banded sunflower moth (BSM) larvae. First, cultivated inbred lines (from two heterotic groups and an additional biparental population) vary from moderately resistant to very susceptible to BSM, indicating crosses to wild material are not needed to produce germplasm resistant to this pest. Second, there is a moderate correlation between damage to inbred parents and hybrids, suggesting the most damaged inbred lines can be discarded if BSM susceptibility is a selective factor in advancing germplasm. Results from 2017 confirmed those from 2016; several lines from a population used to map glandular trichome abundance, a putative defense trait, were resistant to larval feeding, but the resistance was not related to glandular trichome number. Subobjective 2D: Transfer disease resistance, insect resistance, and other agronomic traits from wild Helianthus species into cultivated sunflower and improve methods for interspecific hybridization and release of pre-breeding germplasm. Over the last five years, oilseed sunflower germplasms with resistance to Sclerotinia basal stalk rot (HA-BSR1 to HA- BSR8, BSR-DIV 830, BSR STR 1623, BSR CAL 2376, BSR MAX 1018/1314/1323, BSR NUT 1008/1324) and Sclerotinia head rot (HR MAX 1018/1323 and HR NUT 1324/1008) were released. Interspecific sources of cytoplasmic male- sterility (CMS GRO1, CMS GRO1-RV, CMS MAX3-RV, CMS TUB1-HA 89) and fertility restoration (RF GIG2-MAX, RF GIG2-GRO, RF GIG2-ANG, RF GIG2-ATR, RF TUB1-ANG) were also released. Additional useful germplasms derived from wild sunflowers were developed and released, including 10 alloplasmic germplasms, 15 bulk populations, and 10 amphiploid genetic stocks. Additional work planned with alien addition lines for 2017�2018 was incomplete due to a critical vacancy. Subobjective 2E: Characterize and map resistance to pathogens and insect pests, and other agronomic traits. Genetic mapping was accomplished for rust resistance genes (R2, R14, R15, and R16), downy mildew resistance genes in already-released lines (Pl17 in HA 458 and Pl22 in Tx16R), novel downy mildew resistance genes from wild sunflowers (Pl18, Pl19, and Pl20), and a male fertility restoration gene (Rf6). Markers (SNP) were also developed to facilitate marker-assisted selection with other rust resistance genes (R4, R5, R13a, and R13b). QTL mapping for Sclerotinia basal stalk rot (BSR) resistance in an RIL population identified six QTL in an RIL population, and the two most significant QTL explain 32% and 20% of the observed phenotypic variance, respectively. Association mapping with a 260-line population found 52 significant loci associated with resistance to Sclerotinia head rot. Field trials in 2017 included the first year Sclerotinia stalk rot testing of the three AB-populations and a second year for testing a RIL population derived from the cross of HA 89 with HA-R3 for QTL analysis of Phomposis resistance. Subobjective 3A: Develop new inbred lines with novel fatty acid compositions, such as low saturated fatty acids, and high oleic acid. A half-diallel genetic population analyzed in previous years has shown plants with variation in linoleic, stearic, and palmitic acids in a high oleic background. Two lines with contrasting saturated and polyunsaturated fat compositions in a high oleic background were analyzed in three environments, and resulting quantitative loci associated with variation in these fats have been mapped. Meanwhile, the breeding program has been converted to concentrate on developing high oleic sunflower lines with diversity in genetic background and other traits. Several lines with high oleic or high oleic, low saturated fat have been released during this project period, including HOLS1, HOLS2, HOLS3, HOLS4, RHA 476, RHA 478, HA 481, HA 482, RHA 483, RHA 484, and HA 487. Subobjective 3B: Pyramid disease and insect resistance genes with high yield and oil content in a common germplasm. Over 2000 nursery rows of high yield, high oil, disease, insect, and herbicide resistant sunflower experimental lines were grown each year of the project plan in nurseries in Fargo, North Dakota, Puerto Rico, and Chile. Of particular importance are several Sclerotinia and Phomopsis resistant sunflower lines of both heterotic groups that have been released or are near release. During this period, 17 oilseed germplasms with Sclerotinia, Phomopsis, downy mildew, and imidazolinone herbicide resistance have been released. Six sunflower confection germplasms, HA-R12, HA-R13, HA-DM2, HA-DM3, HA-DM4, and HA-DM5 were developed by the backcross and pedigree breeding methods, with selection in each generation for downy mildew and/or rust resistance. These germplasms carry unique pyramids of major downy mildew and rust resistance genes. Breeding programs are ongoing and will continue to advance genetic progress on biotic stress resistance balanced with genes for crop quality and yield. Accomplishments 01 Release of disease-resistant sunflower germplasms with good yield potential. Sunflowers struggle with diseases caused by pathogens such as Phomopsis and Sclerotinia. Resistance to these diseases is the result of several genes working together in a sunflower variety. Sunflower producers and seed companies need new sources of resistance to these diseases in agronomically favorable, high-yielding backgrounds. Through breeding and targeted selection for disease resistance, high yield, and other favorable traits, ARS scientists in Fargo, North Dakota developed 2 new female (maintainer) and 4 male (restorer) oilseed sunflower lines that can fill this need. These lines are being used by seed companies to make new commercial hybrids, which will then be sold to farmers and grown for oil production, limiting the losses traditionally incurred by these diseases. 02 Native pollinators support consistent, high sunflower yields. Low or inconsistent yields are challenging for individual growers and the overall sunflower market. When sunflower hybrids do not effectively self-pollinate because of crop genetics or environmental conditions during flowering, pollinators are needed to ensure high yields. ARS scientists in Fargo, North Dakota grew 15 confection sunflower hybrids over two years, documenting contributions of bee pollination to crop yields. On average, 26% of yield was accounted for by bees, with lines that attracted more bees seeing higher benefits from pollinators. Virtually all bee visits to confection sunflowers were by solitary, wild bees rather than the honey bees, though honey bee colonies were located adjacent to the research plots. Because of wild bees� demonstrated importance to yields and clear preference for certain hybrids, growers can consider bee conservation as part of crop management and breeders can use pollinator attraction as a component of inbred and hybrid development. 03 Mapping a new sunflower rust resistance gene. Rust is one of the most common diseases in sunflower production. The development of genetically resistant sunflower hybrids is economically and environmentally friendly compared to other management practices, such as fungicide application. ARS scientists in Fargo, North Dakota used an inbred line, HA-R8, to locate a gene, R15, which confers resistance to all known rust races identified in North America. This gene is independent of currently known rust resistance genes. The newly discovered rust resistance gene and its associated molecular markers provide a new tool for the management of sunflower rust and help breeders efficiently create rust-resistant sunflowers. 04 Floret size explains frequency of wild bee visits to cultivated sunflowers. By moving pollen between the hundreds of small flowers (florets) on male and female plants, wild bees and honey bees are responsible for 100% of sunflower hybrid seed production. Wild bees have additional downstream benefits when they visit those hybrids in farmers� fields, usually adding 20�30% to yields. However, when bees choose not to visit particular sunflower varieties, the benefits are greatly reduced. ARS scientists and collaborators in Fargo, North Dakota examined floret sizes in female sunflower lines and assessed effects of floret size on pollinator visitation. Floret lengths ranged from about 7 to 10 millimeters, and the values for specific lines were consistent across years. Floret size explained most of the differences in bee visits to sunflower varieties, likely because they are unable to access nectar at the bottom of larger florets. Public and private sunflower breeders now know that selection for varieties just 1�2 millimeters shorter could more than double visits from wild bees, and development of genetic markers for floret size will eliminate the need for tedious examination of floret size to enhance bee visitation to sunflowers. 05 Mapping of genes governing a sunflower defense against insect pests. Glandular trichomes are a type of plant hair which often contains chemicals that repel or kill insects. Previous research shows larvae of the sunflower moth, a flower- and seed-feeding pest, are repelled or stunted by chemicals extracted from sunflower glandular trichomes, and lines vary greatly in the number of these glandular hairs produced. ARS scientists in Fargo, North Dakota used a population made from parents with very few or very many glandular trichomes to find the location of genes that determine glandular trichome number. Two significant markers were found, suggesting that this trait could be bred into any sunflower line. Genes near the two markers are similar to genes known to function in trichome development in other plant species. Identification of the markers provides a way for breeders to include a non-GMO insect resistance trait into their sunflower hybrids, which are used by farmers across the country. 06 Release of disease resistant germplasm from wild sunflowers. Scletotinia basal stalk rot (BSR) and downy mildew are two fungal diseases that are major yield limiting factors in global sunflower production. The use of resistant hybrids, where available, is the most efficient and environmentally friendly means of managing these diseases. ARS scientists in Fargo, North Dakota transferred resistance to BSR from three species of wild annual sunflowers into cultivated sunflower, resulting in the release of seven sunflower germplasms, HA-BSR2 to HA- BSR8. All lines except HA-BSR5 also have resistance to downy mildew derived from one of the crossing parents. These lines represent the first oilseed sunflowers with resistance to Sclerotinia BSR and downy mildew and are being used across the U.S. and internationally to breed for resistance to multiple diseases that reduce seed quality and severely impact yield. 07 Novel plant production from interspecific sunflower. Sunflower is an important crop supplying heart-healthy oil for human consumption. Though wild sunflower species have many unique genes that can be used to improve cultivated sunflower, some combinations of crosses between species result in plants that are sterile and cannot produce seed. In an effort to generate plants from crosses that have sterile offspring, ARS scientists in Fargo, North Dakota developed a tissue culture method of producing plants from the tubular flowers of an interspecific cross between cultivated sunflower and one of its wild relatives. Plants generated from tissue culture had the same chromosome number and similar appearance as their parents. This discovery provides a new method to produce large numbers of plants derived from crosses with wild species, helping scientists and breeders move useful traits from wild relatives into cultivated sunflowers 08 Wild sunflower as an alternate source of hydrocarbons. Industrial chemicals used to produce fuels, feeds and other products are often imported. To reduce dependence on foreign sources and support economic growth in the U.S., preliminary research with wild annual sunflower has shown leaves can provide useful levels of extractable hydrocarbons. In a new study, ARS scientists in Fargo, North Dakota and their collaborators sampled sunflower populations from eastern Oklahoma to North Dakota, to coastal southern California. The highest hydrocarbon yields were observed in the Texas Panhandle, while the lowest were in North Dakota and Minnesota. This study confirms that there are populations and areas where hydrocarbons are particularly high, information that is essential to public or private groups with an interest in producing sunflower-derived hydrocarbons.
Impacts
(N/A)
Publications
- Corbi, J., Baack, E.J., Dechaine, J.M., Seiler, G., Burke, J.M. 2018. Genome-wide analysis of allele frequency change in sunflower crop-wild hybrid populations evolving under natural conditions. Molecular Ecology. 27(1):233-247.
- Mallinger, R.E., Prasifka, J.R. 2017. Benefits of insect pollination to confection sunflowers differ across plant genotypes. Crop Science. 57(6) :3264-3272.
- Portlas, Z.M., Tetlie, J.R., Prischmann-Voldseth, D., Hulke, B.S., Prasifka, J.R. 2018. Variation in floret size explains differences in wild bee visitation to cultivated sunflowers. Plant Genetic Resources.
- Prasifka, J.R., Mallinger, R.E., Hulke, B.S., Larson, S.R., Van Tassel, D. 2017. Plant-herbivore and plant-pollinator interactions of the developing perennial oilseed crop, Silphium integrifolium. Environmental Entomology. 46(6):1339-1345.
- Underwood, W., Somerville, S.C. 2017. Phosphorylation is required for the pathogen defense function of the Arabidopsis PEN3 ABC transporter. Plant Signaling and Behavior. 12(10):e1379644.
- Fu, X., Qi, L., Hulke, B., Seiler, G., Jan, C. 2017. Somatic embryogenesis from corolla tubes of interspecific amphiploids between cultivated sunflower (Helianthus annuus L.) and its wild species. Helia. 40(66):1-19.
- Hulke, B.S., May, W.E. 2018. Registration of oilseed sunflower restorer germplasms RHA 476 and RHA 477, adapted for short season environments. Journal of Plant Registrations. 12:148-151.
- Hulke, B.S., Ma, G., Qi, L.L., Gulya, T.J. 2018. Registration of oilseed sunflower germplasms RHA 461, RHA 462, RHA 463, HA 465, HA 466, HA 467, and RHA 468 with diversity in Sclerotinia resistance, yield, and other traits. Journal of Plant Registrations. 12:142-147.
- Talukder, Z.I., Hu, J., Seiler, G.J., Qi, L.L. 2017. Registration of an oilseed sunflower germplasm line HA-BSR1 highly tolerant to Sclerotinia basal stalk rot. Journal of Plant Registrations. 11:315-319.
- Royaute, R., Wilson, E.S., Helm, B.R., Mallinger, R.E., Prasifka, J.R., Greenlee, K.J., Bowsher, J.H. 2018. Phenotypic integration in an extended phenotype: among-individual variation in nest-building traits of the alfalfa leafcutting bee (Megachile rotundata). Journal of Evolutionary Biology.
- Gao, Q.M., Kane, N.C., Hulke, B.S., Reinert, S., Pogoda, C.S., Tittes, S., Prasifka, J.R. 2018. Genetic architecture of capitate glandular trichome density in florets of domesticated sunflower (Helianthus annuus L.). Frontiers in Plant Science.
- Ma, G.J., Song, Q.J., Markell, S.G., Qi, L.L. 2018. High-throughput genotyping-by-sequencing facilitates molecular tagging of a novel rust resistance gene, R15, in sunflower (Helianthus annuus L.). Theoretical and Applied Genetics.
- Qi, L.L., Talukder, Z.I., Long, Y.M., Seiler, G.J. 2018. Registration of oilseed sunflower germplasms HA-BSR2, HA-BSR3, HA-BSR4, and HA-BSR5 with resistance to sclerotinia basal stalk rot and downy mildew. Journal of Plant Registrations.
- Seiler, G.J., Misar, C.G., Gulya, T.J., Underwood, W.R., Flett, B.C., Gilley, M.A., Markell, S.G. 2017. Identification of novel sources of resistance to Sclerotinia basal stalk rot in South African sunflower germplasm. Plant Health Progress. 18:87-90.
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Progress 10/01/16 to 09/30/17
Outputs
Progress Report Objectives (from AD-416): Objective 1: Identify gaps and acquire new wild species to fill gaps or deficiencies in the sunflower germplasm collection. Objective 2: Identify insect pests and pathogens of sunflower, develop effective screening methods to optimize assessment of resistance to sunflower pathogens, determine mechanisms of plant resistance, phenotype germplasm for resistance to major insect pests and pathogens, and introgress insect and disease resistance genes from the wild species into diverse cultivated germplasm. Subobjective 2A: Identify and monitor pathogens. Subobjective 2B: Develop effective screening procedures for Phomopsis and insect damage. Subobjective 2C: Identify and assess mechanisms of insect resistance. Subobjective 2D: Transfer disease resistance, insect resistance, and other agronomic traits from wild Helianthus species into cultivated sunflower and improve methods for interspecific hybridization and release of pre-breeding germplasm. Subobjective 2E: Characterize and map resistance to pathogens and insect pests, and other agronomic traits. Objective 3: Develop sunflower germplasm with high yield, high oil content, and desirable fatty acid concentrations, as well as novel resistance genes for diseases and insects. Subobjective 3A: Develop new inbred lines with novel fatty acid compositions, such as low saturated fatty acids, and high oleic acid. Subobjective 3B: Pyramid disease and insect resistance genes with high yield and oil content in a common germplasm. Approach (from AD-416): Currently, there are a number of factors that reduce sunflower yield including a host of insects and diseases that require careful and costly management practices, reducing profitability. Research is proposed to reduce the input costs by developing durable pest resistance, herbicide resistance, oil content and quality increasing the oil per acre yield of sunflower. Specifically, we will collect wild sunflower relatives to broaden the crop�s genetic base. This germplasm will be phenotyped for resistance to major insect pests and pathogens, cytoplasmic male sterility, and fertility restoration. Methods for improving interspecific hybridization will focus on techniques to detect introgressed alien chromosome segments in interspecific crosses using the genomic fluorescence in situ hybridization technique. Interspecific gene transfer will be evaluated using molecular markers for desirable agronomic traits such as resistance genes to rust and downy mildew. Interspecific germplasm with useful genes will be introgressed into cultivated sunflower and released as enhanced pre-breeding germplasm. Current diseases will be monitored for shifts in virulence and races, and for newly emerged diseases. A field test will be developed to reliably test for the newly emerged Phomopsis stem canker pathogen. An efficient non- destructive screening method will be developed for detecting damage of banded sunflower moth, sunflower moth, red sunflower seed weevil, and sunflower stem weevil. Insect resistance mechanisms will be identified and assessed for sunflower moth. Resistance genes for pathogens and insects, and other agronomic traits will be characterized and mapped. DNA markers for selected traits will be developed and used for marker- assisted breeding. Enhanced sunflower germplasm with high yield, high oil content, and desirable fatty acids concentration, as well as novel resistance genes for diseases and insects will be developed and released. Accomplishing these objectives will provide producers with improved sunflower that will provide a stable supply of high quality oil and confectionery sunflower, improving on-farm profitability and providing the consumer with a reliable domestic supply of a healthy oil, a staple in the American diet. Objective 1-Identify gaps and acquire new wild species to fill gaps or deficiencies in the sunflower germplasm collection. The specific sampling strategy, collection route, necessary permits and contacts with local officials for an exploration planned in late September-early October to collect crop wild relatives of sunflower in Arkansas, Texas, Oklahoma, Tennesse, North Carolina, South Carolina, and Georgia has been completed. Species that will be collected are perennial H. hirsutus (hairy sunflower) , as well as other species that may have seed to collect at the time to fill gaps in the USDA National Plant Germplasm System sunflower crop wild relatives genebank collection, making it available for research for increasing genetic diversity and improvement of cultivated sunflower, and preserving it for future generations. Subobjective 2B: Develop effective screening procedures for Phomopsis. The third year of field screening of a recombinant inbred line population for Phomopsis is underway at three locations during the 2017 growing season. Subobjective 2C: Identify and assess mechanisms of insect resistance. A first year of testing was completed to examine susceptibility of sunflower hybrids to banded sunflower moth (BSM). Hybrids were created by crossing each of 15 female lines (which varied in their susceptibility to BSM) with one male, RHA 266, which was the least-damaged male line in previous years of testing. Results suggest that female lines that are less damaged by BSM tend to produce hybrids with less damage from BSM. Though damage to an inbred parent cannot precisely predict hybrid damage, results suggest that if a goal is to develop hybrids with resistance to BSM, the most damaged inbred parents can be excluded from testcrosses. A second year of testing on the same lines is underway. Subobjective 2D: Transfer disease resistance, insect resistance, and other agronomic traits from wild Helianthus species into cultivated sunflower and improve methods for interspecific hybridization and release of pre-breeding germplasm. The characterization of a unique high frequency production of triploids observed when cultivated sunflower was pollinated by specific accessions of perennial diploid crop wild relatives progressed. Genomic in situ hybridization analyses indicated that the triploid F1s had two genomes from the wild pollen sources and one from the cultivated line. Mitotic chromosome analyses indicated that the frequency of triploid progenies was significantly higher than those of the polyploid progenies. Pollen stainability analysis suggested the existence of a low percentage of unreduced male gametes that preferred fertilization with the female gametes, due to the dosage factors related to recognition and rejection of foreign pollen during fertilization. Further studies of the genetic control of this trait will facilitate research on sunflower polyploidy speciation and evolution, and the utilization of this trait in sunflower breeding. Screening of South African oilseed germplasm for Sclerotinia basal stalk rot (BSR), a serious fungal disease of sunflower continued. A total of fifty-nine cultivated oilseed sunflower accessions from the Agricultural Research Council, Grain Crops Institute, Potchefstroom, South Africa sunflower collection were evaluated over four environments and two years for resistance to BSR in artificially inoculated field trials. Nine accessions from the South African sunflower collection were identified with a disease incidence of 18%, less than or equal to the moderately resistant sunflower hybrid, with one line with only 3% incidence. These lines represent genetic diversity from other than the traditionally used germplasm in breeding programs to introgress the genes for resistance to Sclerotinia BSR into other adapted lines, providing a more efficient, durable, and environmentally friendly host plant resistance. Research on somatic embryogenesis of sunflower, recalcitrant to manipulations in vitro, progressed in increasing the efficiency of plant multiplication. Interspecific amphiploids (2n=4x=68) G08/2280 (H. pumilus x P21) and G08/2260 (NMSHA89 x H. maximiliani) between cultivated sunflower and wild perennial Helianthus species were used as explant donors. Primary somatic embryos were induced directly from the surface of corolla tubes at the late uninucleate or binucleate microspore development stage. Secondary somatic embryos were rapidly produced from primary embryos when subcultured with an induction frequency of 100 %. Mature embryos were gradually converted into young shoots on hormone-free subculture media. Regenerated plants acclimated successfully and displayed similar morphology and chromosome number to the amphiploid donors. Continued validation and optimization of this system with a larger number of sunflower genotypes will be studied in the future. Subobjective 2E: Characterize and map resistance to pathogens and insect pests, and other agronomic traits. A second year of field testing of two BC2F3 populations for Sclerotinia stalk rot was conducted at two locations the past growing season. These populations were developed from annual sunflower crop wild relatives. These populations will continue to be tested next growing season. A wild Helianthus annuus accession, PI 435414, exhibits resistance to downy mildew. Resistance was introduced into a confection sunflower mapping population. Genetic analysis indicated that a single dominant gene Pl19, controls the most predominant and virulent races of downy mildew currently identified in North America. The Pl19 gene is located on linkage group 4 of the sunflower genome map and is flanked by two single nucleotide polymorphism (SNP) markers, which are well suited for marker- assisted selection in molecular breeding. A new source of resistance to downy mildew was discovered in a wild annual silver leaf sunflower (Helianthus argophyllus) from Texas. Resistance is controlled by a single dominant gene, Pl20, making it easier to transfer into cultivated sunflower. Pl20 controls the most predominant and virulent races of downy mildew currently identified in North America. It is located on linkage group 8 of the sunflower genome, with identified molecular markers for the novel gene that can be used in sunflower breeding programs. Mapping the glandular trichome trait was completed. Published evidence indicates that this trait is a factor for resistance to sunflower moth and banded sunflower moth. The trait is a product of two major genetic loci which determine near-zero density (providing susceptibility) to hundreds of glandular trichomes per floret (providing resistance). Association mapping for Phomopsis resistance was completed. However, plans are to use RNAseq technology to increase marker density and reliability of the resistance model this year. Previously released TX16R germplasm is resistant to all known U.S. sunflower downy mildew and rust races. Additional SNP markers have been identified for downy mildew and rust resistance genes in TX16R, increasing the number of markers and saturating the mapping of these genes. Molecular markers linked to these resistance genes will enhance the development of downy mildew and rust resistant lines for the sunflower industry. Research to unravel the interesting phenomena that causes vigor reduction in the absence of nuclear vigor restoration genes in cytoplasms of perennial Helianthus species continued. Progress was made in further mapping of the vigor restoration gene in the perennial cytoplasm. Following the mapping of a vigor restoration gene commonly existing in cultivated lines, a second vigor restoration gene existing in perennial Helianthus giganteus was mapped. This will facilitate sunflower line development when using cytoplasms of wild perennial Helianthus species for crop improvement. Subobjective 3A: Develop new inbred lines of sunflowers with novel fatty acid compositions, such as low saturated fatty acids, and high oleic acid. A half-diallel genetic population analyzed in previous years has shown plants with variation in linoleic, stearic, and palmitic acids in a high oleic background. A biparental population with a HA 466 genetic background has been developed from two disparate genotypes from the half- diallel and will undergo a quantitative trait loci analysis in future years to determine the genetic structure of these heritable differences and to develop markers for use in breeding. Meanwhile, we have analyzed and selected all of the 2016 breeding lines to optimize oleic acid and saturated fat content of the seed oil. Additional populations were made last year that segregate for high oleic and low saturated fat content. Subobjective 3B: Pyramid disease and insect resistance with high yield and oil content. Over 2000 nursery rows of high yield, high oil, disease, insect, and herbicide resistant sunflower experimental lines were grown in nurseries in Fargo, North Dakota, Puerto Rico, and Chile. Of these, lines from 16 pedigrees are candidates for release, including several Sclerotinia and Phomopsis resistant sunflower lines of both heterotic groups. Lines will be made publicly available. Three sunflower confection germplasms, HA-DM2, HA-DM3, and HA-DM4 were developed by the backcross and pedigree breeding methods, with selection in each generation for downy mildew and rust resistance. The released germplasms carry the gene combinations of PlArg (DM R gene) plus R12 (rust R gene) (HA-DM2), Pl17 plus R13a (HA-DM3), and Pl18 plus R13a (HA-DM4), providing diversity for resistance to downy mildew and rust. Accomplishments 01 Durable sunflower downy mildew and rust resistance. Downy mildew and rust are two devastating diseases that seriously reduce yields for sunflower producers. Very few suitable confection (eatable) inbred sunflower lines with high levels of resistance to downy mildew and rust resistance are available for commercial confection sunflower breeders. ARS scientists in Fargo, North Dakota, developed and released three germplasms resistant to both downy mildew and rust. The germplasms carry a stacking of one downy mildew and one rust gene, with different genes in each germplasm providing resistance to all known races of North American rust and downy mildew, representing the first confection germplasm with combined resistance to both downy mildew and rust. Molecular markers related to both disease genes have been provided to the sunflower industry, enabling breeders to develop additional hybrids with resistance to multiple pathogens, thus assuring sustainable sunflower production in the presence of these two devastating diseases. 02 Novel sources of high yielding Phomopsis and Sclerotinia resistant sunflower. Commercial sunflower hybrids are needed that combine high yield and agronomic quality, with disease resistance and end market traits like high oleic acid. ARS scientists in Fargo, North Dakota, developed one restorer line with imidazolinone herbicide tolerance, high oleic fatty acid oil content, and Sclerotinia head and stalk rot resistance, two restorer lines with imidazolinone herbicide tolerance and Phomopsis stem canker resistance, and a maintainer line with imidazolinone herbicide tolerance and high oleic fatty acid oil content for the sunflower breeding industry and ultimately the producers. The germplasms have been released to commercial seed companies, public researchers, and others to develop improved sunflower hybrids for sunflower producers. The discovery of new sources of resistance and tolerance will provide a more efficient, durable, and environmentally friendly host plant resistance to sustain sunflower as an economically viable crop. 03 Sclerotinia white mold resistant sunflower. Sclerotinia is the causal agent of a serious sunflower disease epidemic that causes three distinctly different diseases on sunflower: head, basal stalk or wilt, and mid-stalk rot with the former two accounting for over 80% of the disease damage. Since limited chemical and biological controls for Sclerotinia are available, and the present-day hybrids lack sufficient resistance, identification of new sources of genetic resistance becomes necessary to manage this disease. The crop wild relatives are native to North America where they are distributed over a large geographic area, which exposes them to a wide range of environmental conditions and disease organisms that coevolved with the crop, providing the opportunity to discover disease resistance genes in natural populations. The genetics of Sclerotinia basal stalk and head rot is quantitative, requiring several genes for control, which complicates the breeding process. Due to the lack of resistance genes in the cultivated sunflower, new resistance genes were discovered by the ARS scientists in Fargo, North Dakota in the perennial sunflower crop wild relatives. Two head and five basal stalk rot interspecific germplasms based on the perennial relatives have been publically released. These germplasms will provide sunflower breeders and producers additional sources of genes to control a major production limiting disease which will help sustain sunflower production in an environmentally friendly manner. 04 Sclerotinia basal stalk rot resistant germplasm. Sclerotinia basal stalk rot (BSR) is a serious fungal disease of sunflower causing significant yield reduction in the cool and humid areas of the world. Host resistance is the most effective method for controlling BSR disease caused by Sclerotinia white mold. The genetics of resistance to BSR is quantitative, requiring several genes for control. ARS scientists in Fargo, North Dakota, identified six significant quantitative trait loci (QTL) associated with BSR tolerance from a recombinant inbred line population. Two loci, each explaining 31.6 and 20.2% of the observed phenotypic variance, respectively contributed to the increased resistance. A highly tolerant Sclerotinia BSR oilseed germplasm was developed and released with 1.6% incidence compared to 20% for the parents. Genetic analysis of the germplasm revealed that it possessed three resistant loci from each parent. The successful transfer of Sclerotinia BSR resistance from crop wild relatives into adapted lines provides a more efficient, durable, and environmentally friendly host plant resistance. 05 Interspecific amphiploid sunflower. Crop wild relatives of sunflower have played an important role in establishing sunflower as a valuable global oilseed crop. Interspecific amphiploids derived from crop wild relatives crossed with cultivated sunflower have been developed to help mine potential genes from the very large gene pool of 53 different species, especially the 39 hard-to-cross perennial species. The value of these genetic stocks is that they can act as a bridge in interspecific gene transfer, allowing for easier backcrossing with the cultivated sunflower to further broaden the genetic diversity of the crop, as well as for the transfer of specific target genes, especially for disease resistance. ARS scientists in Fargo, North Dakota, developed and publicly released 12 amphiploid genetic stocks based on nine perennial species. The genetic stocks will help conventional breeders identify and transfer desirable genes from the perennial species with greater ease. The genetic stocks will also allow for the development of chromosome addition lines, with individual wild species chromosomes added to the background of cultivated sunflower lines for genetic studies of specific chromosomes, similar to marker assisted selection. 06 New downy mildew genes from crop wild relatives. Global sunflower production is plagued by many diseases, among them downy mildew (DM), which is one of the most destructive. New races of DM are continually emerging rendering the current resistant sunflower hybrids ineffective, necessitating the search for new resistance sources. ARS scientists in Fargo, North Dakota, discovered two new DM resistance genes derived from annual sunflower crop wild relatives and transferred the genes into cultivated confection and oilseed sunflower. The new genes are highly effective against the most predominant and virulent races of downy mildew currently identified in North America. Molecular markers for the novel genes were identified so they can be used in sunflower breeding programs. The discovery of new sources of resistance to DM will provide a more efficient, durable, and environmentally friendly host plant resistance to sustain sunflower as an economically viable crop. 07 New sources of Sclerotinia basal stalk rot. Sclerotinia basal stalk rot (BSR) is a serious fungal disease that reduces yield of global sunflower production. Since limited chemical and biological controls for BSR are available, and the present-day hybrids lack sufficient resistance, identification of new sources of resistance becomes a necessity to manage the disease now and in the future. A total of fifty- nine cultivated oilseed sunflower accessions from the Agricultural Research Council, Grain Crops Institute, Potchefstroom, South Africa sunflower collection were evaluated by ARS scientists in Fargo, North Dakota, in four environments over two years for resistance to BSR in artificially inoculated field trials. Nine accessions from the South African sunflower collection were identified with a disease incidence of 18%, less than or equal to the moderately resistant sunflower hybrid, with one line with only 3% incidence. These lines represent genetic diversity from other than the traditionally used cultivated germplasm used in most breeding programs to introgress resistance genes for Sclerotinia BSR into other adapted lines, providing a more efficient, durable, and environmentally friendly host plant resistance. 08 Relationship of floral traits to pollinator visitation and yield. Sunflower and bees have coexisted for years. Multiple years of field testing have shown consistent pollinator preference (mostly wild bees) for specific USDA sunflower inbred lines. ARS scientists in Fargo, North Dakota, examined floral and nectar traits of tested inbred lines shown to vary in the amount of sugar in floral nectar, composition of nectar (sucrose as % of total sugars), and accessibility of nectar (depth of corollas). Increased visitation to inbred lines was associated with both the amount of floral nectar and accessibility (i.e. , shorter corollas make nectar more accessible), suggesting that these traits can increase profitability of hybrid seed production for seed companies. Follow-up studies also show that increased pollinator visits are positively related to increased yields for growers of commercial hybrids. The high sucrose line and corolla depth variation identified in public inbred lines are being used in ongoing research, with a goal of developing sunflowers with traits (and associated genetic markers) that will benefit sunflowers through increased pollination and yield, and likely benefit pollinators though increased availability of food in areas planted to sunflowers. 09 Genetic diversity from perennial crop wild relatives. Cultivated sunflower is still represented by a relatively narrow genetic base, which greatly limits its future success as a competitive major global oilseed crop. A significant number of the perennial crop wild relatives have been identified as highly resistant to diseases and parasites of global concern including broomrape, a parasitic weed, Sclerotinia white mold, Phomopsis stem canker, downy mildew, leaf rust, Verticillium wilt, and Rhizopus head rot. Of the 53 crop wild relatives, 39 are perennial and difficult to cross with cultivated sunflower. Thus, they have been rarely utilized for sunflower improvement and represent unexploited sources of genetic variation for sunflower improvement. ARS scientists in Fargo, North Dakota, developed 15 interspecific bulk populations based on 10 perennial crop wild relatives, providing breeders with the opportunity to incorporate previously unavailable genetic diversity into their programs. These bulk populations will help diversify the sources of disease resistance, helping to sustain sunflower production in an environmentally friendly manner and improving producers� net returns. 10 Diversification of parental lines for hybrid sunflower. Globally, sunflower is the fifth largest hybrid crop. It is currently based on a single female parent, a French sterile cytoplasm developed in 1969, derived from the wild prairie sunflower, and a few male parental lines resulting in a crop with a very narrow genetic base. This leaves sunflower very vulnerable to attack by pests similar to the disaster seen in corn with the outbreak of southern corn leaf fungal blight in the 1970s. Crop wild relatives of sunflower provide a readily available resource for broadening the genetic base of sunflower. ARS scientists in Fargo, North Dakota, discovered a new female cytoplasm derived from perennial Jerusalem artichoke and complementary male parental lines. The new cytoplasm and male parental lines can be used by breeders to diversify the currently used single cytoplasm as an alternative for the development of hybrid sunflower, making it better able to withstand an ever-changing environment.
Impacts
(N/A)
Publications
- Underwood, W. 2016. Contributions of host cellular trafficking and organization to the outcomes of plant-pathogen interactions. Seminars in Cell and Developmental Biology. 56:163-173.
- Long, Y.M., Chao, W.S., Ma, G.J., Xu, S.S., Qi, L.L. 2017. An innovative SNP genotyping method adapting to multiple platforms and throughputs. Theoretical and Applied Genetics. 130(3):597-607.
- Prasifka, J.R., Prasifka, P.L., Lee, D.K. 2016. Efficacy of insecticides to limit caterpillar damage to prairie cordgrass seed. Arthropod Management Tests. 41(1):tsw030. doi:10.1093/amt/tsw030.
- Hulke, B.S., Gao, Q.M., Foley, M.E. 2017. Registration of the sunflower oilseed maintainer genetic stocks HOLS1, HOLS2, HOLS3, and HOLS4, possessing genes for high oleic and low saturated fatty acids, and tolerance to imidazolinone herbicides. Journal of Plant Registrations. 11:200-203.
- Underwood, W., Ryan, A., Somerville, S.C. 2017. An Arabidopsis lipid flippase is required for timely recruitment of defenses to the host- pathogen interface at the plant cell surface. Molecular Plant. 10(6):805- 820.
- L.Qi, L., Talukder, Z.I., Hulke, B.S., Foley, M.E. 2017. Development and dissection of diagnostic SNP markers for the downy mildew resistance genes PlArg and Pl8 and maker-assisted gene pyramiding in sunflower (Helianthus annuus L.). Molecular Genetics and Genomics. 292(3):551-563.
- Ma, G.J., Markell, S.G., Song, Q.J., Qi, L.L. 2017. Genotyping-by- sequencing targeting of a novel downy mildew resistance gene Pl20 from wild Helianthus argophyllus for sunflower (Helianthus annuus L.). Theoretical and Applied Genetics. 130(7):1519-1529.
- Kurt, A., Torun, H., Nesrin, C., Seiler, G., Hayirlioglu-Ayaz, S., Ayaz, F. A. 2017. Nutrient profiles of the hybrid grape cultivar 'Isabel' during berry maturation and ripening. Journal of the Science of Food and Agriculture. 97:2468-2479.
- Seiler, G.J., Gulya Jr, T.J. 2016. Sunflower: Overview. In: Wrigley, C.W., Corke, H., Seetharaman, K., and Faubion, J., editors. Encyclopedia of Food Grains. 2nd edition. Oxford, UK: Elsevier. p. 247-253.
- Seiler, G.J. 2016. Botany of the Sunflower Plant. In: Harveson, R.M., Markell, S.G., Block, C.C., Gulya, T.J. editors. Compendium of Sunflower Diseases and Pests. St. Paul, MN: APS Press. pp.4-11.
- Foley, M.E., Dogramaci, M., West, M.S., Underwood, W.R. 2016. Environmental factors for germination of Sclerotinia sclerotiorum sclerotia. Journal of Plant Pathology & Microbiology. doi:10.4172/2157- 7471.1000379.
- Van Tassel, D.L., Albrecht, K.A., Bever, J.D., Boe, A.A., Brandvain, Y., Crews, T.E., Gansberger, M., Gerstberg, P., Gonzalez-Paleo, L., Hulke, B.S. , Kane, N.C., Johnson, P.J., Pestsova, E.G., Picasso Risso, V.D., Prasifka, J.R., Ravetta, D.A., Schlautman, B., Sheaffer, C.C., Smith, K.P., Speranza, P.R., Turner, M.K., Vilela, A.E., von Gehren, P., Weaver, C. 2017. Accelerating Silphium domestication: an opportunity to develop new crop ideotypes and breeding strategies informed by multiple disciplines. Crop Science. 57(3):1274-1284.
- Liu, Z., Seiler, G.J., Gulya, T.J., Feng, J., Rashid, K.Y., Cai, X., Jan, C. 2017. Triploid production from interspecific crosses of two diploid perennial Helianthus with cultivated sunflower. Genes, Genomes, Genetics. 7(4):1097-1108.
- Mallinger, R.E., Prasifka, J.R. 2017. Bee visitation rates to cultivated sunflowers increase with the amount and accessibility of nectar sugars. Journal of Applied Entomology. 141(7):561-573.
- Xu, S.S., Liu, Z., Zhang, Q., Niu, Z., Jan, C., Cai, X. 2016. Chromosome Painting by GISH and Multicolor FISH. In: Kianian, S.F., Kianian, P.M.A., Editors. Plant Cytogenetics: Methods and Protocols. Methods in Molecular Biology. New York: Springer. p. 7-21.
- Zahirul, T.I., Seiler, G.J., Song, Q., Ma, G., Qi, L. 2016. SNP discovery and QTL mapping of Sclerotinia basal stalk rot resistance in sunflower using genotyping-by-sequencing (GBS). The Plant Genome. 9(3). doi:10.3835/ plantgenome 2016.03.0035.
- Prasifka, J.R., Hulke, B.S. 2016. Relative susceptibility of sunflower maintainer lines and resistance sources to natural infestations of the banded sunflower moth (Lepidoptera: Tortricidae). The Canadian Entomologist. 148:736-741.
- Zhang, Z.W., Ma, G.J., Zhao, J., Markell, S.G., Qi, L.L. 2017. Discovery and introgression of the wild sunflower-derived novel downy mildew resistance gene Pl19 in confection sunflower (Helianthus annuus L.). Theoretical and Applied Genetics. 130:29-39.
- Feehan, J.M., Schneibel, K.E., Bouras, S., Underwood, W., Keller, B., Somerville, S.C. 2017. Purification of high molecular weight genomic DNA from powdery mildew for long-read sequencing. Journal of Visualized Experiments. doi:10.3791/55463.
- Seiler, G.J., Qi, L.L., Marek, L.F. 2017. Utilization of sunflower crop wild relatives for cultivated sunflower improvement. Crop Science. 57:1-19. doi:10.2135/cropsci2016.10.0856.
- Seiler, G.J., Marek, L.F. 2016. Collection of wild Helianthus anomalus and deserticola sunflower from the desert southwest USA. Helia. 39(65):139-155.
- Qi, L., Long, Y., Talukder, Z., Block, C., Gulya, T.J. 2016. Genotyping-by- sequencing uncovers the introgression alien segments associated with Sclerotinia basal stalk rot resistance from wild species�I. Helianthus argophyllus and H. petiolaris. Frontiers in Genetics. doi:10.3389/gene. 2016.00219.
- Prasifka, J.R., Marek, L., Lee, D., Thapa, S., Hahn, V., Bradshaw, J. 2016. Effects from early planting of late-maturing sunflowers on damage from primary insect pests in the United States. Helia. 39(63):45-56.
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Progress 10/01/15 to 09/30/16
Outputs
Progress Report Objectives (from AD-416): Objective 1: Identify gaps and acquire new wild species to fill gaps or deficiencies in the sunflower germplasm collection. Objective 2: Identify insect pests and pathogens of sunflower, develop effective screening methods to optimize assessment of resistance to sunflower pathogens, determine mechanisms of plant resistance, phenotype germplasm for resistance to major insect pests and pathogens, and introgress insect and disease resistance genes from the wild species into diverse cultivated germplasm. Subobjective 2A: Identify and monitor pathogens. Subobjective 2B: Develop effective screening procedures for Phomopsis and insect damage. Subobjective 2C: Identify and assess mechanisms of insect resistance. Subobjective 2D: Transfer disease resistance, insect resistance, and other agronomic traits from wild Helianthus species into cultivated sunflower and improve methods for interspecific hybridization and release of pre-breeding germplasm. Subobjective 2E: Characterize and map resistance to pathogens and insect pests, and other agronomic traits. Objective 3: Develop sunflower germplasm with high yield, high oil content, and desirable fatty acid concentrations, as well as novel resistance genes for diseases and insects. Subobjective 3A: Develop new inbred lines with novel fatty acid compositions, such as low saturated fatty acids, and high oleic acid. Subobjective 3B: Pyramid disease and insect resistance genes with high yield and oil content in a common germplasm. Approach (from AD-416): Currently, there are a number of factors that reduce sunflower yield including a host of insects and diseases that require careful and costly management practices, reducing profitability. Research is proposed to reduce the input costs by developing durable pest resistance, herbicide resistance, oil content and quality increasing the oil per acre yield of sunflower. Specifically, we will collect wild sunflower relatives to broaden the crop�s genetic base. This germplasm will be phenotyped for resistance to major insect pests and pathogens, cytoplasmic male sterility, and fertility restoration. Methods for improving interspecific hybridization will focus on techniques to detect introgressed alien chromosome segments in interspecific crosses using the genomic fluorescence in situ hybridization technique. Interspecific gene transfer will be evaluated using molecular markers for desirable agronomic traits such as resistance genes to rust and downy mildew. Interspecific germplasm with useful genes will be introgressed into cultivated sunflower and released as enhanced pre-breeding germplasm. Current diseases will be monitored for shifts in virulence and races, and for newly emerged diseases. A field test will be developed to reliably test for the newly emerged Phomopsis stem canker pathogen. An efficient non- destructive screening method will be developed for detecting damage of banded sunflower moth, sunflower moth, red sunflower seed weevil, and sunflower stem weevil. Insect resistance mechanisms will be identified and assessed for sunflower moth. Resistance genes for pathogens and insects, and other agronomic traits will be characterized and mapped. DNA markers for selected traits will be developed and used for marker- assisted breeding. Enhanced sunflower germplasm with high yield, high oil content, and desirable fatty acids concentration, as well as novel resistance genes for diseases and insects will be developed and released. Accomplishing these objectives will provide producers with improved sunflower that will provide a stable supply of high quality oil and confectionery sunflower, improving on-farm profitability and providing the consumer with a reliable domestic supply of a healthy oil, a staple in the American diet. Objective 1-Acquire new wild species to fill gaps or deficiencies in the sunflower germplasm collection. An exploration of 2,250 miles was conducted to collect populations of crop wild relatives of sunflower on the barrier islands off the coast of Florida, and coastal Florida and Alabama. This resulted in the collection of 29 accessions represented by one annual Helianthus debilis ssp. debilis, eight annual H. debilis ssp. vestitus, four annual H. debilis ssp. cucumerifolius, four annual H. debilis ssp. tardiflorus, four perennial H. angustifolius, one perennial H. floridanus, two perennial H. heterophyllus, four perennial H. radula, and one perennial H. simulans. These additions to the USDA National Plant Germplasm System crop wild relatives sunflower genebank collection help to fill gaps in the collection, making them available for research for increasing the genetic diversity and improvement of cultivated sunflower, and preserving them for future generations. Objective 2B-Develop effective screening procedures for Phomopsis. Field screening of a recombinant inbred line population for Phomopsis is underway at three locations during the 2016 growing season. Objective 2C-Identify and assess mechanisms of insect resistance. A third year of testing was completed for 15 female lines along with developing inbred lines and putative sources of banded sunflower moth resistance in Casselton, ND. Results indicate wide variation in susceptibility to banded sunflower moth in released USDA inbred lines, but also show the best USDA lines are better than some resistance sources originally intended for use in future breeding. A newer elite line, HA 466, received very little banded moth damage indicating its potential for hybrid breeding or additional research on resistance to this pest. Research on possible resistance to the sunflower stem weevil using X-ray imaging found that most (90%) of the variation in the number of larvae found in stems of different cultivated sunflowers can be explained by the diameter of the inbred or hybrid stems. The influence of stem diameter on stem weevil infestation was later confirmed by planting hybrids with different within-row spacing to artificially create different stem sizes. Results of these trials suggest that host plant resistance may be an inefficient method to manage this pest. Objective 2D-Transfer disease resistance and other agronomic traits from wild species and release pre-breeding germplasm. In order to further characterize novel quantitative trait loci (QTL) for Sclerotinia stalk rot resistance derived from H. argophyllus (PI 494573), an advanced backcross population with 140 BC2F6 recombinant inbred lines was developed by single-seed descent. Two families resistant to Sclerotinia head rot have been selected for germplasm release. These lines had an average disease rating of 0.7, well below the 2.3 of the recurrent parent, and the 2.2 of the two resistant checks. Six families resistant to Sclerotinia stalk rot have also been selected for germplasm release. These lines had an average disease incidence of 4.7%, well below the 23% of the recurrent parent and 13% for the two resistant checks. Confirmation of wild species chromosome or chromosome segments conferring resistance using GISH, and crosses for QTL mapping of the resistance are in progress. Progress has been made in characterizing a white cotyledon trait, in somatic embryogenesis from corolla tubes of interspecific amphiploids between cultivated sunflower and wild crop relatives, and in the triploid F1 production of crosses between a wild H. nuttallii accession and cultivated sunflower. New interspecific crosses involving three accessions of perennial H. tuberosus, two accessions of H. strumosus, and one accession each of H. hirsutus and H. simulans were crossed and backcrossed with cultivated line HA 410. Monosomic alien addition lines, with one additional chromosome of various wild species in a cultivated background were selected for further characterization and evaluation for disease resistance. Seeds of six interspecific amphiploids have been increased and agronomic characteristics collected for germplasm release. These amphiploids include cultivated lines P21 or HA 89 crossed with perennial Helianthus hirsutus, H. divaricatus and H. grosseserratus, H. strumosus, H. maximiliani, and H. nuttallii. These interspecific amphiploids have a full set of chromosomes (2n=34) from both wild species and the cultivated lines and have restored fertility for further crossing with the cultivated lines utilizing conventional plant breeding. Objective 2E-Characterize and map disease resistance genes and other agronomic traits. Molecular mapping of two downy mildew resistance genes, Pl17 from HA 458, and Pl18 from a sunflower wild species H. argophyllus was completed. Downy mildew (DM) resistance in the USDA inbred line HA 458 has been shown to be effective against all DM virulent races currently identified in the U.S. Phenotypic evaluation of 186 F2:3 families derived from a cross of HA 458 with HA 234 and bulked segregant analysis using 849 single sequence repeat (SSR) markers located the Pl17 resistance gene in linkage group 4, making it the first downy mildew gene discovered in this linkage group. Both SSR and single nucleotide polymorphism (SNP) markers linked to Pl17 were developed. Two flanking markers, SNP SFW04052 and SSR ORS963, delineated Pl17 in an interval of 3.0 cM, facilitating marker- assisted selection in sunflower breeding programs. A new dominant DM resistance gene (Pl18) transferred from wild Helianthus argophyllus into cultivated sunflower was mapped to linkage group (LG) 2 of the sunflower genome using bulked segregant analysis with 869 SSR markers. Since no other Pl gene has been mapped to LG2, this gene was novel and was designated as Pl18. SSR markers CRT214 and ORS203 flanked Pl18 at a genetic distance of 1.1 and 0.4 cM, respectively. Six co- segregating SNP markers were 1.2 cM distal to Pl18, and another four co- segregating SNP markers were 0.9 cM proximal to Pl18. This new gene is highly resistant to all DM races identified in the U.S. providing breeders with an additional gene to stack with other newly identified downy mildew genes, providing a new more durable source of resistance against this devastating pathogen. TX16R germplasm is resistant to all known U.S. sunflower downy mildew and rust races. Mapping of the downy mildew resistance gene in TX16R was completed last year, and mapping of the rust resistance gene was completed this year. Molecular markers linked to these resistance genes will enhance the development of downy mildew and rust resistant lines for the sunflower industry. Cytoplasms of perennial Helianthus species cause vigor reduction in the absence of nuclear vigor restoration genes. Following the mapping of a vigor restoration gene commonly existing in cultivated lines, a second vigor restoration gene existing in perennial Helianthus giganteus has also been mapped. This will facilitate sunflower line development when using cytoplasms of wild perennial Helianthus species for crop improvement. Two fertility restoration genes for restoring male-sterile cytoplasm of CMSGIG2 were mapped. The SSR markers linked to these genes will enhance the utilization of this cytoplasm to help diversify the use of the currently used single cytoplasm in sunflower. An F2 mapping population of CMSSAL1/RHA 801, a new perennial H. salicifolius male-sterile cytoplasm has been developed with an F3 progeny confirmation in progress. Fertility restoration genes for this new cms source were found in many cultivated lines, with 18 of 20 cultivated lines tested, with only HA 410 and HA 89 not possessing fertility restoration genes for this new cms source. This new cytoplasm will provide additional genetic diversity to the already narrow genetic base of sunflower. Objective 3A-Develop new inbred lines with novel fatty acid composition. A half-diallel genetic population for low saturated fatty acids in a high oleic background was analyzed. F3 seed was tested for variation in the low saturated fat trait using a single plant bulk assay and gas chromatography. The seeds were planted in the field and will be self- pollinated for additional study as progeny lines in the F4 generation. Crosses with a superior F3 individual, with 3.7% saturated fats and 93.6% oleic acid, have been made into several genetic backgrounds, including lines CM 595 and RHA 476, which are the parents for a new hybrid �Honeycomb NS�. Additional crosses of F4 plants are planned in the coming year to reduce saturated fat in the breeding program. Releases of the parents of the diallel were made last year, a year ahead of our original plan, in the form of HOLS1, HOLS2, HOLS3, and HOLS4. Objective 3B-Pyramid disease and insect resistance with high yield and oil content. Nearly 2000 nursery rows of high yield, high oil, disease, insect, and herbicide resistant sunflower experimental lines were grown in nurseries in Fargo, Puerto Rico, and Chile. Of these, several are candidates for release, including several Sclerotinia and Phomopsis resistant sunflower lines of both heterotic groups. We recently completed thorough genotyping of our experimental inbred lines dating back to 2007 using a genotyping by sequencing (GBS) approach, supplemented with whole- genome data of the parental stocks. The genomic data and historic phenotypic data sets will be modeled this summer and fall to determine the feasibility of genomic selection methods for quantitative traits in hybrid sunflower breeding, as well as to make selections for traits in which useful markers have already been found, such as downy mildew. New releases this year include RHA 477, which is a downy mildew, imidazolinone herbicide tolerant, early maturing inbred, and RHA 478, RHA 479, RHA 480, and HA 481, which are Sclerotinia and Phomopsis resistant inbred lines with high yield and oil content potential. Accomplishments 01 Collection of sunflower crop wild relatives. Solving pest problems and environmental stresses in the production of sunflower requires new sources of genetic diversity. ARS scientists at Fargo, North Dakota, and Ames, Iowa collected new annual and perennial sunflower crop wild relatives� germplasm from Florida and Alabama. Populations of the beach, Florida, narrow-leaf, variable-leaf, ray-less, and muck sunflower were added to the USDA National Plant Germplasm System wild crop relatives sunflower genebank collection. The germplasm collected has the potential to develop disease resistant sunflower that can be grown on marginal agricultural areas and also to lessen the impact of changing environmental conditions. The beach sunflower has recently been identified as highly resistant to the most virulent race of broomrape, one of the leading threats to sustained global sunflower production. The collection of the crop wild relatives not only makes them available for research related to the improvement of the sunflower crop, but also fills gaps in the collection and preserves them for future generations. 02 Durable sunflower rust resistance. In the U.S., oilseed sunflower is challenged by a serious foliar leaf rust disease that has been increasingly prevalent in much of the production area with the development of new virulent races. Few suitable inbred sunflower lines exist that have a high level of rust resistance, which poses risks of a potential disease epidemic from the use of a single resistance gene. ARS scientists at Fargo, North Dakota developed and released a germplasm derived from the annual crop wild relative of sunflower that incorporates a single dominant gene with resistance to all known races of North American rust with related molecular marker for marker- assisted breeding. Interestingly, this germplasm also contains a single dominant gene with resistance to all known races of another devastating sunflower pathogen, downy mildew with related molecular markers. Stacking these genes provides the sunflower industry with an opportunity to develop durable resistant sunflower lines for these pathogens in an environmentally friendly manner, sustaining sunflower production in large portions of the U.S., improving net returns for sunflower growers, and providing food processors with an abundant source of healthy oil for the American consumers. 03 Discovery of two sunflower downy mildew resistance genes. Downy mildew (DM) is one of the most serious widespread fungal diseases of sunflower that can cause significant yield losses of 50 to 80 percent in cool wet years. ARS researchers at Fargo, North Dakota discovered the two new DM resistance genes that are resistant to all virulent races currently identified in the U.S. Molecular mapping indicated these genes are different from all currently known DM resistance genes in sunflower. DNA markers linked to these genes called Pl17 and Pl18 were developed to facilitate marker-assisted selection in sunflower breeding programs. This offers the potential to control a major sunflower disease in an environmentally friendly manner, improving net returns for sunflower growers, and providing food processors with an abundant source of healthy oil for American consumers. 04 White mold head rot resistant sunflower. Sclerotinia white mold is the causal agent of a serious sunflower disease epidemic worldwide causing stalk, head, and mid-stem rot with the former two accounting for over 80% of the disease incidence. The genetics of resistance to head rot is quantitative, requiring many genes for control, which complicates the breeding effort. There is a lack of sunflower germplasm with high yield potential, good agronomic performance, and seed quality traits with Sclerotinia head rot resistance. ARS scientists at Fargo, North Dakota developed four fertility restoration germplasms with resistance to Sclerotinia head rot and good agronomic performance in an elite genetic background. These germplasms will provide sunflower breeders and producers with additional sources of genes to control a major disease limiting production and will help sustain sunflower production in an environmentally friendly manner. 05 White mold stalk rot resistant sunflower. Sclerotinia white mold is the causal agent of a serious sunflower disease epidemic worldwide causing stalk, head and, mid-stem rot with the former two accounting for over 80% of the disease incidence. The crop wild relatives are native to North America and are distributed over a large geographic area, which exposes them to a wide range of environmental conditions and disease organisms that coevolved with the crop, providing the opportunity to discover disease resistance genes in natural populations. The genetics of resistance to stalk rot is quantitative, requiring many genes for control, which complicates the breeding effort. ARS scientists at Fargo, North Dakota discovered high levels of resistance to stalk rot in several perennial crop wild relatives including Maximillian, Nuttall�s, California, woodland, and muck sunflowers. Six progeny families have been developed that have a disease incidence three times lower than the most resistant hybrids. These germplasms will provide sunflower breeders and producers with additional genes to diversify the genetic base of sunflower and will provide additional control for a major disease that limits production helping, to sustain sunflower production in an environmentally friendly manner. 06 New female parent for hybrid sunflower production. Globally, sunflower is the fifth largest hybrid crop. It is currently based on a single female parent, CMS PET1, developed in 1969 derived from the wild prairie sunflower, leaving sunflower with a very narrow genetic base. This potentially makes sunflower very vulnerable to attack by pests similar to the disaster seen in corn with the outbreak of the southern corn leaf fungal blight in the 1970s. ARS scientists at Fargo, North Dakota discovered six new female cytoplasms, derived from the wild perennial willow-leaf, Jerusalem artichoke, sawtooth, giant, and Maximillian sunflowers. Complementary male fertility restorer lines were also developed. The new cytoplasm lines and male fertility restoration lines can be used to diversify the currently used single cytoplasm as an alternative source for parental line development for hybrid sunflower, making it better able to withstand the ever-changing environment where it is grown. 07 Interspecific sunflower amphiploid genetic stocks. Interspecific amphiploids derived from crop wild relatives of sunflower help mine potential genes from a very large gene pool of 53 different species, especially the hard-to-cross perennial species. Amphiploids contain a full balanced set of chromosomes from both the crop wild relatives and the cultivated sunflower overcoming common fertility problems often encountered when making wide crosses. ARS scientists from Fargo, North Dakota, developed six genetic stocks derived from wild sunflower species. The value of these interspecific amphiploid genetic stocks is that they can act as a bridge in interspecific gene transfer, allowing for easier backcrossing with the cultivated sunflower to further broaden the genetic diversity of the sunflower crop, as well as to transfer specific target genes. The genetic stocks will also allow for the development of chromosome addition lines, with individual wild species chromosomes added to the background of cultivated sunflower lines, for genetic studies of wild species specific chromosomes. These amphiploids will give sunflower breeders increased access to more genetic diversity that has been previously extremely difficult to obtain using traditional breeding methodology. 08 Development of a sunflower line adapted to northern climates. Commercial hybrids for the northern growing zones in North America are few in number, with most of Canada limited to one suitable hybrid. In partnership with Agriculture and Agri-Food Canada, an ARS scientist at Fargo, North Dakota developed an inbred fertility restorer line, RHA 476, which is a high oleic line that produces very early maturing and higher yielding hybrids (when crossed to other early maturing, public lines) than the common commercial hybrids in the region. Oleic acid is a monounsaturated fat known to be beneficial in the human diet by increasing high-density lipoproteins cholesterol and reducing low density lipoproteins. Oils with high oleic acid will not require transesterification to increase oxidative stability, which is noteworthy since the FDA has now changed trans-fats to the status of �not generally recognized as safe.� Local seed growers have expressed interest in propagating seed of one testcross with especially high yield potential, CM 595/RHA 476, also known as �Honeycomb NS�. Joint development of hybrids using this line will expand production in more northern latitudes, and help sunflower adapt to the ever changing environmental conditions that it faces now and in the future.
Impacts
(N/A)
Publications
- Mallinger, R.E., Werts, P., Gratton, C. 2015. Pesticide use within a pollinator-dependent crop has negative effects on the abundance and species richness of sweat bees, Lasioglossum spp., and on bumble bee colony growth. Journal of Insect Conservation. 19:999-1010. doi:10.1007/ s10841-015-9816-z.
- Prasifka, J.R., Spring, O., Conrad, J., Cook, L.W., Palmquist, D.E., Foley, M.E. 2015. Sesquiterpene lactone composition of wild and cultivated sunflowers and biological activity against an insect pest. Journal of Agricultural and Food Chemistry. 63(16):4042-4049. doi:10.1021/acx.jafc. 5b00362.
- Hulke, B.S., Grassa, C.J., Bowers, J.E., Burke, J.M., Qi, L., Talukder, Z. I., Rieseberg, L.H. 2015. A unified SNP map of sunflower (Helianthus annuus L.) derived from current genomic resources. Crop Science. 55:1696- 1702. doi:10.2135/cropsci2014.11.0752.
- Hulke, B.S., Gulya, T.J. 2015. Registration of the oilseed restorer sunflower germplasms RHA 472, RHA 473, RHA 474, and RHA 475, possessing resistance to Sclerotinia head rot. Journal of Plant Registrations. 2:232- 238. doi:10.3198/jpr2014.12.0084crg.
- Prasifka, J.R., Rinehart, J.P., Yocum, G.D. 2015. Nonconstant thermal regimes enhance overwintering success and accelerate diapause development for Smicronyx fulvus (Coleoptera: Curculionidae). Journal of Economic Entomology. 108(4):1804-1809. doi:10.1093/jee/tov173.
- Prasifka, J.R., Bazzalo, M.E. 2016. Susceptibility of sunflower inbreds to Melanagromyza minimoides in Argentina and potential association with plant resistance traits. International Journal of Pest Management. 62(2):105-110.
- Dehaan, L.R., Van Tassel, D.L., Anderson, J.A., Asselin, S.R., Barnes, R., Baute, G.J., Cattani, D.J., Culman, S.W., Dorn, K.M., Hulke, B.S., Kantar, M., Larson, S., Marks, M.D., Miller, A.J., Poland, J., Ravetta, D.A., Rude, E., Ryan, M.R., Wyse, D., Zhang, X. 2016. A pipeline strategy for grain crop domestication. Crop Science. 56:917-930.
- Ayaz, F.A., Colak, N., Topuz, M., Tarkowski, P., Jaworek, P., Seiler, G., Inceer, H. 2015. Comparison of nutrient content in fruit of commercial cultivars of eggplant (Solanum melongena L.). Polish Journal of Food and Nutrition Sciences. 65(4):251-259. doi:10.1515/pjfns-2015-0035.
- Zhang, M., Liu, Z., Jan, C. 2016. Molecular mapping of a rust resistance gene R14 in cultivated sunflower line PH 3. Molecular Breeding. 36:32. doi:10.1007/s11032-016-0456-0.
- Kantar, M.B., Sosa, C.C., Khoury, C.K., Castaneda-Alvarez, N.P., Achicanoy, H.A., Bernau, V., Kane, N.C., Marek, L., Seiler, G., Rieseberg, L.H. 2015. Ecogeography and utility to plant breeding of the crop wild relatives of sunflower (Helianthus annuus L.). Frontiers in Plant Science. doi: 10.3389/ pls.2015.00841.
- Qi, L.L., Foley, M.E., Cai, X.W., Gulya, T.J. 2016. Genetics and mapping of a novel downy mildew resistance gene, Pl18, introgressed from wild Helianthus argophyllus into cultivated sunflower (Helianthus annuus L.). Theoretical and Applied Genetics. 129:741-752. doi:10.1007/s00122-015-2662- 2.
- Harveson, R.M, Nelson, A., Mathew, F.M., Seiler, G.J. 2015. First report of Orobanche ludoviciana parasitizing sunflowers. Plant Health Progress. 16(4):216-217. doi:10.1094/PHP-BR-15-0043.
- Ma, G.J., Seiler, G.J., Markell, S.G., Gulya, T.J., Qi, L.L. 2016. Registration of two double rust resistant germplasms, HA-R12 and HA-R13 for confection sunflower. Journal of Plant Registrations. 10:69-74.
- Qi, L.L., Seiler, G.J. 2016. Registration of an oilseed sunflower germplasm HA-DM1 resistant to sunflower downy mildew. Journal of Plant Registrations. 10:195-199.
- Qi, L.L., Long, Y.M., Ma, G.J., Markell, S.G. 2015. Map saturation and SNP marker development for the rust resistance genes (R4, R5, R13a, and R13b) in sunflower (Helianthus annuus L.). Molecular Breeding. 35:196.
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Progress 10/01/14 to 09/30/15
Outputs
Progress Report Objectives (from AD-416): Objective 1: Identify gaps and acquire new wild species to fill gaps or deficiencies in the sunflower germplasm collection. Objective 2: Identify insect pests and pathogens of sunflower, develop effective screening methods to optimize assessment of resistance to sunflower pathogens, determine mechanisms of plant resistance, phenotype germplasm for resistance to major insect pests and pathogens, and introgress insect and disease resistance genes from the wild species into diverse cultivated germplasm. Subobjective 2A: Identify and monitor pathogens. Subobjective 2B: Develop effective screening procedures for Phomopsis and insect damage. Subobjective 2C: Identify and assess mechanisms of insect resistance. Subobjective 2D: Transfer disease resistance, insect resistance, and other agronomic traits from wild Helianthus species into cultivated sunflower and improve methods for interspecific hybridization and release of pre-breeding germplasm. Subobjective 2E: Characterize and map resistance to pathogens and insect pests, and other agronomic traits. Objective 3: Develop sunflower germplasm with high yield, high oil content, and desirable fatty acid concentrations, as well as novel resistance genes for diseases and insects. Subobjective 3A: Develop new inbred lines with novel fatty acid compositions, such as low saturated fatty acids, and high oleic acid. Subobjective 3B: Pyramid disease and insect resistance genes with high yield and oil content in a common germplasm. Approach (from AD-416): Currently, there are a number of factors that reduce sunflower yield including a host of insects and diseases that require careful and costly management practices, reducing profitability. Research is proposed to reduce the input costs by developing durable pest resistance, herbicide resistance, oil content and quality increasing the oil per acre yield of sunflower. Specifically, we will collect wild sunflower relatives to broaden the crop�s genetic base. This germplasm will be phenotyped for resistance to major insect pests and pathogens, cytoplasmic male sterility, and fertility restoration. Methods for improving interspecific hybridization will focus on techniques to detect introgressed alien chromosome segments in interspecific crosses using the genomic fluorescence in situ hybridization technique. Interspecific gene transfer will be evaluated using molecular markers for desirable agronomic traits such as resistance genes to rust and downy mildew. Interspecific germplasm with useful genes will be introgressed into cultivated sunflower and released as enhanced pre-breeding germplasm. Current diseases will be monitored for shifts in virulence and races, and for newly emerged diseases. A field test will be developed to reliably test for the newly emerged Phomopsis stem canker pathogen. An efficient non- destructive screening method will be developed for detecting damage of banded sunflower moth, sunflower moth, red sunflower seed weevil, and sunflower stem weevil. Insect resistance mechanisms will be identified and assessed for sunflower moth. Resistance genes for pathogens and insects, and other agronomic traits will be characterized and mapped. DNA markers for selected traits will be developed and used for marker- assisted breeding. Enhanced sunflower germplasm with high yield, high oil content, and desirable fatty acids concentration, as well as novel resistance genes for diseases and insects will be developed and released. Accomplishing these objectives will provide producers with improved sunflower that will provide a stable supply of high quality oil and confectionery sunflower, improving on-farm profitability and providing the consumer with a reliable domestic supply of a healthy oil, a staple in the American diet. An exploration of 2,450 miles was conducted to collect populations of annual Helianthus anomalus, H. deserticola, and other annual sunflower crop wild relatives as encountered in Utah and Arizona. This resulted in the collection of 20 accessions represented by eight H. anomalus, five H. deserticola, five H. petiolaris, and two H. annuus accessions added to the USDA National Plant Germplasm System wild crop relatives sunflower collection helping to fill gaps in the collection, making them available for research for improving cultivated sunflower, and preserving them for the future. A second year of testing was completed for 30 public inbred lines evaluated as part of a larger field trial for banded sunflower moth resistance. Moth damage to HA lines was relatively consistent between the two years and the best cultivated inbred lines appeared similar in damage to a resistance source, PI 494859. Phenotypic data was collected on the abundance of capitate glandular trichomes in an F4 population (from HA 300 � RHA 464); because the number of glandular trichomes correlates with the abundance of defensive compounds in sunflower florets, the corresponding genetic data should provide a way to more easily breed for chemical resistance to floret-feeding insects. Preliminary work on an F4 mapping population for resistance to red sunflower seed weevil was positive. With a cool period following (artificial) infestation of weevils, most larvae did not chew exit holes in pericarps, making a normal visual examination of achenes inadequate for damage assessment. However, an assessment of weevil damage using X-rays proved to be effective and indicated clear separation of weevil-susceptible and- resistant lines in the population. New interspecific crosses involving three accessions of perennial H. tuberosus, two accessions of H. strumosus, and one accession each of H. hirsutus and H. simulans were backcrossed with cultivated line HA 410. Previous crosses involving H. hirsutus, H. salicifolius, H. occidentalis, and H. divaricatus were advanced a generation to identify chromosome addition lines, plants with reduced vigor, cytoplasmic male-sterility, and plants with the same chromosome number as cultivated sunflower. Six accessions of wild annual H. annuus species previously reported to be resistant to downy mildew were crossed with lines NMS HA 89 (oil sunflower) and CMS CONFSCLB1 (confection sunflower). Twelve F1 hybrids were obtained for transferring new downy mildew resistance genes from wild species into cultivated sunflower. Germplasm PH3 released in 2004 for rust resistance and is now known to be resistant to all rust races in the U.S. The rust resistance gene has been named R14, with linked molecular markers that will help accelerate marker assisted breeding for rust resistant sunflower. Germplasm TX16R was also released in 2004 with resistance to all known U.S. downy mildew races. Mapping of the downy mildew resistance gene in TX16R has been completed. This will provide molecular markers for sunflower breeders to assist in the selection and development of durable rust and downy mildew- resistant hybrids. Cytoplasms of perennial Helianthus species cause vigor reduction in the absence of nuclear vigor restoration genes. An F3 mapping population confirmed the nuclear vigor restoration gene, and mapping of a commonly existing vigor restoration gene for perennial Helianthus cytoplasms was completed. This will aid in sunflower line development while using perennial Helianthus species cytoplasms to increase genetic diversity in the sunflower genome. Additionally, an F3 generation progeny confirmation involving a vigor restoration gene derived from H. giganteus has been completed with the mapping of the gene in progress. Mapping of a fertility restoration (Rf) gene restoring male-sterile cytoplasm for CMS ANN3 has been completed, providing markers to help utilize this wild H. annuus cytoplasm to diversify the narrow genetic base of cultivated sunflower. A new male-sterile cytoplasm was identified in backcross progenies of wild perennial H. salicifolius with cultivated sunflower line HA 410. An F2 mapping population for the fertility restoration gene from H. salicifolius was established and F3 progeny confirmation is in progress. Sclerotinia head rot resistance was mapped using an association mapping approach on a 260 population lines with 52 significant loci found. The 52 loci tended to cluster and in most breeding populations would act as a haplotype (closely linked genes). Single nucleotide polymorphism (SNP) markers were used to genotype four F2 populations previously used for SSR mapping to identify SNP markers linked to four rust R genes, R4, R5, R13a, and R13b. Of the 67 linkage group (LG) 2 SNP markers screened, two SNPs flanked R5 at a genetic distance of 0.6 cM and 1.2 cM, respectively. A total of 69 LG13 SNP markers were analyzed in the R4, R13a, and R13b populations. In the R4 consensus map, the R4 gene was flanked by seven SNP loci; three co- segregating SNPs are on one side (0.7 cM proximal) and four on the other side (0.6 cM distal). Similarly, SNP markers that are tightly linked to both R13a and R13b were identified. R13a was flanked by SNP markers at genetic distances of 0.4 and 0.2 cM. The SNP SFW00757 co-segregated with R13b, and another three co-segregating SNPs were 2.4 cM proximal to R13b. A mapping population of 140 F2 individuals was created between rust susceptible parent HA 89 and rust resistant parent HA-R8. Phenotyping of the 140 F3 families indicated that rust resistance was controlled by a single dominant gene from the resistant line HA-R8. Genotyping of the F2 population was conducted using genotyping by sequencing (GBS). The new R gene in HA-R8 was mapped to the upper end of LG8. The closest SNP marker linked to the R gene was at genetic distance of 0.2 cM. The rust resistance R2 gene was relocated from linkage group (LG) 9 to LG14. Based on phenotypic assessments and simple sequence repeat (SSR) analyses of the 117 F2 individuals derived from a cross of HA 89 with MC29 (USDA), R2 was mapped to LG14 of the sunflower genome, and not to the previously reported location on LG9. The closest SSR marker HT567 was located at 4.3 cM distal to R2. Furthermore, 36 selected SNP markers from LG14 were used to saturate the R2 region. Of the three closely linked markers, SFW00211 amplified an allele specific for the presence of R2 in a marker validation set of 46 breeding lines, and SFW01272 was also shown to be diagnostic for R2. Two double rust-resistant confection germplasms, HA-R12 and HA-R13 were developed by the pedigree breeding method and DNA marker-assisted selection, each containing two different rust resistance genes. HA-R12 is homozygous for both the R2 and R13a genes derived from MC29 and HA-R6, and HA-R13 is homozygous for the both the R5 and R13a genes derived from HA-R2 and HA-R6. Both lines have high levels of resistance to the predominant and the most virulent rust race currently identified in the U. S. These germplasms will be a welcome addition to the confection sunflower breeder�s efforts to provide urgently needed rust resistance genes that can be incorporated into finished commercial confection hybrids. Downy mildew resistant germplasm HA-DM1 is a BC2F3-derived BC2F4 oilseed maintainer selection from the cross of HA 89*2/NMS HA 89/Helianthus argophyllus accession PI 494573 developed by the backcross breeding method and DNA marker-assisted selection for the downy mildew resistance gene Pl18 introgressed from wild H. argophyllus PI 494573. The cross between NMS HA 89 and PI 494573 was made in 2009 and the selected resistant F1 plants were backcrossed twice to HA 89. The BC2F3-derived HA- DM1 is homozygous for the Pl18 gene verified by DNA markers, and immune to all known races of downy mildew, providing breeders with an effective and unique source of resistance against downy mildew in sunflower. A half-diallel genetic population for low saturated fatty acids in a high oleic background was analyzed. F2 seed was tested for variation in the low saturated fat trait using a cut-seed assay and gas chromatography. The seeds were planted in the field and will be self-pollinated for additional study as progeny lines in the F3 generation. Additional crosses of F3 plants are planned to further reduce saturated fat content. Parental materials of the diallel cross were released this year as genetic stocks HOLS1, HOLS2, HOLS3, and HOLS4. All were derived from low saturated fat plant introductions and mutagenesis stocks backcrossed to inbred line HA 466, a high oleic, imidazolinone resistant, Sclerotinia and Phomopsis resistant inbred line. Nearly 2000 nursery rows of high yield, high oil, disease, insect, and herbicide resistant sunflower experimental lines were grown in nurseries in Fargo, Puerto Rico, and Chile. Of these, several are candidates for release, including an early maturing, high yielding restorer line with high oleic acid, and a sunflower line with a simply inherited, dominant resistance to red sunflower seed weevil. The red sunflower seed weevil resistance is being mapped this year to release both germplasm and markers to the sunflower community. These planned releases for late FY15 are in addition to those already released and described for the purpose of gene pyramiding. This year, we have also genotyped the majority of the breeding lines for which testcross yield and disease resistance data have been accumulated, using a genotyping by sequencing (GBS) approach supplemented with whole-genome data of the parental stocks. The genomic data and historic phenotypic data sets will be modeled to determine the feasibility of genomic selection methods in hybrid sunflower breeding, as well as to make selections for traits in which useful markers have already been found, such as downy mildew. Accomplishments 01 Stacking durable sunflower rust resistance genes. In confectionery sunflower grown as a seed crop in the U.S., leaf rust is a serious foliar disease that has been increasingly prevalent in much of the production area with the development of new virulent races. Few suitable inbred confection sunflower lines exist that have a high level of rust resistance, which poses risks of a potential disease epidemic from the use of a single resistance gene. ARS scientists at Fargo, North Dakota released two confectionery sunflower germplasms each incorporating two different single dominant rust resistance genes, R2 and R13a, and R5 and R13a, respectively. These genes will enhance durable rust resistance to this devastating disease in confectionery sunflower, sustaining sunflower production in large portions of the US, improving net returns for sunflower growers, and providing food processors with an abundant source of a healthy snack for the American consumers. 02 New high oleic acid reduced saturated fat sunflower lines. Oleic acid is a monounsaturated fat known to be beneficial in the human diet by increasing high-density lipoproteins cholesterol and reducing low density lipoproteins. Saturated fats are generally known to be neutral or negative to human health, depending on the length of the carbon chain. Oils with high oleic acid and low saturated fats will not require transesterification to increase oxidative stability, which is noteworthy since the FDA has now changed trans-fats to the status of �not generally recognized as safe.� ARS researchers at Fargo, North Dakota released four genetic stocks with very high levels of oleic acid and very low saturated fats in the seed oil. Use of these lines will provide the sunflower industry the opportunity to develop hybrids with higher quality oil allowing consumers a choice for selecting healthier oils in their diet. 03 Collection of sunflower crop wild relatives. Solving insect and disease pests and environmental stresses in the production of sunflower requires new sources of genetic diversity. ARS scientists at Fargo, North Dakota, and Ames, Iowa collected new annual sunflower crop wild relatives� germplasm from Utah and Arizona. Populations of the desert, anomalus, and prairie sunflower were added to the USDA National Plant Germplasm System wild crop relatives sunflower collection. The germplasm collected has the potential to develop water stress tolerant sunflower that can be grown on marginal agricultural areas and also to lessen the impact of changing environmental conditions. The collection of the crop wild relatives not only makes them available for research related to the improvement of the sunflower crop, but also fills gaps in the collection and preserves them for future generations. 04 New female parent for hybrid sunflower production. Globally, sunflower is the fifth largest hybrid crop. It is currently based on a single female parent, CMS PET1, developed in 1969 derived from the wild prairie sunflower leaving sunflower with a very narrow genetic base. This potentially leaves sunflower very vulnerable to attack by pests similar to the disaster seen in corn with the outbreak of the southern corn leaf fungal blight in the 1970s. A newly identified female cytoplasm line, CMS SAL1, derived from the wild perennial willow-leaf sunflower and associated male restorer line is different from CMS PET1 and its associated male lines. The new CMS and male fertility restoration line can be used to diversify the currently used CMS PET1 cytoplasm as an alternative source for parental line development for hybrid sunflower. 05 Differences in defensive chemistry between wild and cultivated sunflowers. Sesquiterpene lactones (STL) are defensive compounds in sunflower and other related plants that provide natural defense from pests, including insects and pathogens. These compounds, contained in glandular hairs, are thought to be one reason that sunflower crop wild relatives are less damaged by floret-feeding insects such as larvae of the sunflower moth than the cultivated crop. An analysis of wild sunflowers, public inbred lines, and commercial hybrids showed that a group of closely related compounds were deficient in most cultivated germplasm, and that at least one of these compounds causes delayed development in sunflower moth larvae. An initial cross between the most STL-rich wild material, Plant Introduction, and a USDA inbred was made in an attempt to transfer the defensive chemistry of wild sunflowers into cultivated material. This offers the potential to control a major sunflower pest in an environmentally friendly manner.
Impacts
(N/A)
Publications
- Prasifka, J.R. 2015. Variation in the number of capitate glandular trichomes in wild and cultivated sunflower germplasm and potential for use in host plant resistance. Plant Genetic Resources. 13:68-74.
- Seiler, G.J. 2015. Comparison of fatty acid composition of oil from original and regenerated populations of wild Helianthus species. Plant Genetic Resources: Characterization and Utilization. 13(1):83-89. DOI:10. 1017/S1479262114000677.
- Tinsley, N.A., Spencer, J.L., Estes, R.E., Prasifka, J.R., Schrader, P.M., French, B.W., Gray, M.E. 2015. Larval mortality and development for rotation-resistant and rotation-susceptible populations of the western corn rootworm on Bt corn. Journal of Applied Entomology. 139:46-54.
- Qi, L.L., Ma, G.J., Long, Y.M., Hulke, B.S., Gong, L., Markell, S.G. 2015. Relocation of a rust resistance gene R2 and its marker-assisted gene pyramiding in confection sunflower (Helianthus annuus L.). Theoretical and Applied Genetics. 128(3):477-488. DOI:10.1007/s00122-014-2446-0.
- Qi, L.L., Long, Y.M., Jan, C.C., Ma, G., Gulya, T.J. 2015. Pl17 is a novel gene independent of known downy mildew resistance genes in the cultivated sunflower (Helianthus annuus L.). Journal of Theoretical and Applied Genetics. 128(4):757-767. DOI:10.1007/s00122-015-2470-8.
- Mathew, F.M., Prasifka, J.R., Gaimari, S.D., Shi, L., Markel, S.G., Gulya, T.J. 2015. Rhizopus oryzae associated with Melanagromyza splendida and stem disease of sunflowers (Helianthus annuus) in California. Plant Health Progress. 16(1):39-42. DOI:10.1094/PHP-RS-14-0042.
- Seiler, G.J., Jan, C.C. 2014. Wild sunflower species as a genetic resource for resistance to sunflower broomrape (Orobanche cumana Wallr.). Helia. 37(61):129-139. DOI:10.1515/HELIA-2014-0013.
- Jan, C.C., Liu, Z., Seiler, G.J., Velasco, L., Perez-Vich, B., Fernandez- Martinez, J. 2014. Broomrape (Orobanche cumana Wallr.) resistance breeding utilizing wild Helianthus species. Helia. 37(61):141-150.
- Cainong, J.C., Bockus, W.W., Feng, Y., Chen, P., Qi, L., Sehgal, S.K., Danilova, T.V., Koo, D., Friebe, B., Gill, B.S. 2015. Chromosome engineering, mapping, and transferring of resistance to Fusarium head blight disease from Elymus tsukushiensis into wheat. Theoretical and Applied Genetics. 128(6):1019-1027. DOI:10.10.1007/S00122-015-2485-1.
- Liu, Z., Cai, X., Seiler, G.J., Jan, C.C. 2014. Interspecific amphiploid- derived alloplasmic male sterility with defective anthers, narrow disk florets, and small ray flowers in sunflower. Plant Breeding. 133(6):742- 747. DOI:10.1111/PBR.12216.
- Qi, L., Gong, L., Markell, S.G., Seiler, G.J., Gulya Jr, T.J., Hulke, B.S. 2014. Registration of two confection sunflower germplasm Lines, HA-R10 and HA-R11, Resistant to sunflower rust. Journal of Plant Registrations. 8:329- 333. DOI: 10.3198/jpr2014.02.0010crg.
- Feng, J., Liu, Z., Seiler, G.J., Jan, C.C. 2015. Registration of cytoplasmic male-sterile oilseed sunflower genetic stocks CMS GIG2 and CMS GIG2-RV, and fertility restoration lines RF GIG2-MAX 1631 and RF GIG2-MAX 1631-RV. Journal of Plant Registrations. 9:125-127. DOI:10.3198/jpr2014. 050029crgs.
- Qi, L., Seiler, G.J. 2013. Registration of a male fertility restorer oilseed sunflower germplasm, HA-R9, resistant to sunflower rust. Journal of Plant Registrations. 7(3):353-357.
- Pearson, T.C., Prasifka, J.R., Brabec, D.L., Haff, R.P., Hulke, B.S. 2014. Automated detection of insect-damaged sunflower seeds by X-ray imaging. Applied Engineering in Agriculture. 30(1):125-131.
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Progress 10/01/13 to 09/30/14
Outputs
Progress Report Objectives (from AD-416): Objective 1: Identify gaps and acquire new wild species to fill gaps or deficiencies in the sunflower germplasm collection. Objective 2: Identify insect pests and pathogens of sunflower, develop effective screening methods to optimize assessment of resistance to sunflower pathogens, determine mechanisms of plant resistance, phenotype germplasm for resistance to major insect pests and pathogens, and introgress insect and disease resistance genes from the wild species into diverse cultivated germplasm. Subobjective 2A: Identify and monitor pathogens. Subobjective 2B: Develop effective screening procedures for Phomopsis and insect damage. Subobjective 2C: Identify and assess mechanisms of insect resistance. Subobjective 2D: Transfer disease resistance, insect resistance, and other agronomic traits from wild Helianthus species into cultivated sunflower and improve methods for interspecific hybridization and release of pre-breeding germplasm. Subobjective 2E: Characterize and map resistance to pathogens and insect pests, and other agronomic traits. Objective 3: Develop sunflower germplasm with high yield, high oil content, and desirable fatty acid concentrations, as well as novel resistance genes for diseases and insects. Subobjective 3A: Develop new inbred lines with novel fatty acid compositions, such as low saturated fatty acids, and high oleic acid. Subobjective 3B: Pyramid disease and insect resistance genes with high yield and oil content in a common germplasm. Approach (from AD-416): Currently, there are a number of factors that reduce sunflower yield including a host of insects and diseases that require careful and costly management practices, reducing profitability. Research is proposed to reduce the input costs by developing durable pest resistance, herbicide resistance, oil content and quality increasing the oil per acre yield of sunflower. Specifically, we will collect wild sunflower relatives to broaden the crop�s genetic base. This germplasm will be phenotyped for resistance to major insect pests and pathogens, cytoplasmic male sterility, and fertility restoration. Methods for improving interspecific hybridization will focus on techniques to detect introgressed alien chromosome segments in interspecific crosses using the genomic fluorescence in situ hybridization technique. Interspecific gene transfer will be evaluated using molecular markers for desirable agronomic traits such as resistance genes to rust and downy mildew. Interspecific germplasm with useful genes will be introgressed into cultivated sunflower and released as enhanced pre-breeding germplasm. Current diseases will be monitored for shifts in virulence and races, and for newly emerged diseases. A field test will be developed to reliably test for the newly emerged Phomopsis stem canker pathogen. An efficient non- destructive screening method will be developed for detecting damage of banded sunflower moth, sunflower moth, red sunflower seed weevil, and sunflower stem weevil. Insect resistance mechanisms will be identified and assessed for sunflower moth. Resistance genes for pathogens and insects, and other agronomic traits will be characterized and mapped. DNA markers for selected traits will be developed and used for marker- assisted breeding. Enhanced sunflower germplasm with high yield, high oil content, and desirable fatty acids concentration, as well as novel resistance genes for diseases and insects will be developed and released. Accomplishing these objectives will provide producers with improved sunflower that will provide a stable supply of high quality oil and confectionery sunflower, improving on-farm profitability and providing the consumer with a reliable domestic supply of a healthy oil, a staple in the American diet. An exploration of 3650 miles to collect populations of annual Helianthus bolanderi and perennial H. gracilentus crop wild relatives of sunflower from California and Oregon resulted in the addition of nine accessions of H. bolanderi and four H. gracilentus. Additionally, three accessions of a newly discovered species, perennial H. winteri were collected and added to the ARS National Plant Germplasm System wild crop relatives collection to fill gaps, making this species available for research for the first time for improving cultivated sunflower and preserving it for future generations. A survey of sunflower fields for downy mildew was undertaken in North Dakota, South Dakota, Minnesota, and Nebraska. A total of 120 fields were surveyed with 36% of the fields having one or more races present with the highest incidence of 58%, and 3.6% of the fields with economic damage levels. The prevalent race was 714, followed by races 774, 734 and 704. The commonly used genetic resistant PL6 gene was overcome by 72% of races found in the samples. The evolution and increasing spread of these races may account for the increase in downy mildew races noted in recent years. Three isolates of each of two Phomopsis species were inoculated onto a wounded sunflower stem at three different dates. Inoculation techniques consisted of an infected agar plug placed on the wounded stem and a Phomopsis-infected toothpick inserted into the stem. All inoculations at all dates were successful. Differences in virulence were observed in the isolates of the two species with the common species, P. helianthi slightly more aggressive. The toothpick method was just as effective as the agar plug in terms of infection, and was four times faster. Thus, for future germplasm testing for stem canker, the toothpick inoculation is both effective and time-efficient. Thirty public inbred lines were evaluated as part of a larger field trial for banded sunflower moth resistance in the field in Casselton, ND. Among these cultivated inbred lines, there was as much as a fourfold difference in seed damage by banded moth larvae and the best cultivated inbred lines appeared statistically similar to a resistant parent, PI 494859. PI 494859 (and other resistance sources that retain undesirable wild characteristics) is more difficult to use in breeding than existing inbred lines. The data from 2013 suggest some released inbred lines may provide useful resistance to banded moth with little additional breeding. Assessment of physical (pericarp hardness) and chemical resistance traits (sesquiterpene lactones) for sunflower moth indicate that significant amounts of variation exist for both within USDA germplasm. However, other germplasm sources (i.e., partially improved breeding material or wild sunflowers) have greater potential to reduce damage from sunflower moth than do available inbred lines. Work to document the relative value and inheritance of these traits is underway. Two wild H. strumosus, three H. tuberosus, and one H. hirsutus perennial species accessions showed total immunity to the predominant rust races in the U.S. These accessions were crossed with cultivated line HA 410 and progenies obtained via embryo rescue. Progenies were further backcrossed with cultivated line HA 410 and will be evaluated against rust races in the next generation. Advanced interspecific lines based on wild perennials crossed with cultivated lines screened for Sclerotinia stalk and head rot resistance in replicated field tests this year will be evaluated this fall to identify new sources of resistance to the new virulent races of rust. New crosses involving three accessions of H. tuberosus, two accessions of H. strumosus, and one accession each of H. hirsutus and H. simulans were successfully crossed and backcrossed with cultivated line HA 410. In addition, previous crosses involving H. hirsutus, H. salicifolius, H. occidentalis, and H. divaricatus were further advanced to identify chromosome addition lines, plants with reduced vigor, cytoplasmic male- sterility, and the plants with the same chromosome number as cultivated sunflower. Significant progress was made in completing a recombinant inbred line population derived from the cross of HA 89 with HA-R3 for QTL analysis of Phomopsis resistance. The banded sunflower moth population is currently at the F5 generation. A single seed descent F6 generation will be produced this field season. The F6 derived plants will be grown next year to produce large quantities of F6:7 seed for phenotyping purposes. Mapping of a rust resistance gene PH3 was completed. PH3 was released and registered in 2004 for rust resistance and is resistant to all rust races in the U.S. Molecular marker ORS 542 and a purple hypocotyl color gene linked to this rust resistance gene was identified, which will help select rust resistant lines derived from PH3 for hybrid sunflower development. F3 progeny confirmation of a downy mildew resistance gene in TX16R was completed, but rust resistance gene confirmation needs further clarification. Downy mildew resistance phenotyping of the F3 population of HA-R8 � RHA 468 together with the two parents was conducted. One hundred and ninety F2-derived F3 families were inoculated with DM race 734 and recorded for performance. Primary marker analysis indicated that the DM resistance gene in RHA 468 may be located on linkage group 13 of the sunflower genome. Cytoplasms of perennial Helianthus species cause vigor reduction in the absence of nuclear vigor restoration genes. Mapping populations with vigor restoration genes from cultivated sunflower and from wild sunflower species H. giganteus were established, and F3 progeny confirmations are in progress. A half diallel genetics population for low saturated fatty acids in a high oleic background was analyzed. F1 seed was tested for all matings to confirm that a cross was made (and not an accidental self pollination) using a cut-seed assay and gas chromatography. The F1 seeds of each mating that deviated in fatty acid composition from the female parent were selected for advancement. The seeds were planted in the field and will be self-pollinated for additional study of segregation in the next generation. Populations for combining yield, oil content, oil quality, agronomic traits, and biotic stress resistance were grown in both rural Santiago, Chile, during the winter season, and Fargo, ND, during the summer season. In all, three cage increases of near-release early maturing inbred lines were produced in Chile, along with a population that segregates for an insect resistance trait in an imidazolinone herbicide, Sclerotinia and Phomopsis resistant, and high oleic background. About 1000 progeny rows are being grown in Fargo, which includes both confectionery and oilseed lines at various stages before release. Two germplasm lines were released this year for confectionery sunflower that contain multiple rust resistance loci for durable resistance. Several other lines are planned for release in late FY-14 or early FY-15, pending data from our field nursery this summer. Accomplishments 01 Durable sunflower rust resistance genes. Sunflower is a confectionery seed crop grown in the US where leaf rust is a serious disease that has been increasingly prevalent in much of the production area with the development of new virulent races. Few suitable inbred confection sunflower lines exist that have a high level of rust resistance, which poses risks of a potential disease epidemic from the use of a single resistance gene. ARS scientists in Fargo, North Dakota released two confectionery sunflower germplasms with rust resistance controlled by two genes, R4 and R5. These genes will enhance durable resistance to this devastating rust disease in confectionery sunflower, sustaining sunflower production in large portions of the US, improving net returns for sunflower growers, and providing food processors with an abundant source of a healthy snack for the American consumers. 02 New cytoplasms for hybrid sunflower production. Globally, sunflower is the fifth largest hybrid crop. Sunflower is currently based on a single female cytoplasm parent CMS PET1 developed in 1969 derived from a wild prairie sunflower. This leaves sunflower very vulnerable to attack by pathogens similar to the disaster seen in corn in the 1970s. A newly identified female line, CMS GIG2, derived from a wild perennial sunflower and an associated male line are clearly different from the CMS PET1 cytoplasm and the male lines. The new combination could be used to substitute for the older CMS PET1 cytoplasm currently used in hybrid sunflower production. Additionally, closely linked molecular markers were discovered for the male line that can be used to speed up the breeding process, facilitating marker-assisted selection. The new CMS and male fertility restoration line will provide an alternative source for parental line development for hybrid sunflower production. 03 High density molecular map for sunflower rust. Leaf rust is a serious disease of sunflower that has been increasingly prevalent in much of the production area with the development of new virulent races. Molecular markers and high density genetic linkage maps are important tools for understanding genome organization. ARS scientists in Fargo, North Dakota developed a high-resolution genetic map of sunflower. The map consists of 5,019 single nucleotide polymorphism (SNP) DNA markers derived from random amplified polymorphic DNA tag sequencing and 118 publicly available single sequence repeat (SSR) markers distributed in 17 linkage groups. Fine mapping and marker validation of the rust resistance gene R12 were performed, providing closely linked SNP markers for marker-assisted selection in sunflower breeding programs. This high resolution genetic map will serve as a valuable tool for the sunflower community for studying marker-trait association of important agronomic traits, marker- assisted breeding, map-based gene cloning, and comparative mapping. 04 Exploration for sunflower wild crop relatives. Solving insect and disease pests and production problems in sunflower requires new sources of genetic diversity. ARS scientists in Fargo, North Dakota collected new sunflower crop wild relatives from California and Oregon. Collections were made for a newly discovered perennial species in California, Winter�s sunflower, representing the first germplasm of this species to be publicly available. Other germplasm collected has the potential to develop salt-tolerant sunflower that can be grown on salt-impacted lands and with saline irrigation water. The collection of the crop wild relatives for the ARS National Plant Germplasm System not only makes them currently available for improvement of the sunflower crop, but also fills gaps in the collection and preserves them for future generations.
Impacts
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Publications
- Talukder, Z.I., Hulke, B.S., Marek, L.F., Gulya, T.J. 2014. Sources of resistance to sunflower diseases in a global collection of domesticated USDA plant introductions. Crop Science. 54:694-705.
- Fernandez-Cuesta, A., Jan, C., Fernandez-Martinez, J., Velasco, L. 2014. Variation for seed phytosterols in sunflower germplasm. Crop Science. 54:190-197. DOI: 10.2135/cropsci2013.05.0285.
- Jan, C., Seiler, G.J., Hammond, J.J. 2014. Effect of wild Helianthus cytoplasms on agronomic and oil characteristics of cultivated sunflower (H. annuus L.). Plant Breeding. 133:262-267.
- Prasifka, J.R., Hulke, B.S., Seiler, G.J. 2014. Pericarp strength of sunflower and its value for plant defense against the sunflower moth, Homoeosoma electellum. Arthropod-Plant Interactions. 8:101-107.
- Agindotan, B.O., Prasifka, J.R., Gray, M.E., Dietrich, C.H., Bradley, C.A. 2013. Transmission of Switchgrass mosaic virus by Graminella aureovitatta. Canadian Journal of Plant Pathology. 35(3):384-389.
- Chirumamilla, A., Knodel, J.J., Charlet, L.D., Hulke, B.S., Foster, S.P., Ode, P.J. 2014. Ovipositional preference and larval performance of the banded sunflower moth (Lepidoptera: Tortricidae) and its larval parasitoids on resistant and susceptible lines of sunflower (Asterales: Asteraceae). Environmental Entomology. 43(1):58-68. DOI: 10.1603/EN13157.
- Gong, L., Gulya, T.J., Markell, S.G., Hulke, B.S., Qi, L.L. 2013. Genetic mapping of rust resistance genes in confection sunflower line HA-R6 and oilseed line RHA 397. Theoretical and Applied Genetics. 126(8):2039-2049.
- Gong, L., Li, C., Capatana, A., Feng, J., Qi, L., Seiler, G.J., Jan, C.C. 2014. Molecular mapping of three nuclear male sterility mutant genes in cultivated sunflower (Helianthus annuus L.). Molecular Breeding. 34:159- 166.
- Kantar, M.B., Betts, K., Michno, J.-M., Luby, J.J., Morrell, P.L., Hulke, B.S., Stupar, R.M., Wyse, D.L. 2014. Evaluating an interspecific Helianthus annuus x Helianthus tuberosus population for use in a perennial sunflower breeding program. Field Crops Research. 155:254-264. DOI: 10. 1016/j.fcr.2013.04.018.
- Pegadaraju, V., Nipper, R., Hulke, B., Qi, L., Schultz, Q. 2013. De novo sequencing of sunflower genome for SNP discovery using RAD (Restriction site Associated DNA) approach. Biomed Central (BMC) Genomics. 14:556.
- Prasifka, J.R., Spencer, J.L., Tinsley, N.A., Estes, R.E., Gray, M.E. 2013. Adult activity and oviposition of corn rootworms, Diabrotica spp. (Coleoptera: Chrysomelidae), in Miscanthus, corn, and switchgrass. Journal of Applied Entomology. 137(7):481-487.
- Qi, L.L., Wu, J.J., Friebe, B., Qian, C., Gu, Y.Q., Fu, D.L., Gill, B.S. 2013. Sequence organization and evolutionary dynamics of Brachypodium- specific centromere retrotransposons. Chromosome Research. 21(5):507-521.
- Talukder, Z., Gong, L., Hulke, B.S., Pegadaraju, V., Song, Q., Schultz, Q., Qi, L. 2014. A high-density SNP map of sunflower derived from RAD- sequencing facilitating fine-mapping of the rust resistance gene R12. PLoS One. 9(7): e98628. Available
- Talukder, Z.I., Hulke, B.S., Qi, L., Scheffler, B.E., Pegadaraju, V., McPhee, K., Gulya, T.J. 2014. Candidate gene association mapping of Sclerotinia stalk rot resistance in sunflower (Helianthus annuus L.) uncovers the importance of COI1 homologs. Theoretical and Applied Genetics. 127:193-209.
- Hulke, B.S., Kleingartner, L.W. 2014. Sunflower. In: Smith, S., Diers, B., Specht, J., and Carver, B. editors. Yield Gains in Major U.S. Field Crops. CSSA Special Publications 33. Madison, WI: American Society of Agronomy, Inc., Crop Science Society of America, Inc., and Soil Science Society of America, Inc. pp.433-457.
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