Progress 10/01/22 to 09/30/23
Outputs
PROGRESS REPORT Objectives (from AD-416): The long-term goal of this project is development and introduction of new, high-quality and disease resistant cultivars of Prunus (almond and apricot) and Vitis (table grapes and raisins) that will sustain American agriculture and supply high quality, nutritious fruits and nuts to U.S. consumers and international markets. Further, the project will strive to identify molecular markers linked sufficiently close to fruit quality traits of interest such that marker-assisted selection will be possible in future breeding efforts. Specifically, during the next five years we will focus on the following objectives: Objective 1: Enhance breeding efficiency for table grape fruit quality, and other priority traits, by identifying associated molecular markers, and through trials, to determine commercial acceptability of advanced table grape selections. Sub-objective 1A: Develop segregating populations and map fruit quality traits related to flowering time, rachis architecture, and berry size. Sub-objective 1B: Through trials, determine commercial acceptability of advanced table grape selections. Sub-objective 1C: Identify sources of resistance and develop molecular markers associated with resistance to Botrytis cinerea. Objective 2: Develop durable resistances to powdery mildew and Pierce⿿s disease in table grapes and natural dry-on-vine raisins. Sub-objective 2A: Develop durable resistance to powdery mildew in table grapes and natural dry-on-vine raisins. Sub-objective 2B: Identify sources of durable resistance to Pierce⿿s disease and determine the relative susceptibility of existing commercial cultivars. Sub-objective 2C: Develop table grape and natural dry-on vine raisin cultivars with durable resistance to Pierce⿿s disease. Objective 3: Develop, select, and evaluate new, high quality scions of Prunus, e.g., high yielding self-compatible almond and glabrous-skinned apricot. Sub-objective 3A: Develop, select, and evaluate new high-yielding self- compatible almonds. Sub-objective 3B: Develop, select, and evaluate new glabrous-skinned apricots. Approach (from AD-416): Classical breeding has been used to create segregating populations in Prunus and Vitis where the expression of quantitative traits has been concentrated and newly available characters have been transferred into adapted germplasm. New segregating populations will be created in Vitis to develop molecular markers for fruit quality traits, rachis architecture, resistance to Botrytis, flowering time and berry size. Advanced table grape selections will be compared for production timing and fruit quality after cold storage with existing table grape cultivars through public fruit showings held during each ripening season. Commercially acceptable advanced table grape selections will be introduced as new cultivars through consensus evaluation with the table grape industry. New powdery mildew resistance sources will be evaluated in established segregating populations, and resistant accessions will be backcrossed with high quality table grapes and natural dry on the vine raisins as molecular markers are being developed. These new resistance sources will be used along with other mapped PM resistance sources in hybridizations designed to stack the resistances for durability. Empirical screening of Vitis germplasm for reaction to Xylella fastidiosa will continue, and existing commercial table grape cultivars will be evaluated for their relative susceptibility to Pierce⿿s disease. Crosses will be conducted to stack Xf resistances from Vitis arizonica and southeast U.S. Vitis germplasm into hybrids with high product quality. Promising high quality accessions with will be evaluated for survival and productivity in regions with high Pierce⿿s disease pressure. In Prunus, hybridizations will be performed to identify and select new high-yielding self-compatible almonds that are California-adapted and have Nonpareil-like kernel characteristics. Apricot populations will be developed through hybridization among glabrous-skinned accessions, and new glabrous apricots will be evaluated for fruit quality and productivity. Newly-available glabrous-skinned apricot accessions from Kyrgyzstan will be propagated when available from plant protective quarantine and used in hybridizations to assist in the glabrous-skinned apricot breeding effort. This is the final report for project 2034-21220-007-000D, ⿿Breeding Prunus and Vitis Scions for Improved Fruit Quality and Durable Pest Resistance⿿ that will be replaced with project 2034-21220-008-000D, ⿿Breeding Prunus and Vitis to Improve Disease Resistance, Fruit Quality, and Climate Change Adaptation.⿿ This project had continued support from industry stakeholders to carry out hybridizations in table and raisin grapes to develop new varieties that perform better and have natural disease resistance to fungal and bacterial pathogens. However, a vector-transmitted virus impacted the progress of the project. Virus-infected grapevines (95 percent of the germplasm) were removed to protect the germplasm. Germplasm in four grapevine blocks was evaluated and hardwood cuttings were taken. Plants were propagated and are maintained in greenhouses until field blocks are prepared for new plantings. Grapevines maintained in the greenhouse will be tested for the presence of pathogenic viruses before being transplanted to the field. In support of Objective 1, evaluations continued on advanced table grape selections. However, COVID restrictions hampered in-person evaluations and showings of grape clusters to industry stakeholders. Only two showings of selections were conducted to interested stakeholders. Six new table grape selections were identified that warrant placement in the advanced trial block for future evaluation. Due to infection by a vector- transmitted virus, all of the segregating populations developed and established for fruit quality traits including flowering time, berry shape, size, texture, color, and bud break were destroyed to protect the remaining grapevine germplasm collection in Parlier. Similarly, the grapevine population that segregated for development of resistance to Botrytis was destroyed. Virus infection disrupted the planting of the advance selection trial as well. Plant material was sent to Foundation Plant Services at the University of California, Davis, and Microparadox for disinfection after implementation of material transfer agreements. Virus-free grapevines of advance selections will be trialed in the new project 2034-21220-008-000D. A genetic map is being constructed to identify potential loci associated with resistance to powdery mildew in four genetic backgrounds (populations). The four populations were selected for computer vision phenotypic analysis to estimate powdery mildew infestation. In support of Objective 2, for both table and raisin grapes, hybridizations were completed to develop lines that have more than one resistance locus and could provide durable resistance to powdery mildew and Pierce⿿s disease. Reflex-flowered vines with combination of Run1Ren1Ren4 loci were used as females in backcrosses with high quality table grapes and natural dry-on-vine raisin selections. Pollen from Run1Ren1Ren4 hybrids was also used in hybridizations with powdery mildew resistant selections of Vitis amurensis, where a new locus for powdery mildew resistance was identified and named Ren12. To increase the durability of resistance to Pierce⿿s disease, hybridizations were conducted to combine the two different Pierce⿿s disease resistance sources. Currently, resultant seeds from these hybridizations are stored in a cold room for future germinations, and seedlings will be planted in the next season. Multiple sources of Pierce⿿s disease resistance from V. arizonica and an interspecific hybrid V. caribae were evaluated for sensitivity to seven isolates of Xylella fastidiosa to test the durability of resistance. Evaluation efforts continue in support of Objective 3 for the development of new self-fertile almonds and glabrous-skinned apricots. A self-fertile cultivar named Yorizane was released from the breeding program at Parlier, California, after four years of yield evaluation. Yield evaluations were conducted by the Almond Board of California- sponsored Regional Almond Variety Trials in which Yorizane was tested and compared with other Almond cultivars. Another early ripening self-fertile almond selection was identified from recent hybridizations. The new selection lacks perfect kernel quality; however, its early-ripening character makes it an attractive parent in the development of new self- fertile selections. During the 2021 fruit ripening season, several new high quality glabrous-skinned apricots were selected from segregating populations. Queries to plant protective quarantine during the early 2021 fruit season have indicated that the large-fruited Kyrgyzstan glabrous- skinned apricots are still in a juvenile stage of development and not yet ready for selection and propagation. New apricot cultivar CASTLECREST, tested previously as Y112-215-04 was released in 2022. CASTLECREST was released as a mid-season apricot suitable for fresh market production. ACCOMPLISHMENTS 01 Release of apricot variety Castlecrest. The California fresh fruit market desires a mid-season apricot suitable for fresh market production. ARS scientists at Parlier, California, selected a new cultivar among 24 siblings for excellent fruit quality in June 2009. Its pedigree can be traced through seven generations of apricot breeding in the central San Joaquin Valley of California. Trees exhibit intermediate vigor and have an upright growth habit. This variety can be easily maintained to provide an open center to enhance light interception by developing flower buds.
Impacts
(N/A)
Publications
- Massonnet, M., Riaz, S., Pap, D., Figueroa-Balderas, R., Walker, M.A., Cantu, D. 2022. The grape powdery mildew resistance loci Ren2, Ren3, Ren4D, Ren4U, Run1, Run1.2b, Run2.1, and Run2.2 activate different transcriptional responses to Erysiphe necator. Frontiers in Plant Science. 13. Article 1096862. https://doi.org/10.3389/fpls.2022.1096862.
- Xiao, H., Liu, Z., Wang, N., Long, Q., Cao, S., Huang, G., Liu, W., Peng, Y., Riaz, S., Walker, M.A., Gaut, B.S., Zhou, Y. 2023. Adaptive and maladaptive introgression in grapevine domestication. Proceedings of the National Academy of Sciences (PNAS). 120(24). Article e2222041120. https:// doi.org/10.1073/pnas.2222041120.
- Huerta-Acosta, K., Riaz, S., Tenscher, A., Walker, M.A. 2022. Genetic characterization of Pierce⿿s disease resistance in a Vitis arizonica/ monticola wild grapevine. American Journal of Enology and Viticulture. 74(1). Article 0740003. https://doi.org/10.5344/ajev.2022.22021.
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Progress 10/01/21 to 09/30/22
Outputs
PROGRESS REPORT Objectives (from AD-416): The long-term goal of this project is development and introduction of new, high-quality and disease resistant cultivars of Prunus (almond and apricot) and Vitis (table grapes and raisins) that will sustain American agriculture and supply high quality, nutritious fruits and nuts to U.S. consumers and international markets. Further, the project will strive to identify molecular markers linked sufficiently close to fruit quality traits of interest such that marker-assisted selection will be possible in future breeding efforts. Specifically, during the next five years we will focus on the following objectives: Objective 1: Enhance breeding efficiency for table grape fruit quality, and other priority traits, by identifying associated molecular markers, and through trials, to determine commercial acceptability of advanced table grape selections. Sub-objective 1A: Develop segregating populations and map fruit quality traits related to flowering time, rachis architecture, and berry size. Sub-objective 1B: Through trials, determine commercial acceptability of advanced table grape selections. Sub-objective 1C: Identify sources of resistance and develop molecular markers associated with resistance to Botrytis cinerea. Objective 2: Develop durable resistances to powdery mildew and Pierce⿿s disease in table grapes and natural dry-on-vine raisins. Sub-objective 2A: Develop durable resistance to powdery mildew in table grapes and natural dry-on-vine raisins. Sub-objective 2B: Identify sources of durable resistance to Pierce⿿s disease and determine the relative susceptibility of existing commercial cultivars. Sub-objective 2C: Develop table grape and natural dry-on vine raisin cultivars with durable resistance to Pierce⿿s disease. Objective 3: Develop, select, and evaluate new, high quality scions of Prunus, e.g., high yielding self-compatible almond and glabrous-skinned apricot. Sub-objective 3A: Develop, select, and evaluate new high-yielding self- compatible almonds. Sub-objective 3B: Develop, select, and evaluate new glabrous-skinned apricots. Approach (from AD-416): Classical breeding has been used to create segregating populations in Prunus and Vitis where the expression of quantitative traits has been concentrated and newly available characters have been transferred into adapted germplasm. New segregating populations will be created in Vitis to develop molecular markers for fruit quality traits, rachis architecture, resistance to Botrytis, flowering time and berry size. Advanced table grape selections will be compared for production timing and fruit quality after cold storage with existing table grape cultivars through public fruit showings held during each ripening season. Commercially acceptable advanced table grape selections will be introduced as new cultivars through consensus evaluation with the table grape industry. New powdery mildew resistance sources will be evaluated in established segregating populations, and resistant accessions will be backcrossed with high quality table grapes and natural dry on the vine raisins as molecular markers are being developed. These new resistance sources will be used along with other mapped PM resistance sources in hybridizations designed to stack the resistances for durability. Empirical screening of Vitis germplasm for reaction to Xylella fastidiosa will continue, and existing commercial table grape cultivars will be evaluated for their relative susceptibility to Pierce⿿s disease. Crosses will be conducted to stack Xf resistances from Vitis arizonica and southeast U.S. Vitis germplasm into hybrids with high product quality. Promising high quality accessions with will be evaluated for survival and productivity in regions with high Pierce⿿s disease pressure. In Prunus, hybridizations will be performed to identify and select new high-yielding self-compatible almonds that are California-adapted and have Nonpareil-like kernel characteristics. Apricot populations will be developed through hybridization among glabrous-skinned accessions, and new glabrous apricots will be evaluated for fruit quality and productivity. Newly-available glabrous-skinned apricot accessions from Kyrgyzstan will be propagated when available from plant protective quarantine and used in hybridizations to assist in the glabrous-skinned apricot breeding effort. Due to infection by a vector-transmitted virus, all of the segregating populations that were developed and established for fruit quality traits including flowering time, berry shape, size, texture, color and bud break had to be destroyed to protect the remaining grapevine germplasm collection in Parlier. Similarly, the grapevine population that segregated for development of resistance to Botrytis was destroyed. Field evaluations were carried out for Powderly mildew (PM) resistance in a grapevine population with Vitis cinerea genetic background. In support of Objective 2, for both table and raisin grapes, hybridizations were carried out to develop lines that have more than one resistance locus and could provide durable resistance to powdery mildew and Pierce⿿s disease. Female flowered vines with combination of Run1Ren1Ren4 loci have been used as females in backcrosses with high quality table grapes and natural dry-on-vine raisin selections. Pollen from other perfect-flowered Run1Ren1Ren4 vines have been collected and shared with Vitis breeders in Minnesota and New York for use with hybrids having different combinations of powdery mildew resistance genes. Pollen from Run1Ren1Ren4 hybrids was used in hybridizations with powdery mildew resistant selections of Vitis amurensis, in which a new locus for powdery mildew resistance has been identified and named ⿿Ren12. Relative to increasing durability of resistance to Pierce⿿s disease, hybridizations were made to combine the two different Pierce⿿s disease resistance sources. Pierce⿿s disease- resistant vines with Vitis arizonica background were used as seed parents in hybridizations with Pierce⿿s disease-resistant vines with a southeast U.S. background. ACCOMPLISHMENTS 01 Grapevines resistant to powdery mildew. Estimates indicate the potential economic benefit of powdery mildew (PM)-resistant varieties of grapes to producers in California can reach $48 million per year because nearly all grape varieties are highly susceptible to PM. ARS scientists in Parlier, California, and Geneva, New York, collaborated to discover genetic regions responsible for two mechanisms of PM resistance in grapevines. Traditional breeding was combined with molecular approaches using DNA markers to introduce the different PM resistance modes into table grapes. Additional grape breeding and selection will augment the impact of this research at the national level where in the case of table grapes PM resistance would enable 90% reduction in pesticide use, which represents approximately $287 production savings per acre per year. 02 Castlecrest apricot variety release. Nearly 75% of the apricots grown in the United States come from California. ARS scientists in Parlier, California, developed a new mid-season apricot variety that is suitable for fresh market production. Evaluations of the new variety in comparison with other varieties were carried out for three years. The fruit of Castlecrest is larger, has higher Brix (sugar content) and finer texture, and is juicer than other varieties, which provides a significant improvement for fresh eating quality.
Impacts
(N/A)
Publications
- Karn, A., Zou, C., Brooks, S., Fresnedo-Ramirez, J., Gabler, F., Sun, Q., Ramming, D.W., Naegele, R.P., Ledbetter, C.A., Cadle Davidson, L.E. 2021. Discovery of the REN11 locus from Vitis aestivalis for stable resistance to grapevine powdery mildew in a family segregating for several unstable and tissue-specific quantitative resistance loci. Frontiers in Plant Science. https://doi.org/10.3389/fpls.2021.733899.
- Krugner, R., Rogers, E.E., Burbank, L.P., Wallis, C.M., Ledbetter, C.A. 2022. Insights regarding resistance of ⿿Nemaguard⿿ rootstock to the bacterium Xylella fastidiosa. Plant Disease. 106(8):2074-2081. https://doi. org/10.1094/PDIS-01-22-0136-RE.
- Ledbetter, C.A. 2021. 'Yorizane': A new self-compatible almond cultivar suitable for California production. HortScience. 56(9):1142-1143. https:// doi.org/10.21273/HORTSCI16066-21.
- Chen, J., Ledbetter, C.A., O'Leary, M.L. 2022. Complete genome sequence of Curtobacterium sp. strain TXMA1, isolated from a grapevine in Texas, USA. Microbiology Resource Announcements. 11(1). Article e00968-21. https://doi. org/10.1128/mra.00968-21.
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Progress 10/01/20 to 09/30/21
Outputs
PROGRESS REPORT Objectives (from AD-416): The long-term goal of this project is development and introduction of new, high-quality and disease resistant cultivars of Prunus (almond and apricot) and Vitis (table grapes and raisins) that will sustain American agriculture and supply high quality, nutritious fruits and nuts to U.S. consumers and international markets. Further, the project will strive to identify molecular markers linked sufficiently close to fruit quality traits of interest such that marker-assisted selection will be possible in future breeding efforts. Specifically, during the next five years we will focus on the following objectives: Objective 1: Enhance breeding efficiency for table grape fruit quality, and other priority traits, by identifying associated molecular markers, and through trials, to determine commercial acceptability of advanced table grape selections. Sub-objective 1A: Develop segregating populations and map fruit quality traits related to flowering time, rachis architecture, and berry size. Sub-objective 1B: Through trials, determine commercial acceptability of advanced table grape selections. Sub-objective 1C: Identify sources of resistance and develop molecular markers associated with resistance to Botrytis cinerea. Objective 2: Develop durable resistances to powdery mildew and Pierce⿿s disease in table grapes and natural dry-on-vine raisins. Sub-objective 2A: Develop durable resistance to powdery mildew in table grapes and natural dry-on-vine raisins. Sub-objective 2B: Identify sources of durable resistance to Pierce⿿s disease and determine the relative susceptibility of existing commercial cultivars. Sub-objective 2C: Develop table grape and natural dry-on vine raisin cultivars with durable resistance to Pierce⿿s disease. Objective 3: Develop, select, and evaluate new, high quality scions of Prunus, e.g., high yielding self-compatible almond and glabrous-skinned apricot. Sub-objective 3A: Develop, select, and evaluate new high-yielding self- compatible almonds. Sub-objective 3B: Develop, select, and evaluate new glabrous-skinned apricots. Approach (from AD-416): Classical breeding has been used to create segregating populations in Prunus and Vitis where the expression of quantitative traits has been concentrated and newly available characters have been transferred into adapted germplasm. New segregating populations will be created in Vitis to develop molecular markers for fruit quality traits, rachis architecture, resistance to Botrytis, flowering time and berry size. Advanced table grape selections will be compared for production timing and fruit quality after cold storage with existing table grape cultivars through public fruit showings held during each ripening season. Commercially acceptable advanced table grape selections will be introduced as new cultivars through consensus evaluation with the table grape industry. New powdery mildew resistance sources will be evaluated in established segregating populations, and resistant accessions will be backcrossed with high quality table grapes and natural dry on the vine raisins as molecular markers are being developed. These new resistance sources will be used along with other mapped PM resistance sources in hybridizations designed to stack the resistances for durability. Empirical screening of Vitis germplasm for reaction to Xylella fastidiosa will continue, and existing commercial table grape cultivars will be evaluated for their relative susceptibility to Pierce⿿s disease. Crosses will be conducted to stack Xf resistances from Vitis arizonica and southeast U.S. Vitis germplasm into hybrids with high product quality. Promising high quality accessions with will be evaluated for survival and productivity in regions with high Pierce⿿s disease pressure. In Prunus, hybridizations will be performed to identify and select new high-yielding self-compatible almonds that are California-adapted and have Nonpareil-like kernel characteristics. Apricot populations will be developed through hybridization among glabrous-skinned accessions, and new glabrous apricots will be evaluated for fruit quality and productivity. Newly-available glabrous-skinned apricot accessions from Kyrgyzstan will be propagated when available from plant protective quarantine and used in hybridizations to assist in the glabrous-skinned apricot breeding effort. In support of Objective 1, evaluations continued on advanced table grape selections with two virtual showings of selections to interested stakeholders. Nine advanced selections and six commercial cultivars were cultured with best known practices for comparative evaluations in fruit quality characteristics and box yield. From planted seedling populations, six new advanced table grape selections were identified during 2020 that warrant placement in the advanced trial block for future evaluation. Propagation materials of the new selections have been collected to produce sufficient vines for establishment in the advanced trial block. Segregating populations for fruit quality traits including flowering time, berry shape, size, texture and color and bud break were evaluated. Genetic maps are being constructed for quantitative trait locus (QTL) analyses. A grape population segregating for powdery mildew and Botrytis resistance was evaluated for disease resistance to powdery (field) and gray mold (postharvest storage). A genetic map is being constructed to identify potential loci associated with resistance in a V. cinerea genetic background. Hybridizations continue in both table grapes and raisins to develop durable resistances to both powdery mildew and Pierce⿿s disease in support of Objective 2. Reflex-flowered Run1Ren1Ren4 vines have been used as females in backcrosses with high quality table grapes and natural dry- on-vine raisin selections. Pollen from other perfect-flowered Run1Ren1Ren4 vines have been collected and shared with Vitis breeders in Minnesota and New York for use with hybrids having different combinations of powdery mildew resistance genes. Pollen from Run1Ren1Ren4 hybrids has also been used in hybridizations with powdery mildew resistant selections of V. amurensis, an as yet-to-be characterized powdery mildew resistance source. Relative to increasing durability of resistance to Pierce⿿s disease, hybridizations were made to combine the two different Pierce⿿s disease resistance sources. Pierce⿿s disease resistant vines with Vitis arizonica background were used as seed parents in hybridizations with Pierce⿿s disease resistant vines with a southeast U.S. background. Sources of Pierce⿿s Disease resistance from V. arizonica, southeast U.S. background and an interspecific hybrid V. caribae were evaluated for sensitivity to seven isolates of Xylella fastidiosa to test the durability of resistance. Evaluation efforts continue in support of Objective 3 for the development of new self-fertile almonds and glabrous-skinned apricots. After four years of yield evaluation in the Almond Board of California- sponsored Regional Almond Variety Trials, the new self-fertile Yorizane cultivar has been released from the Parlier, California, breeding program. Recent hybridizations have yielded a new early-ripening self-fertile almond selection. While the new selection lacks perfect kernel quality, its early-ripening character makes it an attractive parent in the development of new self-fertile selections. Numerous backcrosses were performed during the 2021 bloom period between large-fruited apricots carrying the glabrous-skin gene (seed parent) and high quality glabrous- skinned selections. During the 2021 fruit ripening season, several new high quality glabrous-skinned apricots were selected from segregating populations. Queries to plant protective quarantine during the early 2021 fruit season have indicated that the large-fruited Kyrgyzstan glabrous- skinned apricots are still in a juvenile stage of development and not yet ready for selection and propagation. Record of Any Impact of Maximized Teleworking Requirement: Maximized telework requirements had a negative impact on the lab⿿s ability to complete planned in-lab activities due to the limitations in the number of individuals who could be present in the lab at one time. This negatively impacted training of new hires and the overall quality and quantity of data collected. Travel restrictions limited the lab⿿s ability to collect field samples from surrounding locations. Due to the Covid-19 lockdown issued March 2020, field work was put on hold at the Parlier, California, location. ACCOMPLISHMENTS 01 Self-fertile Yorizane almond. Eighty percent of the world⿿s almonds are grown in California with the majority of the 1.5 million acres being planted to self-infertile cultivars. The California almond industry desires new self-fertile cultivars to assist honeybees with nut set. ARS researchers in Parlier, California, developed the new self-fertile Yorizane cultivar in response to industry desires. The new cultivar has yielded well in trials throughout the San Joaquin Valley and has been rated highly in marketing potential and kernel appearance. The Yorizane release has been noted in the almond industry with dormant budwood being provided to six requesting tree nut nurseries for the development of mother trees. 02 Major source of resistance to Pierce⿿s Disease is resistant to multiple bacterial strains. Pierce⿿s Disease is a bacterial disease of grape causing loss of production. Breeding for resistance has focused on a single source in grape from Vitis arizonica. ARS Researchers in Parlier, California, tested the major source of resistance against a panel of seven different Xylella fastidiosa strains, the bacteria causing Pierce⿿s Disease. Little to no disease was observed in the resistant V. arizonica when challenged with each bacterial strain. This suggests that the currently used major source of resistance in grape breeding will be effective in multiple grape growing regions.
Impacts
(N/A)
Publications
- Bourguiba, H., Scotti, I., Sauvage, C., Zhebentvaeva, T., Ledbetter, C.A., Krska, B., Remay, A., D'Onofrio, C., Iketani, H., Christen, D., Krichen, L. , Trifi-Farah, N., Liu, W., Roch, G., Audergon, J. 2020. Genetic structure of a worldwide germplasm collection of Prunus armeniaca L. reveals three major diffusion routes for the varieties issued from the species⿿ centre of origin. Frontiers in Plant Science. https://doi.org/10.3389/fpls.2020. 00638.
- Zou, C., Karn, A., Reisch, B., Nguyen, A., Sun, Y., Bao, Y., Campbell, M.S. , Church, D., Williams, S., Xu, X., Ledbetter, C.A., Patel, S., Fennell, A. , Glaubitz, J., Clark, M., Ware, D., Londo, J.P., Sun, Q., Cadle Davidson, L.E. 2020. Haplotyping the Vitis collinear core genome with rhAmpSeq improves marker transferability in a diverse genus. Nature Communications. https://doi.org/10.1038/s41467-019-14280-1.
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Progress 10/01/19 to 09/30/20
Outputs
Progress Report Objectives (from AD-416): The long-term goal of this project is development and introduction of new, high-quality and disease resistant cultivars of Prunus (almond and apricot) and Vitis (table grapes and raisins) that will sustain American agriculture and supply high quality, nutritious fruits and nuts to U.S. consumers and international markets. Further, the project will strive to identify molecular markers linked sufficiently close to fruit quality traits of interest such that marker-assisted selection will be possible in future breeding efforts. Specifically, during the next five years we will focus on the following objectives: Objective 1: Enhance breeding efficiency for table grape fruit quality, and other priority traits, by identifying associated molecular markers, and through trials, to determine commercial acceptability of advanced table grape selections. Sub-objective 1A: Develop segregating populations and map fruit quality traits related to flowering time, rachis architecture, and berry size. Sub-objective 1B: Through trials, determine commercial acceptability of advanced table grape selections. Sub-objective 1C: Identify sources of resistance and develop molecular markers associated with resistance to Botrytis cinerea. Objective 2: Develop durable resistances to powdery mildew and Pierce⿿s disease in table grapes and natural dry-on-vine raisins. Sub-objective 2A: Develop durable resistance to powdery mildew in table grapes and natural dry-on-vine raisins. Sub-objective 2B: Identify sources of durable resistance to Pierce⿿s disease and determine the relative susceptibility of existing commercial cultivars. Sub-objective 2C: Develop table grape and natural dry-on vine raisin cultivars with durable resistance to Pierce⿿s disease. Objective 3: Develop, select, and evaluate new, high quality scions of Prunus, e.g., high yielding self-compatible almond and glabrous-skinned apricot. Sub-objective 3A: Develop, select, and evaluate new high-yielding self- compatible almonds. Sub-objective 3B: Develop, select, and evaluate new glabrous-skinned apricots. Approach (from AD-416): Classical breeding has been used to create segregating populations in Prunus and Vitis where the expression of quantitative traits has been concentrated and newly available characters have been transferred into adapted germplasm. New segregating populations will be created in Vitis to develop molecular markers for fruit quality traits, rachis architecture, resistance to Botrytis, flowering time and berry size. Advanced table grape selections will be compared for production timing and fruit quality after cold storage with existing table grape cultivars through public fruit showings held during each ripening season. Commercially acceptable advanced table grape selections will be introduced as new cultivars through consensus evaluation with the table grape industry. New powdery mildew resistance sources will be evaluated in established segregating populations, and resistant accessions will be backcrossed with high quality table grapes and natural dry on the vine raisins as molecular markers are being developed. These new resistance sources will be used along with other mapped PM resistance sources in hybridizations designed to stack the resistances for durability. Empirical screening of Vitis germplasm for reaction to Xylella fastidiosa will continue, and existing commercial table grape cultivars will be evaluated for their relative susceptibility to Pierce⿿s disease. Crosses will be conducted to stack Xf resistances from Vitis arizonica and southeast U.S. Vitis germplasm into hybrids with high product quality. Promising high quality accessions with will be evaluated for survival and productivity in regions with high Pierce⿿s disease pressure. In Prunus, hybridizations will be performed to identify and select new high-yielding self-compatible almonds that are California-adapted and have Nonpareil-like kernel characteristics. Apricot populations will be developed through hybridization among glabrous-skinned accessions, and new glabrous apricots will be evaluated for fruit quality and productivity. Newly-available glabrous-skinned apricot accessions from Kyrgyzstan will be propagated when available from plant protective quarantine and used in hybridizations to assist in the glabrous-skinned apricot breeding effort. In completion of Sub-objective 1A, 1,000 images of grape clusters were collected from 150 grapevines during the 2019 fruit season. Mature vines were evaluated for flowering time and images were collected to evaluate rachis architecture and berry shape/size. Leaf samples from two segregating populations were collected and genotyped using rhAmpSeq. Genetic maps of both populations have been constructed. Flowering time data (2016-2019) has been formatted both as calendar days and growing degree days for quantitative trait locus (QTL) mapping. QTL mapping has identified significant associations with flowering, veraison, full color time and other fruit quality traits. Additional samples from genetically different vines with known fruit quality traits have been collected to confirm identified QTL markers in unrelated populations. Images from the 2019 season were submitted to ARS in Kearneysville, West Virginia, for image analyses. In support of Sub-objective 1B, 10 new table grape selections were identified in seedling blocks during the 2019 fruit season that had sufficient fruit quality and production characteristics to warrant placement in the advanced trial block. Propagation materials were collected from the mother vines during dormancy for clonal rooting to be established for future trials. In support of Sub-objective 1C, a segregating population derived from a V. labrusca x V. vinifera cross is maintained in the field. Five clusters from each vine were inoculated with a mixed spore suspension of B. cinerea isolates for evaluating resistance potential under field conditions. For Sub-objective 2A, grape progenies derived from Run1Ren1 x Ren4 hybridizations have now been field evaluated for fruit and crop qualities. Weak vines and those lacking powdery mildew resistance have been eliminated from the populations. Vines with all three powdery mildew resistance genes have been identified. Evaluations during bloom periods have allowed identification of numerous reflex-flowered vines including three male sterile Run1Ren1Ren4 hybrids that are currently being used for breeding. Table grape cultivars were evaluated for relative susceptibility to Pierce⿿s Disease (Sub-objective 2B). Cuttings from known and novel sources of resistance to Pierce⿿s disease have been propagated (~ 200 individuals for each genotype) and are in the greenhouse for testing against 20 Xylella fastidiosa isolates. Xylella isolates representing the genetic and geographic distribution diversity of California were activated by inoculating grape seedlings and recovered isolates are being propagated for inoculations. Hybridizations during the 2020 bloom included crosses between Pierce⿿s disease tolerant Southeast U.S. grape selections and similarly tolerant selections derived from B43-17 (V. arizonica-based tolerance) in support of Sub-objective 2C. Crosses were made to develop both new table grape and raisin progenies. Crosses involved both seed cultured accessions and combinations requiring embryo culture to rear embryos from stenospermic ovules. In support of Sub-objective 3A, almond seedlings derived from hybridizations among self-fertile almond accessions have been screened for the presence of the self-compatibility gene. Self-incompatible seedlings were identified and removed prior to field planting the self- compatible seedlings. In support of Sub-objective 3B, glabrous-skinned apricot germplasm has been evaluated for fruit quality characteristics to identify elite individuals for use in hybridizations. Specifically, larger-fruited accessions and accessions with neutral-flavored (non-acidic) skin were identified for use as parents in planned crosses. The glabrous-skinned accessions have been hybridized with F1 pubescent-skinned heterozygotes (carrying the glabrous gene). Accomplishments 01 Marginal soils in western San Joaquin Valley may now prove valuable with new ⿿FXA⿿ rootstock. In the southern San Joaquin Valley of California, there are over 1.3 million acres of salt-affected and boron- laden soils that are currently unsuitable for almond production. However, a recent rootstock release by ARS researchers in Parlier, California, may soon render the affected acreage usable for almond culture. The new rootstock, a hybrid of Flordaguard and Israeli alnem named FXA, has performed well in several rootstock trials established on boron-laden or salt-affected soils. Almond scions grown on FXA rootstock accumulate less chloride in vegetative tissues than when alternative rootstocks are used. Similarly, FXA-grown almonds accumulate lower levels of boron in hull tissue as compared with alternative rootstocks when cultured in boron-laden soils. These factors lead to healthier and more productive trees under marginal growing conditions.
Impacts
(N/A)
Publications
- Ledbetter, C.A. 2019. ⿿Solbrio⿿ table grape. HortScience. 54(10):1864-1865.
- Naegele, R.P., Delong, J.A., Saito, S., Xiao, C. 2020. Population genetics and fungicide resistance of Botrytis cinerea on Vitis and Prunus spp. in California. Phytopathology. 110(3):694-702.
- Naegele, R.P., Daane, K.M., Cousins, P. 2020. Identification of vitis cultivars, rootstocks and species expressing resistance to a Planococcus mealybug. Insects. 11(2):86.
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Progress 10/01/18 to 09/30/19
Outputs
Progress Report Objectives (from AD-416): The long-term goal of this project is development and introduction of new, high-quality and disease resistant cultivars of Prunus (almond and apricot) and Vitis (table grapes and raisins) that will sustain American agriculture and supply high quality, nutritious fruits and nuts to U.S. consumers and international markets. Further, the project will strive to identify molecular markers linked sufficiently close to fruit quality traits of interest such that marker-assisted selection will be possible in future breeding efforts. Specifically, during the next five years we will focus on the following objectives: Objective 1: Enhance breeding efficiency for table grape fruit quality, and other priority traits, by identifying associated molecular markers, and through trials, to determine commercial acceptability of advanced table grape selections. Sub-objective 1A: Develop segregating populations and map fruit quality traits related to flowering time, rachis architecture, and berry size. Sub-objective 1B: Through trials, determine commercial acceptability of advanced table grape selections. Sub-objective 1C: Identify sources of resistance and develop molecular markers associated with resistance to Botrytis cinerea. Objective 2: Develop durable resistances to powdery mildew and Pierce⿿s disease in table grapes and natural dry-on-vine raisins. Sub-objective 2A: Develop durable resistance to powdery mildew in table grapes and natural dry-on-vine raisins. Sub-objective 2B: Identify sources of durable resistance to Pierce⿿s disease and determine the relative susceptibility of existing commercial cultivars. Sub-objective 2C: Develop table grape and natural dry-on vine raisin cultivars with durable resistance to Pierce⿿s disease. Objective 3: Develop, select, and evaluate new, high quality scions of Prunus, e.g., high yielding self-compatible almond and glabrous-skinned apricot. Sub-objective 3A: Develop, select, and evaluate new high-yielding self- compatible almonds. Sub-objective 3B: Develop, select, and evaluate new glabrous-skinned apricots. Approach (from AD-416): Classical breeding has been used to create segregating populations in Prunus and Vitis where the expression of quantitative traits has been concentrated and newly available characters have been transferred into adapted germplasm. New segregating populations will be created in Vitis to develop molecular markers for fruit quality traits, rachis architecture, resistance to Botrytis, flowering time and berry size. Advanced table grape selections will be compared for production timing and fruit quality after cold storage with existing table grape cultivars through public fruit showings held during each ripening season. Commercially acceptable advanced table grape selections will be introduced as new cultivars through consensus evaluation with the table grape industry. New powdery mildew resistance sources will be evaluated in established segregating populations, and resistant accessions will be backcrossed with high quality table grapes and natural dry on the vine raisins as molecular markers are being developed. These new resistance sources will be used along with other mapped PM resistance sources in hybridizations designed to stack the resistances for durability. Empirical screening of Vitis germplasm for reaction to Xylella fastidiosa will continue, and existing commercial table grape cultivars will be evaluated for their relative susceptibility to Pierce⿿s disease. Crosses will be conducted to stack Xf resistances from Vitis arizonica and southeast U.S. Vitis germplasm into hybrids with high product quality. Promising high quality accessions with will be evaluated for survival and productivity in regions with high Pierce⿿s disease pressure. In Prunus, hybridizations will be performed to identify and select new high-yielding self-compatible almonds that are California-adapted and have Nonpareil-like kernel characteristics. Apricot populations will be developed through hybridization among glabrous-skinned accessions, and new glabrous apricots will be evaluated for fruit quality and productivity. Newly-available glabrous-skinned apricot accessions from Kyrgyzstan will be propagated when available from plant protective quarantine and used in hybridizations to assist in the glabrous-skinned apricot breeding effort. In support of Sub-objective 1A, six biparental table grape populations were developed. These populations segregate for rachis architecture, flower time, fruit quality and berry size. Populations were transplanted to the field and are being maintained and trained for fruit production and evaluation in year two. For individuals in populations with fruit in year one, initial evaluations were performed for cluster differences. Existing populations (11-3527) are continuing to be evaluated for cluster architecture, berry size/shape, and fruit development. In support of Sub-objective 1B, 16 advanced table grape selections and six competing cultivars were evaluated in three fruit showings conducted during the harvest season. Interested growers and stakeholders participated in the evaluations to identify those selections worthy of continuing in the effort to identify new cultivars with fewer cultural inputs necessary to produce a commercial crop. A major source of grapevine resistance to Botrytis cinerea was identified in support of Sub-objective 1C. Hybridizations were made with this source of resistance and the F1 progeny planted into field plots. Evaluations for cluster susceptibility to Botrytis were initiated this spring and will continue throughout fall of 2019. Field inoculations and evaluations will be repeated in subsequent years. Grape populations segregating for resistance to powdery mildew (PM) are currently being evaluated for fruit quality and harvest timing. In support of Sub-objective 2A, these populations are also being evaluated for susceptibility to PM on leaves, stems, rachis and berries. These populations were derived from PM resistant female-flowered wild Vitis species (amurensis, cinerea, riparia and vulpina) and high quality V. vinifera table grapes Fresno Seedless and Valley Pearl. Vines are evaluated in the field twice a year (one month after berry set and after fruit harvest) to determine PM susceptibility in the various plant organs. In support of developing Pierce⿿s disease (PD) resistance, as part of Sub- objective 2B, green and dormant cuttings were collected from known and putative sources of resistance. Sufficient numbers of materials (approximately 300 plants per genotype) are still being generated to assess durability of resistance to multiple isolates of the pathogen. Two biparental crosses were made using a previously unidentified source of Xylella fastidiosa resistance, and seedlings planted into the field. Another grape mapping population that was developed for identifying molecular markers linked to PD tolerance is now being evaluated for fruit/ crop quality in support of Sub-objective 2C. Vines found to have fruit quality inferior to parental PD-tolerant vine BD5-117 are being rogued from the population. BD5-117 is an early generation PD-tolerant cultivar developed in the southeast U.S., and distinctly different germplasm than V. arizonica-based hybrids for which a molecular marker linked to PD tolerance has been developed. Through empirical screening, it was determined that vines in this population segregate for bacterial titer and expression of PD symptoms; however, no molecular markers were ever identified that were linked to PD tolerance or susceptibility. Hence, vines exhibiting improved fruit and crop qualities in the BD5-117 population will be used as parental germplasm in future hybridizations with V. arizonica-based PD-tolerant grapes. Numerous self-fertile almond selections have been identified over the last decade that would be suitable parents in planned hybridizations. The California almond industry desires early-ripening cultivars having high yields of undamaged Nonpareil-shaped kernels. In support of Sub-objective 3A, hybridizations have been performed among self-fertile selections having Nonpareil-like kernels. Multivariate kernel analyses are being used to identify new selections with Nonpareil-shaped kernels. A research-sized roller/cracker provides data on kernel durability at harvest. Several glabrous-skinned apricots were collected from Central Asia and imported to the U.S. in the early 1990s. These accessions were hybridized with California-adapted apricots as soon as the young trees became reproductively fit. Glabrous-skinned apricots were not identified in the initial crosses, but when these first-generation trees were crossed amongst themselves, 25% of the offspring produced glabrous-skinned fruit. In support of Sub-objective 3B, trees with glabrous-skinned fruit are being evaluated for fruit quality characteristics and ranked for use as parents. Of particular concern is fruit size and detrimental skin characteristics. The initial glabrous-skinned plant introductions were small-fruited, being only 20⿿25 gram fresh weight. Compared to the neutral-flavored skin that predominates pubescent-skinned apricots, glabrous-skinned apricots can exhibit both acidic or astringent skin flavors. Current fruit evaluations of the glabrous-skinned accessions will identify the largest-fruited accessions having neutral skin flavor for use in planned crosses. Accomplishments 01 Solbrio: making table grape growing easier. While consumers may find that table grape varieties are diverse in appearance, flavor and ripening season, growers know that varieties are also diverse in the cultural treatments necessary to produce quality table grapes. ARS researchers in Parlier, California, have released a new early-season table grape named Solbrio that has both exceptional eating quality and reduced cultural input needs. Consumers have shown a strong interest in the new variety because of its large berry size, crisp and crunchy flesh and fully colored berries. Many of the standard cultural practices used to enhance characteristics of other table grape varieties were evaluated on the new variety, but none of the treatments produced a significant change on berry quality or yield. Hence, growers are very pleased with the new variety that is both easy and inexpensive to grow.
Impacts
(N/A)
Publications
- Ledbetter, C.A., Lee, S.A. 2018. Diversity of Xylella fastidiosa host suitability among siblings from a non-traditional almond X peach cross. Euphytica. 214:84.
- Baumgartner, K., Fujiyoshi, P.T., Ledbetter, C.A., Duncan, R., Kluepfel, D. A. 2018. Screening almond rootstocks for sources of resistance to Armillaria root disease. HortScience. 53(1):4-8.
- Ledbetter, C.A., Lee, S.A. 2019. Maintaining product quality in raisins throughout the introgression of powdery mildew resistance. Journal of Horticultural Science and Biotechnology. 94(4):460-467.
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Progress 10/01/17 to 09/30/18
Outputs
Progress Report Objectives (from AD-416): The long-term goal of this project is development and introduction of new, high-quality and disease resistant cultivars of Prunus (almond and apricot) and Vitis (table grapes and raisins) that will sustain American agriculture and supply high quality, nutritious fruits and nuts to U.S. consumers and international markets. Further, the project will strive to identify molecular markers linked sufficiently close to fruit quality traits of interest such that marker-assisted selection will be possible in future breeding efforts. Specifically, during the next five years we will focus on the following objectives: Objective 1: Enhance breeding efficiency for table grape fruit quality, and other priority traits, by identifying associated molecular markers, and through trials, to determine commercial acceptability of advanced table grape selections. Sub-objective 1A: Develop segregating populations and map fruit quality traits related to flowering time, rachis architecture, and berry size. Sub-objective 1B: Through trials, determine commercial acceptability of advanced table grape selections. Sub-objective 1C: Identify sources of resistance and develop molecular markers associated with resistance to Botrytis cinerea. Objective 2: Develop durable resistances to powdery mildew and Pierce�s disease in table grapes and natural dry-on-vine raisins. Sub-objective 2A: Develop durable resistance to powdery mildew in table grapes and natural dry-on-vine raisins. Sub-objective 2B: Identify sources of durable resistance to Pierce�s disease and determine the relative susceptibility of existing commercial cultivars. Sub-objective 2C: Develop table grape and natural dry-on vine raisin cultivars with durable resistance to Pierce�s disease. Objective 3: Develop, select, and evaluate new, high quality scions of Prunus, e.g., high yielding self-compatible almond and glabrous-skinned apricot. Sub-objective 3A: Develop, select, and evaluate new high-yielding self- compatible almonds. Sub-objective 3B: Develop, select, and evaluate new glabrous-skinned apricots. Approach (from AD-416): Classical breeding has been used to create segregating populations in Prunus and Vitis where the expression of quantitative traits has been concentrated and newly available characters have been transferred into adapted germplasm. New segregating populations will be created in Vitis to develop molecular markers for fruit quality traits, rachis architecture, resistance to Botrytis, flowering time and berry size. Advanced table grape selections will be compared for production timing and fruit quality after cold storage with existing table grape cultivars through public fruit showings held during each ripening season. Commercially acceptable advanced table grape selections will be introduced as new cultivars through consensus evaluation with the table grape industry. New powdery mildew resistance sources will be evaluated in established segregating populations, and resistant accessions will be backcrossed with high quality table grapes and natural dry on the vine raisins as molecular markers are being developed. These new resistance sources will be used along with other mapped PM resistance sources in hybridizations designed to stack the resistances for durability. Empirical screening of Vitis germplasm for reaction to Xylella fastidiosa will continue, and existing commercial table grape cultivars will be evaluated for their relative susceptibility to Pierce�s disease. Crosses will be conducted to stack Xf resistances from Vitis arizonica and southeast U.S. Vitis germplasm into hybrids with high product quality. Promising high quality accessions with will be evaluated for survival and productivity in regions with high Pierce�s disease pressure. In Prunus, hybridizations will be performed to identify and select new high-yielding self-compatible almonds that are California-adapted and have Nonpareil-like kernel characteristics. Apricot populations will be developed through hybridization among glabrous-skinned accessions, and new glabrous apricots will be evaluated for fruit quality and productivity. Newly-available glabrous-skinned apricot accessions from Kyrgyzstan will be propagated when available from plant protective quarantine and used in hybridizations to assist in the glabrous-skinned apricot breeding effort. This report documents progress for project 2034-21220-007-00D, which started in May 2018 and continues research from project 2034-21220-006- 00D, "Genetic Improvement of Prunus and Vitis Scions and Rootstocks for Fruit Quality and Pest Resistance." In support of Sub-objective 1A, a mapping population segregating for rachis architecture and berry size was evaluated for time to anthesis on five clusters per vine this spring. Images of clusters and rachis collected in FY17 are being analyzed. A new mapping population segregating for cluster architecture (Cabernet Sauvignon x Rangspray) was planted in the field to be evaluated in 2020. In support of Sub-objective 1C, a mapping population with potential segregation for Botrytis cinerea resistance was developed. For Sub-objective 2A, evaluation of powdery mildew reaction continues in four new grape mapping populations. Approximately, 1,100 vines are scored for resistance/susceptibility to powdery mildew on leaves, stems, rachis, and grape berries. Selected vines found without traces of powdery mildew on these organs have been used in backcrosses with high quality table grapes and raisins. These unique powdery mildew resistance sources will be maintained separately until a marker is available for the resistance source. In support of Sub-objective 2B, cuttings of table grape varieties, breeding lines, and grape species were collected for evaluations for susceptibility to two isolates of Xylella fastidiosa. Grape cuttings have been collected from known and putative sources of resistance to Pierce�s Disease and are currently being rooted for disease evaluations.
Impacts
(N/A)
Publications
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