Progress 10/01/10 to 09/30/15
Outputs
Target Audience:Commercial floricultural businesses (growers, nurseries, and landscapers), county extension agents, and researchers, and interested general public. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?This project provided technical and professional training for five graduate students (one MS and four PhD students) and two undergraduate students. How have the results been disseminated to communities of interest?Results from this project were presented at three international conferences (International Horticultural Congress and the Plant & Animal Genome Conferences), four national conferences (the American Society for Horticultural Science Annual Meetings), nearly 20 state and local scientific or extension meetings. Results were published in two book chapters, 19 refereed papers in five scientific journals including HortScience, Journal of the American Society for Horticultural Science, Plant Breeding, Plant Cell, Tissue and Organ Culture, and Scientia Horticulturae, six non-refereed papers, seven research reports, more than 10 extension publications, and two trade magazine articles. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Objective 1 - Develop new caladium and gerbera cultivars: Eight superior advanced breeding lines were released as new caladium cultivars ('UF 44-4', 'UF 4412', 'UF 4424', 'UF 432', 'UF 4015', 'UF-R304', 'UF-R813', and 'UF-R1012'). Florida growers have licensed all eight cultivars for production and sale. These cultivars are marketed under these names 'Cherry Tart', 'Fairytale Princess', 'Red Hot', 'Sizzle', 'Passionista', 'Cosmic Delight', 'Hearts Desire', and 'Fiesta', respectively. 'Cherry Tart' was selected as "Top Choices for New Cultivars" at the 2014 Florida Nursery, Growers and Landscape Association Floriculture Field Days, and 'Fiesta' and 'Passionista' were selected as "Plant of Distinction" at the University of Georgia Garden Trials in 2015. Plant patent has been received for three caladium cultivars. In addition, more than 100,000 caladium progeny were generated and evaluated in planter trays and caladium fields, and hundreds of new advanced breeding lines have been selected for future field and greenhouse trials. Two superior breeding lines (UFGE 7031 and UFGE 7080) have been released as powdery mildew-resistant cultivars. Plant patent has been received for both cultivars. In addition, approximately 7,000 new gerbera progeny were generated and screened for powdery mildew disease resistance, plant growth habit, flower color, flower count, etc. Several dozens of promising breeding lines have been selected for future trials. Objective 2 - Produce sterile, non-invasive lantana and nandina cultivars: Two sterile, non-invasive lantana cultivars (UF-T3 and UF-T4) have been released, and plant patents have been received. In addition, more than 2,500 new lantana tetraploid progeny and approximately 1,200 new lantana triploids were created from interploid crosses. The pollen stainability, fruit production, seed germination, and hybridization potential of 13 superior triploids were determined. A number of promising triploid lines are under evaluation as potential releases. Results from studying the ploidy level and pollen stainability of lantana cultivars and breeding lines has revealed that ploidy level is the most important factor determining the pollen stainability or male sterility of lantana. Generally, triploids showed the lowest pollen stainability or the highest male sterility. Thus triploid production and selection should be an effective approach to achieving genetic male sterility in lantana. Nearly two dozens of nandina tetraploids have been obtained. They are highly sterile and produce few fruit. These tetraploids will be valuable for development of sterile, non-invasive nandina Objective 3 - Improve cultivar development through understanding the mode of inheritance of important disease resistance traits: Gerbera breeding line UFGE 31-19 has shown consistent powdery mildew resistance in greenhouse and ground evaluations and provided the powdery mildew resistance in several new gerbera cultivars. Results from this project have shown that the powdery mildew resistance in UFGE 31-19 and its progeny UFGE 4033 is a quantitative trait with major genes involved. The resistance mechanism in these breeding lines is primarily through restricting fungal growth and sporulation, not by inhibiting spore germination, germ tube formation, or appressorium formation. Objective 4 - Expedite breeding process through application of cellular and molecular biotechnological tools: Genome size analysis and chromosome counting of caladium species accessions revealed a wide range of variation among caladium species and the existence of four caladium cytological groups in these accessions. Future interspecific hybridization efforts may benefit more from crossing caladium cultivars with Caladium rebicundrum. Through in vitro colchicine treatment, caladium tetraploids were obtained. They showed significant changes in leaf shape, sunburn tolerance, and petiole strength. Chromosome counting and genome size analysis indicated that some of the "tetraploids" gained additional chromosomes or lost some chromosomes. Tetraploid caladium seems to have increased plant performance and sunburn tolerance. Thus tetraploid induction can serve as a new breeding approach for caladium breeding. Fifty-three robust informative simple sequence repeat (SSR) markers have been developed from mining existing EST sequences of gerbera and designing appropriate primers. DNA fingerprint data produced by these SSR markers separated commercial gerbera cultivars into two clusters largely corresponding to breeding approaches and/or propagation methods. Degenerate primers based on conserved amino acids in the nucleotide-binding leucine-rich repeat class resistance (R) genes amplified the genomic DNA of powdery mildew-resistant gerbera breeding lines, resulting in the cloning of 84 gerbera resistance gene candidate sequences. These sequences and SSR primers were used in molecular marker analysis of a gerbera backcross population segregating for powdery mildew resistance. A localized genetic linkage map was developed, and two QTL (Rpx1 and Rpx2) for powdery mildew resistance were identified. Together the QTL explained greater than 70% of the phenotypic variance in the segregating population. Molecular markers associated with the QTL will be useful for future characterization of the resistance loci and selection of breeding parents in gerbera breeding.
Publications
|
Progress 10/01/14 to 09/30/15
Outputs
Target Audience:Commercial floricultural businesses (growers, nurseries, and landscapers), county extension agents, and researchers, and interested general public. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?This project provided technical and professional training for three graduate students and one undergraduate student. How have the results been disseminated to communities of interest?Results from this project were presented at the 2015 Florida State Horticultural Society Annual Meeting, the Plant & Animal Genome XXIIV, the Florida Floriculture Field Days, the (Florida) Manatee County Extension meeting, the UF Caladium Research Forum (intended for caladium growers), etc. Part of these results were published in scientific journals including HortScience, the Journal of the American Society for Horticultural Science, and the Plant Cell, Tissue and Organ Culture. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
1. Field trials of advanced caladium breeding lines: Nineteen advanced caladium breeding lines were planted in the caladium field, in three blocks with 10 widely grown commercial caladium cultivars. The breeding lines were evaluated for plant growth, plant performance, sunburn tolerance, and tuber yields. A number of these advanced breeding lines performed very well and have good potential to be released as new cultivars, upon growers' request. 2. Release three new caladium cultivars: Based on leaf color, plant performance and tuber yield in experimental plots as well as plant performance and tuber yield in growers' fields, three advanced caladium breeding lines were selected and released as new cultivars. 'UF-R304', 'UF-R813', and 'UF-R1012' showed excellent sunburn tolerance, produced high quality pot plants, and performed well in sunny and shady landscapes. 'UF-R304' produces white lance-shaped leaves and is a good replacement of old cultivars such as 'White Wing'. 'UF-R813' 'UF-R1012' is characterized by large white heart-shaped leaves in sharp contrast with multiple dark red main veins. 3. Morphological, cytological and molecular characterization of caladium somaclonal variants: Twenty-four somaclonal variants were identified among 'Red Flash' plants regenerated from cultivated leaf segments. Fourteen of the variants lost one or two chromosomes. Molecular marker analysis indicated allele loss or allele size change in some variants. Results indicate that several cytological and/or molecular causes are involved in the origin of somaclonal variation in this caladium cultivar and chromosome number change is likely the most important cause. One chromosome seemed to be exceptionally unstable and prone to loss during tissue culture. 4. Evaluating plant performance and downy mildew resistance of impatiens and New Guinea impatiens (NGI) cultivars: Twenty-six NGI and 14 impatiens cultivars were tested in ground beds in central Florida for their landscape performance. In the meantime, they were inoculated with Plasmopara obducens, the causal agent of downy mildew, to characterize their resistance or susceptibility responses. A top performing cultivar in each flower color category was identified. Some differences were observed among NGI cultivars in response to P. obducens inoculated onto cotyledons, first pair, or second pairs of true leaves. 5. Phenotyping Petunia recombinant inbred lines (RILs) and identifying quantitative trait loci (QTL): One population of more than 200 RILs derived from Petunia axillaris and P. exserta and one population of more than 170 RILs derived from P. integrifolia and P. axillaris were phenotyped in replicated field beds for plant height, days to anthesis, flower count, flower length, and flower diameter. The phenotype data as well as linkage mapping data were analyzed in the software MapQTL and a total of 17 QTL were identified. About 50% of the QTL were significant and consistent in both 2014 and 2015 growing seasons. Several major QTL each could explain up to 26.8% of the phenotypic variation observed in the two RIL populations. 6. Developing sterile, non-invasive lantana cultivars: Thirteen advanced lantana breeding lines as well as their parents, a sterile control, and a fertile control cultivar were trialed at two sites in Florida; the plant performance, fruit production, and pollen viability of these lines were determined. These lines were also cross-pollinated with the Florida native Lantana depressa to determine their hybridization potential. Experimental data showed that at least two of these advanced breeding lines were male and female sterile, lacked the ability to hybridize with L. depressa, and performed as well as or better than existing commercial cultivars. The promising lantana lines also performed very well in industry trials. 7. Evaluating commercial lantana cultivars: Twenty-one commercial lantana cultivars were evaluated in replicated ground trials in central and south Florida for plant performance, fruit production, seed germination, and pollen stainability. These cultivars were also tested in a greenhouse for hybridization potential with Florida native species Lantana depressa. A number of highly sterile, non-invasive cultivars were selected as alternative to the fertile, invasive types.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Cai, X., Z. Cao, S. Xu, and Z. Deng. 2015. Induction, regeneration and characterization of tetraploids and variants in Tapestry caladium. Plant Cell, Tissue and Organ Culture 120:689-700.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2015
Citation:
Cao, Z., S. Sui, and Z. Deng. 2015. Genome size and chromosome number variation among caladium species and somaclonal variants. Abstract to the International Plant and Animal Genome XXIII Conference, San Diego, CA, January 10-14, 2015.
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Deng, Z., B.K. Harbaugh, and N.A. Peres. 2015. UF 432 and UF 4015 Two lance-leaved caladium cultivars. HortScience 50(7):1099-1103.
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Smith, S.M. and Z. Deng. 2015. Interspecific hybridization between Coreopsis leavenworthii and Coreopsis tinctoria affected progeny growth, development and reproduction differently. Journal of the American Society for Horticultural Science 140(1):27-37.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2015
Citation:
Wang, W., A. Palmateer, and Z. Deng. 2015. Evaluating the plant performance and downy mildew resistance of impatiens and New Guinea impatiens cultivars in central Florida. Abstract to the 128th Annual Meeting of the Florida State Horticultural Society, St. Augustine, FL, May 31-June 2, 2015.
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Progress 10/01/13 to 09/30/14
Outputs
Target Audience: Commercial floricultural businesses (growers, nurseries, and landscapers), county extension agents, and researchers, and interested general public. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? One PhD student and one MS graduate student were trained in 2014. The PhD student learned techniques for developing segregating caladium populations, conducting inheritance studies, determining nuclear DNA contents, counting chromosomes, analyzing karyotypes, etc. The MS student learned plant tissue culture techniques and how to conduct variety trials. How have the results been disseminated to communities of interest? The results produced from this project have been disseminated to interested growers, customers, and others through multiple channels, including more than several on-site demonstrations or field visits, public demonstrations and guided tours at the 2014 Florida Floriculture Field Days event and the 2014 FL AgExpo event, and extension publications at the University of Florida's extension website (http://edis.ifas.ufl.edu/). These extension publications are available to any interested party at almost any time. The University of Florida website has recorded nearly more than 8,500 website visit to the extension article on caladium and gerbera breeding and new cultivars. In addition, the results from this project were presented to researchers at the 2014 American Society for Horticultural Science annual meetings and the 2014 International Horticultural Congress, and published in HortScience, the Journal of the American Society for Horticultural Science, and the Plant Cell, Tissue and Organ Culture. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Develop and screen new caladium breeding populations: More than 100 populations totaling nearly 100,000 caladium progeny were screened first in the 128-cell planter trays and then in the caladium field. Nearly 3,000 new breeding lines have been selected based on their growth habit, leaf development, leaf color, and/or leaf coloration pattern. Replicated field and greenhouse trials of advanced caladium breeding lines: Thirty advanced caladium breeding lines were planted in the caladium field, in three blocks with 14 widely grown commercial caladium cultivars. The breeding lines were evaluated over 6 months for plant growth, plant performance, and sunburn tolerance. Ten of these lines were also tested in replicated greenhouse trials and their plant growth, leaf size, plant quality were compared to those of 12 widely grown commercial caladium cultivars. A number of advanced breeding lines performed better than commercial cultivars in containers and in ground beds, and have good potential to be released as new cultivars, upon growers’ request. Release new caladium cultivars: Based on plant performance and tuber yield in experimental plots as well as plant performance and tuber yield in growers’ fields, two advanced caladium breeding lines were selected and were released as new cultivars. ‘UF 432’ is a new lance-leaved caladium cultivar whose leaves are characterized with thick dark red to purple veins and a dark red to purple overtone. This cultivar is as productive as or more productive than ‘Florida Sweetheart’, currently the most widely grown lance-leaved caladium cultivar. ‘UF 432’ produces high quality pot plants like ‘Florida Sweetheart and performs very well in the landscape with excellent sunburn tolerance. ‘UF 4015’, also a lance-leaved cultivar, shares an overall plant growth habit with ‘Florida Red Ruffles’, currently the most widely grown red lance-leaved caladium cultivar, but is distinct with bright pink leaves and high tuber yield potential. Understand the natural variation among caladium species in genome size and chromosome number: The genome sizes (pg/2C) of 63 caladium accessions representing 10 caladium species were determined using flow cytometry. Subsequently the root tip cells of 39 caladium accessions were squashed to count chromosome numbers. Results showed that caladium genome sizes ranged from 2.98 pg/2C to 9.89 pg/2C and seemed to fall into two size groups (large and small). The average genome size of 36 caladium accessions in the large genome size group was 9.29 pg/2C, roughly twice that of the 27 accessions in the small genome size group (4.50 pg/2C). Microscopic examination of squashed root tip cells revealed seven somatic chromosome numbers among 39 caladium accessions, including 2n = 18, 20, 24, 26, 30, 34, and 38. Results support the species status of C. marmoratum, C. picturatum, and C. steudneriifolium that were merged into C. bicolor previously, and also support the species status of C. clavatum, and C. praetermissum, two species recently established in or transferred to Caladium. The results suggest that C. bicolor and C. schomburgkii, not C. picturatum or C. marmoratum, are the chief parents of the fancy-leaved caladium (C. ×hortulanum). Four caladium cytotype groups (CCG-1 to 4) were identified in scatter plot of chromosome number versus genome size. The genome size of C. bicolor, C. schomburgkii, and C. ×hortulanum in the CCG-4 is about twice that of C. humboldtii and C. picturatum in the CCG-2, and the chromosome number of C. clavatum and C. marmoratum in the CCG-3 is close to twice that of C. humboldtii and C. picturatum in the CCG-2, both suggesting possible genome duplication or tetraploidization events in Caladium. However, the chromosome number of the CCG-4 species does not correspond to an expected 2n = 36 or 40, and the genome size of the CCG-3 species does not correspond to an expected 8.98 pg/2C. Conflicts between genome size and chromosome number indicate that genome duplication events were likely followed by chromosome fusions/losses in the formation of CCG-4 species and DNA losses likely followed tetraploidization in the formation of the CCG-3 species. Induce and characterize tetraploids in caladium: Leaf segments of 'Tapestry' caladium were pre-cultured in vitro, treated with colchicine, and then cultured to regenerate tetraploid plants. Out of 501 established plants, 56 showed considerable variation from the wildtype in leaf shape, color, coloration pattern, and/or thickness. Ploidy analysis showed that 48 appeared to be tetraploids, and the remaining eight appeared to be diploids. In two treatments with 0.1% or 0.2% (w/v) colchicine for 4 days, 13.74% and 24.14% of the regenerated plants were tetraploids. Caladium tetraploids exhibited round and thick leaves with thick petioles. These morphological changes were a reliable morphological indicator for visual screening for tetraploids in caladium. Based on observed morphological changes, the eight diploid variants were categorized into five variant types (VT1 through VT5), and the 48 tetraploid variants were categorized into another five variant types (VT6 through VT10). Most caladium plants in VT1, VT2, VT3, VT6, and VT7 showed much improved ornamental values and held potential as promising new selections for container and landscape performance trials and tuber yield tests. Nuclear DNA content and chromosome number analysis were conducted on 17 representative variants; results revealed the two diploid variants had gained one or two additional chromosomes, one tetraploid variant gained four additional chromosomes, and two tetraploid variants lost two or four chromosomes. These results demonstrate that in vitro induction of tetraploids is a powerful tool for generating novel phenotypes for genetic improvement and breeding and that chromosome gain or loss is a common type of cytological variation in caladium. Determine the ploidy level and pollen stainability of commercial lantana cultivars: A polyploid series was identified among 32 Lantana camara cultivars and breeding lines. Male fertility, based on pollen stainability, varied widely among the cultivars/breeding lines. Ploidy level was the most important factor determining L. camara pollen stainability/male sterility. On average, diploids exhibited the highest pollen stainability (64.6%), followed by tetraploids (45.1%), pentaploids (34.6%), and hexaploids (18.0%). Triploids showed the lowest pollen stainability (9.3%), suggesting that generating triploids would be an effective genetic approach to producing sterile L. camara and reducing its pollen-mediated invasiveness. Pollen stainability of triploid cultivars, LandmarkTM Pink Dawn, Lemon Drop, Miss Huff, New Gold, New Red Lantana, Red Butler, Red Spread Lantana, Samson Lantana, and Sunset Lantana, was consistently below 10%. A number of triploid cultivars had pollen stainability approaching 20% to 30%, indicating a necessity for careful examination and screening of newly produced triploids to ensure high sterility in selected triploids. Pollen stainability variation was observed within ploidy levels, implying the existence of other genetic and environmental factors that influence the pollen stainability/male fertility of L. camara.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Cai, X., Z. Cao, S. Xu, and Z. Deng. 2014. Induction, regeneration and characterization of tetraploids and variants in Tapestry caladium. Plant Cell, Tissue and Organ Culture doi:10.1007/s11240-014-0636-8.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2014
Citation:
Cai, X., S. Xu, and Z. Deng. 2014. Induction, regeneration and characterization of tetraploids in caladium. The ASHS (American Society for Horticultural Science) Archived Conference Presentations https://ashs.confex.com/ashs/2014/webprogramarchives/Paper18832.html.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2014
Citation:
Cao, Z., Z. Deng, and M. McLaughlin. 2014. Genome size and chromosome number variation among Caladium species. PAG XXII (International Plant and Animal Genome Conference XXII .
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2014
Citation:
Cao, Z. and Z. Deng. 2014. Determining the genotype for and genetic distance between loci controlling caladium leaf spotting and main vein colors. The ASHS (American Society for Horticultural Science) Archived Conference Presentations https://ashs.confex.com/ashs/2014/webprogramarchives/Paper19045.html.
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Czarnecki II, D.M., A. Hershberger, C.D. Robacker, and Z. Deng. 2014. Ploidy level and pollen stainability of Lantana camara cultivars and breeding lines. HortScience 49:1271-1276.
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Deng, Z. and B.K. Harbaugh. 2014. Royal FlushTM UF-18-49 A red fancy-leaved caladium for large containers and sunny landscapes. HortScience 49 (8):1113-1115.
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Cao, Z., Z. Deng, and M. McLaughlin. 2014. Interspecific genome size and chromosome number variation sheds new light on species classification and evolution of Caladium (Araceae). Journal of the American Society for Horticultural Science 49(4):449-459.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2014
Citation:
Deng, Z., Z. Cao, and M. McLaughlin. 2014. Relationships among Caladium species: New insights from cytological and molecular marker analyses. The ASHS (American Society for Horticultural Science) Archived Conference Presentations https://ashs.confex.com/ashs/2014/webprogramarchives/Paper18667.html.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2014
Citation:
Wang, W. and Z. Deng. 2014. Induction and characterization of tetraploids and octoploids in impatiens (Impatiens walleriana). The ASHS (American Society for Horticultural Science) Archived Conference Presentations https://ashs.confex.com/ashs/2014/webprogramarchives/Paper19166.html.
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Progress 10/01/12 to 09/30/13
Outputs
Target Audience: Commercial floricultural businesses (growers, nurseries, and landscapers), county extension agents, and researchers, and interested general public. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? One graduate student was trained in 2013. The student learned techniques for developing and screening breeding populations, conducting greenhouse and field evaluations, and performing cytological studies. How have the results been disseminated to communities of interest? The results produced from this project have been disseminated to interested growers, customers, and others through multiple channels, including more than 10 on-site demonstrations or field visits, public demonstrations and guided tours at the 2013 Florida Floriculture Field Day event, and extension publications at the University of Florida's extension website (http://edis.ifas.ufl.edu/) and at the InTheField magazine website. These extension publications are available to any interested party at almost any time. The University of Florida website has recorded nearly 15,000 website visit to the extension article on caladium and gerbera breeding and new cultivars. In addition, the results from this project were presented to researchers at the American Society for Horticultural Science annual meetings and published in HortScience and the Journal of the American Society for Horticultural Science. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
1) Develop new caladium cultivars: More 100 large caladium breeding populations totaling more than 75,000 caladium progeny were created. The progeny were evaluated first in the greenhouse and then in the field. Multiple rounds of screening have resulted in the selection of approximately 3000 new caladium breeding lines. These lines will be further evaluated and screened in the next six years. Fifty advanced caladium breeding lines were trialed in the caladium breeding field as well as in growers production fields. At least two of these advanced breeding lines showed superior potential for release. 2) Develop new gerbera cultivars: Two new gerbera cultivars, UFGE 7031 and UFGE 7080, were released in 2013. Gerbera is one of the most important floricultural crops in the United States. Recently, interest in producing gerbera in large containers is increasing and there is a real lack of suitable cultivars for such use. UFGE 7031 and UFGE 7080 produce attractive flowers and quality plants with peduncle and plant heights appropriate for use in large containers. These cultivars share many plant and flower characteristics with the existing FuntasticTM series but offer two new flower colors, orange-red ray and disc florets (UFGE 7031) and yellow/orange ray florets with orange disc florets (UFGE 7080), respectively. Introduction of UFGE 7031 and UFGE 7080 can help expand the plant palette of the existing series. These cultivars also have shown a moderate to high level of resistance to powdery mildew, the most common and important disease in gerbera production and gardening. 3) Understand the mode of inheritance of important disease resistance traits: Powdery mildew (PM) caused by Podosphaera xanthii is the most common and destructive disease in gerbera production and landscape use. Gerbera breeding line UFGE 31-19 is one of the few sources of resistance to PM in gerbera and has contributed its resistance to new gerbera cultivars. To determine the mode of inheritance for PM resistance in UFGE 31-19, one of its PM-resistant progeny, UFGE 4033, was crossed with a PM-susceptible cultivar, Sunburst Snow White, and their progeny were evaluated for PM severity. Distribution of PM severity ratings among the progeny was continuous but with two peaks, suggesting that the PM resistance in UFGE 4033 and UFGE 31-19 is a quantitative trait. Conidia of P. xanthii inoculated on the leaf surface of UFGE 4033 germinated, formed secondary germ tubes, and formed appressoria at high percentages, similar to those on the leaf surface of ‘Sunburst Snow White’. However, P. xanthii hyphae branched significantly less, were significantly shorter, and produced substantially fewer conidia on the leaf surface of UFGE 4033 and its PM-resistant progeny than on the leaf surface of ‘Sunburst Snow White’. 4) Develop and apply molecular biotechnological tools: Molecular markers and bulked segregant analysis were used to identify molecular markers associated with PM resistance in gerbera breeding line UFGE 31-19. Eleven molecular markers were mapped to one genetic linkage group of gerbera, and two regions on the linkage group explained 71.1% of the phenotypic (PM severity rating) variance in a segregating population. The two regions were named Rpx1 and Rpx2 (resistance to P. xanthii).
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
Cao, Z., Z. Deng, and M. McLaughlin. 2013. Variation in nuclear DNA content and chromosome number among and within Caladium species. HortScience 48(9):S413.
- Type:
Book Chapters
Status:
Published
Year Published:
2013
Citation:
Deng, Z. Molecular markers in caladium: Development, characterization and applications. P214-227. In: K.G. Ramawat and J.M. Merillon (eds). Bulbous Plants Biotechnology. CRC Press, Boca Raton, FL, USA.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
Deng, Z. 2013. Breeding lance-leaved caladiums. HortScience 48(9):S137.
- Type:
Other
Status:
Published
Year Published:
2013
Citation:
Deng, Z. 2013. 'Fairytale Princess and Red Hot' Red lance-leaved caladium cultivars. University of Florida / IFAS, EDIS Extension Fact Sheet ENH1220 . 9 pages.
- Type:
Other
Status:
Published
Year Published:
2013
Citation:
Deng, Z. 2013. New gerbera daisy varieties for large containers and flower gardens. University of Florida / IFAS, EDIS Extension Fact Sheet ENH1221 . 8 pages.
- Type:
Other
Status:
Published
Year Published:
2013
Citation:
Deng, Z. 2013. Powdery mildew-resistant gerbera daisy. In the Field Magazine: 43 (October 2013).
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Deng, Z., and B.K. Harbaugh. 2013. UFGE 7031 and UFGE 7080 gerbera cultivars. HortScience 48(5):659-663.
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Deng, Z., B.K. Harbaugh, and N.A. Peres. 2013. UF 4412 and UF 4424 Red lance-leaved caladium cultivars. HortScience 48(2):239-244 (Cover page).
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
Deng, Z., X. Song, and L. Gong. 2013. Development and application of molecular markers in gerbera (Gerbera hybrida). Plant & Animal Genome XXI International Plant & Animal Genome Conference, 12-16 January 2013, San Diego, California https://pag.confex.com/pag/xxi/webprogram/Paper7135.html.
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Song, X. and Z. Deng. 2013. Powdery mildew resistance in gerbera: Mode of inheritance, quantitative trait locus identification, and resistance responses. Journal of the American Society for Horticultural Science 138(6):470-478.
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Progress 10/01/11 to 09/30/12
Outputs
OUTPUTS: (1) Developing new caladium breeding populations: Five commercial cultivars and more than 20 new breeding lines were cross-pollinated in approximately 120 combinations. More than 100,000 seeds were produced, and more than 35,000 new progeny were produced. (2) Evaluating advanced caladium breeding lines: 78 advanced caladium lines were evaluated in the field for plant growth, landscape performance, sun tolerance, and tuber yield. The most promising lines have been selected for 2013 trials. (3) Replicated garden trials were performed to compare the tolerance of 11 advanced breeding lines and 11 commercial cultivars to full sun and shading, respectively. Significant differences in plant growth and performance were observed among breeding lines and varieties in response to shading. (4) Screening caladium breeding lines for improved disease resistance: Tubers of 34 advanced caladium breeding lines were inoculated with Fusarium solani, and root balls of 32 advanced caladium breeding lines were inoculated with Pythium myriotylum. The tolerance of these caladium lines to the two diseases was assessed. A number of caladium lines were found to be resistant to Fusarium tuber rot and moderately resistant to Pythium root rot. (5) Caladium cultivar introduction: UF 4412 and UF 4424 were released in 2012. In replicated field and greenhouse trials, they were comparable or superior to Florida Red Ruffles and Florida Sweetheart (the most popular red lance-leaved commercial cultivar and the most popular lance-leaved cultivar in all colors, respectively) in tuber yield potential, pot plant quality, and landscape performance. Both cultivars are suited for producing pot plants and hanging baskets, and de-eyeing is not required for forcing in small or medium-size containers. (6) Induction and characterization of tetraploid nandina: Approximately 10 new nandina tetraploids were induced by applying colchicine germinating seeds. All together nearly 20 solid tetraploid nandina plants have been obtained. The most of the nandina tetraploids seem to be highly female fertile. (7) Developing new gerbera breeding populations: More than 7,000 new progeny were produced. They are being screened for powdery mildew resistance. (8) Eight advanced breeding lines were evaluated in two replicated trials for plant growth, flowering, flower count, flower characteristics, and powdery mildew resistance. Two advanced lines have been selected as new releases. (9) Developing EST-SSR markers for use in gerbera: 115 pairs of primers were designed from SSR-containing expressed sequence tags in the GenBank database; 99 pairs of the primers amplified discrete PCR products. Each pair of primers detected 2 to 6 alleles in gerbera. Further analysis identified 53 robust, informative markers. SSR marker analysis suggests that commercial gerbera cultivars could be grouped into two clusters largely corresponding to breeding approach and/or propagation methods. (10) Cloning and characterizing resistance gene candidate sequences in gerbera: 84 resistance gene candidate sequences were identified from cloned PCR products amplified from powdery mildew-resistant gerberas. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Caladium is an important crop to greenhouse growers and widely used by landscapers and home gardeners. The caladium cultivars released from this project (UF 4412 and UF 4424) produce attractive leaves, have a growth habit very suitable for pot plant production and landscape use, and possesses superior sun tolerance. These cultivars should be very valuable to growers and consumers for them to expand their plant palette. Gerbera is one of the most important flowers in the United States. Interest in growing gerberas in large containers for indoor or outdoor use has been increasing. Two advanced breeding lines have been selected for release. With their good level of powdery mildew resistance, they are expected to perform well in large containers (as well as landscapes). The development of highly specific, very discriminative SSR markers will be very useful for fingerprinting commercial gerbera cultivars, understanding genetic relationships, and protecting breeders rights. The resistance gene candidate sequences should provide a valuable entry point to obtain full-length nucleotide-binding site-leucine-rich repeat class gerbera disease resistance genes. Nandina is a very important landscape plant in the United States, but it has escaped cultivation in the southeastern United States and Hawaii. The primary determinant of nandina's invasive potential is its prolific seed production. Results from this project indicate that seed production can be reduced by greater than 90% through tetraploid induction. The obtained tetraploids will be extremely valuable for developing highly sterile, non-invasive nandina cultivars.
Publications
- Deng, Z. 2012. Summer Pink - A new pink fancy-leaved caladium variety. University of Florida/IFAS, EDIS Extension Fact Sheet ENH1200. . 4 pages.
- Deng, Z. 2012. Strawberry Star - A spotted, fancy-leaved caladium for use in containers and landscapes. University of Florida/IFAS, EDIS Extension Fact Sheet ENH1201. . 5 pages.
- Deng, Z. and B.K. Harbaugh. 2012. Summer Pink - A new pink fancy-leaved caladium. HortScience 47(5):672-674.
- Gong, L. and Z. Deng. 2012. Selection and application of SSR markers for variety discrimination, genetic similarity and relation analysis in gerbera. Scientia Horticulturae 138:120-127 (http://dx.doi.org/10.1016/j.scienta.2012.02.020).
- Song, X., Z. Deng, L. Gong, J. Hu, and Q. Ma. 2012. Cloning and characterization of resistance gene candidate sequences and molecular marker development in gerbera (Gerbera hybrida). Scientia Horticulturae 145:68-75 (http://dx.doi.org/10.1016/j.scienta.2012.07.027).
- Deng, Z. 2012. Fancy-leaved caladium varieties recently introduced by the UF/IFAS caladium breeding program. Abstracts of the 2012 Meeting of the Florida State Horticulture Society, page 27.
- Song, X. and Z. Deng. 2012. Disease resistance gene candidate sequences in gerbera: Cloning, characterization and utilization for molecular marker development. HortScience 47(9) (Supplement): S197.
- Song, X., Z. Deng, and J. Hu. 2012. Inheritance study and molecular marker development for powdery mildew resistance in gerbera. HortScience 47(9) (Supplement): S198.
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Progress 10/01/10 to 09/30/11
Outputs
OUTPUTS: (1) Evaluating advanced caladium breeding lines: A total of 118 advanced caladium lines were evaluated in the field for plant growth, landscape performance, sun tolerance, and tuber yield. The most promising 22 lines are selected for 2012 trials. Replicated garden trials were performed to compare the tolerance of 13 advanced breeding lines and 8 commercial varieties to full sun and shading, respectively. Results indicate significant variations among breeding lines in response to shading. Twenty advanced caladium breeding lines were inoculated with Fusarium solani (causal agent of caladium Fusarium tuber rot) and Pythium myriotylum (causal agent of caladium Pythium root rot), respectively, and the relative tolerance of these caladium lines to the two diseases were evaluated. A number of caladium lines appeared to be much less susceptible to Fusarium tuber rot and or Pythium root rot. (2) Caladium cultivar introduction: UF44-4 released in April 2011 is an attractive lance-leaved cultivar with a novel combination of leaf characteristics (bright red color, slightly undulate and rounded leaf shape). In replicated field and greenhouse trials, it was comparable or superior to Florida Red Ruffles and Florida Sweetheart (the most popular red lance-leaved commercial cultivar and the most popular lance-leaved cultivar in all colors, respectively) in tuber yield potential, pot plant quality, and landscape performance. UF 44-4 is well suited for producing pot plants and hanging baskets, and de-eyeing is not required for forcing in small or medium-size containers. (3) Induction and characterization of tetraploid gerbera: More than 10 tetraploid gerbera breeding lines were obtained by treating seedlings with chromosome doubling agents. Tetraploid gerberas showed significant changes in morphology and pollen stainability. (4) Induction and characterization of tetraploid nandina: Two chemicals were used to treat three types of nandina plant materials. None of the treatments with oryzalin applied to in vitro cultured nandina shoots or shoot tips of pot plants produced polyploids. Colchicine, applied to growing shoots or germinating seeds, resulted in chromosome doubling. Strong diplontic selection was observed in colchicine treated plants and it caused rapid losses of tetraploid cells in shoot tips. Effective treatments have been applying colchicine to germinating seeds. More than a dozen of solid tetraploid nandina plants have been obtained. Compared to diploids, tetraploid nandina plants appear to be shorter and narrower in size, have shorter internodes and thicker stems, and have narrower and smaller leaves. Tetraploids had slightly lower pollen stainability than diploids. The most obvious difference between tetraploids and diploids appears to be in female fertility: with tetraploids having much lower fruit set than diploids. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Caladium is an important crop to greenhouse growers and widely used by landscapers and home gardeners. The caladium cultivar released from this project produces attractive leaves, shows a growth habit very suitable for pot plant production and landscape use, and possesses superior sun or shade tolerance. This cultivar should be very valuable to growers and consumers for them to expand their plant palette. Gerbera is one of the most important flowers in the United States. Interest in growing gerberas in large containers for indoor or outdoor use has been increasing. The tetraploid gerbera lines may offer novel strategies to produce new cultivars suitable for use in large containers. Nandina is a very important landscape plant in the United States, but it has escaped cultivation in the southeastern United States and Hawaii. The primary determinant of nandina's invasive potential is its prolific seed production. Results from this project indicate that seed production can be reduced by greater than 90% through tetraploid induction. The obtained tetraploids will be extremely valuable for developing highly sterile, non-invasive nandina cultivars.
Publications
- Dabreau, M.D., Z. Deng, R. Rixom, and D. Schwaninger. 2011. Rain lilies for central Florida. HortScience 46(9): S353.
- Deng, Z. and B.K. Harbaugh. 2011. UF 85-5 - A spotted caladium cultivar for use in containers and sunny landscapes. HortScience 46(9):1326-1329.
- Deng, Z. and B.K. Harbaugh. 2011. UF 44-4 - A dwarf red lance-leaved caladium cultivar. HortScience 46(7):1049-1051.
- Deng, Z., B.K. Harbaugh, and N.A. Peres. 2011. UF-172, a pink fancy-leaved caladium cultivar for large containers and landscapes. HortScience 46(1):132-134.
- Deng, Z., S.M. Smith, G.W. Knox, and S.B. Wilson. 2011. Induction and characterization of tetraploids in nandina. HortScience 46(9): S169.
- L. Gong and Z. Deng. 2011. Development and characterization of microsatellite markers for caladium (Caladium Vent.). Plant Breeding (doi:10.1111/j.1439-0523.2011.01863.x).
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