Location: Southern Horticultural Research Unit
Project Number: 6062-21000-011-000-D
Project Type: In-House Appropriated
Start Date: Feb 6, 2023
End Date: Feb 5, 2028
Objective:
1. Discover and characterize superior traits from natural collections, mutants, and interspecific populations to enhance stress tolerance in woody ornamental species, such as Hibiscus.
1.A. Generate genetic information and characterize the genetic diversity and population structure of important ornamental species.
1.B. Characterize and develop improved germplasm with superior ornamental value and wide adaptation to prevalent conditions in southeastern U.S.
1.C. Use phenotypic and genomic tools to identify quantitative trait loci and candidate genes associated with important traits in Rosa and Weigela.
2. Develop and use novel tissue culture and transformation systems to improve key horticultural traits of blueberry, muscadine grape, and woody ornamental plants.
2.A. Develop a regeneration and transformation system to improve Hibiscus mutabilis.
2.B. Develop new germplasm of muscadine grapes using induced mutation, invitro ploidy manipulations, and wide hybridization.
3. Dissect the genetics and environmental factors affecting fruit quality and adaptation traits in blueberry and muscadine grape.
3.A. Use genomics resources to discover genomic regions associated with fruit quality and adaptation traits in blueberry.
3.B. Dissect the genetics and environmental factors affecting fruit quality and adaptation traits in muscadine grape.
4. Use conventional and genomic technologies to breed improved blueberry cultivars with excellent flavor and broad adaptation to biotic and abiotic stresses.
4.A Use interspecific hybridization to introduce useful genetic variability, incorporate adaptation traits into existing germplasm, and develop new rabbit-eye cultivars.
4.B Establish field trials and develop and implement effective breeding system for rapid development of improved blueberry germplasm.
Approach:
Genetic diversity in Weigela. A diverse population will be characterized for horticultural traits and genotyped. Population structure, principal components, and phylogenetic analyses will be performed to assess the structure of the diversity. Principal component analysis will be performed to investigate the relationships among trait variables and the factors underlying genotype variation.
Comparative genomics of Hibiscus species. 27 genotypes from nine Hibiscus species will be sequenced using different sequencing platforms. The pan-genomes will be assembled, annotated, and phylogenetic analyses will be performed to determine the relationship between tested species.
Induction of mutation and polyploidy in Weigela. Vegetative buds from mature plants of four Weigela species and three concentrations of colchicine solution and three durations will be used in meristem culture in modified Murashige and Skoog media for the induction of polyploidy.
GWAS of important traits in Rosa. A diverse panel of 125 Rosa genotypes will be evaluated for different horticultural traits and genotyped. The SNPs data will be used to analyze the genetic diversity and locate genomic regions associated with important traits.
Develop a regeneration and transformation system to improve Hibiscus mutabilis. Agrobacterium rhizogenes transformation will be performed and gene construct containing the gene of interest and selectable marker will be used. PCR or RT-PCR test will be conducted on putative transgenic microshoots and hairy roots to select stably transformed plants.
Generation of interspecific grape hybrids. For this purpose, 14 reciprocal crosses between V. rotundifolia and seven accessions of V. mustangensis will be performed. In addition, 36 reciprocal crosses between, V. rotundifolia and nine Vitis species will be performed. F1 seeds will be soaked for 3 days in various concentrations of oryzalin to induce polyploidy. Phenotypic observations by means of visual observations, leaf thickness, and flow cytometry will be used to identify the interspecific hybrids.
Map genomic regions associated with important traits. A diverse panel of 264 SHB genotypes will be characterized for phenology and fruit quality traits and genotyped using the 3,000 DArT array platform. GWAS analysis and linkage mapping will be performed to identify genomic regions associated with traits of interest.
Dissect the genetics and environmental factors affecting fruit quality and adaptation traits in muscadine grapes. Parents and 516 individuals will be characterized for different fruit quality traits and resistance to Pierce’s disease. GBS will be used to genotype the individuals and data will be used in QTL analysis.
