Recipient Organization
UNIVERSITY OF FLORIDA
G022 MCCARTY HALL
GAINESVILLE,FL 32611
Performing Department
Gulf Coast Research and Education Center
Non Technical Summary
The UF/IFAS strawberry breeding program develops varieties that are adapted to the climate and market needs of the Florida strawberry industry. Genetics and cultural practice research will inform breeding practices to develop varieties with the best combinations of traits and ultimately that succeed in the market and in growers fields.
Animal Health Component
65%
Research Effort Categories
Basic
5%
Applied
65%
Developmental
30%
Goals / Objectives
1. Enhance UF strawberry germplasm and release commercially successful cultivars2. Identify and breed for chemical constituents of flavor3. Identify and breed for resistance to diseases4. Develop and implement genomics-assisted breeding methodologies5. Examine interactions between genetics and cultural practices
Project Methods
Each year 75-100 biparental crosses are made in the UF strawberry breeding program and up to 15,000 seedlings and 600 advanced selections are evaluated weekly during the strawberry season. These crosses are primarily within the elite germplasm pool and are designed to result in seedlings of potential commercial quality. Additional crosses are made to introgress genetics from wild species and cultivars outside the program, in order to maintain genetic diversity and harness new traits.Germplasm exchange agreements havebeen established with the Queensland Australia government breeding program, USDA breeding program in Beltsville, MD, and a government breeding program in Japan. Seed, pollen and clonal germplasm will be shared via these agreements and crosses made to introgress traits of interest.Large chemical-sensory studies will be performed to identify volatile organic compounds that are the most important contributors to sweetness, flavor and ultimately consumer liking. These studies will in turn drive genetic studies for understanding the genetic control of these compounds. Simultaneously, UF germplasm, other elite germplasm worldwide, and wild accessions are being screened for the presence of unique flavor volatiles. Both consumer and trained sensory panels will be utilized.For well-characterized disease resistances, we will continue to perform inoculated trials of advanced selections each season to validate marker results and provide high quality information to inform selection decisions. These will be performed in collaboration with Dr. Natalia Peres. Since powdery mildew resistance is polygenic, we will primarily utilize genomic selection methodologies to improve resistance to this disease. For some other diseases there is still a need to identify resistance loci. For resistance to charcoal rot caused by Macrophomina phaseolina, three resistance loci have been discovered. Further work will 1) determine the effects of the loci singly and in combination and 2) identify new loci/alleles from novel resistance sources. Because there are no effective post-fumigation controls for this disease, these activities are of high importance. Therefore, both advanced selection and seedling inoculated trials will be performed for this disease. For Neopestalotiopsis spp., work will focus on finding and characterizing sources of resistance. A new and more aggressive strain of this fungus has very recently emerged in Florida strawberries that represents a grave threat to the industry. Germplasm screening and backcrossing of resistance sources will become a priority in the program over the next few years.The development of genomics-assisted breeding strategies is a priority for the program, both for simply inherited traits and for polygenic traits. For polygenic traits, genomic prediction is the method of choice. We will continue to develop this methodology for both parent and seedling selection. Genome-wide markers from SNP arrays are routinely assayed on all advanced breeding selections and analyzed together with phenotypic data from multi-year trials for traits such as yield, soluble solids content and fruit size. Breeding values are estimated for every individual in the breeding program and used to inform parent selection decisions. Methodology for Bayesian model estimation will continue to be developed for this purpose. Lower-cost, lower-density genotyping platforms will be developed to facilitate seedling genomic selection.For simply inherited traits, we will continue to collaborate actively with the lab of Dr. Seonghee Lee for DNA test development and application. Markers will be developed for charcoal rot resistance loci and any other loci discovered in the future. In addition, existing markers will be improved for ease of scoring and accuracy. Functional markers will be developed when candidate genes are identified within any relevant locus. Our two programs will continue to partner together to assay these markers on tens of thousands of seedlings each spring.Research on the interactions of cultural and genetic factors will be carried out in collaboration with Dr. Shinsuke Agehara. Advanced selections slated for release will be tested in comparison with industry standard cultivars for various management practices as appropriate, including nitrogen rates, in-row spacing, planting dates and plastic mulch colors. Differences in plant growth and yield will be evaluated over repeated time points across seasons for all traits evaluated. Both yield and fruit quality attributes, such as soluble solids content, will also be measured. From these results, cultivar-specific management practices and recommendations will be developed.