2013 Annual Report
1a.Objectives (from AD-416):
We will expand close working relationships among breeders, extensionists, and growers of major Alliums in the U.S. to evaluate germplasms for prioritized pest resistances (thrips and Iris Yellow Spot Virus) and lay the foundation for the long-term translational genomics of the Allium vegetables. Workshops will be held at regional onion meetings.
We will evaluate in the field onion populations for resistance or tolerance to thrips and Iris Yellow Spot Virus. Resistance or tolerant germplasms will be released to the onion breeders in the public and private sectors.
1b.Approach (from AD-416):
Work with extension professionals to empower growers to complete on-farm evaluations for resistances or tolerances to thrips and Iris Yellow Spot Virus. Self-pollinate and testcross selected plants and return seed for validation of phenotypes; Deliver validated germplasms to private and public sector breeders; Develop workshops for public and private-sector researchers, students, and regional grower and consumer groups for onion to illustrate the usefulness of genomics to solve high-priority research goals.
This is the final report for project 3655-21000-048-13A, terminated 12/31/2012. In 2009 and 2010, plant introduction (PI) accessions from the United States (US) germplasm collection, commercial cultivars, and experimental breeding lines of onion were evaluated in field plots for the number of thrips per plant, leaf color, leaf waxiness, Iris yellow spot (IYS) disease symptoms, and bulb yield. Individual plants that exhibited few IYS disease symptoms were selected at bulb maturity in both years. These bulbs were self-pollinated and testcrossed to male-sterile lines for re-evaluations in field plots. Individual plants from these families that exhibited fewer IYS disease symptoms at bulb maturity were selected and seed produced. Therefore, 59 unique lines have received two cycles of selection for resistance to IYS. These 59 lines originated from 34 first generation selections that in turn originated from 16 unique sources that were first evaluated during the summer of 2009. Foliage characteristics were identified associated with onion thrips non-preference, suggesting that there is genetic potential for reduced thrips feeding and possibly reduced Iris yellow spot virus (IYSV) spread. Germplasm were also identified that exhibited less severe IYS disease symptoms than most entries, which may indicate that a genetic source of increased IYS tolerance may exist. Seed of numerous selected lines has been produced and will be distributed to onion breeders in the public and private sectors for use in their breeding programs.
This research relates to Objective 1, Determine the genetic basis of and initiate selection for carrot, onion, cucumber, and melon quality attributes influencing human nutrition and health, disease resistances, and yield and quality components, and stress tolerance in cucurbits, and perform field performance and quality trials and Objective 2, Utilize current biotechnology to discover and evaluate genetic variation and to map agriculturally important traits in Allium, Cucurbit, and Daucus germplasm, and to develop genetic and breeding stocks.