2007 Annual Report 1a.Objectives (from AD-416) Determine the adaptability of USDA advanced table grape selections and varieties to the climatic conditions of the grape production region in the Coachella Valley of California. Emphasis will be placed on tolerance of the fruit during development to heat, the uniformity of bud break and flowering with and without Dormex, and timing of maturity based on standard commercial varieties. 1b.Approach (from AD-416) Seven USDA advanced table grape selections and varieties planted on a standard gable trellis will be evaluated using three treatments. The treatments consist of: 1. the best commercial cultural treatments determined from trials in Fresno; 2. the best commercial cultural treatments plus Dormex; and 3. No cultural treatments, but crop load adjustments will be made to equal those in treatment 1 and 2. Data will be collected to determine: uniformity of bud break and flowering; amount of heat damage on fruit; maturity time in relation to commercial cultivars; color development in red skin grapes; production and fruit quality. Documents Trust with California Table Grape Commission. 3.Progress Report This report serves to document joint research conducted under a Trust Agreement between ARS and the California Table Grape Commission for research on the evaluation of USDA advanced table grape selections in the Coachella Valley. Additional details of research can be found in the report for the parent project 5302-21220-004-00D Improvement of Prunus and Vitis Scion and Rootstocks for Fruit Quality and Pest Resistance. Table grape varieties are needed that are economically profitable, productive and resistant to heat damage under the hot desert climatic conditions of the Coachella Valley. The varieties currently grown require Dormex for uniform and early bud break, which can reduce production. Varieties can be sensitive to heat, especially when treated with gibberellic acid and girdled to increase berry size. Three early white, 2 mid-season red, and 2 late season white seedless grape selections with 3 check varieties were planted in 2004. Since planting this trial, the two mid-season red and one late season white selections have been named. The Dormex treatment developed earlier bud break and more uniform bud break than without Dormex. Heat damage was not significant and was not increased this year by either the cultural treatment or Dormex, except in Thompson Seedless where a girdle increased heat damage. Two of the early white seedless selections had small berries that were not commercially acceptable and were discarded from this trial. One early white and one mid-late season white selection had favorable production and fruit quality and will be continued in the trial. Flame Seedless and Sweet Scarlet developed excellent red color when Ethrel was applied. One new mid to early season red seedless selection was added to the planting this year for evaluation. The project’s activities and performance were monitored through meetings with the research committee of the California Table Grape Commission, and through four working meetings with the University of California co-principal investigator.