2007 Annual Report 1a.Objectives (from AD-416) Develop new raisin grape cultivars for mechanical harvest and evaluate existing raisin selections in the breeding program to determine their commercial potential. 1b.Approach (from AD-416) Standard sexual hybridization will be used to combine traits between seedless raisins and in some instances seeded parents will be used for traits not found in seedless germplasm. Embryo rescue will be used to recover plants from seedless parents. Plants will be evaluated in the field for fruit and vine characteristics. Selected individuals will be put in six vine plots to test production and raisin quality. Cultivars with good raisin quality that ripen early and that can be mechanical harvested will be released to the industry. Documents Trust Agreement with California Raisin Marketing Board. Log 24131.Formerly 5302-21220-003-12T (10/03). 3.Progress Report This report serves to document joint research conducted under a Trust Agreement between ARS and the California Raisin Marketing Board for research on the development of new raisin grape cultivars, including types resistant to powdery mildew. 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. Early ripening raisin grapes are needed that dry before damaging fall rains occur and lend themselves to mechanical harvest. A total of 309 seedlings developed from 9 seedless x seedless crosses were planted in the field. Nine new seedless x seedless crosses resulted in 2,653 ovules, 745 embryos and 396 plants. Four seeded crosses produced 878 seed. A total of 241 raisin selections with natural dry-on-the-vine (DOV) potential were evaluated. Of these, 19 new selections were propagated and added to the 128 selections already in the natural DOV advanced test plot. The three best natural DOV selections fruited for the fifth year in the advanced DOV plot. Their fruit was harvested October 18, 2006 with a moisture range from 12.2 to 18.1%. The best selection, B82-43 yielded 8.4 and 7.8 Kg per vine for spur and cane pruned respectively. It averaged 16.8 % moisture at harvest and graded 90.1% B or Better and 3.8% Sub Standard. Powdery mildew is the most important fungal disease attacking grapes in California. Powdery mildew resistant raisin grape varieties are needed to reduce the need for chemical control. From two advanced no-spray plots, 215 selections were evaluated and 49 were resistant to powdery mildew on leaves, stems, rachis and fruit. Six seeded x seedless crosses produced 3,095 seed which are being screened for resistance in the greenhouse. The project is monitored by the ADODR through active involvement in the day-to-day research activities, and through regular on-site scheduled meetings with the Cooperator and interested stakeholders.