Location: Crop Diseases, Pests and Genetics
2012 Annual Report
We developed table grape seedling populations for use in the development of table grape cultivars with the following characteristics; reduced cultural input, large seedless red, white or black fruit ripening in a sequence from early to late in the season, and powdery mildew resistance.
Powdery mildew (PM) resistant table grape cultivars will reduce the need for chemical control. Modified backcrosses were continued to combine high fruit quality table selections with the best powdery mildew (PM) resistant selections. A total of 27 seedless x seedless crosses were made using a total of 49,714 emasculations. Twenty-six families representing five sources of resistance were screened in the greenhouse and only resistant seedlings planted in the field. The 252 advanced selections in no-spray plots were evaluated in August. Eighty-six selections remained free of PM after three years. Twenty new selections based on fruit quality and resistance were added to the advanced no spray plots for use as parents. One PM resistant table grape selection with mid to late-season red seedless fruit was added to the 27 vine advanced trial. There is a continued need for a series of improved red, white and black seedless table grape cultivars that ripen from early to late in the season. More than 748 table grape in vitro-derived seedlings from 35 seedless x seedless crosses were planted in the field. Thirteen seedless x seedless crosses were made using a total of 36,237 emasculations. Nine new seedless grape selections (4 red, 2 white and 1 black) were propagated into 27 vine advanced trials. Cultural trials were conducted on 15 advanced selections to determine commercial potential in comparison with 8 commercial cultivars.