Location: Crop Diseases, Pests and Genetics
2011 Annual Report
This research contributes to development of table grape seedling populations to develop table grape cultivars requiring reduced cultural input with large seedless red, white or black fruit ripening from early to late in the season and with powdery mildew resistance. This project also provides support for evaluation of seedlings and testing of various cultural treatments on advanced selections.
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 35 seedless x seedless and 27 seeded x seedless crosses using a total of 57,373 and 36,313 emasculations respectively, were made. Over 294 mildew resistant table grape seedlings from 26 families screened for powdery mildew-resistance in the greenhouse were planted in the field. The 238 advanced selections in no-spray plots were evaluated in August and September, with 100 selections free of PM. Ninety-eight advanced selections were evaluated in the laboratory and 29 noted for use as parents based on fruit quality and resistance. Eleven new selections were added to the advanced no spray plots for use as parents. One PM resistant table grape selection is fruiting in the 27 vine advanced trial. This mid-season white seedless grape has firm, 5.4 g berries, and small seed traces the size of Thompson Seedless. There is a continued need for improve red, white and black seedless table grape cultivars that ripen early to late in the season. More than 132 table grape in vitro-derived seedlings from 20 seedless x seedless crosses were planted in the field. Thirty-five seedless x seedless crosses were made using a total of 78,307 emasculations. Eight new seedless grape selections (3 red, and 5 white) were propagated into 27 vine advanced trials. Cultural trials were made on 10 advanced selections and 11 cultivars.