Location: Crop Diseases, Pests and Genetics
2010 Annual Report
This funding and research contributes to development and evaluation of grape seedling populations and advanced selections with the goal of improving table and raisin grape germplasm with resistance to PD. The project is also developing new molecular markers based on a family from a complex background of PD resistance.
PD-resistant table and raisin grape varieties are needed to overcome increased incidence of PD as a result of the introduction of glassy-winged sharpshooter. Fruit quality of resistant varieties needs to be equivalent to varieties currently grown to be commercially acceptable. Progress in making additional backcross generations to combine high quality table and raisin grapes with PD resistance is continuing. An example of increased fruit quality is this year’s selection of five raisin grapes made from BC3 V. arizonica x V. vinifera families which were propagated into production trials. An additional fifteen BC2 V. arizonica x V. vinifera raisin selections were propagated into production trials. Thirty-nine seedless x seedless crosses to develop additional BC3 and BC4 V. arizonica x V. vinifera families were made. The crosses required 69,884 emasculations. Powdery mildew resistance was combined with PD resistance in 18 additional crosses of 40,122 emasculations. Molecular markers were used to detect Pierce's Disease resistant individuals at the young seedling stage in test tubes for one BC2, nine BC3 and 19 BC4 families from crosses made in 2009. A total of 392 of 910 seedlings were rated resistant and planted in the field. Greenhouse screening for Pierce's Disease resistance was continued to verify that plants with PD resistance markers are indeed resistant.