|Walker, Andrew - UC DAVIS|
Submitted to: CDFA Pierce's Disease Control Program Research Symposium
Publication Type: Proceedings
Publication Acceptance Date: October 27, 2008
Publication Date: December 15, 2008
Citation: Ramming, D.W., Walker, A., Lin, H. 2008. Breeding Pierce’s disease resistant table and raisin grapes and the development of markers for additional sources of resistance 2008. CDFA Pierce's Disease Control Program Research Symposium. Pg. 235-238. Interpretive Summary: The spread and severity of Pierce’s disease(PD)has increased with the introduction of the glassy-winged sharpshooter into California. The table and raisin grape varieties grown in California are very susceptible to Pierce’s disease. Resistance is being added to high quality table and raisin germplasm by hybridizing with different sources of Pierce’s disease resistance. This year 22 seedless cross combinations were made and plants are being produced. Molecular markers have been used to identify 363 resistant seedlings from over 1,000 seedlings in 14 families from the V. arizonica source of resistance. Greenhouse screening for resistance was completed on 57 selections and 20 of the 21 resistant individuals were from V. arizonica. Resistant selections have been planted in the field at Weslaco, Texas to determine their field resistance compared to greenhouse results. This germplasm provides the basis for developing Pierce’s disease resistant table and raisin grape varieties for California which will make it possible to keep the table and raisin grape industries viable in PD infested areas. Work to develop a framework map to identify molecular markers associated with PD resistance from a Southeastern United States source of Pierce’s disease resistance is continuing. Greenhouse screening of 75 seedlings showed 21 were resistant. A total of 105 SSR primers were found to be polymorphic between the parents and screening of the first 154 individuals to develop a framework map has started. Over 300 individuals are now available in this family for marker development. The development of molecular markers associated with PD resistance will make selection of resistant seedlings easier and more efficient.
Technical Abstract: Twenty-two seedless x seedless crosses to develop additional BC2 and BC3 V. arizonica and BC1 SEUS BD5-117 families were made in 2008. Powdery mildew resistance was included in five of these crosses. These crosses produced 5,148 berries, 8,824 ovules and 1,861 embryos. Nine seeded BC1 crosses based on V. arizonica and SEUS PD resistance sources were made, resulting in 1,393 seed. Two BC2 and 12 BC3 families (V. arizonica source of resistance) consisting of 1,191 individuals were screened at the seedling stage in the greenhouse with SSR markers for resistance. A total of 363 were resistant and planted in the field. Greenhouse screening was completed on 57 selections and 20 of the 21 resistant individuals were from V. arizonica. Twelve resistant selections have been planted in the field at Weslaco, Texas to determine their field resistance. An additional 89 plants and 692 embryos have been produced to increase the size of the C33-30 x BD5-117 family for molecular maker development. A total of 105 SSR primers are polymorphic between the parents and screening of the first 154 individuals to develop a framework map has started. Greenhouse testing of 75 individuals was completed with 21 being resistant. An additional 49 are currently in greenhouse tests.