|Walker, Andrew - UC, DAVIS|
Submitted to: CDFA Pierce's Disease Control Program Research Symposium
Publication Type: Proceedings
Publication Acceptance Date: September 25, 2006
Publication Date: November 13, 2006
Citation: Ramming, D.W., Walker, A.M., Lin, H. 2006. Breeding Pierce's Disease Resistant Table and Raisin Grapes and the Development of Markers for Additional Sources of Resistance. 2006 CDFA Pierce's Disease Control Program Research Symposium. p. 298-300. Interpretive Summary: The spread and severity of Pierce’s disease has been 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 introgressed into high quality table and raisin germplasm by hybridizing different sources of Pierce’s disease resistance. This year 25 cross combinations were made and plants are being produced. Over 120 selections with good fruit quality from previous crosses have been made and are ready to be tested for resistance to Pierce’s disease in the greenhouse. Molecular markers have been used to identify 72 resistant seedlings in three families from the V. arizonica source of resistance. This germplasm provides the basis for developing Pierce’s disease resistant table and raisin grape varieties for California. DNA has been extracted from a family derived from a Southeastern United States source of Pierce’s disease resistance. A molecular map will be produced to develop markers associated with resistance. Selection of resistant seedlings will be easier with molecular markers from this source of resistance.
Technical Abstract: This year six crosses for Pierce's disease (PD) resistant table and raisin grapes using seedless parents were made, resulting in 2,398 ovules and 747 embryos. These crosses were based on Muscadinia and V. tiliifolia sources of resistance. Nineteen seeded crosses consisting of 3,950 emasculations and 49 bagged clusters were made. These crosses were based on V. arizonica, Muscadinia, and SEUS sources of resistance. Over 120 selections have been made based on fruit quality and are ready for greenhouse screening for resistance to PD. Two BC2 families from 89-0908 V. arizonica source of resistance segregated in a 1:1 ration for resistance:susceptibility, based on molecular markers associated with the PdR1 locus. A smaller family from the same source of resistance had unexpectedly small number of resistant seedlings. DNA samples have been collected from 154 seedlings from the C33-30 x BD5-117 family and are ready for SSR marker analysis. Additional seedlings are being produced to increase the probability of identifying markers associated with this source of resistance.