Progress 08/18/10 to 05/30/11
Outputs
Progress Report Objectives (from AD-416) To identify groups of remaining pure examples of Vitis californica and V. girdiana using molecular markers and to define genetic diversity within these species. Selecting vines from different subpopulations will maximize the genetic diversity with the fewest accessions introduced into the NPGS. Approach (from AD-416) The study will include 51 accessions of V. californica and V. girdiana vines currently maintained by the Department of Viticulture and Enology at UC Davis. Additionally, 50 vines of wild V. californica (selected based on phenotype) will be collected from the wild in diverse geographic areas in California isolated from V. vinifera cultivation. Genetic profiles will be generated for 20 or more previously described Simple Sequence Repeat (SSR) markers cloned from V. vinifera and V. riparia. These will include six markers known to be associated with resistance to Pierce�s disease, powdery mildew and the dagger nematode, Xiphinema index. DNA marker analysis was used to characterize 62 Vitis californica and 31 Vitis girdiana candidate selections that are currently maintained at UC Davis. These vines are readily available for introduction into the NPGS. The results of the DNA marker analysis, combined with the original geographic location and observations of vine morphology were used to identify candidate selections suitable for introduction into the NCGR-D. Over 80 vines of �wild� V. californica from diverse geographic areas in Northern CA were sampled and analysed and used as a reference population. Additional �wild� vines of V. girdiana were not collected; allele frequencies for this species were based solely on the candidate selections. Over 30 previously described Simple Sequence Repeat (SSR) markers cloned from V. vinifera and V. riparia were used to generate DNA profiles for the candidate selections and the reference population. Many of these markers were not polymorphic for the study set, especially within V. californica. Final analysis was based on nine markers from nine different linkage groups that were polymorphic in the study set. The statistical analyses requires that the markers be unlinked. The final reference population allele frequencies for V. californica were based on 83 wild vines collected from diverse geographic areas in northern California. These samples came from 3 sources. In a preliminary effort, fifty vines were collected from Sonoma County in proximity to cultivated V. vinifera. When these Sonoma County �wild� vines were subjected to the same simple matching analysis described above, we found, not surprisingly, that 10 were F1 hybrids with currently important wine grape cultivars as one parent (�Cabernet Sauvignon�, �Merlot�, or �Zinfandel�) and several groups in which the vines were identical. The identical vines were often found 20 to 40 meters from one another and in several cases over 80 meters apart. After removing hybrids and duplicate genotypes, 25 Sonoma County �wild� vines were retained for V. californica allele frequencies. From Sonoma County 38 vines and 4 were F1 hybrids, all of which had �Mission� as one parent. The initial results of the likelihood analysis for the 104 �V. californica� genotypes showed many samples with varying but obvious degrees of introgression from V. vinifera. Since the reference population is supposed to be a true representation of the species, another 21 of the most obvious hybrids were removed from the reference pool. Twelve of these genotypes were from candidate selections; though they were removed from the reference pool, they were not removed from the �candidate pool�. The final V. californica reference population for all subsequent likelihood analysis was based on 83 genotypes. The reference population for Vitis girdiana was comprised solely of the 25 �candidate� selections. Allele frequencies for V. vinifera were based on available profiles of 45 diverse cultivars. After removing all candidate selections that show obvious introgression, geographic diversity may be the best criterion for choosing candidate selections for inclusion into NCGR-D. Monitoring was by e-mails, phone calls and meetings.
Impacts
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Publications
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