Genetic Architecture of Dormancy Induction, Dormancy Release and Winter Survival in Grapevine

Dormancy is an adaptive winter survival strategy for the grapevine. In contrast to many model woody species the grapevine does not transition through terminal bud development prior to dormancy. Instead it exhibits shoot tip abscission, lateral emergence cessation, periderm development and axillary bud dormancy in response to decreasing photoperiod or low temperature. In this study, several developmental and physiological traits associated with dormancy and low temperature survival were measured in a F2 wine grape mapping population (n =100) to identify quantitative trait loci (QTL) for dormancy induction and release and winter survival. QTL analysis was conducted on data collected in multiple years in greenhouse or field for tip abscission, lateral emergence, periderm development, bud dormancy, freezing tolerance, bud break and vine winter survival using a genetic map with 1449 SNP markers across 19 linkage groups. Multiple QTLs were identified for individual traits; however, QTLs for photoperiod induced traits were repeatedly found on linkage groups 11 and 13. QTLs for freezing tolerance were found on linkage group 13, winter survival on 11 and 14, and chilling fulfillment QTL was identified on linkage group 18. The QTLs identified in multiple years accounted for 10-20% of the phenotypic variation. Woody plant dormancy and abiotic stress tolerance are complex biological traits and clarifying the genetic relationship and identifying underlying loci of morphological and physiological traits provides information needed to generate markers for marker assisted selection.