2009 Annual Report
1A. Identify molecular markers tightly linked to QTL controlling phenotypic variation in grape for environmental adaptation and fruit quality. 1B. Identify candidate genes for environmental adaptation through characterization of differences in gene content and global gene expression among wild grapes with divergent phenotypes.
2. Develop grape germplasm with novel phenotypes for fruit quality traits.
Light-perception is a key biological process in plants and proper light-interception as well as photo-period are critical environmental cues affecting grape quality and winter hardiness. In order to better understand the interaction of a grapevine with light, genes known to be involved in light perception were isolated from cultivated and wild grapes. 4 phytochrome and 1 cryptochrome gene were isolated from accessions of V. vinifera and 8 wild grape species housed in the Geneva grape germplasm repository including: V. labrusca, V. acerifolia, V. aestivalis, V. riparia, V. cinerea, V. palmata, V. amurensis, V. rupestris. The identification of the grape forms of these genes is an important step in determining how a grapevine receives light signals from its environment and relays that information to changes in plant physiology.
Grapevines grown in many regions of the Eastern United States are poorly adapted to low-temperature and frequently are damaged by severe winters and fluctuating temperature during the spring and fall. There is tremendous variation among cultivated and wild grapes for tolerance to low-temperature stress, including some types that are capable of initiating dormancy in response to shortening day-length in early fall. To understand the genetic control of day-length sensitivity, the locations of genes controlling photo-periodic induction of dormancy were identified in the grape genome based on the analysis of offspring of parents that differ in their sensitivity to day-length. This experiment was conducted in a population of 131 individuals and utilized over 120 molecular markers to help identify regions of the genome that are important for photo-period responses. One region of the genome accounting for over 40% of the variation observed for photo-periodic induction of dormancy. The mapping of this trait is the first step in developing an assay that will improve the selection efficiency within grape breeding programs for this trait and generating improved cultivars of grape for cold climates.
Grape aroma is a primary determinant of table grape, unfermented juice, and wine quality. In collaboration with the University of British Columbia a project was initiated to conduct an association genetics screen for grape aroma in a subset of the USDA grape germplasm collection. For FY ’09 leaf and fruit tissue was collected for 374 accessions. SNP discovery of 61 candidate genes related to aroma content was completed in a panel of diverse accessions. Profiles of aromatic compounds was initiated in FY-09.
Garris, A.J., Clark, L., Owens, C.L., Mckay, S., Luby, J., Matthiason, K., Fennel, A. 2009. Mapping of photoperiod induced growth cessation in the wild grape vitis riparia michx. using microsatellite markers. Journal of the American Society for Horticultural Science. 134:261-272.
Garris, A.J., Cousins, P.S., Ramming, D.W., Baldo, A.M. 2009. Parentage Analysis of Freedom Rootstock. American Journal of Enology and Viticulture. Am. J. Enol. Vitic. 60(3):357-361.