Location: Grape Genetics Research2012 Annual Report
1a. Objectives (from AD-416):
To genetically examine, characterize, improve, and evaluate grapevine rootstocks, selections, germplasm, and populations with attributes that indicate and predict increased yield and fruit quality.
1b. Approach (from AD-416):
We will identify grape genes and molecular markers that predict increased yield and quality, including genes and markers from grape rootstocks and other germplasm and selections, and we will select and evaluate improved high yielding and high quality varieties and clones. To identify the genes and molecular markers, we will cross elite varieties with rootstock and germplasm sources of high cluster count and high cluster zone saturation. Populations developed from crosses rootstock and germplasm with elite grape parents will segregate for useful traits from both parents. We will screen the population to identify seedlings that combine superior traits from rootstock and germplasm sources (high cluster count, high cluster zone saturation) and from elite grape parents (excellent quality, large cluster size). First generation cross seedlings may include selections that are directly useful for production, but second and successive generations of backcross to elite grape varieties are likely to be necessary to deliver increasing yield (esp. cluster size) and commercial quality. We will determine the genetic control of important quality and yield traits and develop 1) methods (molecular markers) to forecast seedling performance in advanced generations and 2) methods for directly genetically improving yield of existing varieties (recombinant DNA and non-recombinant approaches). The cross populations will segregate for key yield traits, including clusters per shoot, berries per cluster, berry weight, and cluster zone saturation (proportion of nodes in cluster zone with a cluster), as well as fruit flavor and aroma, flowering, veraison, and ripening date and target rootstock traits, such as pest and disease resistance, branching and lateral meristem development, and environmental adaptation. Segregation for these traits will enable the genetic analysis of these key traits, including cloning and sequencing of genes and development of yield component predictive molecular markers.
3. Progress Report:
Identified grape germplasm and rootstock selections with growth and development traits that indicate high yield potential and fruit quality. Crossed elite varieties with rootstock and germplasm sources of high cluster count and high cluster zone saturation. Populations developed from crosses rootstock and germplasm with elite grape parents will segregate for useful traits from both parents. Screened grape germplasm and a segregating population to determine the inheritance of lateral meristem distribution, an indicator of cluster zone saturation (proportion of nodes in cluster zone with a cluster). Established the relationship between the distribution of lateral meristems in discrete parts of the primary shoot, which enables earlier physiological testing for indicators of increased yield potential. Collected tissue samples and extracted DNA from the segregating population to enable development of molecular markers that help predict lateral meristem distribution and yield potential.