VitisGen Breeding Team

1. VitisGen Breeding Team The VitisGen Breeding Team is responsible for maintaining the mapping populations selected to use in the VitisGen project and to supply the genotyping and phenotyping centers plant material. Data generated from the genotyping and the phenotyping centers will be integrated with feedback from trait economics and consumer surveys. Breeders will use these integrated analyses to select individuals segregating desirable traits from each population. These selections will be planted in vineyards and used in future crosses. Breeders will benefit from these analyses because they can discard plants with undesirable traits before transferring them to the vineyard. This will preserve valued space in their vineyards and reduce production costs.

2. Marker-assisted selection of a new mapping population Postharvest, seeds from one of the selected VitisGen mapping populations were removed from the flesh of the grape and cleaned. Prior to planting, the grape seeds were stratified by being placed on a damp paper towel in a plastic bag and incubated at 32°F for three months. Stratification is a process that simulates the natural winter conditions required for germination. Fifty seeds were planted in each flat and the temperature of the greenhouse was set high (~82°F) to induce germination Two weeks after planting, the cotyledons of germinated seedlings have fully expanded. One month after planting, seedlings have initiated several leaves. Approximately two months after seeds were first planted, leaves were harvested from seedlings for genotyping-by-sequencing (GBS) or SSR marker analysis.

3. The Genotyping Team sent pre-labeled 96-well plates to each breeder to collect leaf samples for genotyping-by-sequencing (GBS) and SSR marker analysis. Steve Luce (Research Support Specialist) harvests dime-sized leaves from each seedling and puts each sample into a specific position in a 96-well plate. To track each sample, Bruce Reisch (Project Director and Breeding Team leader) records the plant identification number, the 96-well plate identification number, the location of the seedling in the flat , and the leaf position in the 96-well plate. The plates containing the leaf samples are shipped back to the Genotyping Team for DNA extraction and subsequent GBS or SSR marker analysis (see Genotyping Workflow). The plants are transferred to a nursery for the summer. SSR marker analysis and natural disease infection of plants in the nursery will be used to select disease resistant plants. Selected plants will be planted in the vineyard next year for further analyses.