Summer scholar maps path to rot-resistant grapes

Anne Repka in vineyard
Anne Repka '17 in a vineyard at Cornell's New York State Agricultural Experiment Station in Geneva scouting for evidence of the black rot fungus. Photo: Elizabeth Takacs

By Amanda Garris Ph.D. ‘04

In the final week of her internship, Anne Repka ’17 set parameters, pressed go, and in less time than it takes to eat lunch, her summer’s worth of field work was translated into a statistically significant genome discovery. She had identified several regions of chromosomes that can make grapevines prone to infection by a fungus that rots the berries as they ripen on the vine.

Repka was one of 25 students who spent the summer at Cornell’s New York State Agricultural Experiment Station as part of the Geneva Summer Scholars Program, tackling projects from bumblebee pollination to plant viruses. The program, established in 2009, introduces top undergrads from across the country to the rigors of research on agricultural crops. For Repka, no such introduction was necessary; she is double majoring in plant science and viticulture and enology and is planning to minor in crop and soil science.

Repka worked with postdoctoral associate Elizabeth Takacs and Bruce Reisch, professor of horticulture and grape breeder in the School of Integrative Plant Science, on a vineyard challenge posed by the black rot fungus (Guignardia bidwellii). According to Reisch, it is nearly impossible for organic farmers to stop its spread using approved treatments, so developing resistant varieties with the help of new genetic markers is a priority for his breeding program.

To make progress, Repka collected data on the resistance and susceptibility of two populations, using lab-reared spores to inoculate developing clusters and checking the progress of disease at three-day intervals. At the end of the experiment, the clusters were collected, scored for symptoms and photographed. This field data, when combined with genetic data that had already been collected in Reisch’s lab, helped them identify regions of the genome that made grapevines more susceptible.

“The experiment was so well laid out that we were able to get it done in a short time during the summer,” Repka said. “It was a really good experience.”