Scientists analyze how rootstock affects grapevine characteristics

Professor Anne Fennell, who has been doing research on cold hardy grapes for more than 20 years, and assistant professor Qin Ma, whose expertise is in bioinformatics and computational systems biology, are part of a multi-institutional research team working on the five-year, $4.6 million National Science Foundation project.

The two SDSU Department of Agronomy, Horticulture and Plant Science researchers will receive nearly $830,000 in total funding to support their work. Fennell will focus on data generation, while Ma will do data mining and modeling using computational resources available through the state's collaborative research center, Biosystems Networks and Translational Research and Extreme Science and Engineering Discovery Environment.

Allison Miller, an associate professor in biology at Saint Louis University, is the lead for the NSF project, which also involves researchers from the University of Missouri, Missouri State University, Danforth Plant Center and Missouri Botanical Garden in St. Louis, as well as the Grape Genetics Research Unit of the U.S. Department of Agriculture in Geneva, New York.

Grapes are commonly grafted, so the root system is genetically different from the top portion that produces the stems, leaves and fruit, referred to as the scion, explained Fennell. The practice allows producers to graft a desirable variety of grapes onto rootstock that is resistant to pests and diseases.

"Though grafting is a standard way of propagating grapes worldwide, we don't have a good handle on how that rootstock affects the scion," Fennell noted. However, she pointed out that researchers know that the genotype of the rootstock impacts the characteristics expressed in the scion, known as its phenotype.

"This is a very complex study; each facet of the project addresses a different type of rootstock-scion interaction," she explained. First, the Missouri researchers will find out how three different rootstocks affect variation in the grape scion and how varying amounts of water affect rootstock-scion interactions. All will be grown in the same vineyard.

The second portion examines different environments in northern and southern California and how they affect two different scions grafted onto two different rootstocks. "The red grape scion are grafted onto a different rootstock than the white grape scion," Fennell pointed out.

In the second year of the project, the research team will begin looking at 200 different rootstock genotypes with the same red grape scion, Marquette, grown at four climatically diverse sites -- Parlier, California; Mt. Vernon, Missouri; Geneva, New York; and Brookings, SD.

The rootstocks are a population developed by Jason Londo of the USDA Grape Genetics Research Unit and derived from two native grapevine species, V. rupestris and V. riparia, which have frequently been used to produce commercial rootstocks. Fennell said, "There are a lot of characteristics you can select for in rootstocks. What we're interested in is how the rootstock affects the scion, how the communication of two genetic systems impacts the scion phenotype."