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ARS Home » Northeast Area » Geneva, New York » Plant Genetic Resources Unit (PGRU) » Research » Research Project #439231

Research Project: Breeding and Selection of Apple Rootstocks to Match California Industry Needs

Location: Plant Genetic Resources Unit (PGRU)

Project Number: 8060-21000-029-007-R
Project Type: Reimbursable Cooperative Agreement

Start Date: Oct 1, 2020
End Date: Jun 30, 2022

1. Develop on-farm field trials for diverse apple grower locations throughout California featuring novel and yet to be released apple rootstocks. 2. Monitor growth, productivity and nutrient absorption and study potential virus effects of Granny Smith on apple rootstocks. 3. Develop and provide virus clean nursery stock to California Nurseries of selected materials.

Apple orchards throughout the United States are undergoing a foundational transformation to more productive and disease resistant rootstocks. Rootstocks are the foundation of a healthy and productive orchard. The California apple industry needs location and variety compatible recommendations with regards to newly developed rootstocks by the Geneva breeding program. The breeding program has been cooperating with the California Apple Commission, some California nurseries (Sierra Gold and ProTree) for the evaluation and development of a special set of apple rootstocks that is focused for the challenges faced by California Apple Growers which include compatibility with mechanization, per acre productivity, low chill climate, water and nutrient use efficiency, resistance to fire blight, tolerance to replant disease (a genetic alternative to methyl bromide fumigation), interaction with apple viruses, crown rot and wooly apple aphids. The Geneva® apple rootstock breeding program is the only one in the world that has delivered on these traits in other locations and is poised to conduct grower requested, on farm field trials to identify a set of apple rootstocks compatible with California specific needs. The breeding program cooperates with several California nurseries in order to develop clean nursery stock for propagation – the project includes a component of nursery stock development, evaluation of virus effects on apple rootstocks and micropropagation. As it has done in other apple growing states like WA, NY, MI, PA, etc. the project will benefit the California apple nursery industry by developing localized, improved apple rootstocks and providing the virus free nursery stock to cooperating California nurseries. A change from traditional (ancient technology) to localized improved apple rootstocks has enabled other U.S. and world industries to increase their productivity by 25%-75%, decreased the quantity of fumigants used in the establishment of an orchard and saved millions of trees from the deadly fire blight disease. We expect the same impact for the California apple industry. A special attention to virus interaction with rootstocks will allow nurseries and apple growers to understand the effects of apple viruses on production and identify stocks that are symptomatic in the presence of viruses.