A Genetic Map of Vitis Vinifera: A Foundation for Improving the Management of

We have continued to steadily add information to a genetic linkage map of Vitis vinifera. We have now mapped 145 microsatellite DNA markers to 18 linkage groups. New DNA markers have been developed within the Vitis Microsatellite Consortium, 20 cooperating research groups in 12 countries. Our map is now the most advanced genetic map of Vitis vinifera in the world. It is a resource that can be used by many viticulture researchers to facilitate the identification and isolation of individual grape genes so that we can learn how these genes work and how their functions are influenced by external factors, such as vineyard cultural practices. Our map is now being used by research groups in France, Germany, Italy, Spain and Australia to connect genetic maps being developed in their programs and to further gene identification efforts. These groups are also sharing their own results with us. We have also analyzed quantitative fruit and cluster characteristics that contribute to berry size and cluster tightness. Most of these characteristics map to only 3 regions of the grape genome, suggesting that key genes controlling berry size and cluster structure are located there.