Grape Collection
Bernard Prins, USDA-ARS National Clonal Germplasm Repository, One Shields Drive, University of California, Davis, California 95616
Gayle M. Volk, USDA-ARS National Laboratory for Genetic Resources Preservation, 1111 S. Mason St., Fort Collins, Colorado 80521
John E. Preece, USDA-ARS National Clonal Germplasm Repository, One Shields Drive, University of California, Davis, California 95616
Outline
1. Introduction
Vineyards and wineries are present throughout the United States, with California being the largest producer of grapes and wine. Vitis vinifera cultivars are grown for production of fresh fruit, raisins, and wine. These V. vinifera cultivars are vulnerable to biotic and abiotic stresses, and other Vitis species may provide valuable genes for resistance for improved cultivars. For example, breeding programs have used wild species to identify genes of resistance to Pierce’s disease, which is caused by a bacterium (Xylella fastidiosa) and transmitted by the glassy-winged sharpshooter and other insects (Hickey et al., 2019).
Vitis vinifera originated in the Middle East and spread across northern Africa and eastern and central Europe to northern Europe. Vitis vinifera has one ancestral subspecies, V. vinifera spp. sylvestris, that is found in north Africa, and in widely scattered regions from Germany to Spain and across to Eastern Europe. These true V. sylvestris land races are likely sources of important genes, and the Davis repository has >200 individuals representing wild populations. These individuals may offer improved cold hardiness in northerly accessions, shortened growth cycle in accessions from higher elevations, and other traits for climatic adaptation (Grape Crop Germplasm Committee, 2004).
Asia is another center of origin for 10 to 50 Vitis species. Vitis is found in many areas of China from the dry west, the foothills of the northern and southern side of the Himalayas, the very cold northeast near Korea and the hot and humid southeast. Chinese cultivars based on V. amurensis are grown in the northeast of China. These cultivars have relatively large berries, very good cold tolerance and some disease resistance. This species has been utilized in the former Soviet Union as well as Eastern Europe in crosses with V. vinifera to produce numerous hybrid series, widely known for their high levels of cold tolerance and Plasmopara resistance. These hybrids were produced in an attempt to extend the northern range of viticulture, and have also been utilized for breeding in Minnesota, Canada, and Germany (Grape Crop Germplasm Committee, 2004).
North American grape species are found throughout North America from southern Canada to northern South America. There are about 20 species in North America, although that number may be as high as 40 by some accounts. All the species within Vitis are interfertile and they freely hybridize. Some of these species have been hybridized with V. vinifera especially to incorporate Phylloxera resi