|BRUCE, REISCH - CORNELL UNIVERSITY
Submitted to: Fruit and Nut Breeding
Publication Type: Book / Chapter
Publication Acceptance Date: 7/21/2011
Publication Date: N/A
Technical Abstract: Grapes are grown worldwide, on about 7.9 million ha., and are used to produce wine, raisins, juice, jam, concentrate, and seed oils, as well as fresh fruit. Grapes (Vitis sp.) are members of the Vitaceae. Vitis includes two subgenera, Euvitis (38 chromosomes) and Muscadinia (40 chromosomes), with about 60 species total. The primary centers of species diversity are North America and East Asia. Scion cultivars are derived chiefly from the European grape, Vitis vinifera, which was domesticated ca. 6,000 to 10,000 years ago in the region between the Black and Caspian Seas. Grapes spread east into Asia and west into the Mediterranean region. Rootstocks were developed from North American species, including V. riparia, V. rupestris, and V. berlandieri. Scion breeding programs focus on the development of cultivars adapted to biotic and abiotic stress, with high fruit quality, and time of ripening during desirable periods of market demand. Fungal disease resistance is a primary goal of many programs, while cold hardy cultivars help extend the limits of grape cultivation. Rootstock breeding focuses on providing protection against phylloxera and nematodes as well as adaptation to high pH, low pH, and/or water-stressed conditions. Rootstocks should propagate easily by grafting and cuttings. New cultivars are more rapidly adopted in the raisin and table grape sectors than in the wine industry, although there are several notable examples of successful wine grape cultivars developed by breeding. The availability of two published genomic DNA sequences has stimulated numerous projects to further understand the function of the ca. 30,000 grapevine genes. Marker-assisted selection, primarily for disease resistance and seedlessness, is being applied in many breeding programs. Projects that focus on breeding seedless cultivars commonly use embryo rescue techniques, enabling the crossing of two seedless parents, to increase the percentage of seedlings that are seedless. Genetic transformation is a routine procedure and is being used for both functional analysis of gene action as well as directly for cultivar improvement (both scions and rootstocks), although transgenic grape cultivars currently are not in commercial production.