Breeding grapevines for tropical environments

Grapevines are increasingly grown in the latitudes between the Tropics of Cancer and Capricorn. In many cases environments modified by elevation are utilized to create temperate growing conditions. The majority of tropical grapes are consumed fresh but some are dried (India) and others are made into wine (Brazil, Venezuela). Currently most plantings are of pure Has vinifera varieties. Early ripening, low acid cultivars such as Cardinal, Perlette, Ribier and Thompson Seedless which have a relatively short cycle between budburst and harvest are commonly used, and pruning is timed to ensure maturation before the onset of heavy tropical rains. Other V vinifera varieties used in the tropics such as Muscat Hamburg, Teneron, Anab-e-Shahi, and Italia have bunch and skin characteristics that give them some resistance to rain damage. There are a number of grapevine varieties that are hybrids between V. vinifera and other Vitis species which are currently grown in the tropics. These have some degree of resistance to fungal diseases and include Isabella, Kyoho, Delaware, Himrod, Campbell Early (V. labrusca hybrids), the Criolla hybrids (V. caribaea hybrids and Villard blanc (a complex French hybrid based on American species). There is considerable scope to increase the resistance of grapes to the main fungal diseases encountered in the tropics such as downy and powdery mildew, anthracnose and bunch rots by using a range of Vitis species as parents. These hybrids should be based on species that do not give strong 'foxy' flavours and could involve complex French hybrids, V rotundifolia and also Asian species such as V amurensis and V. armata. CSIRO Merbein has a small hybridisation program aimed at developing new varieties for tropical environments.