Grapevine Genetics: Probing the Past and Facing the Future

The development and application of DNA technology is changing the face of grapevine genetics. DNA markers facilitate investigations into the origins of existing cultivars and provide powerful tools for the creation of new cultivars. Microsatellite markers, the most powerful type of DNA markers, provide a unique genetic profile for every cultivar, permitting unambiguous identification that is unaffected by environment, disease or farming methods. Because they are locus-specific and co-dominant, microsatellite markers also detect family relationships and have revealed the origins of some of the world´s most important wine cultivars. For the first time, genetic linkage maps of grapevine are now being developed. The long generation time, large plant size, genetic heterozygosity and lack of conventional morphological genetic markers prohibited map development in the past. Now molecular marker based mapping programs are accelerating grape breeding programs by permitting early selection of promising seedlings. Genetic mapping in combination with physical mapping can lead to the isolation of grape genes that control important traits but for which the mechanism is not known. Other grape genes are being isolated by comparing expressed grape DNA sequences with large databases of well-characterized genes from other plants and animals. Methods to introduce genes, either from grapevines or other organisms, into existing grape cultivars are now well-established and permit the targeted modification of existing grape cultivars. This may provide a means to reduce disease losses and pesticide usage in classic cultivars without otherwise changing their wine attributes