Genetic Improvement of Grapevine: Tailoring Grape Varieties for The Third Millennium - A Review

Abstract

The remarkable propagative aptitute of grapevine is one of the key factors contributing to its success as a cultivated\rspecies and to the spread of the domesticated grapevine, establishing it as one of the most important fruit species\rworldwide. Today there are some 8 million hectares of vineyards across the world. It is therefore fitting that the successful\rimplementation of the powerful technology of gene manipulation in grapevine is to a large extent reliant on\rthis regenerative ability. Currently, several varieties of grapevines have been successfully genetically transformed,\rlargely by employing somatic embryogenesis to generate highly regenerative target material. Especially attractive\rin the wine industry is the possibility of improving grapevine varieties by the addition of genes that confer useful\rtraits, such as resistances against biotic and abiotic factors and manipulation of certain metabolic functions. In\rprinciple, gene transfer technology allows for the directed manipulation of a specific trait without altering the characteristic\rnature of the cuItivar, permitting the improvement of the traditional cuItivars while maintaining their\restablished varietal characteristics. For the most part, targeted traits currently include disease resistance and\rimproved berry quality. The promise of this technology is threatened by worldwide resistance to genetically modified\rorganisms, and in the wine industry by complications surrounding the property rights and naming of transgenic\rvines. If it is not possible to maintain the varietal name when a transgenic vine has the same properties as the\roriginal well known variety, the significant advantages of gene technology over traditional breeding programmes\rare to a large extent lost. If these and other complications can be overcome, the integration of this powerful technology\rwith traditional breeding programmes, and with other initiatives such as the study of the grapevine genome,\rwill ensure a new era in the cultivation of this ancient species.