Applications of tissue culture to the genetic improvement of grapevines

Abstract

The grapevine was among the first plants to be cultured in vitro (1944). Regeneration by somatic embryogenesis and organogenesis was reported in the 1970s and plantlet production from cell suspensions or callus is now a routine procedure in many laboratories. Methods for isolating grapevine protoplasts have yet to be achieved. The fragmented apex technique, involving high-frequency adventitious bud formation, is a novel and efficient method for rapid multiplication of grapevines but culture of anthers and pollen has been generally unsuccessful. Micropropagation procedures for vinifera grapes, Vitis species and interspecific hybrids, including rootstocks, are all available. Seedless-seedless hybridization, involving embryo rescue in crosses with stenospermocarpic female parents, is of major significance in breeding seedless table grapes.
There has been substantial progress in protoplast cell, tissue and organ culture of grapevines, but this technology is still less well developed than with some other fruit crops (notably citrus and apples). So far, tissue culture has little impact on genetic improvement. Exploitation of somaclonal variation for clonal selection is an attractive option for premium wine cultivars. There is evidence of somaclonal variation in vitro but the usefulness of this random genetic variation in viticulture is still uncertain. To date, results of field trials with vines from somatic embryos have been disappointing. The grapevine is proving to be a difficult subject for Agrobacterium-mediated genetic transformation (A. tumefaciens and A. rhizogenes) and microprojectile technology is another option which is being investigated.