The selection and breeding of cultivar-specific wine yeasts for Chenin blanc and Pinotage
Van Rensburg, P
University of Stellenbosch. Faculty of AgriSciences. Institute for Wine Biotechnology
Lambrechts, M G
Muller, C A
Eksteen, J M
To increase the quality of Pinotage and Chenin blanc wines. To establish a knowledge base of how to use neural networks in breeding programmes and in the wine industry in general.
Although it is now becoming clear that the accumulation of secondary metabolites in the grape is the most important contributing factor to wine flavour, the role of wine yeast strains remains the subject of considerable interest to increase wine flavour. The development of cultivar-specific wine yeasts for varietals such as Chenin blanc (25% of existing vines) and Pinotage (the flagship of South African red wines) is of pivotal importance for the local wine industry. Selection of yeast variants is a simple, direct means of strain development that depends on the genetic variation normally present in all wine yeast strains. Clonal selection of variants can be used in conjunction with intra-species hybridisation. The latter technique involves the mating of opposite mating-types to yield a heterozygous diploid. Dramatic improvements in most characteristics cannot be expected; nevertheless, intra-strain selection and intra-species hybridisation have been used for decades to improve wine yeasts and remain the most effective methods for improving and combining traits under polygenic control.