TY - JOUR T1 - Breeding of Useful Killer Wine Yeasts JF - American Journal of Enology and Viticulture JO - Am J Enol Vitic. SP - 28 LP - 33 DO - 10.5344/ajev.1980.31.1.28 VL - 31 IS - 1 AU - S. Hara AU - Y. Iimura AU - K. Otsuka Y1 - 1980/01/01 UR - http://www.ajevonline.org/content/31/1/28.abstract N2 - For producing a good wine by pure culture as in brewing beer, useful killer yeast strains of Saccharomyces cerevisiae were bred by back-crossing KL-88, a wild killer sake yeast, with a repetitive parent, OC-2, one of the best wine yeasts.Haploids of KL-88 were crossed with haploids of OC-2 to yield first-generation hybrids (1HYs). Haploids possessing both killing activity and SO2 tolerance were selected from 1HYs and back-crossed with haploids of OC-2 to yield second-generation hybrids (2HYs). Several strains of killer hybrids were comparable to OC-2 in fermentation ability, SO2 tolerance, TTC stain, and growth in a β-alanine medium at 35°C. One strain (2HY-1) was further confirmed to produce wine of as good quality as that of OC-2 in fermentation on a subindustrial scale.The hybrids could kill only Saccharomyces yeasts in grape must. In the last stage of fermenting musts with the killer hybrid 2HY-1, no sensitive yeasts and few neutral yeasts (Kloeckera, Pichia, Hansenula, etc.) were detected; the former were killed by the killer yeast and the latter were markedly inhibited by the SO2 added and the alcohol formed.Furthermore, no film formation occurred during storage for 60 days at 25°C on the wine made with the hybrid because pseudo-film-forming Saccharomyces (S. bayanus, S. oviformis, S. fermentati, etc.) had been killed by the killer hybrid, whereas film formation was abundant on wine made with OC-2 unless SO2 was added after fermentation. ER -