ABERRATIONS IN SEXUAL-BEHAVIOR IN SOME BREWING AND OTHER INDUSTRIAL YEASTS

The mating behavior of a number of brewer's and distiller's yeasts was determined with a and α haploid and aa and αα diploid tester strains. Mating frequencies were not high, ranging from one to (rarely) 2,000/108 cells in the mating mixture. Sporulating hybrids were obtained in most matings, though the percentage spore viability initially obtained was often low. Notable the spore viability obtained in hybrids with the α haploid tester strains and the brewing strains DIB and DICH was much higher than from the a haploid tester strain, and higher in hybrids between these strains and the aa diploid tester than in those from the αα tester strain. With the brewing strain NBA, the spore viability in hybrids with the a haploid tester strain was higher than in the case of strains DIB and DICH, but the spore viability in the hybrid of NBA x the α haploid strain was higher still. The data are consistent with the hypothesis that with the a and aa tester strains, most of the industrial yeasts tested mate as diploids, and with the α and αα testers, they mate as haploids, an hypothesis which is supported by the segregation of adenine markers in the progeny of these hybrids. © 1979 Springer-Verlag.