• Saccharomyces cerevisiae;
  • homothallic genetics;
  • genetic hybrids;
  • wild-type yeast;
  • heterosis


We made a library of Saccharomyces cerevisiae F1 hybrids from all possible crosses of 16 wild-type strains, including two common laboratory strains and two commercial winemaking varieties. Fourteen of the starting strains have been sequenced. Thus, the sequences of both genomes are known in 182 novel hybrids, and the sequence of one genome is known in 56. All tested strains sporulated. Fertilities were in the range 0–100%. Hybrids showed no more variation than parental strains for ethanol production, ethanol tolerance or growth at temperature extremes, but some F1s appeared to display hybrid vigour (heterosis). We tested four tetrads from one hybrid for their ability to grow at low temperature or in the presence of an inhibitory concentration of ethanol. Only one F2 was as tolerant as the most tolerant F0 parent. A few showed intermediate tolerance, but most were less tolerant than either parent or the F1 hybrid, consistent with uncoupling of genes contributing to an optimized quantitative trait. The diversity and structure of the library should make it useful for analysis of genetic interactions among diverse strains, quantitative inheritance and heterosis, and for breeding. Copyright © 2010 John Wiley & Sons, Ltd.