The main aim of the work was to utilize heterozygosity of industrial yeast strains to construct new baker's yeast strains. Commercial baker's yeast strain ALKO 743, its more ethanol tolerant descendant ALKO 554 selected initially for growth over 300 generations in increasing ethanol concentrations in a glucose medium, and ALKO 3460 from an old domestic sour dough starter were used as starting strains. Isolated meiotic segregants of the strains were characterized genetically for sporulation ability and mating type, and the ploidy was determined physically. Heterozygosity of the segregant strains was estimated by a variety of molecular characterizations and fermentation and growth assays. The results showed wide heterozygosity and that the segregants were clustered into subgroups. This clustering was used for choosing distantly or closely related partners for strain construction crosses. Intrastrain hybrids made with segregants of ALKO 743 showed 16-24% hybrid vigour or heterosis. Interstrain hybrids with segregants of ALKO 743 and ALKO 3460 showed a wide variety of characteristics but also clear heterosis of 27-31% effects as assayed by lean and sugar dough raising. Distiller's yeast ALKO 554 turned out to be a diploid genetic segregant and not just a more ethanol tolerant mutant of the tetraploid parent strain ALKO 743.

中文翻译：

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利用工业酵母中的杂合性来创造新的和改进的面包酵母。

这项工作的主要目的是利用工业酵母菌株的杂合性来构建新的面包酵母菌株。商业面包酵母菌株 ALKO 743、其更耐乙醇的后代 ALKO 554 最初选择在葡萄糖培养基中增加乙醇浓度的情况下生长超过 300 代，以及来自旧的国内酸面团发酵剂的 ALKO 3460 被用作起始菌株。菌株的分离减数分裂分离子在遗传上表征了孢子形成能力和交配类型，并通过物理方法确定了倍性。分离菌株的杂合性通过多种分子表征以及发酵和生长测定来估计。结果显示广泛的杂合性，并且分离子聚类成亚组。该聚类用于选择远距离或近距离相关的伙伴以进行菌株构建杂交。用 ALKO 743 的分离子制成的株内杂种显示出 16-24% 的杂种优势或杂种优势。具有 ALKO 743 和 ALKO 3460 分离子的品系间杂种显示出广泛多样的特性，而且通过瘦肉面团和糖面团发酵测定的 27-31% 效应的明显杂种优势。事实证明，酒糟 ALKO 554 是一种二倍体遗传分离子，而不仅仅是四倍体亲本菌株 ALKO 743 的一种更耐乙醇的突变体。具有 ALKO 743 和 ALKO 3460 分离子的品系间杂种显示出广泛多样的特性，而且通过瘦肉面团和糖面团发酵测定的 27-31% 效应的明显杂种优势。事实证明，酒糟 ALKO 554 是一种二倍体遗传分离子，而不仅仅是四倍体亲本菌株 ALKO 743 的一种更耐乙醇的突变体。具有 ALKO 743 和 ALKO 3460 分离子的品系间杂种显示出广泛多样的特性，而且通过瘦肉面团和糖面团发酵测定的 27-31% 效应的明显杂种优势。事实证明，酒糟 ALKO 554 是一种二倍体遗传分离子，而不仅仅是四倍体亲本菌株 ALKO 743 的一种更耐乙醇的突变体。