玉米自交系微小遗传差异对产量优势的贡献

对3个玉米自交系遗传差异不同的株系自交3代后株系间产量及相互间杂交优势进行分析。结果表明,同一自交系在遗传上存在微小差异的株系,产量水平及其产量构成因素仍然存在一定差异。自交系初始遗传差异越大,后代株系间的产量差异越大;初始单株遗传差异较小的两个玉米自交系昌7-2和郑58具有微小遗传差异株系间杂交组合的超中亲优势分别达到10.55%、4.77%,超高亲优势分别达到3.69%、3.94%。对杂交优势贡献主要来自行粒数,其次是千粒重。通过关联分析找出行粒数相关基因的SNP标记14个(-Log P4),千粒重相关基因的SNP标记3个(-Log P3)。在开放授粉的条件下,株系间微小遗传差异有利于提高亲本和杂交制种产量。

Contribution of Maize Tiny Genetic Differences on the Yield Heterosis

Through analyzed the genetic differences and the yield of three maize inbred lines among different strains, the results showed that the yield was different for the sister strains of the same inbred line with the tiny genetic differences. The bigger the initial genetic difference of inbred lines before self-bred selection was, the higher the yield of the strains after S3 generation was. The mid-parent yield heterosis of the two maize inbred strains with a smaller initial individual genetic difference, Chang 7-2 and Zheng58, were 10.55% and 4.77%, respectively, while of which over-parent yield heterosis were 3.69% and 3.94%, respectively. The yield heterosis mainly came from the row grains, secondly from 1 000-kernel weight. It was found that SNPs associated with row grains were 14(-logP>4) and kernel weight were 3(-logP>3) through the correlation analysis. Under the condition of open pollination, small genetic difference among the strains was benefit to improve the seed yield of inbred lines and hybrid seed.