State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, School of Advanced Agriculture Sciences and School of Life Sciences, Peking University, Beijing, China.
Ava Seed Academy of Sciences, Changsha, Hunan, China.
Sci Rep. 2017 Aug 9;7(1):7635. doi: 10.1038/s41598-017-06742-7.
Heterosis has been widely utilized in agriculture and is important for world food safety. Many genetic models have been proposed as mechanisms underlying heterosis during the past century, yet more evidence is needed to support such models. To investigate heterosis in two-line hybrid rice, we generated a partial diallel crossing scheme, which consisted of approximately 500 F1 hybrids derived from 14 male sterile lines and 39 restorer lines. In this population, increased panicle number played the most important role in yield heterosis of hybrid rice. Genome-wide association studies identified many QTLs related to the yield traits of F1 hybrids, better paternal heterosis and special combining ability. Relevant genes, including Hd3a, qGL3, OsmiR156h, and LAX2, were identified as candidates within these QTLs. Nearly forty percent of the QTLs had only two genotypes in the F1 hybrids, mainly because the maternal lines were under intense selective pressure. Further analysis found male sterile lines and restorer lines made different superior allele contributions to F1 hybrids, and their contributions varied among different traits. These results extend our understanding of the molecular basis of heterosis in two-line hybrid rice.
杂种优势在农业中得到了广泛应用，对世界食品安全至关重要。在过去的一个世纪中，许多遗传模型被提出作为杂种优势的机制，但需要更多的证据来支持这些模型。为了研究两系杂交稻的杂种优势，我们设计了一个部分双列杂交方案，该方案由来自 14 个不育系和 39 个恢复系的约 500 个 F1 杂种组成。在该群体中，增加穗数对杂交稻的产量杂种优势起着最重要的作用。全基因组关联研究鉴定了许多与 F1 杂种产量性状相关的 QTL，更好的父本杂种优势和特殊配合力。相关基因，包括 Hd3a、qGL3、OsmiR156h 和 LAX2，被鉴定为这些 QTL 中的候选基因。近 40%的 QTL 在 F1 杂种中只有两种基因型，主要是因为母本系受到强烈的选择压力。进一步的分析发现，不育系和恢复系对 F1 杂种做出了不同的优势等位基因贡献，并且它们的贡献在不同性状之间存在差异。这些结果扩展了我们对两系杂交稻杂种优势分子基础的理解。
