有利基因和有利的基因互作能够提高籼粳杂种育性

Favorable Genes and Favorable Genie Interactions Enhancing F_1 Fertility in indica/japonica Hybrids

利用一套籼粳交DH系与两份具有广亲和性的水稻光（温）敏核不育系测交，构建两个测交F_1群体，同时用92个多型性的RFLP标记分析了杂交亲本和另外30个不同类型的籼、粳品种（对照组）的基因型。利用对照组舢或粳表型与分子标记的关联性，检测出41个与籼粳分化高度相关的RFLP标记。结果表明，87．8％的这种标记参与了对杂种优势显著或极显著的影响，表明在水稻的演化过程中，参与适应性进化的基因与控制经济产量的QTLs存在平行进化关系。进一步分析表明，杂种F_1育性是一个影响籼粳杂种产量优势的主要因子，而F_1育性同时受分化标记位点内和位点间基因互作的重要影响，提出了解释籼粳杂种育性现象的新模式。

Two test cross populations were developed by crossing a set of DH lines as male parents to two wide compatibility rice lines, photoperiod-sensitive genie male sterile (PGMS) line-N422S and thermosensitive-genic male sterile (TGMS) line-Peiai64S. Polymorphism of the cross parents and another set of diverse indica or japonica lines (as a control) was assayed by using 92 RFLP markers. 41 RFLP markers were detected highly associated with indica and japonica phenotypes, which can be used as diagnostic markers to differentiate indica and japonica. Our results indicated that 87.8% of the diagnostic markers were also highly associated with grain yield and its components in at least one of the test cross populations, suggesting parallel relationships between the genes involving in evolution and QTLs controlling grain yield and yield components in the process of differentiation of rice (O. sativa L). Further analysis indicated that fenility was a main factor affecting the heterosis for grain yield in inter-subspecific rice hybrids. The fertility was conditioned by both intra-locus and inter-locus gene interactions and favorable genie intcractions could raise it accordingly.