上位性对光敏核不育水稻不育性不稳定性的影响

Importance of Epistasis as the Genetic Basis of Sterility Instability for Photoperiod-sensitive Genic Male Sterile Rice

以来源于农垦 5 8S的籼型光敏核不育水稻 (OryzasativaL .)培矮 6 4S(长日低温下不育性稳定 )和 890 2S(长日低温下不育性不稳定 )及其F1、F2 群体为材料 ,通过长日低温和不同长日生态条件的 7种处理 ,并结合RFLP分子标记 ,研究了影响光敏核不育基因的育性不稳定性的遗传及其基因定位和基因互作对其育性不稳定性的影响。结果表明 :影响光敏核不育基因的育性不稳定性表现为微效基因的作用 ,定位了 7个影响光敏核不育水稻的育性不稳定的数量性状位点 (QTL) ,即L2、L3a、L3b、L5、L6、L7和L10 ,它们分别位于水稻连锁图谱的第 2、3、5、6、7和 10染色体上。证实了上位性真实存在于光敏核不育水稻中并影响其育性稳定性。基因互作类型表现以加性与加性互作和加性与显性互作为主 ,同一互作对表现多种互作类型并存。互作所解释的遗传变异处于 2 .0 4%～ 11.94%之间 ,不同处理之间有较好的重复性。

In this study the authors selected two indica photoperiod_sensitive genic male sterile (PSGMS) rice ( Oryza sativa L.), Peiai 64S (the sterility is stable) and 8902S (the sterility is instable), and their F 1,F 2 populations. The genetic basis for sterile stability of PSGMS lines was studied under long_day low_temperature environments and different ecological conditions, and the genes which affected the sterile stability were mapped using RFLP analysis. The major results are as follows: The sterility instability of PSGMS lines was controlled by minor effective genes. The linkage map of Peiai 64S and 8902S has been constructed. According to Mapmaker/QTL program, seven QTLs were identified that influence the sterile stability for PSGMS lines under the long_day condition, such as L2, L3a, L3b, L5, L6, L7 and L10. They were located on the chromosomes 2, 3, 5, 6, 7, and 10 of the rice linkage map, respectively. The interaction was detected under different long_day conditions and affected the sterility stability of PSGMS. The major interactions were between additive and additive and between additive and dominance. The variances explained of epistasis were between 2.04% and 11.94%. The repeatability of the interaction was very high under different long_day conditions. The implications of these findings in hybrid rice development are also discussed.