不同环境下水稻谷粒重发育的杂种优势和遗传相关性分析

选用9个不同类型的水稻品种(系)，按双列杂交设计(6×5)配成两套亲本和F12个世代的遗传材料,采用数量性状的加性、显性遗传模型、发育遗传模型比较分析了水稻谷粒重发育的杂种优势和遗传相关性。结果表明，早季在谷粒充实前期(1～12d)群体平均优势较小，中后期(13～28d)正向优势趋于明显，在谷粒充实的全过程均表现较小的负向群体超亲优势；晚季则在谷粒充实前中期(1～18d)表现正向群体平均优势。后期(19～28d)优势不明显，在谷粒充实前期(1～12d)表现正向群体超亲优势，之后转为明显的负向群体超亲优势，表明晚季谷粒发育的杂种优势表现较之早季更有利于提高籽粒充实质量，不同发育时期谷粒重之间以及与最终谷粒重之间的遗传相关分析表明，早季以显性相关为主，晚季以加性相关为主，随着发育进程的推进，相关趋于密切。

Heterosis and genetic correlation analysis of rice ( Oryza sativa L.) grain weight development under different environmental conditions

Two sets of test materials were derived from diallel cross among nine different types of selected rice varieties (lines). Based on the experimental data at different development stages of early and late rice, the estimation of heterosis and genetic correlation of rice grain weight at some development stages (0-->t) or at some special development phases (t--1-->t) was conducted by using additive-dominant genetic model and developmental genetic model for quantitative traits. The results indicated that the heterosis over mid-parent value based on population mean was not significant at 5% level at the early stages (1-12 d), and turned to positively significant as the development process proceeded in early rice. The heterobeltiosis based on population mean appeared to be small negative during the entire courses of grain filling. The heterosis over mid-parent based on population mean appeared to be positively significant at the early and middle grain filling stages (1-18 d), but became insignificant at the late stages (19-28 d) in late rice. The heterobeltiosis based on population mean appeared to be positively significant at the early grain filling stages (1-12 d), but turned to be significantly negative as the development process proceeded in late rice. It also indicated that the heterosis of grain weight development was beneficial to improve the quality of grain filling in late rice, compared to that in early rice. The genetic correlation between the grain weights per se at different stages and the final grain weight was mainly controlled by dominant effects, and became closer with the development process in the early rice, while by additive effects in the late rice. It's suggested that indirect selection of final grain weight throughout the process of grain filling would be more effective in late rice.