甘蓝型油菜不同发育时期角果重量的遗传分析

Genetic analysis for pod weight at different developmental stages in Brassica napus L.

采用可以估算不同发育时期基因累加效应和特定发育时期净遗传效应的遗传模型和统计分析方法,研究油菜角果成熟过程中其重量的发育遗传规律.结果表明,控制不同发育时期油菜角果重量表现的基因累加效应以加性效应为主,仅在第22d时其显性效应大于加性效应.条件分析的结果表明,控制角果重量的基因在角果多数发育时期中均有新的表达,且其表达方式有所不同,其中角果重量的净遗传效应表达量以开花后第16～22d最大.角果重量在不同发育时刻具有较高的狭义遗传率,低世代选择可以取得良好的育种效果.亲本遗传效应分析表明,双20-4、中R-888和Tower3个亲本有利于增加杂种后代的角果重量,其中以中R-888最优.杂种优势分析表明,角果发育的前中期(16～29d)群体平均优势明显大于其他发育时期.

Pod weight （PW）, an important quantitative trait very closely related to seed yield, was analyzed using conditional and unconditional genetic models to find out the dynamic effects of genes for this trait during rapeseed development, which comprised of pods harvested at 15, 22, 29, 36 and 43 days after flowering and fertilization. For the unconditional analysis, the additive effects were found to be more important at most stages except for the developmental time of 22 day at which the dominant effects were more prominent. For the conditional analysis, 16 - 22 days after flowering was found to be the most active period for dynamic expression of genes related to pod weight as many new genes were expressed during this period. Heritability analysis revealed that selection in early generations could be effective for improving pod weight in oilseed rape breeding. Prediction of genetic effects for oilseed rape parents showed that Double 20-4, Zhong R-888 and Tower could be used for improving PW in oilseed rape breeding, which Zhong R888 was the best one. The results further indicate that the heterosis over mid-parent value based on population mean at the stages of 16-22 and 23-29 days was significantly larger than those at other stages.