不同世代玉米株系配制组合产量杂种优势表现规律研究

Performance on Yield Heterosis of Combinations Combined by the Maize Inbred Lines in Different Generations

【目的】系统研究不同世代玉米株系配制组合产量杂种优势表现规律,为玉米早代选择,实现自交系和杂交种同步定向选育,提高玉米育种效率提供参考。【方法】本研究以阿单9号为基础材料,研究S_2与S_4代株系配制组合产量杂种优势的表现规律,及其与双亲遗传距离的相关性。【结果】(1)同一世代不同株系配制组合,其杂种优势均表现出较大差异,用同一测验种在S_2代株系所配组合杂种优势高的,其衍生的S_4代株系,组配高杂种优势组合的概率较大,且S_2与S_4杂种优势最大值组合具有较高的同源一致性,不同世代株系配制组合的杂种优势表现达极显著相关;(2)SSR标记的早代组合双亲间遗传距离与其产量SCA和杂种优势间的相关系数较小,未达显著水平,但产量SCA相对效应值与杂种优势之间有很好的一致性。【结论】在玉米育种实践中,可用早代组合杂种优势的高低作为指标,对早代株系及组合进行选择;但测验种的选择十分重要,且不能随意淘汰S_2株系,在不同世代适时更换测验种,可能会收到更好的育种效果;亲本间的遗传距离不足以预测杂种优势。

【Objective】Studying the performance on yield heterosis of different generation combinationscould provide the evidence for early generation selection,implement directed breeding for inbred linesand hybrids in the same time,and also provide reference for effective breeding in maize.【Method】Inthis research,studying the performance of yield heterosis of combinations prepared by S2and S4strainswhich derived from hybrid Adan9,and the correlation between yield heterosis and parental geneticdistance.【Results】淤The yield heterosis of combination combined from the different strains in thesame generation is different.For a same tester,the stronger yield heterosis of combinations in S2strains,the probability of the stronger yield heterosis in derivative S4is greater,moreover the combinationswith the strongest heterosis between S2and S4by descent have high identity,and the correlation ofyield heterosis of combinations which prepared by S2and S4strains is extremely significant positive.于There were no significant correlation between the genetic distance of early parents marked by SSR and the SCA of yield and the heterosis,however there is a good consistency between the relative effectvalue of yield SCA and heterosis.【Conclusion】The level of heterosis could be used as an effectivetarget for selecting early combination in the maize breeding.Then,selecting the testers is alsoimportant,and S2could not eliminate optionally.Furthermore,change testers in different generationswould raise the efficiency in breeding.Finally,the genetic distance of parents could not deduce theheterosis.