RFLP分子标记杂合性与玉米F_1产量性状相关的研究

Relationship of RFLP Marker Diversity with F_1 Yield Performance in Maize(Zea mays L.)

【目的】探讨RFLP分子标记在杂种优势预测研究中的作用。【方法】在利用分子标记划分玉米杂种优势群的基础上,选用在我国南方广泛推广的33个自交系和4个测验种,按NC-II遗传设计估计了132个杂交组合的产量表现,分析了基于RFLP分子标记杂合性与杂交组合F1产量性状的相关性。【结果】杂合性与F1穗粒重、百粒重和行粒数等产量性状之间相关极显著,但相关程度不高,与F1穗粒重相关系数仅为0.431;亲缘关系较近组合的F1产量与杂合性的相关明显高于亲缘关系较远的组合;杂合性低于0.60的组合几乎都表现为负优势(91.67%),其杂合性与F1产量平均优势有极显著的正相关(r=0.771**),当杂合性范围增大时,则相关不显著,表明要获得较强的杂种优势必须保证亲本之间有相当的杂合性,但并非杂合性越高杂种优势越强。【结论】尽管利用分子标记杂合性预测杂种优势表现有一定的局限性,但是,分子标记杂合性小于0.60可作为衡量弱优势组合的一个指标,这对帮助育种家提高组合鉴定的效率有一定的指导意义。

[Objective] To learn the utility of RFLP heterozygosity in prediction on maize heterosis. [Method] In this investigation, 132 of single crosses between 33 inbred lines extended in South China and four testers representing different heterotic groups were employed to evaluate the yield performance with NC-II method and heterozygosity （H） was calculated based on RFLP marker diversity in order to analyze relationship between genetic diversity and F1 performance. [ Result] The results showed thatH vs. F1 performance of some yield traits, such as grain weight （GW）, had significant positive correlations respectively, but the correlation coefficients were quite low, they were 0.431. The correlations of heterozygosity with FI performance of crosses within heterotic groups were higher than those between different heterotic groups. 91.67% of crosses with low H （less than 0.60） performed negative heterosis, there were significant correlations of H with yield characteristics among these crosses and their correlation coefficients reached to more than 0.77. No significant correlations were detected between H with yield characteristics when H values increased. [Conclusion] The results suggested that though it is very limited to predict high heterotic crosses based on the genetic distance of molecular markers, H 〈 0.60 should be considered as a cretieroian for crosses with low heterosis, which will be helpful for maize breeders to raise the efficiency of breeding.