选择符合需要的基因型个体是育种实践中的重要环节，而理想基因型的预测则又是其前提。本文以水稻“珍汕97B×明恢63”的F1杂种（汕优63）所衍生的永久F2群体为材料，对单穗粒重进行了QTL定位分析，并对不同环境下单穗粒重的最优株系（SL）和最优杂种（SH）的基因型及其遗传效应值进行了预测。结果表明，QTL定位分析共检测到9个与单穗粒重相关的QTL，其中7个具有环境互作效应；上位性是控制水稻单穗粒重遗传变异的一个重要的遗传组分。最优基因型预测显示，不同环境下最优株系（SL）与最优杂种（SH）的基因型及遗传效应值不同。在两个环境中，SH的遗传效应值都是最高的。因此，SH将能够充分挖掘单穗粒重的最大潜力。9个QTL全为杂合或全为纯合均不是最佳选择，预测得到的SH有近一半的QTL是纯合基因型。同时讨论了在育种中获得SL和SH的途径。
Selecting individuals with improved genotype is important in breeding practice, while predicting superior genotype is the basis of selection. An immortalized F2 population in rice (Oryza sativa L.) derived from F1 hybrid between Zhenshan 97 and Minghui63 was used for QTL mapping on grain weight per panicle (GWP). Based on the results of QTL mapping, the genotypes and genetic effects of superior lines (SL) and superior hybrids (SH) in two different environments were predicted. Results showed that a total of nine QTLs controlling grain weight per panicle were detected in two environments. Epistatic effects were largely contributed to GWP as well as QE interaction effects had an impact on GWP. The genotypes and genetic effects of SL and SH in the two environments were different. The genetic effects of the predicted SH were the highest in the two environments, so SH could fully bring out the great potentialities of GWP. Nearly a half of QTLs of the predicted SHs in two environments were homozygous, which implyed that heterozygotes at all nine loci were not always advantageous for performance. The paper also mainly discussed how to obtain SL and SH in breeding.
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