影响水稻株高和剑叶宽主效QTL对人工选择的响应

 利用粳稻Lemont导入籼稻特青背景构建的高代回交导入系和重组自交系群体，在北京和海南两地检测影响株高和剑叶宽的稳定表达的主效QTL，分析这些主效QTL在导入系和重组自交系群体的不同选择强度（5%、10%和20%）的极端群体中的等位基因偏离，研究不同性状的主效QTL对不同选择强度的响应及不同遗传结构群体对主效QTL人工选择响应的影响。结果表明，导入系的选择群体中所有主效QTL等位基因的偏离方向都使得供体等位基因频率增加，等位基因产生偏离的性状选择方向及供体等位基因的偏离方向与基因的加性效应方向完全一致，而重组自交系的选择群体中主效QTL等位基因的偏离既有供体等位基因增加的，也有等位基因降低的，两种群体中不同性状的主效QTL等位基因偏离与选择强度密切相关。通过比较不同群体结构的主效QTL定位及对选择响应的异同，发现一些假阳性QTL和在随机作图群体中漏检的QTL，强调作图群体QTL定位结果验证的重要性。鉴于不同群体、不同性状和不同主效QTL的选择响应特点，对不同主效QTL在基于常规表型选择和分子标记辅助选择回交育种中的利用价值及注意事项进行了探讨。

Response of Main-Effect QTL for Plant Height and Flag Leaf Width to Artificial Selection in Rice

Artificial selection is a key procedure for animal and plant breeding. To detect response of main effect QTL (M-QTL) in mapping populations to artificial selection, stably expressed M-QTL was identified from backcross inbred lines in Teqing background (TQ-BIL) in Beijing and Hainan. Deviation of the alleles at the stably expressed M-QTLs in the extreme populations selected from TQ-BILs and Lemont/Teqing recombinant inbred lines (RILs) based on different selection intensities (5%, 10% and 20%) was detected, to analyze response of M-QTL of different traits to different selection intensities and effect of different genetic structures on selection response of M-QTL. The results indicated that the deviation of all alleles at M-QTLs identified from TQ-BILs resulted in increase of donor’s alleles in the extreme populations, and the directions of allele deviation and trait selection with allele deviation were consistent with that of additive effect of gene. However, donor’s alleles at M-QTLs were distorted to either increase or decrease in extreme populations selected from RILs. The deviation of alleles at M-QTLs for the two traits in the two kinds of populations was tightly associated with selection intensity. Some false positive and overlooked M-QTLs were found by comparison of M-QTL mapping results and their responses to selection in the populations with different genetic structures. Importance of confirmation was emphasized for the M-QTL identified from mapping populations. Considering characters of selective responses of different M-QTLs for different traits in different populations, utilization and caution of different M-QTLs in backcross breeding based on traditional phenotyping selection and marker assisted selection were discussed.