水、旱稻千粒重和产量QTL效应的验证

 【目的】验证水稻和旱稻千粒重、单株产量QTL定位的真实性、准确性及其表型效应。【方法】（1）利用水、旱稻杂交、回交所产生的BC1、F2 3个分离群体对重组自交系（RIL）群体定位到的千粒重、单株产量的QTL效应进行选择验证。（2）依据千粒重、单株产量QTL两侧的分子标记按双标记、单标记进行选择验证。【结果】（1）千粒重、单株产量QTL在不同群体、不同的遗传背景中的遗传稳定，表型效应明显。旱田种植条件下，2个回交群体和自交育种群体携带有千粒重QTL tgw6.1有利等位基因的个体与没有携带tgw6.1有利等位基因个体的均值差为3.18～3.62 g，均达到极显著水平，表型效应为13.94%～18.15%；携带有单株产量QTL yp6.1有利等位基因的个体与没有携带yp6.1有利等位基因个体的单株产量均值差为5.04～8.18 g，达到显著或极显著水平，表型效应为34.89%～58.88%。（2）QTL标记区间较大（如本研究中的标记区间，13.5 cM）时，利用双标记选择更为可靠；标记与QTL距离较小（如本研究中的RM527，1.5 cM）时，利用靠近QTL的单侧标记进行选择也可以获得较好效果。此外，本文还就QTL定位中的一因多效现象及MAS对数量性状选择的有效性等进行了讨论。【结论】利用QTL分子标记辅助选择提高抗旱等复杂性状的选择效率是可行的。

Verification of the Effects of QTLs for Grain Weight and Yield in Lowland Rice and Upland Rice

【Objective】Accuracy mapping of the target traits is the prerequisite of the effectiveness of marker-assisted selection (MAS). 【Method】 Two previously identified quantitative trait loci (QTLs) conferring 1000-grain weight (TGW) and grain yield per plant (YP), on the same location of chromosome 6, designated tgw6.1 and yp6.1 respectively, were chosen as target QTLs to verify the QTL effects by using three segregating populations through marker-assisted selection (MAS). Three segregating populations (BC1, F2) derived from crosses between an upland rice variety (IRAT109, donor of target QTLs) with big grain weight and high yield potential, and two lowland rice varieties (recipients) with small grain weight and better grain quality, were used in this study. 【Result】The results showed that QTLs conferring bigger TGW and higher YP were genetically stabilized in different populations with different genetic backgrounds. The differences between the means of TGW of individuals carrying and not carrying donor's favorable alleles of tgw6.1 were 3.18﹣3.62 g, significant at 1% level. The phenotypic effects of MAS for tgw6.1 were 13.94%﹣18.15%. The differences between the means of YP of individuals with and without donor's favorable alleles of yp6.1 were 5.04﹣8.18 g, significant at 5% or 1% level. The phenotypic effects of MAS for yp6.1 were 34.89%﹣58.88%. Compared the phenotypic effects based on one or both of the flanking markers of target QTLs, the results showed that it was more reliable to select with both of the flanking markers when the interval of the target QTL was longer, (such as the interval of TGW and YP QTL, 13.5 cM); when the map distance between the marker and the target QTL was very short ( such as RM527 in present study, 1.5 cM ), it was also more effective to select with the marker which was nearer to the target QTL. Moreover, the phenomena of QTL with pleiotropic effects and the effectiveness of MAS for complex traits were also discussed. 【Conclusion】In this paper, the reality and accuracy mapping of TGW and YP QTLs and their phenotypic effects were verified. The feasibility of MAS based on QTL for complex traits such as drought resistance was confirmed.