水稻粒形与千粒质量的QTL分析

QTL analysis of rice grain shape and thousand-grain weight

【目的】挖掘控制水稻粒形和千粒质量的QTL位点,为水稻高产育种提供有利资源。【方法】以水稻大粒品种大粒稻和小粒品种东北小粒种杂交获得的256个单株F 2群体为材料,利用124对亲本间多态性SSR标记对控制粒长、粒宽、长宽比和千粒质量等性状进行QTL分析。【结果】F 2群体粒形性状均呈现连续变异的双峰分布,且粒长、长宽比和千粒质量分布均偏向于大粒亲本。相关分析表明,粒长、粒宽和千粒质量性状间均呈极显著正相关。共检测到17个QTL位点,与粒长、粒宽、长宽比和千粒质量有关的QTL位点分别为6,3,5和3个,分布于水稻第2、3、4、5、9、10号染色体上,贡献率为4%~18%。贡献率大于10%的主效QTL位点有4个,分别为qGL-2-1、qGW-2-2、qGW-2-3和qL/W-2-1,其中qGW-2-2、qGW-2-3和qL/W-2-1与克隆的粒宽基因GW2在同一区间内,可能为同一基因,qGL-2-1可能是新的控制粒形的主效QTL位点;其余贡献率小于10%的位点也可能有新位点。【结论】检测到的QTLs具有稳定性,可用于控制水稻粒形性状表现的基因精细定位及克隆。

【Objective】This study identified the QTL loci for controlling rice grain size and thousand-grain weight to provide favorable resources for high-yield rice breeding.【Method】The rice F 2 population consisting of 256 individual plants derived from a cross was obtained using large-grain varieties and small-grain varieties of Northeast small-grain varieties as materials.A total of 124 SSR markers were used to perform QTL mapping analysis for controlling grain length,grain width,length-width ratio and thousand grain weight.【Result】The F 2 population showed a bimodal distribution of continuous variation in grain shape traits.The distributions of grain length,aspect ratio and thousand grain weight were all biased towards large-grain parents.The correlation analysis showed that there was a significant positive correlation between grain length,grain width and thousand-grain weight traits.A total of 17 QTLs were detected,and the QTLs related to grain length,grain width,aspect ratio,and thousand-grain weight were 6,3,5,and 3,respectively.They were mainly distributed on chromosomes 2,3,4,5,9,and 10 with contribution rate of 4%to 18%.There were 4 main QTLs of qGL-2-1,qGW-2-2,qGW-2-3 and qL/W-2-1 with a phenotypic contribution rate greater than 10%.Among them,qGW-2-2,qGW-2-3 and qL/W-2-1 were in the same interval as the cloned gene GW2 with the possibility of being the same gene,while qGL-2-1 might be a new gene controlling grain type.The remaining sites with contribution rate of less than 10%could also have new sites.【Conclusion】The detected QTLs with stability can provide basis for fine mapping and cloning of genes controlling rice grain shape traits.