棉属野生种克劳茨基棉第7染色体上马克隆值QTL的挖掘与定位

为了深入挖掘和利用棉属野生种克劳茨基棉(Gossypium klotzschianum)的优异等位基因，构建了一个(陆地棉泗棉2号×克劳茨基棉)×泗棉2号的BC₁F₂群体，对纤维品质性状初步定位，单标记相关分析表明位于第7染色体上的SSR标记NAU1362与马克隆值表现极显著相关。进一步选择在第7染色体上含有克劳茨基棉渐渗片段的BC₁F₂单株与轮回亲本泗棉2号回交，构建BC₂F₃和BC₂F₄分离群体，通过两年的田间重复试验验证该QTL的位置与效应。结果表明，该QTL (qFMIC-7-1)在BC₂F₃、BC₂F₄世代均被检测到，位于相同的标记区间，分别可以解释9.0%、8.8%的表型变异，增效基因来源于野生种克劳茨基棉，与BC₁F₂群体定位结果基本一致。同时在第7染色体上检测到另一马克隆值QTL (qFMIC-7-2)，同样在BC₂F₃、BC₂F₄两个世代均能够被检测到，分别可以解释3.7%、4.7%的表型变异，但增效基因均来源于泗棉2号。

Molecular Mapping and Identification of QTLs for Fiber Micronaire on Chromosome 7 from Gossypium klotzschianum

Gossypium klotzschianum, carrying the elite alleles, is a diploid species of D genome originated from Galapagos Island, harboring the lethal genes to cause inconsistency of apical bud growth. In this research, we overcame the obstacle and established a BC1F2 population derived from (Simian 2 × G. klotzschianum) × Simian 2 (G. hirsutum). The SSR marker NAU1362 on chro-mosome 7 showed significant correlation with micronaire value by single marker analysis. The BC2F3 and BC2F4 populations were developed from the cross between BC1F2 individuals containing target segments of chromosome 7 from G. klotzschianum and recurrent parent Simian 2. The software Cartographer (V2.5) and the composite interval mapping were further employed to identify quantitative trait loci (QTL) associated with fiber micronaire in two generations. The fiber micronaire QTL qFMIC-7-1 identified in BC1F2 population was confirmed in BC2F3 and BC2F4, which explained 9.0% and 8.8% of the phenotypic variances, respectively. The G. klotzschianum allele decreased the fiber micronaire value. Another micronaire QTL, qFMIC-7-2, on chromo-some 7 was also detected in BC2F3 and BC2F4 generations with phenotypic variance of 3.7% and 4.7%, respectively. Simian 2 was genotyped as decreased micronaire value. These results provide valuable resources for effectively utilization of potential elite genes from G. klotzschianum.