陆地棉种质资源抗旱性状的关联分析

干旱是导致全世界棉花严重减产、纤维品质下降的重要因素,因此获得高产、优质、耐旱的棉花新品种一直是棉花的育种目标。本研究选取217份陆地棉栽培种组成的自然群体为研究对象,采用全生育期处理组灌水量为对照组50%的干旱胁迫处理,并在处理后期对217份材料的株高、衣分、单铃重等18个性状进行2年2点的表型鉴定,干旱胁迫后,群体间响应差异明显,多个表型性状在对照和处理间表现显著差异。通过BLUP分析表型数据并计算各性状的抗旱系数;全基因组范围选取的214对多态性SSR分子标记扫描群体,共检测到393个多态性位点,基因多样性系数平均值为0.402,范围为0.072~0.631,PIC值平均为0.329,范围为0.070~0.560;群体结构分析表明,该群体可分为2个亚群。用上述SSR标记分别对18个性状的抗旱系数进行关联分析,共关联到76个极显著位点(P<0.01),表型变异解释率为2.930%~7.218%,其中共有14个标记位点能同时被2种或以上性状检测到。研究结果可为后期棉花杂交育种亲本选择及抗旱分子标记辅助育种提供理论基础及参考依据。

Association analysis of drought tolerance traits of upland cotton accessions(Gossypium hirsutum L.)

Drought stress is an important factor that leads to severe reduction in cotton fiber yield and quality worldwide,and new cotton varieties with high-yield,high-quality and drought-tolerant characteristics have been the goal for cotton breeding.In this study,217 upland cotton accessions were selected for drought stress experiments and association study.The drought stress treatment panels were supplied with 50%the water volume of the controls,until the seedlings emerged.A total of 18 traits including agronomic traits,fiber yield indices and fiber quality indices,were investigated at two locations and for two years.After drought stress,there were significant differences in response between populations,and significant differences in phenotypic traits between control and treatments.The phenotypic data were analyzed by BLUP,and the drought resistance coefficient of each trait was calculated.A total of 393 loci were detected by 214 SSR marker in the tested cotton accessions.The average gene diversity coefficient was 0.402,with the range of 0.072–0.631;and the average PIC value was 0.329,ranging from 0.070 to 0.560.Genetic structure analysis showed that the group could be divided into two subgroups and it had no obvious correspondence with geographical origin.There were detected extremely 76 significant loci(P<0.01),with explanation rate ranging from 2.931%to 7.218%,by association study using drought resistance coefficient(DRC)of 18 traits.Fourteen SSR marker could be detected by two or more traits at the same time.These results could provide a theoretical basis and reference for the parents selection and drought-resistant molecular marker-assisted breeding in cotton.