Genetic diversity of six reproductive characters was studied in 50 Elymus nutans populations collected from various regions of Gansu, Qinghai and Sichuan provinces in China. The characters included ear length,ear width, spikelet number per ear, seed length, awn length and thousand-seed weight. Shannon-Weaver index analysis showed that there was an abundant genetic diversity (H1= 1. 873) among populations. The genetic variation within populations (63.8％) was greater than that between populations (36.2％). Genetic variation was different for each character, that for ear width (CV=0. 347 2) was the greatest while seed length (CV=0. 118 4) was the smallest. The 50 populations were divided into three groups by cluster analysis. All reproductive characters were correlated to various extents with altitude, latitude, longitude, mean annual temperature and annual precipitation. Ear length and spikelet number per ear were highly significantly correlated with altitude and mean annual temperature (P＜0.01). Plans for the utilization and protection of E. nutans are proposed.%对采自甘肃、青海以及四川等地的50个垂穗披碱草居群的穗长、穗宽、每穗小穗数、种长、芒长和千粒重等6个与其繁殖相关的性状进行了遗传多样性研究.Shannon-weaver指数分析显示,50个居群在形态性状上具有丰富的遗传多样性(H′=1.873).遗传多样性主要集中在居群内部(63.8%),居群间存在一定的遗传变异(36.2%).各性状间的遗传变异具有不均衡性,穗宽变异较大(CV=0.347 2),种长变异最小(CV=0.1184).聚类分析表明,50个居群可分为3组;相关分析结果表明,海拔、经度、纬度、年均温和年均降水量对垂穗披碱草的繁殖性状变异有不同程度的影响,其中海拔和年均温对穗长和每穗小穗数影响极显著(P＜0.01).此外,提出了垂穗披碱草的利用和保护建议.
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