Abstract: To provide the fundamental evidences of screening,utilizing and breeding for germplasm resources of covered oats (Avena sativa L.) in alpine region of Qinghai-Tibet plateau,phenotypic diversity originating from a set of 590 covered oat cultivars were compared through analyzing 9 qualitative traits and 16 quantitative traits of spikelet. We observed that grain color (1.48) was the highest index in 9 qualitative traits of the genetic diversity;by contrast,the shape of awn was lowest. Moreover,inflorescence length (2.06) was the highest index among 16 quantitative characteristics to demonstrate the phenotypic diversity;in contrast,the number of flowers in main spike was lowest (1.71). The coefficient index of empty floret number was highest (63.97%) while the length of seed was lowest (10.98%). In addition,sampled oat cultivars were categorized into five groups on the basis of their qualitative and quantitative traits;the fifth groups could be used as parental materials for breeding high seed yields,the third group could be considered as a candidate for seed source conservation and utilization. The principal component analysis (PCA) results indicated that the number of flowers in spikelet,weight of seeds,seeds number and weight originating from single plant could be considered as the most important variables to interpret the PCA results in the first and second axis,and the cumulating contribution ratio was 50.59% to interpret these variances.

Key words: Covered oats, Spikelet, Phenotypic traits, Cluster analysis, Genetic diversity

摘要： 本研究以590份皮燕麦(Avena sativa L.)种质资源为研究对象，利用主成分和聚类分析方法，评价其穗部表型性状的遗传变异水平，为青藏高原高寒区皮燕麦种质资源的筛选、利用和品种选育等提供理论依据。结果表明：质量性状遗传多样性指数以粒色最高(1.48)，芒型最低(0.65)；数量性状遗传多样性指数以花序长最大(2.06)，小花数最小(1.71)；变异系数空铃数(63.97%)最大，粒长最小(10.98%)。聚类分析将资源分为5大类群，其中第5类群可作种用型育种目标亲本，第3类群可作核心种质进一步筛选利用。主成分分析表明，第一主成分中主穗粒数和粒重、单株籽粒数和粒重载荷较高，第二主成分中小花数、小穗粒数和粒宽载荷较高，累计贡献率达50.59%。

关键词: 皮燕麦, 穗部, 表型性状, 聚类分析, 遗传多样性