中文摘要：

为选育优良品种并对选育工作提供理论依据及参考,观测了采自海南不同地区的19份弯穗狗牙根（Cynodon arcuatus J. S. Presl ex Presl）种质的19个形态指标,并运用多种分析方法研究其形态多样性。结果表明：不同种源形态性状具有广泛的变异性。其中,叶毛、草层高度、花药颜色、直立枝和匍匐枝的叶长变异最大,其次为小穗数、花序长、草层密度、直立枝及匍匐枝叶宽、节间长、节间直径和穗枝数;而在茎色、叶色、小穗颜色和柱头颜色方面的变异幅度最小;不同种源形态性状间存在着显著或极显著的相关性。狗牙根种源草层越高大,其叶片越长,草层越密,匍匐枝越粗;在欧氏距离8.24处可将19份种质分为3类,即细叶型、普通型和宽叶型。

英文摘要：

Morphological diversity in 19 accessions of Cynodon arcuatus J.S.Presl ex Presl was estimated through nineteen morphological characteristics with numerical analyses.The aim of this study was to evaluate the genetic diversity of C.arcuatus accessions originated from different regions of Hainan Island using morphological markers and the information from this study would be beneficial for the breeding of C.arcuatus.The following results were obtained： Abundant morphological variation existed in accessions of C.arcuatus.The largest variation was found in leaf hair,sward height,anther color,leaf height of upright stem and stolon,followed by spikelet number,inflorescence length,sward density,leaf width of upright stem and stolon,internode length,internode diameter,and inflorescence branch number,and the least variation was found in colors of stem,leaf,spikelet,and stigma.There existed distinct and significant correlations among some of morphological characters of C.arcuatus accessions in Hainan.With sward height increasing,C.arcuatus became denser,longer leaves,and thicker stolons.The accessions were clustered into three major morphological types using the unweighted pair-group method with arithmetic averages（UPGMA） as fine leaf type,common leaf type,and wide leaf type.