期 刊 ：植物遗传资源学报 2015年 16卷 1期
Keywords:Watermelon, Variation coefficient, Diversity index, Cluster Analysis,
摘 要 ：采用变异系数、多样性指数和聚类分析等方法，对国内外 783 份西瓜种质资源 24 个性状进行遗传多样性研究。结果表明：西瓜种质资源13个数量性状的平均变异系数为23.79%，其中单果质量变异系数最大(54.82％)，第一雌花节位最小(0.48％)。11个质量性状的平均变异系数为39.95％，变异系数最大的是种皮覆纹颜色(70.90%)，最小的是茎断面形状(17.95％)。数量性状的平均遗传多样性指数为2.08，质量性状的平均遗传多样性指数为1.23；叶纵径(2.29)、叶横径(2.24)、果实皮厚(2.24)、果实横径(2.23)、果实生育期(2.19)、茎节间长度(2.09)、果实纵径(2.07)、百粒重(2.07)、单瓜种子数(2.04)多样性系数均较大，茎断面形状多样性系数最小(0.59)。基于24个表型性状，供试西瓜材料在欧氏距离为25时聚为2类：A类为普通西瓜种(Citrullus lanatus)；B类为药西瓜（Citrullus colocynthis）。在欧氏距离为20时聚为3类：A1为Citrullus lanatus的普通西瓜亚种(sp.vulgaris)，A2为毛西瓜亚种（sp.lanatus），B类为Citrullus colocynthis的淡味药西瓜亚种(sp.insipidus)。在欧氏距离为15时A11为sp.vulgaris的普通西瓜变种（var.vulgaris），A12为sp.vulgaris的籽瓜变种（var.megalaspermus），A2为sp.lanatus的开普西瓜变种（var.capensis）。西瓜种质资源表型性状的变异程度和多样性指数较高，具有丰富的变异程度和多样性。欧氏距离25可作为西瓜属内划分物种的遗传距离，20可作为划分西瓜亚种的遗传距离，15可作为西瓜变种划分的遗传距离。
Abstract:In order to efficiently use watermelon germplasm，this study analyzed and compared the genetic diversity of 24 main characters of 783 germplasms using genetic diversity indexes，coefficient ofvariation，and cluster analysis． The results showed that coefficient of variation(CV)values of the 13 quantitative characters ranged from 0.48%(The first female flowers node) to 54.82%(Single fruit weight)with an average of 23.79%. CV values of the 11 qualitative characters ranged from17.95%(Stem section shape)to 70.90%(Seed speckle color)with an average of 39.95%. The average diversity indexes( H′) of the quantitative characters was 2.08, and the average diversity indexes(H′) of the qualitative characters was 1.23. The characters with higher diversity indexes(H′)wereleaf longitudinal diameter(2.29)，leaf transverse diameter(2.24)，the fruit peel thickness(2.24)，fruit transect diameter(2.23), fruit development period(2.19), length between nodes(2.09), fruit longitudinal diameter(2.07), 100-seed weight(2.07), Seed per fruit(2.04). Based on clustering analysis of 24 phenotypic traits, the 783 collections, at the Euclidean distance of 25, could be divided into 2 broad headings：A was Citrullus lanatus；B was Citrullus colocynthis. The collections were further classified into 3 categories by cluster analysis at the genetic distance of 20: A1 was sp.vulgaris, A2 was sp.lanatus, B was sp.insipidus. at the Euclidean distance of 15，A11 was var.vulgaris, A12 was var.megalaspermus. A2 was var.capensis. Coefficients of variation(CV)and diversity indexes(H′) of watermelon phenotypic traits were high，indicating that watermelon have abundant variation and diversity.Euclidean distance 25 Can be used as a watermelon divide into species genetic distance，20 can be used as a watermelon divide into subspecies Genetic distance，15 can be used as a watermelon divide into varietas Genetic distance.