苦瓜种质遗传多样性的SRAP标记分析

Genetic Diversity Analysis of Bitter Gourd Germplasm Resources Based on SRAP Markers

从144对SRAP引物中筛选出61对多态性强、重复性好的SRAP引物,对43份苦瓜种质DNA进行了扩增,共得到2078条谱带,其中多态性谱带863条,平均每对引物扩增得到14.15条多态性谱带,多态性位点百分率为42.11%。用UPM-GA方法进行聚类分析,供试苦瓜种质的遗传相似系数为0.50～0.95,在阈值0.65处(L1)可将苦瓜分为2个类群,第Ⅰ类群为野生种,第Ⅱ类群为半栽培种和栽培种;在阈值0.80处(L2)将第Ⅱ类群分为5个亚类群,L2的划分反映了苦瓜种质间的遗传多样性与果实性状、来源或地理分布有较高相关性;在阈值0.83处,第Ⅱ类群1亚类群又分为4类,大致分为滑身苦瓜(粗棱无瘤)、大顶苦瓜(棱细大圆瘤、倒锥形)、棱细圆瘤苦瓜以及尖刺瘤或凸瘤苦瓜,分类结果与苦瓜的刺瘤有无、棱条粗细、瘤的形状和瓜色等密切相关,初步认为刺瘤苦瓜为较原始类型。

61 pairs of SRAP primers with rich polymorphism and good repeatability were chosen from 144 test- ed pairs and used to amplify genomic DNA of 43 accessions of bitter gourds. A total of 2078 amplicons were ob- tained of which 863 （42. 11% ）were polymorphic, with an average of 14. 15 polymorphisms observed per primer pair. Cluster analysis was conducted using UPMGA method. It was concluded that the genetic similarity among 43 bitter gourd germplasms ranged from 0.50 to 0.95. All accessions were clustered broadly into two groups at the simi- larity coefficient of 0.65. The first group included wild accessions and the second group consisted of semi-cultivated and cultivated accessions. The second group was further divided into five subgroups at the similarity coefficient of 0.80 （L2）. The L2 division reflected a high correlation between genetic diversity and fruit characters, sources, and geo- graphic distribution. The first subgroups was further divided into four groups at the similarity coefficient of 0.83, broadly divided into oblong bitter gourd, triangular bitter gourd ,fine-ridge and rounded wart bitter gourd, and acute or obtuse wart bitter gourd. Classification results turned out to be closely related to the traits of presence or absence of acute wart,width of ridge,wart shape, and fruit color. It was speculated that acute wart bitter gourd is a primitive type.