中文摘要：

对我国各地257份有代表性的甜瓜种质资源的20个形态性状进行调查分析,研究其遗传多样性。结果表明,7个质量性状（果实形状、果皮底色、覆纹颜色、覆纹形状、果肉颜色、果肉质地和种子颜色）和6个数量性状（果实横径、果实纵径、单果鲜重、果肉厚度、可溶性固形物含量和种子千粒重）差异明显,其Shannon’s指数分别大于1.00和1.50。所有种质的20个形态性状的平均遗传多样性指数为1.20,不同地区种质资源遗传多样性差异明显,多样性指数高低次序分别为：西北（1.48）、华中（1.32）、华东（1.22）、华北（1.17）、东北（1.13）和华南（0.89）。主坐标分析（PCO）将所有种质划分为3个区域,即厚皮种质优势区、厚皮和薄皮种质混合分布区、薄皮种质优势区,不同地区的种质在PCO图上的分布差异明显,西北地区的厚皮甜瓜种质和华中、华东地区的薄皮甜瓜种质广泛分布于3个区域中,其形态遗传多样性比其他地区的种质更加丰富,支持了新疆地区为厚皮甜瓜次级起源中心、黄淮及长江流域为薄皮甜瓜初级起源中心的观点。

英文摘要：

Genetic diversity of 257 representative melon germplasms from various regions in China was studied based on the investigation of 20 morphological characters.The results showed that the obvious difference was observed with the seven qualitative characters（fruit shape,ground color of fruit skin,vein color of fruit skin,vein shape of fruit skin,flesh color,flesh texture,and seed coat color） and the six quantitative characters（fruit diameter,fruit length,fresh weight of single fruit,fruit thickness,soluble solid content,and 1000-seed weight）.The Shannon’s indices of the seven qualitative characters and the six quantitative characters exceeded 1.00 and 1.50,respectively.The mean Shannon’s index of 20 morphological characters of all the melon germplasms reached to 1.20,and the degree of genetic diversity between various regions was distinctly different.The upper-to-lower older of the various regions based on their Shannon’s indices was Northwest China（1.48）,Central China（1.32）,East China（1.22）,North China（1.17）,Northeast China（1.13）,and South China（0.89）.Principal coordinate analysis（PCO） divided all the germplasms into three regions,i.e.,dominant region for thick-skin germplasms,mixed-distribution region for chick-skin/thin-skin germplasms,and dominant region for thin-skin germplasms.The melon germplasms from various regions distributed differently in the PCO diagram.The thick-skin germplasms from Northwest China widely distributed cross the three regions and revealed higher genetic diversity,so did the thin-skin germplasms from Centralskin melon.