抗虫棉数量性状遗传距离与杂种优势关系的研究

通过对31份抗虫棉种质资源材料的10个数量性状的主成分分析和聚类分析,并采用作图法,研究了数量性状遗传距离与杂种优势指数之间的关系。31份抗虫棉种质资源的10个数量性状可归纳为5个主成分因子,其累积贡献率达87.39%。在评价抗虫棉种质资源时,首先应考虑单株结铃数和衣分等产量结构因子,其次为株型因子,最后考虑果枝始节、生育期及早熟性等因子。31份种质资源被归为4组,地理远近和亲缘关系与遗传距离并不存在必然联系。遗传距离与杂种优势的关系较为复杂,并非遗传距离越大杂种优势越明显。在进行抗虫棉种质资源评价时,不能以地理来源或亲缘关系为唯一标准;在亲本选配时,应选择遗传距离中等偏大的材料。

Study of the Relationship between Genetic Distance and Heterosis in Insect Resistant Cotton

The key components analysis and cluster analysis were performed for 10 quantity traits in 31 insect resistant cotton germplasms.The relationship between the genetic distances of quantity traits and heterosis was also studied by mapping.10 quantity traits in 31 insect resistant cotton germplasms could be concluded to 5 main factors.The contribution of the 5 main factors to total variation of population studied accounted for 87.39%.During evaluating the insect resistant cotton germplasm,the yield construction factor,as bolls per plant and lint percentage etc.,should be considered firstly.Then,the plant type should be chosen,and finally the factor of height of fruit branch,growth period and prematurity be considered.31 insect resistant cotton germplasms were classified into 4 groups.There wasn't necessary relationship among the geographic distance,the pedigree and genetic distance.The relationship between the genetic distance and heterosis was complicated.The largest genetic distance couldn't mean the best heterosis.To evaluate the insect resistant cotton germplasm,geography origin and pedigree shouldn't be only depended on.Selecting parents with medium genetic distance may gain stronger heterosis.