黄瓜数量性状遗传距离与杂种优势关系的研究

探讨数量性状遗传距离与杂种优势的关系,为黄瓜新品种的选育提供理论依据。选择5份黄瓜自交系材料作为母本,6份黄瓜自交系材料作为父本,按半双列杂交法配制出29个杂交组合,对11份黄瓜自交系材料的7个数量性状进行杂种优势分析和聚类分析,并研究数量性状遗传距离与杂种优势的关系。研究结果表明,各数量性状均有不同程度的正向杂种优势,其中株高、结瓜数和单株产量的杂种优势最为明显,而单果重、主蔓20节内雌花数、果实长和果实粗的杂种优势比较微弱。11份黄瓜自交系被分为3大类群,地理远近与遗传距离之间并不存在必然的联系。结瓜数的中亲优势指数和杂种优势指数、果实长和果实粗的中亲优势指数及单株产量的超亲优势指数与亲本遗传距离之间存在显著的相关关系,而株高、单株产量的中亲优势指数和杂种优势指数与亲本遗传距离之间存在极显著的相关关系,大部分数量性状的杂种优势都随着遗传距离的增大而增大。在进行黄瓜种质资源评价时,不能以地理关系作为唯一标准;在进行黄瓜杂交育种时,可根据育种目标,适当选择较大的遗传距离来获得杂种优势。

The Relationship Between Genetic Distance and Heterosis in Cucumber

The aim is to study the relationship between genetic distance and heterosis, and to provide basic genetic theory for cucumber variety breeding. The materials consisted of five female parents, six male parents and their 29 F_l hybrids obtained by half diallel method. The heterosis analysis and cluster analysis were performed to study 7 quantitative characters of 11 cucumber germplasms. The correlation between genetic distances and heterosis was analyzed by using the 7 quantitative characters in cucumber. The results showed that the heterosis of all quantitative characters was positive. The heterosis of plant height, the number of yielded melons and the single plant yield was the most obvious, but the heterosis of single fruit weight, the number of female flowers, the length of fruits and the size of fruits was relatively weak. 11 cucumber germplasms were classified into 3 groups. There was no definite relationship between the geographic distance and the genetic distance. The relationship of genetic distance of plant height, the number of yielded melons, the single plant yield, the length of fruits and the size of fruits between parents and mid-plant heterosis and heterobeltiosis was highly significant. The heterosis of most characters increased with the genetic distance. To evaluate cucumber germplasms, geography origin should not be the only standard. Selecting parents with larger genetic distance might gain stronger heterosis.