西南山地丘陵生态区主要玉米自交系SSR遗传多态性及其与杂种优势的关系

SSR Genetic Polymorphism among Major Maize Inbred Lines in Southwest Mountain and Hill Ecological Region and its Relationships in Heterosis

选用遍布玉米全基因组的SSR引物 ,检测西南山地丘陵生态区主要玉米自交系的遗传多态性 ,以此估算自交系间DNA分子遗传距离并进行聚类分析 ,将 119个自交系划分为 14个类群 ,与自交系的亲缘关系具有较好的一致性。西南山地丘陵生态区的地方种质资源中 ,蕴藏着丰富的遗传变异 ,不能将其简单地划入任何杂交优势群。再从不同及相同类群中选取相互间遗传距离呈梯状分布 ,全国大面积推广杂交种的 9个亲本自交系 ,组配成 36个完全双列杂交组合 ,测定杂交种籽粒产量及其一般配合力和特殊配合力。简单相关、多元回归和通径分析表明 ,虽然杂交种的平均单株籽粒产量及其特殊配合力 ,与亲本自交系间分子遗传距离相关不显著 ,但亲本自交系间分子遗传距离通过父本自交系一般配合力对平均单株籽粒产量的间接作用较大 ,平均单株籽粒产量与母本自交系一般配合力、父本自交系一般配合力和双亲自交系间分子遗传距离的多元回归关系达极显著水平 ,可以此预测杂交种 75 %的产量变异。

SSR primers located all over maize genome were used to detect genetic polymorphism among major maize inbred lines in Southwest mountain and hill ecological region. DNA molecular genetic distance among these inbred lines were estimated and used to cluster the 119 inbred lines into 14 groups, that generally conformed to the pedigrees of the inbred lines. Abundant genetic diversity was stored in local germplasm resources in Southwest mountain and hill ecological region and heterosis group relationship of these resources should be researched furtherly. 9 popularized parent inbred lines with ladder distribution of genetic distance were chose among and within the groups and used to make 36 complete diallel cross combinations and investigate kernel yield and its general and specific combining abilities. Simple correlation, multiple regression and path analysis showed that indirect effect from molecular genetic distance between parent inbred lines through general combining ability of male parent inbred line to average kernel yield per plant of hybrid was significant and 75% yield variance of hybrid could be forecasted by significant multiple regression between average kernel yield per plant of hybrid and general combining abilities of female and male parent inbred lines and their molecular genetic distance, although no significance of simple correlation was found between molecular genetic distance among parent inbred lines and average kernel yield per plant of hybrid as well as its specific combing ability.