杂交稻亲本间成穗率QTL-SSR遗传距离与配合力及杂种优势的关系

Relationship between QTL-SSR marker based genetic distance,combining ability,and heterosis of productive tiller percentage in hybrid rice

【目的】探讨应用分子标记预测杂交稻F1茎蘖成穗率的配合力效应及杂种优势的可行性,为杂交稻亲本的茎蘖成穗性状改良及选配提供理论依据。【方法】利用与成穗率QTL连锁的56个SSR标记检测了13个杂交稻亲本(7个不育系和6个恢复系)之间的遗传距离,结合42个F1杂交组合(7×6NCⅡ)的成穗率表现,对亲本间的QTL-SSR遗传距离与杂种F1的配合力效应及杂种优势进行相关分析。【结果】13个亲本间的QTL-SSR遗传距离为0.15～0.53,平均为0.33;以相似系数0.65为标准可将13个亲本划分为2大类群。亲本间QTL-SSR遗传距离与F1双亲一般配合力之和呈极显著正相关(r=0.614),而与F1特殊配合力相关不显著(r=0.033);亲本间QTL-SSR遗传距离与F1中亲优势、超低亲优势分别呈极显著负相关(r=-0.523)和显著负相关(r=-0.373)。【结论】在一定范围内,杂交稻亲本间QTL-SSR遗传距离的大小可以反映F1成穗率性状的双亲一般配合力总效应,并能预测F1的杂种优势。

【Objective】 The feasibility of using molecular markers based parental genetic distances（GD）to estimate combining ability and heterosis of productive tiller percentage（PTP）in hybrid rice was discussed.【Method】 GD among 13 parents of hybrid rice（7 male sterile lines and 6 restorer lines）were examined using 56 SSR markers linked to QTLs of PTP.The relationship between GD,combining ability and heterosis was analyzed based on the performance of 42 F1 hybrids crossed by a 7×6 diallel crossing method.【Result】 GD among the 13 parents based on QTL-SSR marker were ranged from 0.15 to 0.53 with an average of 0.33,and these parents could be classified into two groups.The correlation between GD and the sum of two parents＇ GCAs（r=0.614）was significant,but was not significant between GD and SCA（r=0.033）.The correlations of GD with mid parent heterosis and low parent heterosis were also significant,and the coefficients of correlations were-0.523 and-0.373,respectively.【Conclusion】 Both the sum of two parents＇ GCAs and heterosis for PPT of F1 could be reflected by QTL-SSR marker based GD.