摘要
通过结实率与遗传距离,遗传距离与杂种优势的相关分析发现:利用籼粳分类性状计算出的遗传距离(D_3~2)可以预测杂种后代的结实率,对克服籼粳杂交后代结实率低使优势难以利用的矛盾具有重要意义,遗传距离对后代的杂种优势预测效果因性状而异,多元分析表明:遗传距离与单株产量的杂种优势呈曲线关系;y=-18.173+8.570x-0.692x^2在一定范围内,随着遗传距离的增大,单株产量优势有增加的趋势,超过这个范围,杂种优势随遗传距离增大反而有下降的可能。综合结实率、杂种优势和遗传距离(D_3~2)的分析结果表明:选择遗传距离(D_3~2)在4.0～9.0之间,农艺性状较好的材料进行"桥梁"育种比较适宜。
Analysis of heterosis,genetic distance and correlation of traits showed that genetic distance(D_2~3)calculated from classificatory characters could be used to predicate fertilty of hybrid progeny.It is important to find a way out of the semi-fertility of progeny between indica and japonica rice crosses. The effectiveness of prediction of heterosis by genetic distance between the parents was different with various characters used in estima- tion.The result of multivariate analysis indicated that the relationship between genetic distance of parents and heterosis of grain weight per plant was curvilineal y=-18.173+8.570x-0.692x^2 and,the greater genetic distance of the parents was showed within a restricted range,the stronger heterosis of grain weight per plant. The heterosis would be decreased as genetic distance went beyond the range. Analysis of fertility,heterosis and genetic distance reveals that it is suitable for bridge breeding of indica-japonica rice if D_3~2 in traits is ranged from 4.0 to 9.0 and the parents posses nice agronomic traits.
关键词
遗传距离
籼粳杂交
亲本选配
稻
genetic distance
indca-japonica cross breeding
parent selection
