【摘要】 籼粳稻亚种间正反交多组合杂种不育的考察,表明籼粳杂种F₁普遍出现结实率不同程度降低,不实率随品种组合而异,有株间分离,穗间变异,正反交差异。数据变异幅度很宽而且不稳定。分析了不同方式回交与单穗选育所得的F₂数据,表明杂种不育的分布可因反回交而缩小,不实率可因选穗而提高。对杂种花粉育性作统计,表明籼粳杂交普遍使花粉趋于败育,花粉育性有分离与变异。作图表明花粉败育率与种子不实率呈直线相关。根据上述结果,对不育基因的假说进行了讨论;认为亚种间杂交中异源细胞质的竹用是小孢子发育发生波动的决定因素。提出了籼粳杂种不育遗传基础的模型,其中心环节是细胞质内蛋白质与酶的平衡在籼粳杂合基因组作用下发生了摆动。更多还原

【Abstract】 Investigations made on the reciprocal crosses between indica and japonica revealed that seed sterility generally occurred in different degree in the hybrids,the percentage of sterility varied with the parental cultivars used,segregation among plants and variation among panicles were observed in F1 and F2,reciprocal crosses always gave different results and numerical variation appeared in.large measure and variable.Analyses were made on F2 data collected from different cases of backcross and from cultures of selected single spike.Pollens collected from intervarietal hybrids were differentially assorted.Pollen sterility generally occurred in intervarietal hybridization,segregation and variation,were observed in every case.On plotting the percentage of pollen sterility against the percentage of seed sterility,the dependence of the latter on the former appeared quite evident.Based on these facts,it is suggested that semi sterility of rice hybrid would not be considered as an.unit class.The gene(s) and the cytoplasmic gene(s) hypotheses about sterility are separately discussed.It seems that in the case of intervarietal cross,effects of hetereogenetic cytoplasm on the microsporogenesis would be considered as a determinant factor.Hence,a model describing the genetic basis for intervarietal sterility is suggected as depicted in figure 3.更多还原