水稻籼粳杂种不育性的多基因遗传不平衡

POLYGENIC UNBALANCE ACCOUNTED FOR F_1 STERILITY IN REMOTE CROSSES OF RICE

本文研究和讨论了水稻亚种间远缘杂种不育性的起源。就杂种不育性的遗传本质,作者提出了多基因遗传不平衡假说:远缘杂种不育性的遗传属于孢子体——配子体的互作,且存在一个多基因系统支配下的一种特殊的配子体选择方式对不育性起作用。具有r个遗传分歧的基因位点(无论连锁或独立)的远缘品种杂交F_1产生的配子中分为平衡配子和不平衡配子。平衡配子的r个基因位点为亲本基因组合类型,拥有亲本之一的整套基因系统而能正常发育;而不平衡配子含有双亲的部分基因系统,由于遗传分歧双亲的基因系统在单倍性细胞中不能很好地配合协调或互补,发育过程的障碍就可能产生败育。在平衡配子和极不平衡配子之间存在各种中间类型,配子体选择按S^(r+u)进行。我们的试验结果结合过去的研究,说明水稻亚种的分化是自然选择作用于遗传变异的结果,生殖隔离是籼亚种和粳亚种连续积累的遗传分歧的产物。

The origin of F_1 sterility and breeding strategy of heterosis were discussed. For the genetic mechanism of F_1 sterility a 'polygenic unbalance' model was postulated. The inheritance of sterility was under effect of sporo—gametophytic interaction and a specialized gametophytic selection (S^((r+u)) under the control of a polygenic system was existed. F_1 hybrid of a cross between distantly (?)elated varieties, which differed at rloci (regardless of linkage of independence) accounted for genetic diversity, should produce balance and unbalance gametophytes. For r loce genotype of balance gametophyte was of parent—type and, it possessed all r genes of one of parents and develop normally. Instead genotype of unbalance gametophyte was composed of diversified genes from distantly related parents and the gametogenesis would abort because of contradiction in the haploid cells.