Abstract: Rice 603 is a line derived from an interspecific hybridization Oryza sativa/O. longistaminata. There was no segregation in F₃ of this line. Line 461 is a descendant of a compound cross of 603 with a F₁, and no segregation was found since F₂. The nonsegregation of these two lines suggested the possibility of apomixis in their embryo development. The adventitious embryos were found in less than 10% of the examinated pistils of 603 and 461. There were abnormal numbers of bivalents in diakinesis of the PMCs: 3, 6, 8, 9, 10, 11 bivalents instead of 12. Micronucleus were observed in tetrads, microspores and in mature pollen grains of both 603 and 461 lines. It seems reasonable to suppose that the abnormal sperms induce the parthenogenesis of egg cell during self-pollination in both 603 and 461 lines.

Key words: apomixis, interspecific hybrid, microspore development

关键词: 小孢子, 发育, 杂种, 远缘杂交, 水稻