Male and female gamete abortions and reduced affi

Authors: H Y Liu C G Xu Qifa Zhang

Publish Date: 2004/05/06

Volume: 17, Issue: 2, Pages: 55-62

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Abstract

Hybrid sterility frequently occurs in crosses between indica and japonica subspecies of Asian cultivated rice In this study we investigated the cytological processes involved in formation and development of male and female gametes as well as their interactions in fertilization using an indica/japonica hybrid in comparison with an indica/indica hybrid It was found that more than 50 of the microspores generated in the indica/japonica hybrid could not develop into functional pollen The abortion rate of microspores in the indica/japonica hybrid was much higher than that in the indica/indica hybrid Abortive embryo sacs made up roughly 70 of the embryo sacs examined in the indica/japonica hybrid which was also much higher than that detected in the indica/indica hybrid Moreover the amount of pollen adherence on stigmas of the indica variety upon handpollination with pollen from the japonica variety was much lower than the indica/indica pollination and the number of pollen adhered on the stigmas by natural selfpollination was much greater in the indica/indica hybrid than in the indica/japonica hybrid The indica/japonica hybrid also encountered difficulties in pollen tube growth after pollination and the fertilization rate of the indica/japonica hybrid was much lower than that of the indica/indica hybrid These results clearly illustrate the complexity of the mechanisms underlying intersubspecific hybrid sterility in rice involving both pre and postzygotic reproductive isolation mechanisms

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