Abstract: One photoperiod-sensitive genic male-sterile (PGMS) rice and three regular rice ( Oryza sativa asp. japonica), cultivars have been used for hybrid combinations. In order to analyse the relation between the heading sensitivity and the male-sterile sensitivity of photoperiod in Fl and F2 progenies, the expreiments were carded out in a controlled environment—the phytotron. The results showed that these three restorers had 2 pairs of restorer genes for the photoperiod sensitive male-ster-ile rice. And the heading sensitivity to photoperiod of Fl tended to late mature PGMS rice (7001S). It was also indicated that the strong response was dominant over the weak response to photoporied in both Fl and F2 generations. As the fertility segragations, the F2 progenies from those of male-sterile rice x regular rice crosses produced clear-cut segregation for both kinds. The Fz data showed that photoperied-sensitive male-sterihty is controlled by two recessive genes, producing F2 ratio of 15: 1. And the sterile plants in Fa generations, which were cultured in long day condition, are attributed to stronger response to photoperied. No sterile plant could be found in weak response progenies. Using such experimental approach, the authors predicted that the heading sensitivity and the male-sterile sensitivity of photoperied are closely related, and not independently inherited. These results also suggested that the photoporied sensitive male-sterile gene might be expressed on the basis of the ex-pression of the photoperiod sensitive alleles.

Key words: Photoperiod-sensitive genic male-sterile rice, Photoperiod sensitivity, Photoperiod-sensitive male-sterility, Developmental genetics