Abstract:

The study of the fertility change mechanism of PTGMS has been a hot topic since 1989, and the prevenient achievements have revealed the fertility alteration models of PTGMS rice in response to photoperiod and temperature condition. There have been mainly four models: the suppose of three developing phase and two photoperiod-sensitive stages, the model of light and temperature in fertility changes, the quantitative model of fertility changes and the three dimensional coordinate model of fertility conversion, and these models and theories had higher utilization values in directing two-line hybrid production. In this paper, fertility photo-thermo characteristics, developmental photo-sensitivity and their relationships in PTGMS rice C815S and its homologous plant lines were studied in 12 controlled combination treatments of 3 daylength with 4 lower temperature, treatments of shading, and short photoperiod, and the treatments of different rowing date. The results showed that C815S and its homologous plant lines were a type of typical lower thermo-sensitivity sterile line and their low critical temperature was below 23.0℃. In Changsha, there were no obvious fertility fluctuation and alteration from sterility to fertility under the long daylength condition while there was slight fertility fluctuation under the short daylength condition. The different degrees of photoperiod sensitivity sterility in C815S and its homologous plant lines were a result of the interaction of daylength ×temperature, and there would be some internal relation between the interaction and developmental photoperiod sensitivity. The interaction of daylength ×temperature was further discussed and the interdynamic effect model of daylength and temperature, being of the quantitative fertility response to photoperiod and temperature, was supposed. This hypothesis can offer the corresponding temperature for fertility alteration under the determinate daylength, being used in the selection of PTGMS, hybrid seed production and propagation of PTGMS scientifically. According to this hypothesis, the breeding strategy of selecting the practical two-line genic sterile line can be put forward in the corresponding environment.

Key words: PTGMS, Fertility alteration, Photo-period sensitivity sterility, Developmental photo-sensitivity