Studies on photo /thermo sensitive characteristics of male fertility conversion for a rice male sterile line Peiai 64S

The photo /thermo sensitive characteristics of male fertility conversion for purifed and unpurified populations of a rice male sterile line Peiai 64S were investigated under different treatments of photoperiod and temperature combinations in phytotron and in greenhouse in winter, Guangzhou. The results showed that Peiai 64S was strongly sensitive to photoperiods at both stages of vegetative growth and pancical development under the condition of average temperature 20~25℃. Although both populations, purified and unpurified, segregated in critical photoperiod and temperature, the purified population had smaller variation in critical photoperiod and temperature than the unpurified one. The average sterile spikelet rate on selfing of the purified population treated with 13 h/24℃ was 99 6%, and reached the sterility standard of practical P/TGMS lines by the national “863” program. It could be used for seed production in the regions or the seasons with the photoperiod of longer than 13h and average temperature of over 24℃.