A Research On Different P(T)GMS Lines Of Rice For Application Safety Along The Yangtse Valley

Photo- / Thermo-sensitive genie male-sterile rice is a kind of important rice varieties. Two-line system hybrid rice is an important technical innovation in agriculture based on photoperiod- / thermo-sensitive genie male-sterile rice ( P(T)GMSR ) . Six practical photo-/ thermo-sensitive genie male-sterile lines,YW-2S,SE21 S, Guangzhan 63S,1103S, Pei'ai 64S and 5088S, were sequentially seeded with 10d interval under natural conditions at Wuchang in 2003 and were studied at sharp drop in temperature under artificially controlled climatic conditions; Yong panicles at their sensitve stage to temperature for fertility alteration of four indica (Oryza sativa L.) practical photo-/ thermo-sensitive genie male-sterile lines were treated with 23.4C low temperature for continuous 3 days and 5 days respectively. Main results as follows:(1) Both photoperiod and temperature are important factors controlling fertility alteration of P(T)GMS lines, none of tested sterile lines is solely photo-sensitive or thermo-sensitive type. To a certain extent, their critical temperature inducing male sterility will be lower under longer day-length and will be higher under shorter day-length. In a word, long day-length effect has compensation for low temperature to a certain extent, high temperature effect has compensation for short day-length to a certain extent.(2) Their fertility expression and characteristics of fertility alteration vary from line to line. The results showed that: the sensitive stage to temperature for fertility alteration was found to be during 21~ 13d before heading in YW-2S, young panicles at its developmental stage 4~6 (based on Ding Ying's 8 stage standard, the same below.), 18~9d in Guangzhan 63S, young panicles at its stage 5~7, 21 ~14d in 1103S, young panicles at its stage 4~6, 21-13d in Pei'ai 64S, yong panicles at its stage 4~6, 20~ 11d in 5088S, young panicles at its stage 4~7, 17~11d in SE21S, young panicles at its stage 4~7.(3) The initial date of fluctuated fertility will be earlier when young panicles at it'ssensitive stage to temperature for fertility alteration under lower temperature.(4) Young panicles at their sensitive stage to temperature for fertility alteration of four tested indica {Oryza sativa L) practical photo-/ thermo-sensitive genie male-sterile lines were treated with 23.4C low temperature for continuous 3 days and 5 days respectively. They had no selfed seeds set, but their mean pollen sterility rate was below 99.5% except YW-2S. Young panicles at their sensitive stage to temperature for fertility alteration of six tested materials were treated with 22.7C low temperature for continuous 5 days, they had showed various degrees of sterility fluctuation.(5) we also found that a sterile line with lower pollen sterile rate would not absolutely had a higher selfed seed set.At last, the technical strategies of developing P(T)GMS lines were discussed for safety application along the Yangtse Valley.