光长和温度变化对光（温）敏核雄性不育水稻育性的影响

EFFECT OF DAY LENGTH AND TEMPERATURE ON THE FERTILITY IN PHOTO(THERMO)-SENSITIVE GENIC MALESTERILE RICE

分期播种试验说明７００１Ｓ，Ｎ５０４７Ｓ和Ｍ１０５－９Ｓ三个ＰＧＭＳＲ在上海自然条件下的育性转换期为８月底至９月初，Ｃ４０７Ｓ育性转换期不明确。在长光下，８５３１１１Ｓ光周期反应强，光周期反应天数为７１ｄ，结实率为０，在小穗雄蕊原基突起后进入长光便开始转入可育，以后就对光周期反应不敏感。在长光下７００１Ｓ和Ｅ４７Ｓ花粉尘不育，３１１１６Ｓ有少量花粉表现正常，高温或低温对花粉育性亦有影响；在较适条件下，多数ＰＧＭＳＲ可育花粉率较低。在高温条件下，ＴＧＭＳＲ二九青Ｓ和８９０２Ｓ花粉接近全不育；安农Ｓ－１无花粉，低温或长光对它们花粉育性也有影响。在较适宜条件下，这些ＴＧＭＳＲ的可育花粉率同样不高。供试的ＰＧＭＳＲ和ＴＧＭＳＲ花粉败育主要表现为典败。作者认为光（温）敏核雄性不育水稻的遗传特性决定其花粉本身的“脆弱性”，其雄性细胞发育过程易受不良条件影响，即使在较适宜条件下，绝大多数核不育系水稻正常花粉率亦较低，是值得注意的一个特点。

Results of sowing date experiment under natural conditions in Shanghai(30°12′N)indicated fertility transition from sterility to fertility occurred within late August to early September in PGMSR(7001S, N50475 and M105-9S). Seed setting rate in C407S from North China decreased with delay of sowing date. This indicated fertility transition date varied with different PGMSR. A photoperiod-sensitive japonica male-sterile line 853111S is very sensitive to day length, the growth period before heading was 71 days longer under long day (15.5 h, 25℃)conditions than under short day conditions, and the expression of sterility was stable. This revealed that although the development of panicle could be retarded by LD before the primordia initiation of spikelets, but it became insensitive afterwards. The effect of day length and temperature on the pollen fertility in 5 lines of PGMSR and 3 lines of TGMSR were also investigated in phytotron. Pollens of 7001S and E47S aborted completely but a little part of 31116S pollens appeared normal under long day photoperiod(25℃, 15 h)conditions. High temperature (HT, 30℃) or lower temperature (LT, 20℃)affected also the pollen fertility for these lines. However, under nearly favourable conditions (SD, 25℃),fertile pollen rates in most of PGMSR were low. At HT, TGMSR(ErjiuqingS and 8902S)were nearly completely sterile. AnnongS-1 pollens aborted throughout and no pollens could be observed in the anthers. LT affected also pollen fertility in ErjiuqingS as well as AnnongS-1.The pollen fertility in 8902S was very low under LD conditions. Even under SD conditions,fertile pollen rate of TGMSR was rather low. And in PGMSR as well as TGMSR tested,most pollen abortive types were mainly'typical abortion'. Authors suggested that the genetic character in PGMSR and TGMSR determined their pollens′ own 'weakness'. Their developmental duration before panicle differentiation not only was sensitive to photoperiod and temperature, but also would be prolonged easily under some unfavourable HT, LT or LD conditions. Even under favourable conditions, the normal pollen rate was comparatively low. Thus it seems a common character for most of the genie male-sterile line rice.