Abstract: The critical-day length inducing the fertility changes of late keng Nong-Ken 58(A-B) and E-Yi 105(A-B) was 13.75-14.00 hours during secondary rachis-branch and spikelet primordia to pollen mother cell formation stage, sterile pollens would be induced by day-length above 14.00 hours. If the long dark period was interrupted by light intensity above 50 lx for l hour or 200 lx for 15 minutes, the sterile plants were also induced as treated under long-day condition. It was thus clear that actually the long dark period determined the pollen fertility of HPGMR. The critical dark period would be 10.00-10.15 hours, the critical light intensity which determined fertility of HPGMR was 5-50 lx, the effects of intensity below 5 lx similar to dark-period and above 50 lx as long-day photo-period. Light period above 50 lx before sunrise and after sunset might be the cause of the difference between artificial light and natural sunshine for inducing fertility changes in HPGMR. These results would be used as a basis to forecast the suitable region and seasons for producing hybrid and self seeds using HPGMR.

Key words: Hubei photo-sensitive genic male sterile rice (O. sativa), photoperiod, fertility change, day length, light intensity

摘要： 湖北光周期敏感核不育水稻是湖北省发现培育的新不育材料，其育性转变受日照长度所控制。本研究通过人工光照和自然日照的调控等手段，初步探明了诱导育性转变的光周期的临界光照长度、光周期阈光值、暗期连续性的作用等。并对曙、暮光在诱导育性转变中的作用进行了论述。

关键词: 湖北光敏感核不育水稻, 光周期, 育性转变, 日长, 光强