湖北光敏感核不育水稻农垦58S的育性转换观察

OBSERVATION ON THE FERTILITY CHANGES OF THE HUBEI PHOTOPERIOD-SENSITIVE GENIC MALE STERILE RICE NONGKEN 58S(Oryzn sativa L. Subsp. japonica)

本试验总结了湖北光敏核不育水稻农垦58S自1986～1989年在广州(23°08′N)人工处理及自然条件下育性转换的特点和诱导因素。结果表明:育性转换是一个量变到质变的过程。在不育期间不育性彻底而稳定,在可育期间可育性变化较大,有些年份只有不育期和半可育期。导致农垦58S育性转换的环境条件是光照长度、诱导天数和温度。温度提高临界光长度将减短。幼穗发育的不同时期对育性转换存在敏感度的差异,以第2次枝梗原基分化至花粉母细胞形成期敏感度最强,这段时期长光诱导可导致全不育。但短光诱导可育时,表现为诱导天数越多可育度越高。

Experiments were conducted to study the fertility change in tbe photoperiod-sensitive genic male sterile rice, Nongken 58 photoperiod-sensitive sterile line (abbr. Nongken 58S). under natural sunshine and different treatments of daylight length. The results revealed that Nongken 58S had two distinct periods of fertility change under natural condition in Guangzhou(23'08N) viz, the first ten days of June from fertility to sterility, the last ten days of August from sterility to fertility. Tbe change of fertility was a process of quantitative alteration to qualitative alteration. Tbe sterility was complete and stable in the sterile period,the fertility ,however, was rather variable in the fertile period. There were only sterile periods and semi- fertile periods in some years. The fertility of Nongken 58S was controlled by environmental factors during the development of the panicle. The panicle at different phase of development showed different sensitivity in the fertility change. Tbe most sensitive was the period from secondary rachis- branch and spikelet primordia to pollen mother cell formation stage. At these stages, the panicles induced by long daylight were completely sterile,but by short daylight, the more tbe days,the higher tbe fertility. The main factors causing fertility change were daylight length,the number of induction days and the temperature. The critical light length for tbe change from fertility to sterility was longer than that for the change from sterility to fertility,and they all shortened with higher temperatures. The number of induction days mainly influenced the development of quantitative alterations into qualitative alterations during the process of fertility change.