冬春温度变化对小麦温敏雄性不育系BNS的育性转换影响

Study on Significant Effects of Temperature Changes in Winter and Spring on Fertility Conversion in Wheat Thermo-sensitive Male Sterile Line BNS

BNS是一个主体受温度控制的新型小麦雄性不育系,表现为花粉发育在低温下(<8℃)不育,高温下(>12℃)可育。BNS不育性稳定,但年份间常有波动,一些年份自交结实率上升显著。为了弄清楚BNS育性波动的原因,连续3a观察不同播期的BNS穗分化过程,分析连续6a调查的BNS自交结实率与对应年份的冬春温度变化,结果发现,冬季和春季温度的改变显著影响BNS的自交结实率。一般规律是,暖冬年份自交结实率低,寒冬较高,暖春年份自交结实率高,寒春较低。该现象的形成主要是BNS冬季生长发育速度所致,暖冬年份BNS冬季仍保持生长,到春季时完成温度敏感期前的发育,较早进入温度敏感期,此时的春季温度较低,因此BNS不育;然而在寒冬年份,BNS停止生长,春季需生长一定时间才进入温度敏感期,进入时气温已较高,因此诱导育性转换,自交结实率增高。BNS冬季生长发育速度在穗分化观察中得到验证。该机理解释了不同年份BNS自交结实率的波动,并根据冬春温度可预测BNS的育性转换。

During the stage of pollen development,BNS is a new type of wheat male sterile line that is mainly controlled by low temperature of 8℃,BNS would develop sterile.when temperature is high（12℃）,it can converse its pollen into fertile itself.Generally,BNS＇sterility is stable,but in some years,it can change,even significantly change.In order to clarify the reason why BNS changes its sterility,both of parameters of BNS self-fertility rate and winter/spring temperature in recently 6 years were investigated and analyzed,and the spike differentiation process of BNS sown in different dates was observed for 3 consecutive years.The results showed that,in the year of warm winter,BNS＇self-fertilization rate was low,and in the year of cold winter,the self-fertility rate was high.In the year of warm spring,the self-fertility rate was high,and cold spring,it low.This phenomenon was caused mainly by the different growth and development of BNS in winter.In warm winter,BNS growth and development did not stop,in the Spring,BNS had completed pre-development of temperature-sensitive period.At this time,the atmosphere temperature was low,so BNS developing was infertile.However,in the year of cold winter,BNS＇growth was slow.In spring,before it developed into temperature-sensitive period,BNS needed another some days to grow for completing pre-development.Therefore,when BNS developed into temperature-sensitive period,the atmosphere temperature was high that could induce the line fertility conversion,and the self-fertility rate must increase.The differential development of BNS in winter was validated in spike differentiation observation.This growth and development mechanism satisfactorily explained the fluctuation of temperature on BNS self-fertility rate,and self-fertility rate,sterility of BNS could be predicted correctly according to temperature in winter and spring.