棉花洞A型核雄性不育完全保持系M_B在不同地区气候条件下育性变化研究

Study on Fertility Change of Full Maintainer Line MB of Cotton Nu-clear Male Sterile Line“Dong A”in Different Climatic Locations

四川省棉花研究所１９８７年育成棉花洞Ａ型核雄性不育完全保持系ＭＢ。在四川简阳地区的气候条件下，ＭＢ自身散粉指数达７６％左右，与洞Ａ不育株杂交，获得不育株和株不育度均达１００％的ＭＡ不育系，ＭＡ不育系可作为配制杂交棉的母本。在武汉市的气候条件下种植，ＭＢ雄性可育性基本丧失，表现近似ＭＡ。ＭＢ的花粉母细胞减数分裂和小孢子发育的单核期，如日平均气温为２４～２７℃，相对湿度在８０％以上时对发育有利，可产生较多的可育小孢子，如温度超过２７℃，相对湿度在８０％以下时则不利，产生大量的不育小孢子。在棉花现蕾开花的主要季节６月中旬至９月中旬，一般情况下，武汉市的日平均气温比简阳高２℃左右，６月下旬已达２８℃，７月下旬比简阳高７℃左右，对小孢子发育不利；这期间武汉市的相对湿度变动在７０％～９５％之间，而简阳稳定在８０％左右。在两气象因子中，日平均气温对小孢子母细胞和小孢子单核期发育的影响比相对湿度更大些。

In l978,Cotton Research Institute of Sichuan Province harvested 19 selfed bollsfrom the normal spreading pollen plants of(Dong A X No。 557)F5.After a series of selfing,crossing and selection,a full maintainer line MB of cotton nuclear male sterile lint “Dong A”was developed.Under the climatic condition of Jianyang(Sichuan Province),the full main-tainer line MB of the cotton nuclear male sterile line“ Dong A”reached about 76%in pollenspreading。 In the progeny of cross combinations with“Dong A”and Ms’the sterile ling MA,which could be used as female parent in hybrid seed production shower 100%sterility.But un-der the climatic condition of wuhan(Huber Province),the fertility of MB disappeared, just thesame as MA. According to 3 year observation,it is good for microspore development as themaen day一temperature ranged from 24 to 27℃ and the relative humidity is about 80%at themeiosis of pollen mother cell and uninuclear stage of microspore development of MB. Many fer- tile microspores were formed under the above condition. But it is bad for microspore develop-ment and many sterile microspores were given when the temperature is higher than 27℃ andthe relative humidity is lower than 80%.During the main season of cotton budding and flow-ering,from June 15 to september 15,the mean day-temperature in Wuhan is generally 2℃higher than that in Jianyang and reaches 28℃ in late June. It is 7℃ higher in Wuhan thanthat in Jianyang in Iate July,which is harmful to microspore development.At the sametime,the relative humidity ranged form 70%to 95%in Wuhan,but it kept at 80%or so inJianyang. Judging from the two meteorological factors,the mean day-temperature play a moreimportant role than the relative humidity in the development of pollen mother cells and uninu-clear microspores。