叶枕距标记法研究低温对粳型光温敏核不育系育性转换的影响

Studies on Effects of Low Temperature on Fertility Alteration of Japonica PTGMS Lines by Marking Upmost Pulvinus Interval

用日均温20℃低温处理3个采用剑叶叶枕距标记幼穗发育时期的粳型光温敏核不育系G317S、G321S和G326S,研究低温对不同发育时期粳型光温敏核不育系育性的影响。结果表明:用20℃低温处理3 d,3个粳型光温敏核不育系花粉不育度明显降低,平均自交结实率为66.41%;3个粳型光温敏核不育系育性敏感期所对应的剑叶叶枕距为-4～4 cm,而剑叶叶枕距<-4 cm或>4 cm时,各不育系育性稳定;剑叶叶枕距为-4～-2 cm和2～4 cm时各不育系不同穗位颖花的花粉不育度比较接近,而剑叶叶枕距为-2～2 cm时,各不育系不同穗位颖花的花粉不育度表现为穗上部<穗中部<穗下部。

Three japonica photo-thermo-sensitive genic male sterile（PTGMS） lines G317S,G321S and G326S were marked with upmost pulvinus interval（UPI）,i.e.,the length from the pulvinus of the 2nd leaf from the top to that of flag leaf,to record young panicle differentiation stages and a daily mean temperature of 20℃ was used as the low temperature to treat them in climatic chamber so that the effects of low temperature at different panicle differentiation stages were studied on fertility alteration of japonica PTGMS lines.The results showed that the pollen sterility of all three PTGMS lines was markedly decreased after the low temperature treatment（20℃ for three days） and their averaged bagged seed-setting percentage was as high as 66.41%,indicating a distinct fertility alteration under the low temperature stress.The fertility sensitive stage of the lines was found to be the developmental period with-4~4 cm of UPI.When the UPI was -4 cm or 4 cm,the pollen sterility of the lines remained as high as over 99.95% without a significant decrease,indicating that the low temperature treatment at these developmental stages had no effect on fertility alteration.When the UPI was-4^-2 cm and 2~4 cm,the pollen sterility of spikelets at different panicle positions（the upper,middle or lower part of a panicle） did not vary much.However,when the UPI was-2~2 cm,the pollen sterility of spikelets at different panicle positions was greatly different with an order of the lowerthe middlethe upper.