Study On Thermo-Sensitive Property And Cytology Of YM-Type Thermo-Sensitive Male Sterile Line KTM3314A Of Wheat

The advantages of wheat photo-thermo-sensitive male sterile line are the line of dual-use and extensive restoring sources, the useful hybridized combination was easily slected in male sterile line of importance status of wheat heterosis using .The basis of improving the two-line hybrid wheat breeding and the efficient usage are to clarify fertility changs, main features and cytological mechanism of YM thermo-sensitive male sterile line wheat line KTM3314A. The experiment was studied on the following two aspects: (1) The wheat CMS lines with Ae.kotschyi cytoplasm, 1B/1R type K3314A, YM-type male sterile line KTM3314A, were sowed in autumn and spring,the regenerated tillers from the individuals sowed at crop season as well. We observed and compared self-seed-setting rate of two types of male sterile lines at diferrent developmental stages under the various photo-thermo-condition. (2) In order to clarify cytological mechanism of fertility restoration on YM thermo-sensitive male sterile line wheat KTM3314A, experiments of cytological mechanism were carried out on the thermo-sensitive male sterile line wheat KTM3314A and 1B/1R line wheat K3314A, which have the same genetic background. We selected the various material of the different sowing and different developmental stages of the ears, deal with anther by acetocarmine and paraffin, determine the period of anther development, observe characteristics of anther and pollen, and further clear the periods of abortion and anther shape, and crystallize cytological features. The results obtained were as followings:1. KTM3314A was completely male sterile while sowed in autumn, but was partially restoration while sowed in appropriate spring and regeneration of tillers, thermo-sensitive period of fertility transition of KTM3314A was 5 days before and after the booting. The threshold temperature was 18.14℃. However, K3314A was completely male sterile whether or not any time, which showed that YM-type sterile wheat line KTM3314A has some thermo-sensitive properties.2. The normal development of anther and microspore of KTM3314A were in the fertile conditions and very small numbers of abnormal development were in the late stages of KTM3314A. In sterile conditions, the critical period of abortion is from the stage of meiosis to the late uninucleate, while the structure of tapetum is abnormal in the stage of development. The anther structure was destroyed and the microspore structure was abnormal, the internal material was inadequate and overfall. Both anther and pollen of K3314A manifest features of abortion in fertility or infertility conditions, while the trend of change of anther and pollen abortion. Microspore abortion occur in the two nuclear phase, and disorganization of tapetum is in advance and invade pollen cavity. Most of the pollen is round abortion and the development of abortion pollen lags behind the normal pollen and the vegetative nucleus is not clear in the stage of two nuclear. The anther structure is not complete, the internal material was inadequate and overfall in the stage of three nuclear.