Breeding of RGMS lines and investigation on their cytology in Brassica napus L.

【Objective】 The study was done to utilize the heterosis of the recessive epistatic interaction GMS(RGMS) in rapeseed breeding and to investigate its anther abortion mechanisms.【Method】 A Brassica napus L.hybrid Wanyou 14 was employed as the primary material to breed the homozygous two-type line and temporary maintainer line via selfing,sib-mating,test-crossing;Paraffin section method was employed to investigate anther development in fertile plant 1740B,sterile plant 1740A in the homozygous two-type line 1740AB and all sterile line 1740CA,which were derived from the cross between 1740A and the temporary maintainer 1740C.【Result】 The temporary maintainer line 1740C and homozygous two-type line 1740AB were successfully developed.Cytological observation revealed that the anther development in fertile plant 1740B was normal and formed pollen.The anther development included typically following stages:archesporial cell stage,sporogenous cell stage,pollen mother cell stage,meiosis stage,uninuclear microspore stage,binuclear microspore stage and trinuclear microspore stage.In 1740A,the anther development was blocked at the tetrad stage.The callose around the tetrads did not break and the tetrads couldn't be released from the callose.The tapetal cells were highly vacuolated and deformed,and they extruded the tetrads to the center anther.At last,the tetrads degenerated and the anther shrank.In 1740CA,pollen abnormal occurred from the microspore stage to the binuclear stage,and the sporopollenin-like deposits on the microspore surface was sparse.The tapetal cells in the sterile anther fell off,enlarged and extruded pollen cells to the center anther,the cytoplasm of pollen cells decayed gradually and at last became empty.【Conclusion】 We propose a breeding method based on test-crossing with temporary maintainer line and successfully developed the homozygous two-type line based on this method.There are some differences between homozygous male sterile plant and heterozygous male plant in their anther abnormality.