Cytology Research of Spontaneous Doubling of Maize Haploid

ZHANG Lihua; LIU Xiaoman; MA Miaomiao; LI Xingxing; ZHANG Qifan; ZHENG Binrui; LIU Zonghua; SONG Yunyun; LI Haochuan

doi:10.15933/j.cnki.1004-3268.2024.10.003

Abstract：The diploid RL36 with high spontaneous doubling ability and its haploid H-RL36 and the haploid H-L119A with low spontaneous doubling ability were used as materials,the pollen viability and anther morphology were observed,the cell ploidy of vegetative and reproductive organs at different development stages were detected,and simultaneously the chromosome behavior during meiosis process was observed,so as to explore the causes of spontaneous doubling of haploid to produce fertile gametes,analyze the underlying cytology mechanisms,and provide theoretical support for biological research related to spontaneous doubling of haploid.The results showed that the high spontaneous doubling haploid H-RL36 had round,full and fertile pollen grains and normal anther tissue,while the low spontaneous doubling haploid H-L119A had sterile pollens with irregular morphology and wrinkled anther tissue.The ploidy detection results showed that the chromosome number in the leaves of the two haploid materials did not double at different growth stages,and there were diploid cells and a few tetraploid cells in the tassel of H-RL36 at trumpet stage,while the H-L119A cells did not show diploidization.4,6-diamidino-2-phenylindole(DAPI)staining was used to observe the chromosome segregation behavior of pollen mother cells,it was found that the chromosomes of most cells in H-RL36 showed segregation distortion and moved to one pole at anaphase of first meiosis,and then underwent normal second meiosis to produce gametes with normal chromosome number,thus producing fertile pollens.In contrast,the chromosome of H-L119A cells eventually degenerated,leading to sterile gametes with abnormal chromosome number.The segregation distortion of chromosomes during meiosis can lead to spontaneous doubling of haploids,and the doubling of haploid germ cells and somatic cells is two independent processes.