Cytological And Embryonic Studies On Hybridization Between Triploid And Diploid In False Pakchoi

Using cytological and genetical techniques, the frequencey and inherited transfer ability of gametes with different chromosome number, and the effect of aneuploid on pollination, fertilization and embryo development were studied in this paper. The results were as follows: (1) The meiosis of microspore mother cells of triploid Fasle Pakchoi is quite complicated, which produced the microspores or pollen grains with different chromosomes, e.g. n =9, n =10, n = 11, n =12, n =13, n =14, n =15, n =16, n =17, n =18, n=19, and n=20, and the rate of each kind of the microspores was 0.53%,1.60%,2.67%,5.87%,12.30%,19.20%,23.50%,17.60%,10.70%,4.80%,1.07% and 0.27% respectively; (2) Both male and female gametes of the triploid False Pakchoi were with relative higher inherited transfer ability, the former with 44.68% and latter with 33.62%; (3) In the progeny of hybridization, the rate of plants with 2n=20, 2n=21 and 2n=22 were 17.2%,33.3%, in 3x 2x and 34.3%, 40.75%, 12.9%, in 2x * 3x respectively, which much higher than that of plants with other chromosome numbers; (4) Many abnormal phenomenon, such as undegenerated synergid cells, fertilization postponed, single fertilization and embryo degenerated were observed in 3x * 2.x and 2xx3x; (5) The chromosome karyotype formula of False Pakchoi was 2n=2x=20=12m+6sm+2st(SAT), and according to the stebings, the karyotype belonged to 2B type in the karyotype evolution; (6) Of the 7 clones of 3x x 2x, 2 clones were trisomics and 2 clones were double trisomics, according to the karyotype analysis.