A Study On The New Tetraploid Embryogeny In The Cross Of Diploid And Tetraploid Chinese Cabbage (Brassica Campestris Var. Pekinensis)

The diploid Chinese cabbage (Brassica campestris var, pekinensis) Bp058, which can produce 2n gametes, and the inbreeding line 252, which can not produce 2n gametes, were used for crossings with the tetraploid 'Shuixianhua' (SXH) in the study of embryogenics of new tetraploid hybrids. The results showed that the germination of pollen grains, growth of pollen tubes, and fertilization of Bp058(2x) x SXH(4x) and 252(2x) x SXH(4x) were normal when compared with the control 252(2x) x 252(2x). However, all the hybrid embryos of 252(2x) x SXH(4x) aborted before differentiation. The embryo abortion was the consequence of endosperm deterioration. Most hybrid embryos of Bp058(2x) x SXH(4x) also aborted, but a few embryos could developed into mature embryos. Therefore, the new tetraploid hybrids were produced by fertilization of 2n gametes of Bp058(2x) and n gametes of SXH(4x). The frequency of 2n female gamete generation was 8.33% by determining the development of hybrid embryos of Bp058 x SXH in which Bp058 was used as the pistillate parent. The 66.03 percent of the 2n female gametes of the diploid Bp058 could be fertilized in the cross Bp058 x SXH.