The Production Of Tetraploid And Application By Sexual Polyploidization In Non-Heading Chinese Cabbage

This paper is done on autotetraploid Non-heading Chinese cabbage from induction of 2n gamete, identification, to sexual polyploidization. The production of tetraploid were studied on the characteristics of agronomy traits, breeding and chromosome configuration, It serves as a method and guide of polyploid breeding of Non-heading Chinese cabbage.1.Taking 11 strains screened from 165 non-heading Chinese cabbage (2n=2x=20) as the materials, which contain the 2n gamete, and the buds of them were treated with different concentration of the colchicines to induce the production of higher 2n gamete; The sexual polyploidization were carried out by the female parent of the strains of the buds who were treated and it, and the tetraploid was obtained by screening the F1 progeny. Results show that:The optimum condition for the induction of 2n gamete was injecting 5—10μL 0.20% colchicine into the bud at 3 mm length for once time. The induction frequency of 2n male gamete was 20.20%, which was 3.63-fold higher than that of the control, untreated with colchicin processing of the plants. In the 80 Fi hybrid progeny,14 plants were identified as tetraploid plants (2n=4x=40) by chromosome counting technology. The ratio was about 17.5%. Compared with the diploid plant, the production of tetraploid by sexual polyploidization showed gigantism in appearance shape.2.Anther anatomical structure and development was observed on the production of 4x CMS by sexual polyploidization and its maintainer line in tetraploid Non-heading Chinese cabbage.There were four types in the degraded stamens as follows:The abortion of stamen occurred at the stage of archesporial cell differentiation, at which there was no differentiation of fibrous layer, middle layers,tapetum and microspore mother cell and no anther sac formed. Peltate stamen of the allogenic cytoplasmic male sterility line belongs to non-sporange cytoplasmic male sterility. And the abortion of other types anther might occur at the stage of stamen anlage polarization.3.Taking the tetraploid male sterile line as the main material.The male sterile lines of tertaploid cabbage were breeded by test cross---saturated backcross and add generations selection. Then doing the research about using heterosis.The experiment result indicated that:a male sterile line and a maintainer line of tertaploid cabbage were breeded, the rate and the level of their sterility were all 100%. The male sterile line 10 plus A-7 was siyubai,the genetic diversity was more widely and the maturing rate was higher. Compareing the diploid and the sexual polyploidization male sterile line of tetraploid cabbage compounded cross combination, the latter had two advantages of ploidy and hybrid were obviously in heterosis breeding. So it performed better in adverse situation, it had some properties.