Induction and breeding of dwarf and tight white petiole autotetraploid non-heading Chinese cabbage with high quality.

Diploid plants of non-heading Chinese cabbage( Brassica campestris ssp. chinensis) were induced by treating the apical portion of seedlings with different solution of colchicine. After selecting and identification, dwarf and tight white petiole autotetraploid plants with high quality were selected and bred. The test result showed that treatment with 2. 0 mg·g-1 for 6 times yielded doubled chromosomes at highest rates and doubling rate was 7. 02%. Compared with diploid plants, autotetraploid plants had significant differences on vegetative mass, stoma, floral organ and silique, with the plant height reduced, the leaf width increased, the petiole shorter, the plant expansion degrees decreased, showing a compact plant type with bright green leaves. Compared with diploid plants, soluble sugar, protein and vitamin C of autoterploid plants contents were significantly increased by 11. 14%, 25-98% and 11. 70%. After two generations of breeding, the tetraploid pure degree was 100% and the uniformity was 95%, the yield of plot was increased by 18. 10% more highly than the diploid, while it has good application prospects. [ABSTRACT FROM AUTHOR]