Objective To create new tetraploid resource of Dioscorea zingiberensis in the hope of potential breeding materials with high yield and high level of diosgenin. Methods Callus with tiny green buds were directly soaked in colchicine solution or cultured in medium plus with colchicine to prohibit the isolation of chromosomes and induce tetraploid mutants. Results Tetraploids were achieved successfully. The most efficient treatment for inducing tetraploid was soaking the tiny buds in 1?103 mg/L colchicine solution for 24 h, the inducing rate could be up to 35. 2%. The induced tetraploids exhibited notable difference with common wild type (diploids) in morphology, physiology, and microscopic structure. ConclusionThe tetraploid plants show the advantages of gigantic size and vigorous growth. Thus, the established technique system to induce tetraploid from tissue cultured callus would provide an efficient alternative pathway for medicinal plants of Dioscorea L. breeding.

Objective By comparing the physiological index and diosgenin content of rhizome between the artificial tetraploid and the wild type diploid of Dioscorea zingiberensis, it is aimed at revealing the potential utility of polyploid breeding in medicinal D. zingiberensis. Methods Three clones of the natural diploid and the artificially induced tetraploid of D. zingiberensis were used as materials in this study. The content of SOD, PPO, and soluble sugar of leaves was determined by spectrophotometry, CAT content was measured by using the method of KMnO_4 titration. And the diosgenin content in rhizome was analyzed by HPLC. Results The tetraploid plants showed higher level of SOD, PPO, CAT, soluble sugar content in leaves, and diosgenin content in rhizome than those of the diploid origins. The diosgenin content in the three clones of tetraploid plants increased to 27% as compared to wild type. Conclusion Artificially induced tetraploid presents high content of diosgenin and great potential in stress resistance, which would be available in good seed breeding for high yield of diosgenin.