Abstract: Results of studies on chromosome doubling treatment with colchicine, identification of polyploid plants, selection for beneficial characteristics and evaluation of relevant drugs of polyploid Isatis indigotica Fort. were reported. By both gemmiferous seeds treated with 0.05%–0.5% aqueous solution of colchicine and growing shoots apices with 0.05%–0.3% aqueous solution of colchicine, polyploid plants were obtained. The most suitable time of treatment was 6–12 hours. In addition to direct cytological examination, some characteristics were able to use for identification of polyploid plants, such as number of chloroplats peraguard cell and number of furrows on the wall of pollen grain. Among the autotetraploid induced or between the polyploids and diploid parents, some morphological characteristics were compared. Polyploid lines with better fertility, good yield, and free amino acid in roots, high content of indigo and indirubin in leaves have been obtained through five years selection.

Key words: lsatis indigotica Fort.: Polyploid, Autotetraploid, Amino acid, Indigo, Indirubin