Stem tip of growing point of diploid Yard long bean(Vigna sesqui pedalis Wight.) at cotyleden stage was treated with colchicine of 0.1%-0.3% concentration. An autotetraploid plant was obtained. The morphological,cytological, and agronomical identification on it was carried out. The results showed that treatment with 0.2% colchicine for 4 times could obtain the best effect of autotetraploid, and the induction rate of tetraploid was 2.809%. Compared with the diploid,the autotetraploid plant had giant leaves,f...