Effects of colchicine treatments on seed germination and seedling growth of Hylocereus polyrhizus

Taking seeds from red pitaya‘ Hongxianmi’ fruit（ Hylocereus polyrhizus） as experiment materials， the effects of 0.01 %～0.30%（ W/V） colchicines with different exposure time on seed germination and seedling growth were studied. The results showed that，compared with the control（ treated by distilled water），the seed germination rate，survival rate and seedling length were inhibited by soaking-seed with the increasing of colchicine concentration and/or the extension of exposure time. The water-soaked-well seeds were more sensitive to colchicine， e.g. the seedling lengths were significant suppressed by the two treatments of 0.01% colchicine for 24 hours or 0.05% colchicine for 12 hours. Meanwhile，colchicine soaking-seed and water-soaked-well seeds would obtain 0.2%～4.2% and 0.2%～15.8% morphological variation seedling，respectively. The most efficient induction combination of ploidy variation was 0.20%，0.3% colchicine soaking-seed with 24～48 hours exposure or 0.20% colchicine water-soakedwell seeds with 12～24 hours exposure.