Study on Polyploid Induction Methods of Watermelon Seedling

[Objective] The research aimed to obtain watermelon polyploidy and increase its induction rate.[Method] Comprehensive treatments such as dripping plantlets with colchicine,top removal in different seedling states and low-temperature were conducted on 3 diploid watermelon germplasm to induce polyploidy.[Result] The results indicated that 3 levels in orthogonal experiment were preliminarily confirmed through experiment on each single factor.When colchicine concentration was at 0.2%～0.4%,low temperatures in treatment were 12,15 and 18 ℃,seedling states of removaling top were at first leaves,two leaves and trefoil and one top-leaf and time was 4～6 d,its effect of increasing induction rate in watermelon polyploidy was better.[Conclusion] Induction with top removal treatment on watermelon seedling could increase the induction rate of polyploidy.