Efforts to form superior varieties of ginger plants can be done by polypoidization breeding. The purpose of this study was to study the effect of concentration and duration of colchicine treatment on the phenotype performance of red ginger plants, to obtain the appropriate concentration of colchicine and duration of treatment for the formation of polyploid potential plants based on morphological characteristics. The was a completely randomized block design trial to examine two factors of colchicine treatment, namely colchicine concentration (0.25% and 0.50%) and treatment duration (3 hours and 6 hours). The variables observed were plant height, number of leaves, number of shoots, leaf thickness, and rhizome weight. The data were analyzed using the F-test and t-test. The results showed that colchicine concentrations of 0.25% and 0.50% significantly affected the growth of plant height, number of leaves, and number of shoots in plants aged 4-8 weeks after planting, but had no effect on rhizome weight. Leaf thickness in colchicine treatment was thicker than without colchicine (control), the thickest leaves were obtained in colchicine concentration 0.5% and treatment duration 6 hours, so this treatment has the potential to produce polyploid red ginger plants.
