Three methods for dihaploidization of haploid melon (Cucumis melo L.) plants were evaluated. Ploidy level was determined morphologically and cytologically for plants treated with colchicine. Immersion of in vitro plantlets or single node explants was compared to immersion of soot tips of greenhouse grown plants in a colchicine solution. In addition, application of single drops of colchicine was applied to lateral buds of greenhouse grown plants. Dihaploidization rate by immersion of apical growing point was about 89%, a rate three times greater than in vitro application by immersion of plantlets or their cuttings into colchicine solution. Colchicine treatment of lateral buds by medicine dropper was found to be ineffective in dihaploid production. (C) 2003 Elsevier Science B.V. All rights reserved.