Occurrence of Tetraploidy in Colchicine-Treated Physic Nut (Jatropha curcas Linn.)

Abstract

A study on the effect of colchicine on the physic nut (Jatropha curcas Linn.) was carried out at a research site in Pathum Thani province. Colchicine was used to treat plants of physic nuts of clones FF25B-14 and FF20SBr-3 at 500–8,000 ppm for 10 d. The results showed that colchicine concentrations at 5,000–6,000 ppm affected the size of vegetative and reproductive parts such as the leaves, infl orescence and staminate fl owers compared with normal plants. The treated plants showed larger stomatal size than nontreated plants. Study of the chromosome number revealed that the treated plants had doubled chromosomes (44) compared to the normal plants. These plants were assumed to be 4n or tetraploids while the normal plants were 2n or diploids (2n = 22). Both the vegetative growth and yield of the tetraploid plants were lower than in normal plants.