Gamma ray induced daylength tolerant mutants in Coleus

Treatment of tubers of Chinese potato (Coleus parviflorus Benth.) with gamma rays resulted in more than 50 morphologically different mutants, which are maintained as clones. These mutant clones were planted bi-monthly from December 1986 to October 1987 in the field as single-row (20 plants) to test tuber production round the year. Chinese potato is normally a seasonal crop which produces tubers only from December to February. Of the 50 mutant clones tested 5 produced tubers all year round. The yield per plant of these 5 clones is given in the paper. Yields from four clones were quite similar. These daylength tolerant mutants could be used for an off-season crop and tubers could be on the market any month of the year. CPM 25 was found to be maturing in 120 days in all the six plantings, however, the other four mutants could have a higher yield if the crop duration would be extended to 140 days