DIOSGENIN ACCUMULATION PATTERN IN COSTUS SPECIOSUS WITH ADVANCEMENT IN CROP AGE UNDER VARYING LEVELS OF NITROGEN

The data from the field experiment conducted for two crop cycle (1978–80 and 1979–81) revealed that the diosgenin yield of rhizomes of Costus speciosus Sims. increased favourably with the advancement in crop age up to 20 months and reduced thereafter. Nitrogen application did not cause marked variations in diosgenin content, however, its yield increased significantly up to 180 kg N/ha. Based on these informations, this crop should be harvested at the age of twenty months for more return.