Indian Institute of Horticultural Research, (I.C.A.R.), Bangalore
One year old tubers of D. composite, D. deltoidea and D. floribunda were divided into dorsal and ventral portions and were also divided into different sections normally used for propagation and analysed for diosgenin content. The D. composita and D. floribunda tubers were cut into crown, median and tip sections and D. deltoidea tubers into portions with sprouted buds, without sprouted buds and portions without any buds, It was found that the diosgenin content was more in the dorsal portion than the ventral portion in D. deltoidea and D. composita, when the results were expressed on fresh weight basis. However, in D. floribunda the ventral portion had relatively more diosgenin than the dorsal. The tip portion in D. composita the median portion in D. floribunda and portions without sprouted buds in D. deltoidea had relatively higher diosgenin on fresh weight basis. It was also found that the crown portion in D. floribunda and D. composita contained relatively less diosgenin. The crown portion sprouts early and uniformly and hence is recommended that in commercial cultivation one should save crown portions from all plants and use them for replanting.
TLC studies showed the presence of diosgenin in all the three species. Quantitative TLC studies revealed that diosgenin contributed 92, 90 and 71 to 76 per cent of the crude diosgenin in D. composita, D. deltoidea and D. floribunda respectively.
