Ethephon for induction of multiple tubers in water yam (D. alata)

Abstract

Yam cultivar Gunung (Dioscorea alata) is resistant to anthracnose (Colletotrichum gloeosporioides Penz.). It has an extraordinary yield potential. Yet its acceptability has been limited because of the frequent production of large-sized and off-shaped tubers which are difficult to market. Local growers will increasingly accept this cultivar if tuber size can be reduced without an undue loss in yield. A study was conducted to determine whether ethephon [(2-chloroethyl) phosphonic acid] can induce multiple stem sprouting and hence multiple tuber production as a means of reducing tuber size and improving shape. Head, middle, and tail tuber sections were treated with a 1% ethephon solution and planted in the field. The ethephon treatment significantly increased stem sprouting in the middle and tail sections but not in the head section. A significant reduction in mean tuber weight was observed in all treated sections. However, this reduction was compensated for by a significant increase in the number of tubers produced per plant. The hormone treatment did not significantly affect total yield but did lead to more production of uniform tubers. Mean yield of marketable tubers was 73,123 kg/ha.