Use of gibberellic acid to prolong dormancy and reduce losses during traditional storage of yams

The annual vegetative cycle of the yam (Dioscorea spp) necessitates a long period of storage. Losses during this period are high and are mainly due to germination. Trials on the effectiveness of gibberellic acid (GA3) for controlling storage losses were carried out on the two main species of yam (D cayenensis rotundata and D alata) grown in the Ivory Coast. Methods of application at the apex adapted to the rural environment were tested. Treatment with GA3 prolonged the dormancy period and thus reduced losses. This substance was effective at low concentration with a long soaking duration (75 mg litre−1 for 2 h) and during a soaking of short duration with a higher concentration (0·5 h at 150 mg litre−1). Because of its stability at ambient temperature, the solution was still active 3 days after being prepared and after reuse of the same dip six times.