Abstract
Two experiments were conducted in 1987-88 in St. Lucia with a view to extend the dormancy of white yam (Dioscorea alata L). Experiment 1 compared different harvest dates, different storage temperatures and presence or absence of the tuber "head" in cultivar Oriental. Experiment 2 studied the effect of gibberellic acid (GA) solution (1000 p/m) on the dormancy of different cultivars of white yam. Tubers from the early harvest (15 November) had the longest dormancy period (over 7 months), which decreased progressively with delay in harvesting. Storing yam tubers at 20 ± 2°C extended the dormancy by over 5 months as compared to storing them at 30 ± 2°C. The presence or absence of the tuber "head" had no effect. The interaction effects due to dates of harvest X storage temperatures and storage temperatures X manipulation were significant. Cultivars of white yam differed significantly in their dormancy period. Treating the harvested tubers with GA (1000 p/m) for 2 hours extended the dormancy by over 4 months as compared to that of the control (water) treatment.