Developing systems for sustainable production of export grade dasheen {Colocasia esculenta (L.) Schott var. esculenta) in Dominica

Sustainability of the dasheen market share was constrained by incorrect projections, resulting from a lack of a detailed understanding of how agro-ecological zones, seasonality and agronomic practices influenced dasheen corm yield and shape in Dominica. Corm yield and shape are the two most important criteria for grading corms for export. Experiments addressing the above, examined the effects of planting depths and spacing on corm yield and shape. The experiments were conducted during the wet and dry season, in Grand Bay, on soils characterized as plastic sticky clay loams without a silica pan, a moisture supply capacity which is low to very low and an average annual rainfall of approximately 2400 mm {zone D3) and in Wet Area on soils characterized as sandy clay loams, with a moisture supply capacity which is moderately high and an average annual rainfall of 5300 mm (zone A2). Results showed that average corm weight per plant of 946 g and 995 g and mean yields per hectare of 12.9 and 14.1 t/ha were obtained in Grand Bay and Wet Area during the wet season, were not significantly different. In the dry season, Wet Area plant (913 g) and per hectare yield (12.3t), were significantly (p<0.01) higher, when compared to plant (645 g) and per hectare yield (7.91) obtained in Grand Bay. The oval corm shape obtained in Wet Area, during the wet and dry season, were significantly (p<0.01) different from the irregular (partially dumb-bell) shape corms obtained in Grand Bay across seasons. In Grand Bay, variation in plant spacing was the major factor influencing individual corm yield, whereas in Wet Area it was plant depth. Per hectare yield was influenced by both spacing and plant depth in Wet Area and by spacing in Grand Bay. Sustainable production of export grade corms, were suited to Wet Area throughout the year. In Grand Bay production was possible during the wet season.