The Tropical Tuber Crops: Yams, Cassava, Sweet Potato, and Cocoyams

3rd Int Agric alata boiled buds bulbils cassava cassava plant cassava tuber cayenensis cells cocoyams corm Coursey cultivars cultivation develop Dioscorea esculenta disease dormancy double-harvesting dry season effective emergence esculenta farmer fertilizer field flooded taro glucoside growing season grown growth hectare herbicides Ibadan increase infected intercrop kg hectare-¹ lamina large tubers layer leaf leaves Manihot esculenta mature mechanical harvesting method moisture mounds mulch nematode Nigeria nitrogen nodes occur Onwueme peeled periderm pests petiole phloem planting material plot potassium pounded yam presprouting problem propagation protein prussic acid rainy season regions relatively result ridges Root Crops root system rotting rotundata seed senescence setts shoot single-harvesting soil species sprouting staking starch stem storage stored surface sweet potato Symp tannia taro temperature tend tissue traditional agriculture tropical tuber crops tuber formation tuber initiation usually vascular vine cuttings virus weed control West Africa xylem yam plant yam production yam tuber yield