Root and Tuber Crops in the Tropics Cassava Cocoyam Potato Sweet Potato Taro Yam

Tropical Horticulture - Texas A&M University Definitions Root (cassava, sweet potato) No leaves or reproductive organs Tuber (potato, yams) Fleshy underground stem Minute scale leaves with buds (eyes) Corm (aroids, cocoyam and taro) Short, bulblike underground upright stem With scale leaves Tropical Horticulture - Texas A&M University

Tropical Horticulture - Texas A&M University Definitions Rhizome Rootlike stem Upper part with leafy stems Lower part with roots Bulb (lily, onion, tulip) A bud, usually underground Short thick stem Roots from below Overlapping scalelike leaves Tropical Horticulture - Texas A&M University

World Production of Root and Tuber Crops (106 mt) FAOSTAT, 2003 About half of the potato production is in the temperate zone Tropical Horticulture - Texas A&M University

Food Utilization of Root and Tuber Crops (1996 data) Tropical Horticulture - Texas A&M University

Feed Utilization of Root and Tuber Crops (1996 data) Tropical Horticulture - Texas A&M University

Origins of Major Root and Tuber Crops Yam Cocoyam Sweet Potato Cassava Taro Potato Tropical Horticulture - Texas A&M University

Cassava - Manihot esculenta Yuca, Mandioca, Tapioca Plant Slender shrub, 5 m Enlarged roots Sweet to bitter White to yellow Palmate leaves Propagation Stem cuttings Tropical Horticulture - Texas A&M University

Cassava - Manihot esculenta Origin South America Distribution Tropics and subtropics Staple food in many tropical regions Excellent carbohydrate source Tropical Horticulture - Texas A&M University

Cocoyam - Xanthosoma sagittifolium Malanga, Tannia, Elephant’s Ear Plant Perennial herb Corms and cormels Propagation Harvest same plant multiple times Portions of central corm Tropical Horticulture - Texas A&M University

Cocoyam - Xanthosoma sagittifolium Malanga, Tannia, Elephant’s Ear Origin West Indies and northern S. America Distribution Tropical regions Common in Indonesia Adaptation Lowland tropics Tropical Horticulture - Texas A&M University

Potato - Solanum tuberosum Plant Herbaceous Subterannean stems Leaves Propagation Eyes from tubers Important staple crop Tropical Horticulture - Texas A&M University

Potato - Solanum tuberosum Origin Highlands of South America Distribution Widely cultivated from highland tropics to temperate zones Adaptation Cool climate adaptation Tropical Horticulture - Texas A&M University

Sweet potato - Ipomoea batatas Plant Creeping herb Enlarged roots vary in shape and color Leaves variable in size, shape, color Propagation Young stem cuttings Important carbohydrate source Tropical Horticulture - Texas A&M University

Sweet potato - Ipomoea batatas Origin Central America Distribution Widely cultivated both in tropics and subtropics Adaptation Tropics to subtropics Below 2200 m altitude Tropical Horticulture - Texas A&M University

Taro - Colocasia esculenta Plant Perennial herb Subterraneous stem Calcium oxalate crystals Heart shaped leaves Propagation Suckers Corm apices with leaf Tropical Horticulture - Texas A&M University

Taro - Colocasia esculenta Origin Southeast Asia Distribution West Africa Caribbean Pacific islands Staple food Tropical Horticulture - Texas A&M University

Tropical Horticulture - Texas A&M University Yam Dioscorea alata, cayenensis and rotundata (Sixty species cultivated for food and pharmaceuticals) Plant Climbing vine, 10 m Tubers vary in shape Leaves ovate with cordate base Propagation Tubers Staple food in arid regions of Africa Tropical Horticulture - Texas A&M University

Tropical Horticulture - Texas A&M University Yam Dioscorea alata, cayenensis and rotundata (Sixty species cultivated for food and pharmaceuticals) Origin Asia and West Africa Production Mainly Africa Adaptation Lowland tropics Drought tolerant Tropical Horticulture - Texas A&M University

Plant Characteristics Tropical Horticulture - Texas A&M University

Tropical Horticulture - Texas A&M University Plant Adaptation Tropical Horticulture - Texas A&M University

Tropical Horticulture - Texas A&M University Plant Soil Adaptation Tropical Horticulture - Texas A&M University

Plant Storage Duration Tropical Horticulture - Texas A&M University

Crops compared for Dry Matter Production Tropical Horticulture - Texas A&M University

Crops compared for Edible Energy Production Tropical Horticulture - Texas A&M University

Crops compared for Edible Protein Production Tropical Horticulture - Texas A&M University

Nutritional aspects of root and tuber crops FW = fresh weight Tropical Horticulture - Texas A&M University

Nutritional Composition of 100 g of Food Tropical Horticulture - Texas A&M University

Importance of Root and Tuber Crops Important source food and income for the most food insecure households Why? High energy production per ha/day Yield better under adverse conditions than other crops Tropical Horticulture - Texas A&M University

Future Trends for Root and Tuber Crops Increased regional production concentration Sub Saharan Africa, 60% cassava production West Africa, 90% yam production China, 82% of sweet potato production Increased specialization of End Use Increase of processed forms of food Increased use of root/tubers for feed and starch derived products Relative importance remain same 10.5% of agricultural value Tropical Horticulture - Texas A&M University

International Research Centers involved with Root and Tuber Crops CIAT (Colombia) Cassava for Americas and Asia CIP (Peru) Potato Sweet potato Andean roots and tubers IITA (Nigeria) Cassava for Africa Yam for Africa Tropical Horticulture - Texas A&M University

International Research Centers involved with Root and Tuber Crops CIAT IITA CIP Tropical Horticulture - Texas A&M University

Tropical Horticulture - Texas A&M University Any Questions? Tropical Horticulture - Texas A&M University