Role of potassium & zinc on sweet potato

The Sweet potato (Ipomoea batatas L.) is a dicotyledonous plant that belongs to the family Convolvulaceae. It is grown as a starchy food crop throughout the tropical sub-tropical and frost-free temperate climatic zones in the world. It is believed to have originated in Central America and the North Western part of South America Sweet potato is cultivated in more than 100 countries (Woolfe 1992). It is the seventh among all food crops worldwide from the point of view of total production thirteenth in value of production and fifth in calorific contribution to human diet (Bouwkamp 1985 and Tortoe 2010). In India it is mainly cultivated in Bihar Orissa Uttar Pradesh Madhya Pradesh Maharashtra Karnataka and approximately 80 per cent of the World''s sweet potato is grown in Asia 15 per cent in Africa and about 5 per cent in rest of the World. The total area in the world under sweet potato is estimated to be 7.95 million ha with a production of 104.26 million tonnes. In India sweet potato covers 1.11 lakh hectare area producing 11.32 lakh tonnes tubers with the productivity of 10.1 metric tonnes per hectare (Anonymous 2013).