Root and tuber crops play a vital role in achieving food and nutritional security of about 500 million people in the tropical and subtropical countries. Tuber crops support the existence of myriads of processors at small scale and large levels as well as traders all around the world. They are projected to remain as an important component in the global food system. Adaptation to marginal environment and agro ecological conditions, flexibility in integrated farming system, ability to produce more dietary energy per unit area and stability of production make roots and  tubers superior to other food crops. Human activities during recent years are altering green house gas concentrations in the atmosphere and causing more....