Sweet potato is considered as the 5th main crop in the world and is able to grow in harsh environment and poor soils (Jordan, Beam, Johnson, p. 32). It is also able to produce large quantity of wine before harvesting as a separate operation (Kobayashi, p. 73). Growth of vegetable which is uncontrollable consists of multiple problems which hold a great economic importance such as encroachment which is considered to increase the harvest cost and also increases the capacity of non economical part of the plant which is known as the sink capacity (Kobayashi, p. 13). Some ...