Maize is an important cereal crop belonging to family, Poaceae. It is one of the staple food crop and widely cultivated crop throughout the world. It is the only cereal which can be used as food at various stages of its plant development. The potential of heterosis is just beginning to be exploited in developing countries through expansion of hybrid seeds. It has the highest potential of per day carbohydrate productivity. Thus, the father of green revolution, the renowned Nobel Laureate, Dr. Norman E. Borlaug, believes that "after the last two decades saw the revolution in rice and wheat, the next few decades will be known as maize era". Shull (1908 and 1911) gave the original concept for production and growing of single cross hybrids. The recent trends even in the developing and under developed countries single cross hybrids are more popular due to their higher yield under favourable environment and uniformity in expression. Hence, there is a greater scope for the exploitation of heterosis through single cross hybrids, than double cross hybrids.