Maize (Zea mays L.) is one of the most important cereal crop. Maize is used as human food, industrial raw material and animal feed. This indicates the importance of maize in the ever-increasing demand for food and warrants the development of new high yielding varieties and hybrids of maize. This book covers the heterosis and combinig ability in maize. Hope this book would be useful to researchers, teachers engaged in in the field of genetics and plant breeding. The Combining ability analysis is an important tool to identify parents with better potential to transmit desirable characteristics to the progenies and identify the best specific cross(s) for yield.