Maize (Zea mays L.) is one of the most important cereals in Egypt due to its vast grown area, total production and cash value. It is essential for human consumption and livestock. Moreover, it is also used for industrial purposes such as manufacturing starch and cooking oils. Many efforts are devoted nowadays to increase its productivity through genetical improvement. Therefore, increasing the productivity of such crop is the main target of corn breeders. To achieve this target more information is needed for the successful breeding programs such as the relative amount of genetic variance components and their interaction with environment for yield and its components. It is hoped that the results of such study would give such information and help in designing successful breeding programs for improving yield and its components in maize.