This Book will helpful to academics, students and researchers to understand gene action and concept of heterosis. Brinjal (Solanum melongena L.) is grown commonly in the country since ancient time. It is an important vegetable crop of the plains and is available throughout the year and used primarily as a cooked vegetable.Exploitation of heterosis on a commercial scale in vegetable crops has resulted in the development of the several high yielding hybrid varieties. This technique has been proved to be the most important genetic tool for enhancing yield potential. And also information on combining ability is a pre-requisite, which employed to identify the desirable parents, cross combinations and provide information on the type of gene action involved in the inheritance of quantitative traits. This information is helpful in selecting the elite parents and desirable cross combinations to be used in breeding programme aimed at varietal improvement or exploitation of heterosis on a commercial scale.