This is a reference book which describes importance, use and basic information relevant to application of heterosis breeding in tomato for yield and quality contributing traits. Tomato is a tropical day neutral plant. It is self-pollinated crop but a certain extent of cross pollination may take place. It is a warm loving crop so easily tolerate heat and drought stress. India is the second top tomato growing country after China contributed about 11% of the World tomato production. Tomato is a rich source of antioxidants (mainly lycopene and β-carotene), Vitamin A, Vitamin C and minerals like Ca, P and Fe in diet. Magnitude of heterosis, combining ability effects and its variances were estimated by line × tester analysis including 30 F1 cross combinations using 13 parents after selfing. These genotypes were evaluated for growth, yield and quality contributing traits. Ratio of general combining ability (GCA) and specific combining ability (SCA) variance revealed preponderance of non- additive genetic variances for all studied traits. Present book is basically written for Vegetable Science Scholar and persons interested in tomato improvement programme.