Tomato hybrid cultivars were extensively used in commercial production since tomato growers prefer to grow their hybrids in order to maximize the net return, since, the hybrids are usually known to be characterized by high yield and good quality as well as many other attractive traits. The hybrid cultivar is, usually, produced through the crossing of two, or more, inbred lines or cultivars. It is necessary to tomato breeders to test and evaluate the ability of a great numbers of cultivars and inbred lines to be combined and select those which can combine well with others to produce good hybrids. This means that the breeders are always interested in selecting the lines having high average performances; i.e. high general combining ability; which means that these lines possess good genes, in general. To determine which hybrid to produce, breeders have to direct their attention towards the particular combination which has the highest specific combining ability, which means that the parents of this particular cross can combine well to produce a hybrid with a superior general performance.