Combining ability analysis in varietal crosses of maize

Eight varieties of maize were evaluated following diallel mating design for determining their utility as parents in the development of hybrids and/or high yielding composites. For days to SOO/. tasselling and silking. and 1000-grain weight, variety (V_i) effects; for plant and earheights, ear length and diameter, both V_i and specific heterosis (S_ij) effects; and for grain yield, sll effects were the most important contributors to the total entries sum of squares. Average heterosis d_i) and variety heterosis (h_i) effects were not so important for any trail. Cross between cvs. Navin and Population 26 showed significant and positive S_ij effects for grain yield, plant height, ear height and ear length. These two varieties represented a good choice to initiate interpopulation improvement.