The yield potential of commercial maize hybrids fully expressed in F1 generation, results from the cross of two inbred lines. However the yield of each line is too low unless their yields have improved with improved management, optimum density with optimum nutrition. Based on this fact, a field experiment was conducted at Bako research farm for two years (2019 and 2020) to determine the optimum plant density and nitrogen level for late maturing maize inbred line. The experiment was laid out in a Randomized Complete Block Design in factorial arrangement with three replications. Five plant densities (44444, 53333, 66666, 88888 and 133333 plants/ha) with three nitrogen levels (111,157 and 203 kg/ha) were combined by factorial combinations and tested in the experimental plots to select the optimum level for high seed production. The combined results indicated that Nitrogen starvation delayed silking date. The highest silking days (94.53) was recorded at lowest nitrogen rate (111 N/ha). On other hand increasing plant density increased days to 50% tasseling and silking, produced tall plants and increased barren plants. Seed yield increased with increase in plant density up to optimum and the maximum yield (4298.2 kg/ha) was achieved at 88888 plants/ha. Increasing plant density above this level has not brought any significant change in seed production. Thus to increase the yield of late maturing maize inbred line, it should be sown at plant density of 88888 plants/ha.

Keywords: Inbred lines, Nitrogen Fertilizer Level, Plant Density, Yield