Response of Some Yellow Maize Crosses to N-fertilizer Rates and Plant Densities at Toshka Region

FIELD studies were conducted at Toshka region, South Valley of ……Egypt , during the summer seasons of 2014 and 2015 to evaluate the some yellow maize single crosses, i.e. SC-162, SC-168 and SC-176 under three plant densities of (21000, 27300 and 33600 plant/fad) and three levels of nitrogen fertilizer (90,120 and 150 Kg N/fad). The results showed that N- levels were affected significantly all characters under study, i.e. growth characters, grain yield, protein content and the nitrogen use efficiency (NUE), except leaf area of the top most ear/plant. The application of 150 kg N / fad was resulted significant increase in grain yield and estimated by 4340 and 4235 kg /fad in 2014 and 2015, respectively. The plant densities also exhibited significant effect on the studied characters, except leaf area of the top most ear/plant, ear length, ear diameter, number of grains/row and protein content. The increasing of plant density from 21,000 to 33,600 plant/fad increased the grain yield up to 13.44 and 17.27 % in 2014 and 2015 seasons, respectively. The single crosses of maize differed significantly for ear length, NUE and grain yield during the 2014 season and the hybrid SC-176 recorded the highest value for grain yield of 4246.6 kg / fad.The interaction N levels x plant densities interaction were significant for plant height and NUE in both seasons and grain yield in the 2015 season. The plant density x maize crosses interaction were significantly also for ear length, grain yield and NUE in the 2014 season and the 500-grain weight in the 2015 season. Moreover, significant interaction among the three factors for grain yield and NUE through the 2014 season and stem diameter in 2015 season.The economic evaluation showed that the highest net return obtained from sowing SC-176 cross by plant density of 33600 plant/fad and supplemented by 150 kg N / fad.