Physiological response of maize hybrids to nitrogen and phosphorus fertilization

Abstract EN

Two field experiments were conducted at the Experimental Farm, Gemmeiza Agriculture Research station, Agricultural Research Center white maize (ARC), Egypt during two growing seasons (2014 and 2015), to study the response of two maize hybrids i.e., white maize single cross 128 and yellow maize single cross 176 to four nitrogen fertilizer levels i.e.

0, 45, 90 and 135 kg N/fad., and three phosphorus fertilizer levels i.e.

0, 15.5 and 31 kg P2O5/fad.

Concerning the obtained results, SC 128 outyielded SC 176 in grain and biological yields (combined data) due to superiority in days to 50% tassiling and silking, leaf chlorophyll content, ear leaf area, leaf area index, relative photosynthetic potential for stover yield/plant, ear length and diameter, stem diameter, number of grains/row, hundred grain weight as well as grain and stover yields/plant, while SC.

176 gave the highest mean for each of plant height and relative photosynthetic potential for grain yield/plant.

No significant differences among maize hybrid could be detected in relative photosynthetic potential for biological yield/plant, number of rows/ear, ear leaf efficiency and migration coefficient.

Data of combined analysis revealed that addition of nitrogen (N) fertilizer and raising its rate up to 135 kg N/fad., was accompanied by asignificant increase in each of leaf chlorophyll content (mg m-2), plant height, leaf area index (LAI), ear length and diameter, stem diameter, number of rows/ear, number of grains/row, hundred grain weight, grain and stover yields/plant, ear leaf efficacy and migration coefficient, but relative photosynthetic potential for both stover and biological yields/plant were decreased.

Increase of phosphorus (P) level up to 31 kg P2O5/fad., was followed by a significant increase in grain yield/fad., and almost all their attributes, but relative photosynthetic potential for both stover and biological yields/plant were decreased.

Meantime, ear diameter responded to phosphorus addition up to 15.5 kg P2O5/fad., however, days to 50% tassling and silking were not significantly affected by varying phosphorus levels according to combined analysis.

In almost cases, maize hybrid SC.

128 was more efficient and more responsive than SC.

176, where the former was is need to 135 kg N/fad., and 31 kg P2O5/fad., in order to maximize the grain yield to only 42.8 ardab/fad