Maize (Zea mays L.) Genotypes Differ in Phenology, Seed Weight and Quality (Protein and Oil Contents) when Applied with Variable Rates and Source of Nitrogen

Abstract

Field experiments were conducted during summer 2008-09 (Y1) and 2009-10 (Y2) at the Agronomy Research Farm of The University of Agriculture Peshawar-Pakistan to investigate the impact of different N-fertilizer sources [urea, calcium ammonium nitrate (CAN) and ammonium sulphate (AS)] and their levels (50, 100, 150 and 200 kg ha-1) on phenology, seed weight and composition (seed protein, oil and starch content) of maize (Zea mays L.) genotypes “Local cultivars (Azam and Jalal) vs. hybrid maize (Pioneer-3025)”. The results revealed that the rest (all the experimental plots applied with N) had delayed phonological development and had produced heavy grains with higher protein, oil and starch contents over control (N not applied). In both years, the maturity was delayed, seed weight and seed protein content increased with the application of two higher N rates (150 and 200 kg ha-1) as compared with the two lower N rates (50 and 100 kg ha-1). Applications of N in the form of ammonium sulphate enhanced maturity and decreased seed weight but increased seed oil content over urea and calcium ammonium nitrate. The maize hybrid (P-3025) with delayed maturity produced heavy seeds and higher seed protein and oil contents as compared to the two local cultivars (Azam and Jalal). The hybrid (P-3025) was considered the more efficient maize genotype that responded very well to different sources and rates of N than the local maize cultivars.