Study the Effect of Nitrogen Fertilization Rates on Grain Yield and Some Physiological Characteristics of Wheat Varieties

Abstract

One of the most important strategies for enhancing wheat grain productivity and physiological processes is the application of appropriate nitrogen (N) and the choice of a suitable variety in an adequate environment. The study goals were to assess the impact of various N application rates on the grain yield and some physiological traits of four wheat cultivars under two growing years as well as determine the relationship between these traits across the experimental factors. Four Egyptian bread wheat varieties (Sakha 93, Gemmiza 12, Sids 12, and Sakha 94) and four nitrogen rates including control (N0), 75 kg N fad-1 (N1), 100 kg N fad-1 (N2), and 125 kg N fad-1 (N3) were evaluated in two experimental fields during the 2020/2021 and 2021/2022 growing years at Sakha, Kafr El-Sheikh Governorate, Egypt. Grain yield (kg ha-1), relative water content (RWC) proline content, malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) activities were the traits under study. The grain yield and the majority of the physiological parameters assessed were significantly influenced by the years, nitrogen treatments, and varieties as well as their first and second-order interactions (p ≤0.05 or 0.01), according to Three-way ANOVA. Grain yield increased with N treatments increased, and N3 treatment was higher than N0, N1 and N3 treatments with values of 31.1%, 22.9%, and 10.6%, respectively. With increased N application there is a tendency for MDA content and SOD activity to decrease and then increase, while RWC, proline content, CAT, and ABX activities to increase and then decrease. The highest values were recorded for grain yield, proline content and CAT activity by Sakha 94 variety and for MDA content, SOD, CAT and ABX activities by Sids 12 variety. According to the interactions among experimental factors, the highest wheat yield and the majority of physiological measures were observed by Sakha 94 variety with N3 rate under the second growing year. The Sakha 94 variety shows a positive correlation with grain production and the majority of physiological parameters under applying N3 treatment during the second growing year based on all variables examined by principal component analysis. Finally, our results recommended using the Sakha 94 variety with 125 kg N fad-1 to increase and improve wheat productivity.