Bread Wheat Productivity in Response to Humic Acid Supply and Supplementary Irrigation Mode in Three Northwestern Coastal Sites of Egypt

Abstract

Drought stress is a major factor limiting wheat crop production worldwide. The application of humic acid (HA) and the selection of the appropriate genotype in the suitable site is one of the most important methods of tolerance of wheat plants to drought-stress conditions. The aim of this study was achieved using a three-way ANOVA, the stress tolerance index (STI), the Pearson correlation coefficient (rp), and principal component analysis (PCA). Three field experiments in three sites (Al-Qasr, El-Neguilla, and Abo Kwela) during the 2019/21 and 2020/21 seasons were conducted, entailing one Egyptian bread wheat variety (Sakha 94) with three HA rates (0, 30, and 60 kg ha−1) under normal and drought-stress conditions (supplemental irrigation). According to the ANOVA, the sites, supplemental irrigation, HA rates, and their first- and second-order interactions the grain yield and most traits evaluated (p ≤ 0.05 or 0.01) were significantly influenced in both seasons. Drought stress drastically reduced all traits registered in all factors studied compared with normal conditions. The wheat plants at the Al-Qasr site in both seasons showed significantly increased grain yield and most traits compared with that of the other sites under normal and drought-stress conditions. HA significantly promoted all studied traits under drought stress, and was highest when applying 60 kg HA ha−1, regardless of the site. The greatest grain yield and most traits monitored were observed in wheat plants fertilized with 60 kg HA ha−1 at the Al-Qasr site in both seasons under both conditions. Grain yield significantly (p ≤ 0.05 or 0.01) correlated with water and precipitation use efficiency as well as the most studied traits under normal and drought-stress conditions. The results of STI, rp, and PCA from the current study could be useful and could be used as a suitable method for studying drought-tolerance mechanisms to improve wheat productivity. Based on the results of statistical methods used in this study, we recommend the application of 60 kg HA ha−1 to improve wheat productivity under drought conditions along the north-western coast of Egypt.

A Comparison of the Pearson, Spearman Rank and Kendall Tau Correlation Coefficients Using Quantitative Variables

“…1). The results of the scree plot were harmonic with Yehia and El-Hashash [25], El-Hashash [32], El-Hashash et al [33] and El Sherbiny et al [34], who reported that there is a break in the plot that separates the meaningful components from the trivial components. Thus, most researchers would agree that PC1 and PC2 are probably meaningful.…”

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

“…The biplot diagram showed how years, N treatments, and varieties all contributed to the variability of all grain yield and physiological parameters assessed. Sharp and obtuse angles between variable vectors indicate positive and negative correlation, respectively [27]. Most of the analyzed traits showed a positive association; however, they varied in terms of degree and quantity consistency.…”

“…Weather often played a role in the variations between years [26]. We can therefore presume that the large variations in grain yield and physiological features of bread wheat were caused by meteorological factors and genotype variability [27] as well as N treatments. Differences in genotypes can be crucial in assisting wheat breeders in creating bread wheat that is more resistant to climate change [28].…”

“…Regarding the two years, 2021/2022 growing season significantly increased proline content, SOD, CAT, and ABX activities, while other examined traits were higher in 2020/2021 growing season. Year-to-year variations significantly affected wheat production [27]. Variability in rainfall during the wheat-growing season may be the cause of the lower grain productivity [29].…”

“…According to Wang et al [3], with increased nitrogen application, antioxidant enzymes and grain production showed an increasing and subsequently decreasing tendency. El-Hashash et al [27] reported that Sakha 94 variety has a good genetic background, leading to improving grain yield under different treatments and conditions. According to Gagliardi et al [34], the genotypes and years each had a unique impact on the grain yield of durum wheat.…”