Response of Bread Wheat Genotypes for Drought and Low Nitrogen Stress Tolerance

Abstract

Drought stress and nitrogen (N) deficiency are the major causes of yield losses in bread wheat (Triticum aestivum) production. Breeding wheat cultivars with combined drought and low N stress tolerance is an economical approach for yield gains. The objective of this study was to evaluate the response of diverse bread wheat genotypes under drought and low N stress conditions to select high-performing genotypes for developing breeding populations and production to mitigate against drought and low N stress. Fifty bread wheat genotypes were evaluated under drought-stressed (DS) and non-stressed (NS) conditions and N application rates of 50, 100 and 200 kg N ha−1. The experiments were conducted in a controlled environment and field conditions during the 2019/20 cropping season. Data on grain yield and yield components were collected and subjected to statistical analysis. The four-way interaction involving genotype, water regime, N treatments and testing environment had a significant (p < 0.05) effect on all assessed agronomic traits, suggesting that genotype response depended on the treatment combinations. Drought stress and 50 kg N ha−1 reduced grain yield by 20% compared to NS and 50 kg N ha−1. The grain yield ranged from 120 to 337 g/m2, with a mean of 228 g/m2 under DS. Under DS and 200 kg N ha−1, the genotype designated as SBO 19 had a higher grain yield of 337 g/m2, followed by SBO 22 (335 g/m2), SBO 16 (335 g/m2), SBO 04 (335 g/m2) and SBO 33 (335 g/m2). Grain yields under DS and 50 kg N ha−1, and NS and 50 kg N ha−1 had a positive and significant correlation (r > 0.5; p < 0.01) with most of the evaluated traits. Highly correlated traits directly contribute to total yield gain and should be incorporated during the selection of high-yielding genotypes. The study identified the 10 best lines that are high-yielding with early flowering and maturity under DS or NS conditions and the three N treatments. The selected lines are recommended as breeding parents to develop drought-adapted and N-use efficient genetic resources. The identified genotypes are important for sustainable wheat production and effective breeding of improved cultivars to mitigate drought stress and soil nutrient deficiencies, to ensure food security in Sub-Saharan Africa.

The wild emmer wheat grain protein content 5B QTL introgressed into bread wheat is associated with tolerance to nitrogen deficiency .

“…However, although wheat cultivation accounts for 18.2% of all N fertilizer used for agronomy (Teng et al 2022), only 30-40% of the applied N fertilizer is taken up by the plant (Swarbreck et al 2019;Milner et al 2022). Ine cient N use leads to water and air pollution, scal losses, and degradation of natural resources; therefore, optimizing and limiting N fertilizer application would improve agricultural and environmental sustainability (Araus et al 2020;Duma et al 2022;Bharati et al 2022; Effah et al 2023). Strategies for managing N include optimizing the amount and timing of N fertilization.…”

“…Under such conditions, even if N is available, it will not be taken up. As a result, water scarcity, N de ciency, or their combination are major causes of yield loss in bread wheat production (De Laporte et al 2021;Fu et al 2022; Kaur et al 2022;Duma et al 2022). Thus, breeding cultivars for improved water-use e ciency and NUE is a cost-effective and sustainable approach to increasing GY in wheat (Ullah et al…”

Nitrogen deficiency tolerance conferred by introgression of a QTL derived from wild emmer into bread wheat

“…Under such conditions, even if N is available, it will not be taken up. As a result, water scarcity, N deficiency, or a combination thereof, are major causes of yield loss in bread wheat production (De Laporte et al 2021 ; Fu et al 2022 ; Kaur et al 2022 ; Duma et al 2022 ). To counteract N deficiency, N can be applied at an early stage of wheat growth; however, this N can be leached from the soil after heavy rains and be lost as a gas, or be immobilized before its uptake by the plant, thus affecting its efficient absorption (Subedi et al 2007 ; Zörb et al 2018 ; Ghimire et al 2021 ).…”

“…Wheat cultivation accounts for 18.2% of all N fertilizer used for agronomy (Heffer et al 2013 ; Teng et al 2022 ), but only 30–40% of the applied N fertilizer is taken up by the plant (Swarbreck et al 2019 ; Milner et al 2022 ). Inefficient N use leads to water and air pollution, economic losses, and degradation of natural resources; therefore, optimizing the efficiency of N-fertilizer uptake by the plants enable lower N input that would improve agricultural and environmental sustainability (Araus et al 2020 ; Fatholahi et al 2020 ; Wang et al 2020 ; Ghimire et al 2021 ; Bharati et al 2022 ; Duma et al 2022 ; Gezahegn et al 2022 ; Effah et al 2023 ). Therefore, an understanding of the complexity of regulatory mechanisms controlling NUE, especially when N is limited in the environment, is of great value (Kant et al 2011 ; Fan et al 2019 ; Hawkesford and Riche 2020 ; Vishnukiran et al 2020 ).…”