https://doi.org/10.37229/fsa.fja.2026.05.08

Drought and sub-optimal nitrogen (N) availability severely threaten wheat production, which is a cornerstone of global food security. Developing climate-resilient wheat varieties is therefore a critical priority. In this study, two field experiments were conducted to assess the performance of novel bread and durum wheat mutant lines as well as two local varieties under varying levels of drought stress and N fertilization, applied at different growth stages according to plant N requirements as climate-smart agricultural (CSA) practices to enhance nitrogen use efficiency (NUE). The findings indicated considerable genotypic variation in response to both stresses. Under severe drought (D2), the mutant lines M34 and M160 exhibited the highest tolerance with the lowest grain yield reductions of 12.5% and 12.9%, respectively, which was further supported by drought tolerance indices. M34 recorded the lowest TOL average of −75.0 and a high STI of 0.95, while M160 demonstrated a balanced STI of 0.90 with competitive MP and GMP values, collectively confirming the resilience and sustained productivity of both mutant lines across moderate and severe drought conditions. Mutant line M160 and the check variety, BS6, showed high NUE, which contributed to increasing grain yield over 25% at the low N level (230 kg N/ha) in climate-smart agriculture practices compared to the recommended level (260 kg N/ha). The mutant line M160 was found to be a unique and valuable genotype because it had both high drought tolerance and high NUE. Consequently, the climate-resilient mutant lines M34 and M160 demonstrated remarkable potential to sustain economically viable wheat production under drought and low-nitrogen conditions, reducing crop losses and supporting farmer livelihoods in arid and semi-arid systems. CSA practices, through optimized N fertilization timing and reduced chemical inputs, effectively enhanced NUE while mitigating soil degradation, nitrogen leaching, and agrochemical pollution. Collectively, the integration of climate-resilient mutants with CSA practices provided a comprehensive, sustainable, and scalable strategy for improving wheat grain yield and resource use efficiency in water-limited and nitrogen-deficient environments.