Crop simulation models can be effective tools to assist with optimization of resources for a particular agroecological zone. The goal of this study was to determine the influence of N rates with different timing of application to wheat crop using prominent varieties using the CSM-CERES-Wheat model of the decision support system for agrotechnology transfer (DSSAT). Data were focused for yield traits, i.e., number of tillers, number of grains, grain weight, grain yield, biomass, and grain N content. To test the applicability of the CSM-CERES-Wheat version 4.7.5 model for agroclimatic conditions of Peshawar, Pakistan, experimental data from two years of experiments (2016–17 and 2017–18) were used for model calibration and evaluation. The simulation results of two years agreed well with field measured data for three commercial varieties. The model efficiency (R²) for wheat varieties was above 0.94 for variables tiller number per unit area (m⁻²), number of grains (m⁻²) and number of grains (spike⁻¹), 1000 grain weight (mg), biomass weight (kg ha⁻¹), grain yield (kg ha⁻¹), and harvest N content (kg ha⁻¹). Statistics of cultivars indicated that yield traits, yield, and N can be simulated efficiently for agroecological conditions of Peshawar. Moreover, different N rates and application timings suggested that the application of 140 kg N ha⁻¹ with triple splits timings, i.e., 25% at the sowing, 50% at the tillering, and 25% at the booting stage of the crop, resulted in the maximum yield and N recovery for different commercial wheat varieties. Simulated N losses, according to the model, were highly determined by leaching for experimental conditions where a single N application of 100% or existing double splits timing was applied. The study concluded that 140 kg N ha⁻¹ is most appropriate for wheat crop grown on clay loam soils under a flood irrigation system. However, the N fertilizer has to be given in triple splits of a 1:2:1 ratio at the sowing, tillering, and booting stages of the crop growth.

Predicted decrease in water availability for crop production and uncertainty in climatic conditions require devising the irrigation strategies to increase water use efficiency (WUE) for sustainable crop production. The development of crop cultivars with higher WUE is a pre-requisite for such strategies, particularly in developing countries, including Pakistan, who face stern food security challenges. A two-year field study was conducted following a split-plot randomized complete block design to understand the effects of wheat cultivars (hybrid cultivars, 18A-1 and 18A-2, and local cultivar Ghaneemat IBGE-2016), sowing dates (15th November, 30th November, and 15th December), and irrigation regimes [I (103 mm), II (175 mm), III (254 mm), and IV (330 mm)] at four different growth stages of tillering, booting, anthesis and grain filling on wheat productivity, biomass production and grain yield, and crop-water relations. Early sown hybrid cultivars 18A-1 and 18A-2 showed significantly higher biological and grain yields compared to the local cultivar (59% and 69% higher than the local cultivar). Trends in biomass production and grain yield were also similar at later sowing dates of 30th November and 15th December. However, biological and grain yields decreased with delay in sowing for each cultivar. The data also revealed that hybrid cultivars were better suited to deficient irrigation and generally produced significantly higher biological and grain yields under each moisture regime. Cultivars, sowing dates, and irrigation regime differed significantly for their effects on the Soil Plant Analysis Development (SPAD) values, chlorophyll a and b contents but not for carotenoids. Sowing dates and irrigation regimes had significant effects on relative water content (RWC), water saturation deficit (WSD), water uptake capacity (WUC), and water retention capacity (WRC); however, only WUC varied significantly between the cultivars. The phenological data show that hybrid cultivars took more days to maturity and grain filling than the local cultivar, and days decreased with delayed sowing. The biological and grain yields show significant positive correlations with SPAD values (p < 0.001) and days to maturity (p < 0.001). Our study shows that hybrid wheat cultivars can be opted for higher biomass production and grain yields under deficit irrigation scenarios of semi-arid climatic conditions in Pakistan. Moreover, the hybrid wheat cultivars can perform better than the indigenous cultivar even for delayed sowing dates of 30th November and 15th December.

The goal of this study is to identify the optimum NPK fertilization to maximize yield and productivity under local environmental constraints. To address this concern, a field experiment was conducted at Agronomy Research Farm, The University of Agriculture, Peshawar, during the rabi seasons of 2019–2020 and 2020–2021 in a randomized complete block design (RCBD) with three replications. Treatments consisted of five Chinese wheat hybrids (18A-1, JM-1215, JM-1683, JM-1216, H-1) and one Australian hybrid (WS-1) with two local checks (Wadan-17 and Pirsabak-15) and two NPK levels, i.e., basal dose (120-90-60 NPK kg ha⁻¹) and 25% higher than basal dose (150-112-75 NPK kg ha⁻¹). The results of the two years’ experimentation exhibited that wheat hybrid WS-1 produced higher tillers (444 and 423 m⁻²), leaf area (32.7 and 30.7 cm²), leaf area index (5.0 and 5.4), plant height (105.3 and 103.1 cm), spike length (21.9 and 21.5 cm), spikes (329 and 322 m⁻²), grains spike⁻¹ (59 and 58), thousand grain weight (62.2 and 62.2 g) and biological yield (9769 and 9906 kg ha⁻¹) as compared to local check varieties. Wheat hybrids WS-1, JM-1683, H-1 and 18A1 produced 31%, 27%, 26% and 26% higher grain yield than local check Pirsabak-15, respectively, while a higher harvest index (61 and 59%) was noted for JM-1683 in both years. Application of NPK at the rate of 150-112-75 kg ha⁻¹ increased emergence (87 m⁻²), tillers (421 and 407 m⁻²), leaf area (23 and 20.5 cm²), leaf area index (3.3), plant height (98.2 and 96.9 cm), spike length (15.9 and 16.3 cm), spikes (317 and 314 m⁻²), grains spike⁻¹ (43), thousand grain weight (56.5 and 56.3 g), biological yield (9057 and 9163 kg ha⁻¹) and grain yield (3702 and 3778 kg ha⁻¹) compared to the lower level of NPK (120-90-60 kg ha⁻¹). It is concluded that Chinese wheat hybrid JM-1683 and Australian hybrid WS-1 responded better to the higher level of NPK (150-112-75 kg ha⁻¹) in terms of grain yield and its components and are therefore recommended for the agro-climatic condition of the Peshawar valley.

Climate change threatens major global crops including wheat of subtropical regions, especially during critical developmental stages. To address this concern, researchers try to identify exotic genetic diversity with pronounced stress tolerance or avoidance or find improved genotypes with optimal sowing time. Current research evaluated seven exotic Chinese wheat genotypes (MY4094, MY1617, MY1416, MY2914, MY1501, MY1419, and MY902) for yield and associated characters along with a local check variety (PS-15) under optimal (1st November), moderate (16th November), and late sowing times (1st December) during both years. The result revealed that delayed sowing reduced yield and yield components of the tested genotypes, including the local check. Genotype MY1617 performed best under optimal sowing in terms of grain yield and yield attributes, with a 5% increase over the local check. MY902 had the highest seed yield among late-sown genotypes. Correlation analysis showed that grain yield was positively correlated with grains per spike, days to anthesis, booting, and heading. The current study provides important information for wheat breeders to exploit exotic genetic materials under a diverse sowing window and develop genotypes with improved traits that may boost wheat growers’ production.