Drought stress, being the inevitable factor that exists in various environments without recognizing borders and no clear warning thereby hampering plant biomass production, quality, and energy. It is the key important environmental stress that occurs due to temperature dynamics, light intensity, and low rainfall. Despite this, its cumulative, not obvious impact and multidimensional nature severely affects the plant morphological, physiological, biochemical and molecular attributes with adverse impact on photosynthetic capacity. Coping with water scarcity, plants evolve various complex resistance and adaptation mechanisms including physiological and biochemical responses, which differ with species level. The sophisticated adaptation mechanisms and regularity network that improves the water stress tolerance and adaptation in plants are briefly discussed. Growth pattern and structural dynamics, reduction in transpiration loss through altering stomatal conductance and distribution, leaf rolling, root to shoot ratio dynamics, root length increment, accumulation of compatible solutes, enhancement in transpiration efficiency, osmotic and hormonal regulation, and delayed senescence are the strategies that are adopted by plants under water deficit. Approaches for drought stress alleviations are breeding strategies, molecular and genomics perspectives with special emphasis on the omics technology alteration i.e., metabolomics, proteomics, genomics, transcriptomics, glyomics and phenomics that improve the stress tolerance in plants. For drought stress induction, seed priming, growth hormones, osmoprotectants, silicon (Si), selenium (Se) and potassium application are worth using under drought stress conditions in plants. In addition, drought adaptation through microbes, hydrogel, nanoparticles applications and metabolic engineering techniques that regulate the antioxidant enzymes activity for adaptation to drought stress in plants, enhancing plant tolerance through maintenance in cell homeostasis and ameliorates the adverse effects of water stress are of great potential in agriculture.

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.

Sowing Dates Effect on Production of High Yielding Maize Varieties

The transitional phase of climate change is becoming a threat worldwide. Fluctuations in temperature are frequently observed in the life cycles of field crops. The current study was intended to evaluate heat stress (HS) at sensitive stages on four wheat cultivars’ growth, grain yield, and quality traits during two consecutive seasons. The experiment included four spring wheat cultivars that were exposed to HS durations (i.e., 0, 48, 96 and 144 h) at booting and anthesis stages. Pots were kept in an open-air, and labeled pots were moved to the glasshouse at the respective growth stage. After HS treatments, pots were moved from the glasshouse to the original position in the open air. The results showed that the cultivars differed in yield and grain quality traits, but their collective mean effect was significantly expressed with HS and HS duration (HSd) on the measured traits. Spike length was significantly affected by HS at the anthesis in comparison to those obtained from the control. However, the increase in HSd did not cause a significant effect on spike length compared to other treatments. Spike weight was significantly decreased in plants exposed to HS at booting and anthesis as well as by increasing HSd. In addition, grain weight and numbers were decreased in plants exposed to HS at booting and anthesis stages with a similar pattern by increasing HSd. Moreover, a reduction in amylose content was observed in grains of plants exposed to HS at booting and anthesis stages or when plants as exposed to a longer period of HSd. Nonetheless, amylopectin, wet gluten (WG) and grain N (GN) showed an increase in plants exposed to HS at booting and anthesis stages and/or extending HSd. This study concludes that plants exposed to different HS treatments during the life cycle had lower values for spike length, grains weight, and grains number per spike including amylose content in comparison to those obtained from the control. The decrease was significantly noted in the yield and grain quality of wheat when plants were exposed to HS at the booting stage in comparison to those exposed to HS at anthesis.

Yield and nitrogen (N)-content in wheat was studied under applied treatments of crop residues (legume vs. cereal), tillage depths (deep vs. shallow) and N-fertilizer rates (0, 40, 80, 120 and 160 kg ha⁻¹) at wheat-maize cropping systems. Experiments were conducted at Agronomy Research farm, the University of Agriculture, Peshawar Pakistan, during winter season 2009–2010 and 2010–2011 crop growth seasons. Well-chopped crop residues (5 t ha⁻¹) on dry matter basis of legume (Vigna unguicuata) and cereal (Zea mays) were applied to soil and subsequently plowed with mold-board plow as deep tillage (DT) and cultivator as shallow tillage (ST) treatment (main plot treatments). A month after residue and tillage application, seedbed was prepared and wheat was planted with drill in rows 25 cm apart in middle of November each year. Phosphorus and potassium were applied uniformly 80 and 40 kg ha⁻¹, respectively during seedbed preparation. N-fertilizer rates were applied in two splits: half 15 days after sowing (DAS) and other half 45 DAS (sub-plot treatment). Uniform cultural practices were applied during crop growth and development. Legumes residues amendments showed better responses than cereal but lower than no-residue treatment for N-content in leaf blade before anthesis (LBA), after anthesis (LAA), straw N-content (SNC), grain N-content (GNC), grain N-uptake (GNU), crop N-removal (CNR), recovery efficiency of added nitrogen (REAN), N-use efficiency (NUE), grain N-uptake (GNU) and grain yield. Likewise, shallow tillage proved better than deep tillage system for LBA, LAA, SNC, GNC, GNU, CNR, REAN, NUE, GNU and grain yield. Increased N-fertilizer from control onwards showed significant (p > 0.05) increments in LBA, LAA, SNC, GNC, GNU, CNR, N-uptake and grain yield. Treatments interaction was also found significant (p > 0.05). Study suggested, regardless of the given treatments, GNU and grain yield were in strong positive linear relationship. Legume residue incorporated shallow out yielded GNU and NUE of spring wheat in wheat-maize cropping system. It is concluded that LR and ST with 120 kg N ha⁻¹ ensures production of good wheat quantity and quality.

| Rains are expected to decrease and temperature has to rise for wheat growth in Pakistan. Wheat crop is planted on more than 52% area as rainfed crop in the providence Khyber Pakhtunkhuwa (KP). The study, therefore, aims to plant wheat in season from early to late i.e. November 15 to December 25 with about 10 days intervals. Field experiment was conducted at Agronomy Research Farm, the University of Agriculture Peshawar in winter season 2015-16. Experiment was in a randomized complete block design, in split plots having three replications. Sowing dates were assigned to main plots and wheat varieties (i.e. Shahkar-2013, Atta-Habib-2010, Pakhtunkhwa-2015, Hashim, Dharabi, Chakwal-50, Pakistan-2013 and Ghanemat-2015) to sub plots. Results revealed that sowing dates and varieties significantly affected yield and yield related traits. Sowing made on November 25 showed higher yield than the expected early sown on November 15 or late sown thereafter on December 5 in season in the region. Overall delay in sowing date i.e. from December 5 onwards resulted in sever losses in biomass and grain yield (GY). On averages of varieties, a decrease in biological- and grain yield was estimated 261 and 89 kg ha -1 , reapectively, per day in wheat in season for Peshawar when sowing was postponed from December 5. Early planting delayed days to anthesis and maturity, which otherwise extended grain development phase of the crop. Among varieties, Ghanemat-2015 showed better grain yield for a relatively longer duration i.e. December 5-15 over the others varieties. Atta-Habib also performed relatively better for sowing made on November 25 and Chakwal-50 on November 15. Overall GY reduced when wheat sowing postpones from December 5 in the season. Grains protein was observed high for sowing made on November 15-25 for wheat varieties Dharabi, Shahkar-2013, Pakhtunkhuwa-2015 and Ghanemat-2015 as un-irrigated crop for the area. The study suggests that none of the existing wheat variety has potential to sustain grain yield of wheat if planted on December 5 or thereafter. However, Ghanemat-2015 is relatively better option over the other varieties for Peshawar.