Improvement of agricultural water use efficiency is of major concern with drought problems being one of the most important factors limiting grain production worldwide. Effective management of water for crop production in water-scarce areas requires efficient approaches. Increasing crop water use efficiency and drought tolerance by genetic improvement and physiological regulation may be a means to achieve efficient and effective use of water. A limited water supply inhibits the photosynthesis of plants, causes changes of chlorophyll contents and components and damage to photosynthetic apparatus. It also inhibits photochemical activities and decreases the activities of enzymes in plants. Water stress is one of the important factors inhibiting the growth and photosynthetic abilities of plants through disturbing the balance between the production of reactive oxygen species and the antioxidant defence, causing accumulation of reactive oxygen species which induce oxidative stress to proteins, membrane lipids and other cellular components. A number of approaches are being used to enhance water use efficiency and to minimize the detrimental effect of water stress in crop plants. Proper plant nutrition is a good strategy to enhance water use efficiency and productivity in crop plants. Plant nutrients play a very important role in enhancing water use efficiency under limited water supply. In this paper we discuss the possible effective techniques to improve water use efficiency and some macronutrients (nitrogen, phosphorus, potassium, calcium and magnesium), micronutrients (zinc, boron, iron, manganese, molybdenum and chloride), and silicon (a beneficial nutrient) in detail to show how these nutrients play their role in enhancing water use efficiency in crop plant.

Temperature is one of the decisive environmental factors that is projected to increase by 1. 5°C over the next two decades due to climate change that may affect various agronomic characteristics, such as biomass production, phenology and physiology, and yield-contributing traits in oilseed crops. Oilseed crops such as soybean, sunflower, canola, peanut, cottonseed, coconut, palm oil, sesame, safflower, olive etc., are widely grown. Specific importance is the vulnerability of oil synthesis in these crops against the rise in climatic temperature, threatening the stability of yield and quality. The natural defense system in these crops cannot withstand the harmful impacts of heat stress, thus causing a considerable loss in seed and oil yield. Therefore, a proper understanding of underlying mechanisms of genotype-environment interactions that could affect oil synthesis pathways is a prime requirement in developing stable cultivars. Heat stress tolerance is a complex quantitative trait controlled by many genes and is challenging to study and characterize. However, heat tolerance studies to date have pointed to several sophisticated mechanisms to deal with the stress of high temperatures, including hormonal signaling pathways for sensing heat stimuli and acquiring tolerance to heat stress, maintaining membrane integrity, production of heat shock proteins (HSPs), removal of reactive oxygen species (ROS), assembly of antioxidants, accumulation of compatible solutes, modified gene expression to enable changes, intelligent agricultural technologies, and several other agronomic techniques for thriving and surviving. Manipulation of multiple genes responsible for thermo-tolerance and exploring their high expressions greatly impacts their potential application using CRISPR/Cas genome editing and OMICS technology. This review highlights the latest outcomes on the response and tolerance to heat stress at the cellular, organelle, and whole plant levels describing numerous approaches applied to enhance thermos-tolerance in oilseed crops. We are attempting to critically analyze the scattered existing approaches to temperature tolerance used in oilseeds as a whole, work toward extending studies into the field, and provide researchers and related parties with useful information to streamline their breeding programs so that they can seek new avenues and develop guidelines that will greatly enhance ongoing efforts to establish heat stress tolerance in oilseeds.

Drought poses a serious threat to oilseed crops by lowering yield and crop failures under prolonged spells. A multi-year field investigation was conducted to enhance the drought tolerance in four genotypes of Camelina and canola by selenium (Se) application. The principal aim of the research was to optimize the crop yield by eliciting the physio-biochemical attributes by alleviating the adverse effects of drought stress. Both crops were cultivated under control (normal irrigation) and drought stress (skipping irrigation at stages i.e., vegetative and reproductive) conditions. Four different treatments of Se viz., seed priming with Se (75 μM), foliar application of Se (7.06 μM), foliar application of Se + Seed priming with Se (7.06 μM and 75 μM, respectively) and control (without Se), were implemented at the vegetative and reproductive stages of both crops. Sodium selenite (Na₂SeO₃), an inorganic compound was used as Se sources for both seed priming and foliar application. Data regarding physiochemical, antioxidants, and yield components were recorded as response variables at crop maturity. Results indicated that WP, OP, TP, proline, TSS, TFAA, TPr, TS, total chlorophyll contents, osmoprotectant (GB, anthocyanin, TPC, and flavonoids), antioxidants (APX, SOD, POD, and CAT), and yield components (number of branches per plant, thousand seed weight, seed, and biological yields were significantly improved by foliar Se + priming Se in both crops under drought stress. Moreover, this treatment was also helpful in boosting yield attributes under irrigated (non-stress) conditions. Camelina genotypes responded better to Se application as seed priming and foliar spray than canola for both years. It has concluded that Se application (either foliar or priming) can potentially alleviate adverse effects of drought stress in camelina and canola by eliciting various physio-biochemicals attributes under drought stress. Furthermore, Se application was also helpful for crop health under irrigated condition.

A pot experiment was conducted to evaluate the foliar applied phosphorous with and without pre-plant dose (50 kg hac.⁻¹) of phosphorous on growth, chlorophyll contents, gas exchange parameters and phosphorous use efficiency (PUE) of wheat. The experiment was conducted in net house at Department of Crop Physiology, University of Agriculture Faisalabad, Pakistan. Two promising wheat cultivar AARI 2011 and FSD 2008 were used as a test crop with 5 foliar phosphorus (P) rates (0, 2, 4, 6, 8 kg ha⁻¹). The foliar applied P with pre-plant performed better than without pre-plant and control treatments. Foliar treatment of phosphorus at 6 kg ha⁻¹ P proved to be the best among other foliar treatments followed by 8 kg ha⁻¹ P. The foliar application of phosphorous at 6 kg hac.⁻¹ with pre-plant soil applied P increased the shoot length, root length, shoot fresh weight, root fresh weight, shoot dry weight and root dry weight. The chlorophyll contents (Chl. a and b) were increased with the foliar application of phosphorous. The gas exchange parameters (net carbon dioxide (CO₂) assimilation rate, transpiration rate, stomatal conductance and sub-stomatal CO₂ rate) were significantly improved by foliar applied P. The maximum values of net CO₂ assimilation rate (5.27 μ mol m⁻² sec.⁻¹), transpiration rate (3.44 μ mol m⁻² sec.⁻¹), stomatal conductance (0.81 μ mol m⁻² sec.⁻¹) and sub-stomatal CO₂ (271.67 μ mol m⁻² sec.⁻¹), were recorded in the treatment where P was foliar applied at 6 kg hac.⁻¹ with pre-plant soil applied Phosphorous. The foliar application of phosphorous with pre-plant soil applied P enhanced Phosphorous use efficiency (PUE) in both varieties. The maximum value of PUE (15.42%) was recorded in the treatment where foliar feeding of P was done at 6 kg hac.⁻¹ with pre-plant soil applied P in both genotypes.

Drought is a burning issue all over the world that has led to remarkable reductions in the growth and yield of crops. Based upon the current problem, a series of two rain out shelter pot research experiments were performed to evaluate the drought tolerance in canola by foliar application of potassium (K) under water deficiency conditions in the Department of Agronomy, University of Agriculture Faisalabad, Pakistan. Four varieties of canola (Faisal Canola, Cyclone, Shiarlae, and Dunkled) were tested under two water deficit levels (100% FC and 50% FC) and two treatments of foliar potassium application i.e., 0% K and 2% K. The data was recorded with standard procedures when the plants were grown up to maturity. Results concluded that drought posed a significant decrease in all parameters under study. However, supplemental foliar application of potassium at the rate of 2% at both (vegetative and reproductive) stages of canola enhanced the water potential (0.24% and 0.23%), osmotic potential (0.12% and 0.11%), turgor pressure (0.66% and 0.58%), respectively. Similarly, the chlorophyll contents as chlorophyll a (0.25% and 0.28%), chlorophyll b (1.26% and 1.80%) and leaf carotenoid contents (0.20% and 0.62%) were also increased where K was applied at the rate of 2% during vegetative and reproductive stages of canola. The foliar applied K at the rate 2% enhanced leaf photosynthetic rate (13.11 µmol CO₂ m⁻² s⁻¹ and 15.96 µmol CO₂ m⁻² s⁻¹), transpiration rate (5.36 µmol CO₂ m⁻² s⁻¹ and 5.54 µmol CO₂ m⁻² s⁻¹) and stomatal conductance (0.22 µmol CO₂ m⁻² s⁻¹ and 0.26 µmol CO₂ m⁻² s⁻¹) of the plants at both stages. Yield attributes such as thousand seed weight (1.03% and 1.03%), seed yield (0.58% and 0.58%) and biological yield (0.35% and 0.38%) were increased by foliar K application under water deficit conditions at both stages. The genotype Shiralae showed significant improvement among all others genotypes under normal as well as water deficit conditions