COMBINED EFFECTS OF DROUGHT STRESS AND NPK FOLIAR SPRAY ON GROWTH, PHYSIOLOGICAL PROCESSES AND NUTRIENT UPTAKE IN WHEAT

The present study investigated the effects of supplemental foliar nitrogen (N), phosphorous (P) and potassium (K) spray, alone or in various combinations, on physiological processes and nutrients uptake in wheat under water deficit conditions. The study comprised of two phases; during the first phase, ten local wheat (Triticum aestivum L.) genotypes were evaluated for their response to PEG-6000 induced osmotic stress. One drought tolerant (Bhakkar-2002) and sensitive (Shafaq-2006) genotype selected from screening experiments were used in the second phase to determine the individual and combined effects of N, P and K foliar spray on physiological mechanisms in wheat under drought stress. The results revealed that limited water supply significantly reduced germination, growth and uptake of N, P and K. Supplemental foliar fertilisation of these macronutrients alone or in different combinations significantly improved the water relations, gas exchange characteristics and nutrient contents in both the genotypes. Bhakkar-2002 maintained higher turgor, net CO2 assimilation rate (P-n), transpiration rate (E), stomatal conductance (g(s)) and accumulated more N, P and K in shoot than Shafaq-2006. The foliar spray of NPK in combination was effective in improving wheat growth under both well-watered and water-deficit conditions.