The Effects of Foliar Application with Potassium and Zinc in the Pollination Stage on Morpho-Physiological Characteristics Under Moisture Stress in Wheat (Triticum aestivum)

Drought, being the most common abiotic stress, is a major factor in crop yields as it limits crop production on a global basis. To evaluate the effects of foliar application with potassium (K) and zinc (Zn) in the pollination stage on morphological and physiological characteristics of wheat under water stress conditions, a split-factorial layout based on a randomized complete block design (RCBD) with three replicates have been carried out at the experimental farm of the Research, Education and Extension Center of Agriculture and Natural Resources of Hamadan during 2017-2018. The main plot includes irrigation levels (normal and water stress) and the subplot, two factors of foliar application of potassium (K) and zinc (Zn) fertilizers. Potassium fertilizer from K2O source (40%) includes 2 liters per ha at three levels; I) without fertilizer (the control), II) leaf spray at the beginning of booting, and III) leaf spray after pollination. Also, zinc fertilizer from water-soluble zinc source (10%) includes four liters per ha in three levels: I) without fertilizer (the control), II) leaf spray at the beginning of booting, and III) the use of leaf spray after pollination. The results of the analysis of variance show a significant difference between treatments in all studied traits. Significant differences in all of the traits are observed under stress and normal irrigation. Co-application of potassium (K) and zinc (Zn) fertilizers, compared to the control, has increased evaluated morphological indices of HI (21%), grain yield (52%), total yield (29%), and TKW (25%) under stress conditions. Therefore, according to the results, the use of K and Zn fertilizers as a foliar application at the beginning of booting reduces the harmful effects of drought stress on the plant, increasing the yield and morphological characteristics of wheat.