IMPROVEMENT OF DROUGHT TOLERANCE IN WHEAT THROUGH INCREASING LEVEL OF POTASSIUM APPLICATION

Abstract

Amelioration of the adverse effect of drought on wheat could be overcome by increasing K supply. To find out the effective method for application of increasing level of potassium to sustain yield of wheat under water deficit stress an experiment was conducted at the research field of Crop Physiology and Ecology department, Hajee Mohammad Danesh Science and Technology University, Dinajpur during the period of November 2015 to April 2016. The experiment was laid out in a split plot design with three replications. The main plot treatment consisted of four K fertilizer treatments in combination with water regimes (T1 = recommended K fertilizer under well water condition, T2 = recommended K under water stress condition, T3 = soil application of additional 50 kg K ha-1 under water stress, T4 = additional foliar application of K with recommended K fertilizer under water stress condition) and sub-plot consisted of two wheat genotypes- BARI Gom 29 (V1) and BARI Gom 26 (V2). Additional soil or foliar application of K increased the plant height at 60 days after sowing (DAS), leaf number at 60 DAS, leaf dry weight at 60 and 75 DAS, leaf area at 75 DAS, stem dry weight at 60 DAS, spike dry weight at 75 DAS, relative leaf water content at 65 DAS and water retention capacity at 75 DAS compared to recommended K fertilizer treatment under water stress condition. But foliar application of K was found more effective and BARI Gom 26 respond better in these respects. Additional soil and foliar application of K in BARI Gom 29 and addition foliar application of K in BARI Gom 26 increased the flag leaf K content under water stressed condition but additional soil or foliar application of K did not show any influence in P uptake under water stressed plant. Under water stress condition, additional foliar application of K improved 18% and 13% grain yield compared to recommended K fertilizer treatment in BARI Gom 29 and BARI Gom 26, respectively and the improvement in grain yield was contributed by the improvement in spikes m-2 , grain spike-1 and 1000-grain weight. Additional foliar application of K improved the above ground biological yield in BARI Gom 29 and both additional soil and foliar application of K improved the above ground biological yield in BARI Gom 26 compared to recommended K fertilizer under water stress condition. From the overall result it can be concluded that additional foliar application of K along with recommended K could improve grain yield of wheat under water stress condition.