پژوهشهای حبوبات ایران (Sep 2019)
Effect of different levels of drought stress and growth regulators on yield and yield components of common bean (Phaseolus vulgaris L.)
Abstract
Introduction Legumes have great nutritional value and are an important source of vegetable protein. Population growth in recent decades has led to increased consumption of protein, especially red meat. The increase in cereal production as supplemental protein sources is considered the country's economic development program. Legumes grain have 18 to 32 percent protein and plays an important role in people's diet. Drought stress is among the main limiting factors for legumes production, and is able to reduce significantly the production of grains, in rainfed areas. Stress inhibits the full expression of the genetic potential of crops and thereby reducing the production. Salicylic acid (SA), a plant phenolic compound is known as a plant hormone and its role in relation to defense mechanisms against biotic and abiotic stresses, is well known. Priming seed is a technique which the seeds before dealing with the ecological condition, will gain ability for better germination in terms of physiological and biochemical functioning. The aim of this study was to investigate the effect of spraying and priming of beans with salicylic acid on common bean yield and its components. It was also tried to determine whether priming or spraying with salicylic acid or both of them can induce tolerance drought stress to or not. Materials & Methods This experiment was performed at Research Station of Agricultural School, Urmia, Iran, during 2015-2016 growing season. The experiment was conducted as split-plot arrangement based on randomized complete block design with three replications. Treatments consisted of three levels of drought stress including severe drought stress (irrigation after 120 mm evaporation by class A pan), moderate drought stress (irrigation after 90 mm evaporation by class A pan), and control (irrigation after 60 mm evaporation by class A pan) as the main factor and treatments in five levels (control, priming with distilled water, priming with salicylic acid, spraying with salicylic acid, spraying and priming with salicylic acid) as subplots. Each experiment consisted of three replication with 5 plots. The first treatment control: conventional planting seeds. Second treatment was primed seeds of beans with distilled water. The seeds were primed for 12 hours in distilled water at room temperature. The third treatment: was seed priming with salicylic acid, so that the seeds for 12 hours in a solution of 0.5 micromoles salicylic acid was used at room temperature. The fourth plot: spraying the plants with a solution of 1 micromoles of salicylic acid on the field when the plants produced about 50 percent pod. Fifth treatment (v) was a combined treatment, priming the seeds before planting (seed for 12 hours in a solution of 0.5 micromoles of salicylic acid at 250C temperature) and spraying the plants of the plot with a solution of 1 micromoles of salicylic acid on the field at 50 percent poding. After physiological maturity of beans, the crop was harvested and biomass, grain yield, 100 grain weight, the number of pods per plant, the number of grains per pods and plant height were measured. The data were analyzed with Tukey’s test at 95 percent probability (P≤0.05) using SAS and MSTATC statistical software. Results & Discussion Analysis of variance showed that grain yield, biological yield, index harvest, the number of pods per plant, the number of grains per pod, pod and seed weight, 100 grain weight and plant height were significantly affected by drought stress and growth regulators. Mean comparison showed that the maximum and minimum of traits were obtained under control (without stress) and severe drought stress, respectively. The highest and lowest values of studied traits were obtained by spraying and priming with salicylic acid and control (without priming). The highest (3362 kg ha-1) and lowest (1864 kg ha-1) grain yield were obtained under control (without stress) and severe drought stress, respectively. Drought stress in comparison with optimum irrigation (control) reduced grain yield by 45 percent. Treatment spraying and priming with salicylic acid in comparison with control (without priming) increased grain yield about 50 percent. Conclusion According to this research, under Urmia climate conditions, for producing high grain yield of common bean, using spraying and priming with salicylic acid can be recommended.
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