seyed mohsen nabavi kalat

In order to study the effect of deficit irrigation on RWC, proline concentration, antioxidant enzymes content, chlorophyll concentration and forage yield of five clover species, a field experiment was conducted during the cropping season 2019-2020.  The experimental design was split plots arranged based on randomized complete blocks design (RCBD) with three replications. Deficit irrigation  at three levels (0 (Full irrigation), 20 and 40% less than the irrigation requirement) were considered as main plots and  five clover species (Trifolium resupinatum ، T. alexandrium ، T. lapaceaum ، T. echinatum و T. diffusum) were allocated as sub plots.The results showed by increasing deficit irrigation up to 40%, proline concentration increased by 93% and the content of antioxidant enzymes catalase, peroxidase and superoxide dismutase increased by 12, 98 and 83% respectively. However, RWC, yield of fresh and dry fodder decreased by 22, 24 and 29% respectively. The highest RWC, chlorophyll concentration and content of antioxidant enzymes were observed without significant difference in T. resupinatum and T. alexandrium species. The interaction effect of two factors (deficit irrigation × species) showed by increasing deficit irrigation, fresh and dry forage yield of all five species decreased significantly. In all three levels of deficit irrigation, the highest yield of fresh (20.39, 18.81 and 13.94 t/h) and dry forage (4.59, 4.25 and 3.06 t/h) were obtained in T. resupinatum species. In general, the results showed that all 5 species do not have the required stability under stress conditions. Therefore, deficit irrigation for the proposed species will be justified only if a 20 and 40 percent irrigation water reduction is more beneficial than the yield reduction.

In order to study the effect of deficit irrigation on antioxidant enzymes content, soluble carbohydrates, chlorophyll concentration and yield of two sweet corn cultivars a field experiment based on randomized complete block design (RCBD) arranged in factorial with three replications was conducted at the Education-Research Farm (With geographical position: 37°33' north, 59°11' east), Mashhad Branch, Islamic Azad University, Mashhad, Iran, during in cropping season 2018-2019. The experimental factors were included at three levels (0 (Full irrigation), 20 and 40% less than the irrigation requirement) and two sweet corn cultivars (Amylapop and Merit). The results showed that with increasing of deficit irrigation (increasing stress) content of catalase, peroxidase, superoxide dismutase enzymes and soluble carbohydrates increased. However, concentration of chlorophyll a, b and total, husked cob yield, dehusked cob yield and conservable grain yield decreased. The content of catalase, peroxidase, superoxide dismutase, husked cob yield, dehusked cob yield and conservable grain yield were higher in Amylapop cultivar than Merit. In general, the results of this research showed that the tested cultivars do not have the necessary stability under conditions. Therefore, applying the method of deficit irrigation in the studied cultivars it will be justified only if a 20 and 40 percent reduction in the amount of water used for this product is more beneficial than the reduction in yield.

In order to study the effect of deficit irrigation and plant density on antioxidant enzymes activity, compatible ‎Osmolytes, relative water content and yield of baby corn (Pashan cultivar) a field experiment based on ‎randomized complete block design (RCBD) arranged in split-plot with three replications was conducted at the ‎Education-Research Farm (With geographical position: 37°33' north, 59°11' east), Mashhad Branch, Islamic ‎Azad University, Mashhad, Iran, during in cropping season 2018-2019. Irrigation deficit at three levels (0 (Full ‎irrigation), 20 and 40% less than the irrigation requirement) was considered as the main plots and plant density ‎at three levels (100, 150 and 200 thousand plants/ha) were considered at the sub plots. Analysis of variance ‎showed that the effect of deficit irrigation on all variables, effect of plant density on relative water content, ‎husked cob yield, dehusked cob yield and dehusked standard cob yield and interaction between of two factors ‎on all variables (Expect: relative water content and superoxide dismutase activity) were significant. The results ‎showed that with increasing deficit irrigation (increasing stress) and increasing plant density, the relative water ‎content decreased. Also, with increasing deficit irrigation, superoxide dismutase activity increased. Mean ‎comparison of traits under influence of two factors showed that with increase of deficit irrigation and plant ‎density proline content, soluble carbohydrates and the activity of catalase and peroxidase enzymes increased ‎due to increased drought stress and intraspecific competition. Husked cob yield, dehusked cob yield and ‎dehusked standard cob yield decreased due to of deficit irrigation. But at all levels of deficit irrigation, cob yield ‎increased with increasing plant density. In general, the results showed that drought stress increased the content ‎of compatible osmolytes and the activity of antioxidant enzymes in the tested cultivar, but this increase was ‎not sufficient to reduce the effects of stress on yield.‎

In order to study effect of seedling age and plant density on yield and yield components of rice (Sadri cultivar), a field experiment was conducted at the Ordukhan Agricultural Research Center, Heart Province - Afghanistan (Geographical longitude: 62°11'29" east and geographical latitude: 34°20'35" north) during the cropping season 2017-2018. The experiment was laid out in complete block design with three replications. Seeding ages with three levels (20, 30 and 40 days) were considered as main plots and plant densities with four levels (13, 17, 22 and 33 plants/m2) were allocated as sub plots. Analysis of variance showed that the effect of seedling age on number of tillers per plant, numbers of grains per panicle and grain yield was significant. The plant density had significant effect on all traits (expect, 1000grains weight). Interaction of two factors had no significant effect on any of the traits. The means comparison showed that the highest of number grains per panicle and grain yield were obtained for 30 days seedling age. Also, the highest of number of tiller per plant, number of fertile tiller per plant, number of grains per panicle and percent of unfilled grain were obtained by 13 plants per m2. But the highest biological yield, harvest index (HI) and grain yield obtained by 33 plants per m2. Based on simple correlation coefficient of traits, grain yield had significant positive correlation with biological yield, number fertile tiller per plant and number grains per panicle.

In order to study effect of deficit irrigation and cultivar on yield and yield components of soybean, a field ‎experiment was conducted at the Ordukhan Agricultural Research Center, Heart Province-Afghanistan ‎‎(Geographical longitude: 62°11'29" east and geographical latitude: 34°20'35" north) during the cropping ‎season 2017-2018. The experiment was conducted in a split-plot arrangement based on randomized complete ‎block design with three replications. Deficit irrigation with three levels (70 (no stress), 90 (moderate stress) and ‎‎110 (severe stress) mm evaporation from class A evaporation pan) were considered as main plots and ‎cultivars with four levels (Glway, Stine, Hong and LD04) were allocated as sub plots. Analysis of variance ‎showed that the deficit irrigation had significant effect on number of pods per plant, number of grains per ‎pod, 100 grains weight, biological yield, grain yield and harvest index The effect of cultivar on all traits and ‎the effect of interaction between two factors on 100 grains weight were significant. The results showed that ‎the deficit irrigation at 110 mm evaporation (severe stress) cased of significantly reduced of all traits. The ‎lowest number of pods per plant (109.8 pods), number of grains per pod (2.4 grains), 100 grains weight ‎‎(15.27g), biological yield (7363 kg/ha), grain yield (2899 kg/ha) and harvest index (35.5%) were obtained in ‎‎110 mm evaporation. The means of traits at 70 mm (no stress) and 90 mm (moderate stress) evaporation had ‎no significant difference. The LD04 cultivar had the highest grain yield (3793 kg/ha), because this cultivar had ‎optimum yield components. Simple correlation coefficient of traits showed that the grain yield had positive ‎significant correlation with biological yield, number of pods per plant, plant height, number of grains per pod. ‎Based on, these results deficit irrigation up to 90 mm evaporation can be considered.‎

In order to study the effect of two factors of irrigation deficit (drought stress) and superabsorbent polymer ‎application on morphological characteristics, plant yield and yield components of green bean, two experiments ‎were conducted in a completely randomized design with factorial arrangement in greenhouse conditions in ‎Educational- Research Greenhouse, Faculty of Agricultural, Mashhad Branch, Islamic Azad University, ‎Mashhad, Iran during in cropping season 2017-2018. In both experiments: experimental factors were included, ‎superabsorbent polymer in 4 levels (0, 3, 5 and 7 g per kg of soil) and irrigation deficit in 4 levels (20, 40, 60 and ‎‎80 % decrease of soil water weight based on Field Capacity). In the first experiment 3 and in the second ‎experiment, 6 replications were considered. The results of analysis of variance showed that in the first ‎experiment, effect of irrigation deficit, superabsorbent polymer and interaction between two factors had ‎significant effect on the plant height, number of leaf, fresh and dry weight of plant, leaf area, number of pod ‎per plant and fresh pod weight. In the second experiment, effect of irrigation deficit and superabsorbent ‎polymer on number pod per plant, number of grain per pod, grain yield per plant and biomass were significant. ‎But, in the second experiment, interaction between to factors had only significant effect on number of pod per ‎plant, grain weight per plant and biomass. In both experiments, means comparison under the influence of ‎irrigation deficit and superabsorbent polymer showed that with decreasing of 40% moisture from field capacity, ‎all traits were decreased. In general, the results of this study showed that application of superabsorbent polymer ‎caused of decreases the negative effects of drought stress.‎