Adding organic amendments to the soil increases permeability, water-holding capacity, biological activity, and nutrient content, and consequently increases the soil fertility and the yield of plants. In order to evaluate the effects of municipal waste compost and sheep manure on yield and yield components of wheat, a three-year field experiment was conducted as a randomized complete block design with three treatments, including the application of sheep manure (17.3 kg m-2), compost (15.6 kg m-2), and control (no organic amendment) in three replications in Agricultural Research Station of Zarghan, Fars province, during 2015-2018. The results showed that organic amendments had a significant effect on the number of fertile tillers per area, plant height, ear length, grain number per ear, thousand-grain weight, grain yield, biological yield, and harvest index; however, straw weight was not significantly affected by organic amendments. In all three years of the experiment, sheep manure and compost significantly increased wheat grain yield compared to the control treatment. On average, compost and sheep manure increased wheat grain yield by 63.9% and 46.1% in the first year, 29.3 and 53.7% in the second year, and 37.4 and 26.9% in the third year, respectively, compared to the no-amendment treatment. However, in the most cases, no significant difference was observed between sheep manure and compost. Therefore, farmers can use any of the sheep manure or solid-waste compost to increase wheat yield, the amount of which should be determined based on the amount of organic carbon in the farm soil.

Improving the nutritional status of plants is an effective method for enhancing their ability to withstand drought stress. To evaluate the quantitative, qualitative, and antioxidant properties of castor plant under water deficit conditions stress and foliar application of chemical fertilizers, an experiment was conducted as a split-plot design in a completely randomized block design with three replications. The first factor was irrigation levels including control (normal irrigation), irrigation after 80 mm and 140 mm evaporation from the pan evaporation in the main plots, and eight spraying chemical fertilizers (sulfur, potassium, nitrogen, sulfur+potassium, sulfur+nitrogen, potassium+nitrogen, sulfur+potassium+ nitrogen and control (no spraying)) were included in subplots. The highest proline content, catalase, peroxidase, superoxide dismutase, and total phenol were obtained under irrigation after 140 mm of evaporation conditions and foliar application of nitrogen+potassium+sulfur. Also, the highest grain yield, oil yield, and the lowest oil percentage were observed in the nitrogen+potassium foliar treatment under irrigation conditions after 20 mm of evaporation. Although the content of malondialdehyde increased in water deficit stress treatments, nitrogen+potassium+sulfur and nitrogen+potassium foliar application significantly reduced the peroxidation of membrane lipids (malondialdehyde) under irrigation conditions after 80 and 140 mm of evaporation compared to the control treatment. In conclusion, foliar application of chemical fertilizers in castor can improve the resistance to water stress by strengthening the antioxidant system and then increase its grain and oil yield.

In order to compare 25 genotypes of bread wheat in terms of morpho-physiological and biochemical traits, an experiment was conducted in a randomized complete blocks design with three replications in the rainfed and irrigated conditions at Razi University, Iran, in 2016-2017. GT-biplot was used to evaluate genetic diversity and to identify stable genotypes with high yield and drought tolerance. Combined variance analysis showed that there was high variability among genotypes for the most of traits. Examining the correlation of traits in two environmental conditions showed that morpho-physiological traits; especially yield components, were the most related to yield. The results of the GT-biplot method showed that the first and second principal components explain 41.7% and 40.1% of the total changes in rainfed and irrigated conditions, respectively. Based on the GT-biplot analysis diagrams of genotypes 10, 15, 6, 13, 2, 14, and the Pishtaz cultivar in terms of physiological traits, yield and its components and the traits related to stem and spike in irrigated conditions, and genotypes 10, 15, 6, 18, and 17 in terms of biochemical traits, yield and its components, and traits related to stem and spike in rainfed conditions were recognized as superior genotypes. The genotypes 2 and 6 in irrigated conditions and the genotype 6 in rainfed conditions had the lowest genotype×trait interaction. Finally, the genotypes 10, 15, and 6 were superior in two environmental conditions and the genotype 6 had the least interaction effect in both conditions. Therefore, these genotypes can be used in breeding programs.

Sunflower is one of the most important oilseed crops with more than 50% of nutritional (table) consumption. Considering the climate changes, the development of genotypes tolerant to abiotic stresses is more important than before. In the present research, the recovery capacity of two oilseed sunflower genotypes (DM-2 and H158A/H543R) was evaluated 24 hours after irrigation following sever drought stress (30% of field capacity) by evaluating the changes in enzymes activity at 8-leaf stage and quality and quantity of end product at adult plant stage. The experiments were conducted in frame of completely randomized design with 3 replications under controlled conditions. A significant difference was observed between genotypes in the terms of guaiacol, ascorbate, lipoxygenase and proline contents, as well as leaf area, leaf length, root weight, plant height and root sodium-potassium ratio in recovery conditions. Based on the results of the evaluations and changes in the mean of traits in the comparison of two normal and recovery conditions, as well as the pattern of fatty acids, genotype DM-2 has a high recovery ability.

The present research was conducted to simulate the impact of climate change on irrigated barley in Lorestan and Hamadan provinces. For this purpose, nine regions including Aligudarz, Borujerd, Khorramabad, Kuhdasht, Pol-e Dokhtar, Hamedan, Malayer, Nahavand, and Kabudarahang were selected in the two provinces. The APSIM-barley model was employed to simulate the growth and development of irrigated barley. Firstly, the APSIM-barley model was evaluated using two independent field experiments. The first experiment was conducted in Khorramabad to calibrate the crop model; while the second experiment was done in Hamedan to validate the crop model. The future climate was projected using the AgMIP methodology under two scenarios (RCP4.5 and RCP8.5) for the period 2040-2070. The results of the model validation showed that the crop model was able to simulate barley yield and biomass with nRMSE of 16.4% and 13.3%, respectively. Additionally, the results indicated that on average across the study locations, barley grain yield would decrease by 3.8% and 5.7% under RCP4.5 and RCP8.5, respectively. However, in Pol-e Dokhtar, barley grain yield is projected to increase by 1.3% and 4.8% under RCP4.5 and RCP8.5, respectively. Based on these findings, adaptation strategies should be considered in the future to prevent the reduction of irrigated barley yield in the studied provinces.

Vernalization genes (Vrn), in addition to controlling the growth habit of wheat (spring and winter), play a key role in flowering time and early maturity of wheat. They are also of great interest in drought tolerance researches. To investigate the effect of Vrn genes on drought tolerance, four isogenic lines were developed. Isogenic lines were resulted from the crosses of the early heading Australian variety, Excalibur, with the late heading Iranian variety, Roshan, and followed by backcrossing with Roshan. Two experiments were conducted based on randomized complete block design with four replications under rainfed conditions of Sepidan during 2019-2020 and under well-watered conditions of Kerman during 2020-2021 cropping years. In the present research, seven important agronomic traits, including days to heading, days to ripening, grain filling period, spike number per meter square, grain number per spike, 1000-grain weight, and grain yield were assessed. Isogenic lines were assessed for drought tolerance using eight indices, including mean of productivity (MP), yield index (YI), stress tolerance index (STI ), geometric mean of productivity (GMP), stress susceptibility index (SSI ), yield stability index (YSI), and stress tolerance score (STS). The results of stress tolerance score (STS) showed that isogenic lines vrn-B1/Vrn-D1a and Vrn-B1a/vrn-D1 had the highest and the lowest stress tolerance score, respectively. In addition, the vrn-B1 and Vrn-D1a alleles, which cause early flowering, improve drought tolerance by utilizing an escape mechanism from dry conditions.

In order to evaluate yield and yield components in intercropping barley with vetch, a two-year field experiment was conducted at the Agricultural and Natural Resources Research Station of Miandoab. The arrangement consisted of 9 mixing treatments with densities of 200 Vetch plant + 300 Barley plant, 200 Vetch plant + 500 Barley plant, 200 Vetch plant + 700 Barley plant, 400 Vetch plant + 300 Barley plant, 400 Vetch plant + 500 Barley plant, 400 Vetch plant + 700 Barley plant, 600 Vetch plant + 300 Barley plant, 600 Vetch plant + 500 Barley and 600 Vetch plant + 700 Barley plant per square meter and sole culture of both crops. The experimental design was a randomized complete block design with four replications. The result showed The highest spikes per square meter, thousand kernel weight, biological yield, and grain yield in barley were observed in the sole culture of barley. Also, the highest plant height, number of seeds per plant, thousand kernel weight, biological yield, and grain yield in vetch belonged to the sole culture of vetch. However, the highest Land equivalent ratio (LER) belonged to treatments of 200 Vetch plants + 500 Barley plants by 1.49,

In order to investigate effects of deficit irrigation and sowing date on qualitative characteristics of oil and fatty acids in Safflower cultivars, a split factorial experiment was conducted based on a randomized complete blocks design with four replications at the research farm of Faculty of Agriculture, University of Zanjan, during the 2015-2016 growing season. In this experiment, irrigation levels included optimal irrigation and deficit irrigation (50% of water requirement) as main plots and combined two sowing dates including (20 March and 20 April) and three spring safflower cultivars (i.e. Gholdasht, Soffeh, and Sina) were allocated to subplots in a factorial arrangement. Drought stress and late sowing date decreased chlorophyll content, seed yield, and oil content. The results showed that deficit irrigation caused decrease in seed yield and oil content. Late sowing date caused a decrease in seed yield. The highest seed yield was obtained on optimal irrigation and on the sowing date 20 March (2036 kg/h) and the lowest seed yield was obtained on 50% of water requirement and the sowing date 20 April (1675.4 kg/h). Among the studied cultivars, the highest seed yield (1986.91 kg/ha) was obtained from Soffeh cultivar. With the sowing date and deficit irrigation, iodine number decreased and acid value increased. Among fatty acids, the content of linoleic and linolenic acids decreased due to deficit irrigation and late sowing date and the amount of oleic and stearic acids was the highest in the second sowing date, while palmitic acid had the highest amount in the first sowing date. Therefore, to obtain the highest yield and the highest oil quality Soffeh cultivar, optimal irrigation and early sowing date are recommended.

To investigate the effect of organic fertilizers on the quantitative and qualitative characteristics of sugar beet under different moisture conditions, a study was conducted as a split plot experiment based on a randomized complete block design with three replications in Mahabad city in 2021. Irrigation treatments, including irrigation after 60 (normal), 90 (mild stress), and 120 (severe stress) mm evaporation from the class A evaporation pan, and organic fertilizer treatments (control, vermicompost, manure, and humic acid) were placed in main plots and sub-plots, respectively. Severe water stress conditions reduced the content of chlorophyll a (22.82 %) and relative water content (RWC) (24.35 %) and increased the content of proline (47.43%), beta glycine (17.89%), catalase (21.30 %), malondialdehyde (47.95 %) and water use efficiency (WUE) (23.83%) compared to normal irrigation conditions. Also, the application of vermicompost increased the amount of chlorophyll a, RWC, proline, glycine beta, catalase content, and WUE by 29.11, 20.15, 34.83, 14.98, 13.70, and 21.56 percent, respectively, and decreased the content of malondialdehyde about 18.53% in comparison to control. In this study, the highest stomatal conductivity (51.01 mol.m-2s-1), chlorophyll b content (16.3 mg.g-1FW), carotenoid (4.27 mg.g-1 FW), roots yield (78.33 t.ha-1) and the lowest content of hydrogen peroxide (0.96 μmol.g-1FW) allocated to the vermicompost treatment under normal irrigation conditions. Root yield showed a positive and significant correlation with stomatal conductance, chlorophyll b, carotenoid, RWC, and WUE, but a negative and significant correlation with catalase enzyme activity, hydrogen peroxide content, malondialdehyde, and sugar content.

In order to investigate the effect of integrated application of biological and organic fertilizers on absorption and phosphorus physiological efficiency in medicago sativa in Aran and Bidgol citiy in 2013, A factorial experiment was conducted in a randomized complete block design with three replications. Experimental factors include four levels of biofertilizers (control, nitroxin fertilizer, Fertilizer Phosphate-2 and the combination of Nitroxin and Fertilizer Phosphate-2) and Four levels of organic fertilizer (control, cow manure, sheep manure and chicken manure) were 10 tons per hectare. The results showed that the use of biological fertilizers had a significant effect on plant height, stem dry weight, leaf dry weight, leaf-to-stem ratio, grain yield, biological yield and harvest index at a significant level of 1%. Also, the effect of organic fertilizers on plant height, stem dry weight, leaf dry weight, leaf-to-stem ratio, grain yield, biological yield, harvest index, physiological efficiency and phosphorus use efficiency were significant at 1% level. Among the comparison of the averages of intraction effects, the highest physiological efficiency of phosphorus related to the treatment (no inoculation with biological fertilizer + consumption of 10 tons per hectare of cow manure) with an average of 35.78 kg of grains produced per kg of phosphorus used and the lowest amount of physiological efficiency of phosphorus. It belonged to the treatment (not using biological fertilizer + not using organic fertilizer.