آبیاری تکمیلی

Lentil (Lens culinaris Medik.) from the Fabaceae family, is a self-fertilizing and diploid annual plant (2n=14), herbaceous and botanically has a short and branched stem with a bright green color. Drought stress is one of the most common climate-related challenges in nature, and few plants can fully overcome it. It is a major factor limiting plant growth. Given that over 80% of the area under lentil cultivation in Iran relies on rainfed agriculture, drought has the greatest impact on reducing yield during various stages of the plant's growth and development. Supplementary irrigation technique is effective in reducing the possible risk and increasing the reliability of crop yield under rainfed conditions. Planting density can play an important and strategic role in plant yield.

The present experiment was conducted in the crop year 2023. The soil of the study site, first, was plowed and then disked and finally leveled with a trowel. Before planting, the seeds were disinfected using Captan fungicide to prevent lightning disease. After the initial preparation of the land, planting was done at the end of March 2023. The experiment was carried out in the form of split plots based on a randomized complete block design with three replications. The main factor (main plots) included two levels (irrigation at the time of planting and no supplementary irrigation) and the sub factor (subplots) was related to planting density (100, 200 and 300 plants per m2). All crop care was done at a certain time according to the customs of the research area. In this research, the characteristics of plant height, number of pods per plant, number of seeds per plant, number of branches per plant, dry weight of a whole plant (biomass), total weight of seeds of a plant (seed yield), 100-seed weight and the SPAD value were measured. Relevant measurements were performed with standard methods. SPSS version 26 software was used for statistical analysis of data.

The results of this study showed that there is significant genetic diversity for the studied traits. Based on the Analysis of variance results, in the case of supplementary irrigation factor, the traits of number of pods per plant, number of seeds per plant, biological yield, 100-seed weight and SPAD value at the probability level of 1% (P≤ 0.01) and for traits of plant height and seed yield were significant at the 5% probability level (P≤ 0.05). Regarding the planting density, traits of number of pods per plant, biological yield, seed yield, 100-seed weight and SPAD value were significant at 1% probability level (P≤ 0.01). Considering the interaction effect of these two factors (supplementary irrigation and planting density), the number of seeds per plant was significant at the 5% probability level (P≤ 0.05) and the 100-seed weight was significant at the probability level 1% (P≤ 0.01). Mojdeh cultivar with a density of 100 and 200 plants per m2 and with additional irrigation conditions at the beginning of flowering had the best yield (3.26 and 2.93 g, respectively). Correlation analysis (Pearson method) of traits showed that there is a significant correlation between the yield and other evaluated traits (P≤ 0.01 and P≤ 0.05), which indicates the relationship between yield components and yield which can pave the way for future agricultural and plant breeding research on the same topics as current research.

According to the results of this experiment, it seems that the density of 100 or 200 plants per m2 is suitable for lentil cultivation in conditions similar to the location of this research. The results also showed the significant diversity and difference for most traits, which can be useful and practical in future agricultural and breeding programs.

Chickpea (Cicer arietinum L.) is one of the most important legumes in the world (Keifer, 2018). After India, Australia, and Pakistan, Iran has taken the fourth rank in terms of chickpea cultivation area, and the decrease in rainfall and especially the plant's exposure to heat and drought stress at the end of the season is the reason for the decrease in crop yield (SabaghPour et al., 2010; FAO, 2018). In general, drought stress and its relationship with the reduction of yield and its components in crops plants can be primarily attributed to the closing of stomata in response to low soil water content, during which the entry of carbon dioxide into the leaf is reduced, and as a result, it causes a reduction in photosynthesis.

In order to investigate the effect of irrigation regimes on the yield and yield components of chickpea (Cicer arietinum L.), an experiment was conducted at the research farm of Shahed University during 2021–2022 as a split plot design in the form of random complete blocks. The first factor is irrigation systems at three levels: 1) supplementary irrigation (Irrigation at two sowing times and before flowering based on 20% available soil water, 2) complete or control irrigation (irrigation based on 20% available soil water), 3) Low irrigation regime (irrigation based on 40% available soil water) is the second factor of autumn (November 15) and spring (March 15) sowing dates. Irrigation was carried out in the form of streams and stacks, and the ends of the plots were completely closed to prevent water from escaping. Data analysis and calculations related to simple Pearson correlation coefficients between traits were performed with SAS (ver 9.4) and SPSS (ver 23) software, respectively, and the average of treatments was compared by LSD test at a statistical level of 5%. The graphs were drawn using Excel software.

The results of the variance analysis of the interaction between irrigation regime and planting date showed that there is a significant difference between the traits of number of branches per plant, number of pods per plant, plant height, number of seeds per plant, harvest index, biological yield and seed yield. The results of comparing the averages also showed the highest number of branches per plant (9.83), the number of pods per plant (30.5), plant height (51.08) cm, and the number of seeds per plant (26.66). The harvest index was 0.48 percent, the biological yield was 4670 kg ha-1, and the seed yield was 2384.17 kg ha-1 for the autumn planting date treatment under the autumn irrigation regime (irrigation based on draining 20% of crop capacity moisture). The highest correlations with grain yield were obtained by traits: plant height (r = 0.986**), number of branches per plant (r = 0.966**), harvest index (r = 0.962**), number of seeds per plant (r = 0.961*), biological yield (r = 0.956**), hundred seed weight (r = 0.933**) and number of empty pods per plant (r = 0.880*).

In general, the results of this experiment indicate that the Low irrigation regime is more efficient than Supplementary irrigation in all traits after the control irrigation regime in autumn sowing. Therefore, the Low irrigation regime is suggested as a low irrigation regime suitable for the conditions of the tested region for the sowing of chickpeas in autumn, and in addition, other autumn sowing dates of this variety should be studied.

Drought stress is known as one of the most important factors limiting the growth and production of agricultural plants in most parts of the world and Iran. It is a multidimensional stress and affects plants at different levels. From a physiological point of view, drought stress causes several changes in the relative water content of leaves and photosynthetic pigments of plants, which in turn causes a decrease in the efficiency of photosynthesis and a significant reduction in plant growth parameters and ultimately grain yield. In Iran, drought stress usually occurs during the filling stage of wheat grains, and due to the limitation of irrigation, supplementary irrigation can play an important role in dealing with drought stress. Durum wheat (Triticum durum, Desf) is an important food product due to its heavy gluten properties and non-sticky dough, ideal for preparing pasta products such as macaroni and spaghetti.
To investigate the physiological characteristics, yield, and yield components of durum wheat cultivars under drought conditions and supplemental irrigation, 10 durum wheat genotypes were evaluated in the form of a split-plot design with the basis of randomized complete blocks in dryland and supplemental irrigation with 3 replications during Crop years 2017-2018 and 2018-2019 in Kohdasht city of Lorestan province. Grain yield and yield components (weight of 1000 seeds, number of seeds per spike, number of spikes per plant) as well as biochemical and physiological properties of photosynthetic pigments, greenness index, relative leaf water, leaf protein and light consumption efficiency were investigated.
Variance analysis showed a significant variation among the examined cultivars, moisture conditions, as well as the interaction of cultivar × humidity conditions for most of the traits except the interaction effect of cultivar × humidity conditions for chlorophyll b and leaf protein. The effect of year and interaction effects of year with other factors were not significant for most of the traits. Performing supplementary irrigation compared to rainfed conditions caused all traits to increase significantly, except greenness index and protein content. Mean comparison of interaction effect of cultivar × moisture environment with Duncan's method at 5% level showed that the genotypes reacted differently for the traits in two moisture conditions and in dry conditions, Omrabi3, Hana, Aria and Saji genotypes were superior to other genotypes in terms of agricultural and physiological traits, and with supplementary irrigation, these for genotypes maintained their superiority, and two genotypes, Shabrang and Behrang, were added to this group.
In general, it can be said that the results were almost the same in the two years studied. Supplementary irrigation compared to rainfed conditions improved the agronomic and physiological characteristics of the cultivars. Among the genotypes, there was a high diversity for all the examined traits and this diversity was different in two humidity conditions. Considering the two-year mean yield, the genotypes of Omrabi3, Saji, Arya and Hana for rainfed conditions and Omrabi3, Hana and Behrang for supplementary irrigation conditions of the studied area are recommended.

In order to study the effect of cytokinin, gibberellin, and cycocle on yield and yield components of two wheat cultivars under different irrigation regimes, a study was conducted as a split-split experiment based on a randomized complete block design with three replications at the Agricultural Research Station of Kurdistan University in 2016. There, the irrigation factor at four levels: dryland, irrigation at booting stage, irrigation at booting + flowering and irrigation at booting + flowering + grain filling stages have served as the main plots, two wheat cultivars (Sirvan and Homa) as sub-plots, and levels of plant growth regulators foliar application including, i.e. control, gibberellin (100 µm), cytokinin (100 µm), and cycocel (3gr. lit-1) at the wheat stem elongation and grain filling stages as the sub-sub plots. Results show that in the foliar application during the stem stage, compared to the dryland treatment, yield increase in one, two, and three irrigation treatments have been 29%, 33%, and 43%, and at the grain filling stage; 22%, 28%, and 33%, respectively. Homa cultivar produced higher yield compared to Sirvan. In the foliar application during the stem stage, the highest grain yield (504 g m-2) belongs to application of three irrigation treatments as well as addition of cytokinin, and at the grain filling stage, the highest grain yield (477.6 g m-2) has been obtained from Homa cultivar under three times irrigation condition and cycocel consumption. Therefore, using even one stage irrigation and the application of cytokinin and cycocel can increase the grain yield of wheat.

In order to investigate the effect of supplementary irrigation on dryland wheat cultivars, an experiment was conducted as a factorial in randomized complete block design with three replications during cropping seasons 2016-2017 and 2017-2018. The factors were drought stress levels (dryland and supplemental irrigation) and wheat cultivars (Homa, Sardari, Rijaw, Ouhadi and Azar2). Supplemental irrigation significantly increased grain yield. In both cropping seasons, drought stress increased free amino acids and glycine betaine and decreased relative water content (RWC) and rate of water loss (RWL). Negative and significant correlation of RWL with free amino acids of leaf and glycine betaine and also positive and significant correlation of RWC with glycine betaine level indicated that the higher the concentration of osmotic compounds in leaves, the lower the rate of leaf water loss and the higher the leaf water content. The results of this study confirmed that adequate water supply by using supplementary irrigation in the most sensitive stages of wheat growth is a viable strategy to improve the physiological traits of the plant and hence obtain an acceptable grain yield under dryland conditions.

In order to evaluate the drought stress tolerance of durum wheat genotypes, an experiment was conducted at Gachsaran Dryland Research Center, Iran during 2017-18. A total of 18 durum wheat genotypes were studied in a randomized complete block design with four replications under rainfed and supplementary irrigation conditions. The results of combined analysis of variance showed that supplementary irrigation significantly increased grain yield. In supplementary irrigation condition, the genotypes 16, 17 and 18 and in rain fed condition the genotypes 4, 16 and 17 had the highest grain yield per hectare. The stress tolerance indices were calculated based on yield of genotypes in rain fed and supplementary irrigation conditions. With considering of significant positive correlation between grain yield in the rain fed condition (YS) with relative drought index (RDI), mean productivity index (MP), stress tolerance index (STI), yield index (YI), geometric mean productivity index (GMP), new drought resistance index (DI), improved stress tolerance index (MSTI), non-Stress Environmental Stress Index (SNPI) and harmonic Mean Index (HARM), these indices are suitable for identification of stress tolerant lines. Stress susceptibility index (SSI), yield stability index (YSI), abiotic stress tolerance index (ATI) and stress sensitivity percentage index (SSPI) did not play a significant role in the differentiation of genotypes. On the other hand, there was a significant positive correlation between grain yield in supplemental irrigation with TOL, MP, YI, MSTI, SSPI, ATI, SSI and STI. Grouping of genotypes using cluster analysis method showed that the genotypes were classified into four distinct groups and genotypes 4, 16 and 17 were in the fourth group with the highest tolerance indices compared to the other. Genotypes 7, 8 and 10, which had the lowest yield and also the lowest amount for the most indices, were identified as the most susceptible to drought stress. The results of factor analysis confirmed the above results.

Chickpea (Cicer arietinum L.) is one of the most important grain legumes in the south Asia and WANA (West Asia North Africa). In Iran, chickpea is the most important pulse crop of rain-fed systems, traditionally grown in rotation with wheat and barley. The annual cultivation and production of chickpea in Iran is about 0.5 million hectares and 270 thousand tons, respectively. High protein content in chickpea seed (about 20-30%) makes it a good food source for developing countries and low-income people. Among the micro-nutrients, iron (Fe) is used more for plants. Fe deficiency has adverse effects on plant morphology and physiology. Earlier studies have shown that Fe deficiency reduced seed yield in chickpea, soybeans, rapeseed and wheat. In a study, application of iron fertilizer increased the branching and yield components of chickpea. In another study, application of iron fertilizer increased the branching and yield components of chickpea. A study showed that Fe deficiency reduced the water use efficiency of chickpea. In another study, iron sulfate foliar application improved the symptoms of Fe deficiency and increased the yield in low-yielding cultivars, but did not have much effect on high yielding cultivars. Foliar application of iron sulfate also increased the seed iron content. The objective of this research was to study the effects of Fe fertilizer on quantitative and qualitative characteristics of chickpea. Comparison of time and methods of Fe fertilization in chickpea was another aim of this study.
 

This research was carried out at the Campus of Agriculture and Natural Resources, Razi University, Kermanshah, Iran, in 2011. The experiment was conducted as split plot based on randomized complete block design with three replications. Dryland conditions and supplementary irrigation were considered as the main factors as well as the time and methods of application of Fe fertilizer as the sub factors. Fe fertilizer treatments included as follow: without application of Fe fertilizer (Fe1), soil application of Fe fertilizer during planting (Fe2), Fe spraying at branching stage (Fe3), Fe spraying during flowering (Fe4) Fe spraying during pod filling (Fe5), Fe soil application+Fe spraying at branching stage (Fe6), Fe soil application+Fe spraying during flowering (Fe7), Fe soil application+Fe spraying during pod filling (Fe8). For irrigation treatment, two supplemental irrigations were performed at flowering and podding stages of chickpea. For rainfed conditions, these irrigations were prevented. To soil application, Fe-EDDHA (OMEX Company, Germany) as much as 10 Kg ha-1 was used. For leaf spraying, a solution of iron sulfate (Cavin Company, Iran) was used as much as 1 lit ha-1. The planting date was March 15, 2011. The density was 50 plants per square meter. Each plot consisted of six rows, five meters long, 25 cm distance between two rows.
 

The results showed that the supplementary irrigation had significant effects on biological yield, grain yield, harvest index, straw yield, the number of pods per plant, 100 seed weight and seed protein content. For these traits, the supplementary irrigation treatment was superior to rainfed conditions. However, supplementary irrigation did not have significant effects on the number of seeds per pod, grain iron content and grain fiber content. The effect of Fe fertilizer on biological yield, grain yield, harvest index, the number of seeds per pod, grain iron content and grain protein content were significant. Straw yield, the number of pods per plant, 100 seed weight and grain fiber content were not influenced by time and methods of Fe fertilizer. The highest grain yield (1614 Kg ha-1), biological yield (3683 Kg ha-1), the number of seeds per pod (1.45 seeds) and seed protein content (27.72%) were obtained in Fe7 treatment. Fe8 treatment had the highest seed iron content.
 

The supplemental irrigation improved seed yield and its components. Also, supplementary irrigation increased the seed iron content, but reduced the seed protein content. The time and methods of application of Fe fertilizer increased the quantitative and qualitative grain yield. Therefore, it seems that in order to increase the quantitative and qualitative grain yield of chickpea, the supplementary irrigation with application of Fe fertilizer (as soil and foliar application) can be recommended.

IntroductionDrought is one of the most important environmental stresses that influence various growth steps of the plant including germination, plantlet establishment, and production all over the world (Bacilar et al., 2007; Ben Ahmad et al., 2009). Drought stress has significantly increased in recent years because of changes in climate and increasing CO2 levels. Therefore, identification of the resistant plant varieties against drought stress in a necessity. Investigation the enabling mechanisms of plants to adapt to drought stress and protect their growth in that condition can help to select the resistant plants against drought stress to be cultivated in dry and semi-dry regions. Identification of the physiological mechanisms Lentil with the scientific name of Lens culinaris is from leguminous, one-year, long-day, self- pollinated, and diploid family (2n=14) with mean 5.28% protein. Lens culinaris is resistant to drought. Materials and methods12 Lens culinaris genotypes (Table 1) were examined in rainfed and deficit irrigation conditions in 2015-2016 agricultural years as the split spots based on randomized complete block designs with three repetitions whose main irrigation factor was in 2 levels (rainfed and deficit) and the secondary factor of genotypes in two individual Ardabil agriculture research stations and central part of Germi city in different conditions and climates to evaluate the genetic varieties of Lens culinaris cultivars, screening the quantitative indexes of resistance against drought, and identification of the resistant cultivars against drought. All plots were simultaneously irrigated in two steps of flowering and pot filling in 10ml in deficit irrigation treatment in each region and weren’t irrigated in stress treatment or rainfed and just raining was used up to the end of harvest. Each test unit was made of 4 cultivation line with 4m length, 30cm row distance, and 133 bushes in each row. Hand weeding was done in several steps to fight with weeds. Each genotype is harvested in proportion to its physiological consideration. In this step, two edge lines and 0.5m of two middle lines end were omitted to remove edge effect. Harvest was with hand. Seed performance was determined after threshing and separating the seeds from the straw based on seed weight (gr). Physiological characteristics were measured after the plant sheathing in both rainfed and deficit irrigation typesResults and discussionTable of the combined variance analysis (Table 1) showed that the significant difference was observed among proline, chlorophyll a and chlorophyll b and peroxidase enzyme values of two cultivation methods, the comparison of the mean chlorophyll a and chlorophyll b (ml/gr) of wet weight in Germi region was 0.22 and 0.079 with the significant difference from Ardabil region. The reaction of chlorophyll a and chlorophyll b to drought stress may be resulted by the plant metabolism tolerance in addition to the genetic differences against drought, and lack of the significant reaction between chlorophyll to stress can be attributed to the growth reduction in leaf. There was a significant difference in proline (μm/gr of wet weight) in Germi and Ardabil, but the amount of enzyme peroxidase (μgr of enzyme/gr of leaf) was higher in Ardabil. Proline accumulation is a popular physiological response of plants to the extensive range of bio and non-bio stresses (Geravandi et al., 2011). The maximum imposed damage by drought stress was for proline of Germi; as though, stress increased 23% of proline than Ardebil condition. In Gunes et al. (2008) research, drought stress after pollination significantly increased proline. There was a significant difference between rainfed and deficit irrigation conditions based on variance analysis. Bilesavar cultivar was considered as a control sample with the maximum peroxidase enzyme. ConclusionsThe results of this test show that in rainfed cultivation (drought stress) enzyme activity of the antioxidant and peroxidase, ascorbate peroxidas, proline and some characteristics for resistance plant against drought stress are increase.

In the present work, an experimental study on seven different wheat cultivars is carried out to assess the most suitable supplementary irrigation stage and the understanding of physiological and biochemical processes associated with drought tolerance. During the years 2015 and 2016, this experiment is conducted in experimental field of Agriculture and Natural Resources of Kurdistan University as split plot in randomized complete block design with 3 replications under supplementary irrigation conditions at the stemming, boating and flowering stages, respectively. For this purpose, the amount of Hydrogen Peroxide (H2O2), Malondialdehyde (MDA), total protein, the activity of Catalase antioxidant enzymes (CAT), Ascorbate peroxidase (APX), Guaiacol peroxidase (GPX) and superoxide dismutase (SOD) are measured. The analysis of variance showed that there was a significant interaction between cultivars and complementary irrigation in most traits. Based on the obtained results, supplemental irrigation resulted in a decrease in H2O2 levels compared to control. The highest levels of H2O2 and MDA are obtained for Aras, Abughraib and Tamuz cultivars, respectively, whilst the lowest one is obtained for Azar 2. Applying the supplementary irrigation during stemming, boating and flowering stages increased the total amount of protein (except Aras), the activity of CAT and SOD in all cultivars, and also increased the activity of APX in Acsed 65, Rozgari, Semito and Azar 2. Furthermore, it is found that the cultivars Azar 2, Rezgari and Ocsede 65, with supplementary irrigation at flowering stage, were able to control the existing conditions by defining their defense mechanisms.

Chickpea (Cicer arietinum L.) is grown predominantly in Mediterranean environment where yield is faced with abiotic stresses such as water deficit. Due to shortage of water resources and sequential cropping in many areas, it is necessary to manage the irrigation water, because this would cause inadequate irrigation. Therefore, in order to achieve the maximum yield and efficient use of available water, prevention of waste of water is necessary. One of the reasons for the use of zeolite in agricultural production and productivity of soil, is the moisture absorption and maintain the property for a long time and prevent environmental pollution. Zeolite acts as a slow release fertilizer, giving the plant access to water and nutrients for more times. Also zeolite caused significant saving in water use and reducing the amount of fertilizer. Thus helping to decrease the amount of water used per crop and the contamination of aquifers due to overuse of chemical fertilizers. Adjustment of drought negative effects by maintaining inflammation pressure, transpiration reduction and increase of water use efficiency has been through consumption of potassium. Although potassium unlike N and P, does not enter into the composition of any product. Potassium has an important role either direct or indirect, under different environments, in major plant processes such as photosynthesis, respiration, protein synthesis, enzyme activation, water uptake, osmoregulation, growth and yield of plant. Considering the importance of chickpea in nutrition of human and weather conditions of arid and semiarid, supplementary irrigation is necessity for cultivation of this plant in Iran; with regard to role of zeolite and potassium in reducing sensitivity of plants to water deficit and since there is limited published work about the effect of application of potassium sulphate combined with zeolite, this research was conducted to compare their effects on some of characteristics and yield of chickpea. In order to study the effect of different irrigation regimes and different Zeolite and Potassium application on quality characteristics and yield of chickpea cv Azad, an experiment was conducted as split factorial arrangement in a randomized complete block design with three replications in Research Station of Agriculture and Natural Resource Research center of Hamadan, during 2015 cropping season. Main plot included supplementary irrigation (check as non-irrigation, supplementary irrigation at flowering, irrigations at both flowering and pod setting and irrigation at pod setting stages) and subplot included three levels of zeolite (Z0=0, Z1=15 and Z2=30 ton ha-1) and three levels of potassium fertilizer (K0=0, K1=150 and K2= 250 kg ha-1 K2SO4) that located as split factorial in each sub plot. In this study, the amount of proline, potassium, protein, chlorophyll content (flowering and pod setting stage), seed yield and Plant weight were determined. Software SAS Ver. 9.1 was used for the statistical analysis and the means were compared by using Least Significant Difference (LSD) test at 0.05 level of significance. The results showed that the different irrigation regimes, Zeolite and Potassium fertilizer levels had significant effect on proline, potassium, protein, chlorophyll (flowering stage), chlorophyll (pod setting stage) and seed yield. The results indicated that drought stress significantly decreased leaf potassium and leaf chlorophyll whereas protein percent and proline were increased. Interaction between irrigation and Zeolite was significant except for chlorophyll (pod setting). In this study, the highest plant weight and seed yield were obtained under irrigations at both flowering and pod setting along with 30 ton ha-1 zeolite. Enhanced proline accumulation during stress indicates that proline is thought to play a cardinal role as an osmoregulatory solute in plants. The flowering stage in chickpea cultivars is the most sensitive stage to drought stress and in deficit watercondition supplemental irrigation in this stage may considerably increases yield of chickpea. Production in dry land farming systems in Iran is limited by deficiency of water. Chickpea has good potential to increase production in dry land conditions. Zeolite and potassium consumption can be positive effects on yield and quality characteristic of chickpea in severity and moderately stress conditions. It is concluded that zeolite and potassium consumption with ameliorate damages due to water stress could be effective on plant and formation economical yield in conditions of Hamadan region. Zeolite application in lands which are exposure to late season drought stress can keep soil water content and improve seed yield and production. Therefore, considering water shortage in drought area of the country, application of zeolite can be useful to save more water that leads to produce more yield. According to results of this study, potassium sulfate consumption has been enhanced 8 to 13 percent grain yield.

Among different environmental stresses, drought is of great importance that induces a highly negative effect on crop production. In order to evaluate drought tolerance in dryland wheat genotypes, 36 genotypes were studied in a randomized complete block design with three replications under rainfed (drought stress) and supplemental irrigation conditions during 2016–2017 growing season in Research Farm of Moghan College of Agriculture and Natural Resources. Results showed that there are significant differences among genotypes for grain yield in both rainfed and supplemental irrigation conditions. Combined analysis of variance over two experiments showed that drought stress significantly increased grain yield. Under supplemental irrigation conditions, the genotypes 22, 34 and 21 had the highest grain yield by an average of 3.143, 3.089 and 2.921 t/ha and under rainfed condition, genotypes 20, 22 and 27 produced the highest grain yield with an average of 2.647, 2.610 and 2.558 t/ha, respectively. In order to identify drought tolerance genotypes, drought resistant indices such as tolerance index (TOL), stress susceptibility index (SSI), mean productivity (MP), geometric mean productivity (GMP), stress tolerance index (STI) and yield stability index (YSI) were used. GMP, MP and STI indices were highly correlated with grain yield under both stress and non-stress conditions. Therefore, they were introduced as suitable indices to identify superior genotypes for both environmental conditions. Based on principal component analysis and three dimensional graph, genotypes 22, 34, 33 and 15 were identified as drought tolerant genotypes and 7, 17, 14 and 1 were identified as drought sensitive genotypes. Cluster analysis with Ward's method based on grain yield under supplemental irrigation (Yp) and rainfed (Ys) conditions and drought tolerance indices divided the 36 genotypes into four major groups. Therefore, this result was consistent by results from principal component analysis.

Yield gap analysis is useful method for prioritization agricultural researches and production to reduce yield constraints. To identify options for increasing chickpea yield, the SSM-chickpea model was parameterized and evaluated to analyze yield potentials, water limited yields and yield gaps for 12 regions representing major chickpea-growing areas of Razavi Khorasan province. For model parameterization, a field experiment was conducted in a randomized complete design with 4 replications in the research field of the Ferdowsi University of Mashhad (36. 15° N, 56. 28° E). The chickpea cultivar ILC482 was used in this experiment. Also, irrigation levels were as (full irrigation, supplemental irrigation at floweringand supplemental irrigation at both flowering and podding). Besides the above experiment, data obtained from a large number of field experiments involving varying seasons and management practices at diverse regions in Iran were also used for model evaluation. The evaluation of model indicated that the model predicted potential yield reasonably well. The results of running the model under different irrigation and sowing dates scenarios (19 February, March 25 , 4 April and 21 April ) showed that optimum sowing date is 19 February in most locations, the highest and lowest potential yield obtained in Taibad and Mashhad with an average yield of 2736 and 2306 Kg ha-1 respectively. Furthermore, in all of irrigation levels and the optimal sowing dates, the highest and lowest yield was observed in Quchan and Taibad respectively. The highest and lowest yield gap between the potential yield and irrigation levels were observed in Taibad and Mashhad respectively. Overall, the results indicated that supplemental irrigation at flowering and podding both reduced yield gap which is strategy in semi-arid areas with low precipitation.

This study was conducted to investigate for the effects of optimum nitrogen application rates and supplemental irrigation on agronomic characteristics and grain yield of bread wheat cultivars in Koohdash under rainfed conditions. The experiments were carried out split- split- plot in randomized complete block design arrangements from 2013- 2015 cropping years. The irrigation treatment (rainfed, planting, planting + flowering with rates of 50 mm), two cultivars (Karim and Koohdasht) and different nitrogen rates (0, 60 and 120 kg/ha) were arrangement in main plots, sub- plots and sub- sub- plots, respectively. The results showed that grain yield, biological yield and number of spike per m2 were significantly increased, but significant difference was not observed between two levels of nitrogen application. Therefore, the most appropriate management of nitrogen application is 60 kg/ha, considering economic issues. Also, the supplemental irrigation significantly increased grain yield, but significant difference was not observed between irrigation treatments. Considering economic issues, it can be concluded that irrigation at planting was superior to non- irrigation and irrigation at planting + flowering. Although, the main effect of cultivar was not significant for evaluated traits, but Karim cultivar produced the highest grain yield under supplemental irrigation at planting and nitrogen application 60 kg/ha. Finally, it can be concluded that wheat grain yield can be improved using supplemental irrigation management and nitrogen under rainfed conditions.

Terminal drought depending on the geographical area and climatic conditions during the growing season reduces 30 to 60 percent of the chickpea grain yield (Kanouni et al., 2003). By developing new crop management practices and irrigation methods and also using drought stress tolerant varieties, we can compensate the reduction in chickpea yield due to drought stress (Saman et al., 2006). One of the agricultural management is the use of antitranspirate substances such as chitosan (Jan- Mohammadi et al., 2014) and drought stress ameliorators in plants that can tolerate plant stress through physiological activities and intensification of defence mechanisms. The main purpose of this study was to investigate the effects of antitranspirants substances and drought stress ameliorators on grain yield of chickpea under different irrigation regimes. This experiment was conducted in Ekbatan Research Station in Hamedan during the 2014-2015 growing season. A factorial split plot experiment based on CRD design with three replications was used. Four irrigation regimes including non-irrigation, irrigation at flowering stage, irrigation at podding stage and two irrigation flowering + podding stages in main plots and anti- transpiration substances (kaolin 5%, chitosan 200 ml-1) and stress ameliorators (chloride calcium 5 mM, sodium selenate 40 mgL-1) with non spray (control) treatments were placed as factorial in subplots. Seeds were planted with 30 cm row spacings and 31 plants per m2 density at 5 cm depth of soil on March 5th. Weed control was done by hand. Application of stress ameliorators was performed in two stages before and after flowering. Spraying of anti-transpiration substances in the middle of the podding stage was done by hand sprayer on the leaves. In this investigation, the traits related to yield were studied. The results of analysis of variance showed that in addition to the effects of two-way interaction factors, the three-way effects of studied factors on pod length, diameter of grain, and leaf area duration at l% level and the number of pods per plant, number of seeds per plant, grain protein, grain yield, biological yield and water use efficiency traits were significant at 5% level. Twice irrigation regime with chitosan and calcium chloride applications had the highest leaf area duration, and then the once irrigation in podding or flowering stages with chitosan and calcium chloride applications had the maximum leaf area duration. Also, the highest grain diameter, number of pods per plant and number of seeds per plant were obtained in two irrigation regimes with the use of chitosan and calcium chloride. The maximum percentage of grain protein in non-irrigation (dryland) regime was obtained by chitosan and calcium chloride consumption, and then by sodium selenate treatment. The grain protein content of seeds in once irrigation at flowering or podding and two irrigation regimes in flowering + podding stages with spraying chitosan and calcium chloride had 4, 8 and 12 percentage reduction, compared to non-irrigated conditions, respectively. In general, in different irrigation regimes, the spray of chitosan and calcium chloride was more effective than kaolin and sodium selenate on most of the studied traits. The chitosan along with calcium chloride protects the leaf water content and has a positive effect on the development of leaf area which prevents the earlier senescence of the leaves during reproductive stages under drought. Also, their application improves the leaf area duration at the end of the growing season and increases the water use efficiency of the plant. In addition leaf area duration, the highest grain yield and water use efficiency were obtained by irrigation regimes during flowering + podding stages and chitosan spray with calcium chloride. The podding stage irrigation to amount 1910 m3 with chitosan spray and calcium chloride application increased the grain yield by 192% and water use efficiency by 65% compared to the non-irrigation regime. As a result, due to the shortage of atmospheric precipitation during the growing season of chickpea, especially the occurrence of drought at the end of the season, once irrigation regime in the podding stage and spray of chitosan and calcium chloride with mentioned concentrations can be beneficial to increasing the grain yield of chickpea, although in the case of water supply, two irrigation is recommended during flowering and podding stages.

Intercropping and use of biofertilizers are important for improving the quantitative and qualitative yield of plants from a sustainable agricultural perspective. In order to evaluate the effect of phosphate solubilizing bacteria on yield and yield components of dragon's head and chickpea sole and intercropping, a 2-years (2013-2014) factorial experiment were conducted based on randomized complete block design with three replications at the agricultural research Campus in Nagadeh, Iran. Treatments including sole and intercropping of chickpea (30 and 40 plants/m2), dragon's head (160 plants/m2) and inoculation with two inoculated phosphates biofertilizer (Bacillus lentus and Pseudomonas putida) and without inoculation. In inoculated chickpea, the highest amount of seeds per pods (1.3), seed yield (674.1 kg/ha) and harvest index (49.96 %) were obtained from sole cropping of 30 plants/m2 at first year. The minimum amounts of them were obtained from intercropping of chickpea 40 plants/m2 and dragon's head at second year under control treatment. At first year, in sole cropping of bacterial inoculated dragon's head, the maximum number of seeds per plant (106.5), seed yield (489.5 kg/ha) and harvest index (22.1 %) were obtained, the minimum of them observed from intercropping of dragon's head and chickpea 40 plants/m2 without inoculated at 2013. LER in inoculated intercropping of chickpea 30 plants/m2 and dragon's head was 1.74, that showed intercropping improved land use efficiency by 74% compared with sole cropping, and this treatment can be effective in stabilizing production and agricultural land utilization.

IntroductionChickpea (Cicer arietinum L.), an annual with indeterminate growth, is one of the most important food legumes. Loss of seeds due to pod borer (Heliothis armigera) attack is prevalent. Such loss of pods may affect the yield and yield components. The source-sink relationship changes during growth stages. Some factors influence this relationship including nitrogen fertilizer and water. This experiment was conducted in order to study the effects of nitrogen fertilizer, supplementary irrigation and depodding on yield and yield components of chickpea (var. ILC482).
Materials & MethodsThe experiment was conducted as split-split plot based on a randomized complete block design with three replications at Agricultural Research Station of Ferdowsi University of Mashhad, during growing season of 2012. Main plot was nitrogen fertilizer including 30, 75 and 150 kg N/ha and sup plot was irrigation regimes including full irrigation, supplementary irrigation at flowering and supplementary irrigation at flowering, seed podding and depodding including 0, 25%, 50% and 75% as sub subplot. Leaf and stem dry weight, seed weight per plant, shoot weight, pod number per plant, grain number per plant, 100-seed weight and harvest index of chickpea were all recorded.
Results & DiscussionThe results indicated that all traits excluded of harvest index were higher in 150 kg N/ha treatment than other treatments. Nitrogen rate of 150 kg/ha produced the highest seed weight (3.8 g/plant). The highest harvest index (36%) was obtained from 30 kg/ha N treatment. Supplementary irrigation at flowering and podding stages with grain yield 4.4 g/plant was higher than full and supplementary irrigation at flowering. Supplementary irrigation at flowering and podding stages produced the highest harvest index (39%). In irrigation regimes including full irrigation and supplementary irrigation at flowering stage, 75% depodding decreased seed weight to 60%, but this was 45% in Supplementary irrigation at flowering and podding stages. In this interaction, full irrigation and 0% depodding (control), produced the highest seed weight (195 g/m2). The lowest seed weight (40 g/m2) was obtained from supplementary irrigation at flowering stage and 75% depodding. Supplementary irrigation at flowering and podding stages with 25% depodding produced the highest harvest index (45%) too. Increase of harvest index mostly was related to improve photosynthesis and remobilization in mid drought stress and also low depodding (by devotion photosynthetic assimilates to un-removed pods). The highest shoot weight was obtained from 150 kg N/ha (12.8 g/plant) and full irrigation (14.3 g/plant). Depodding decreased the most of mentioned traits significantly. 75% depodding decreased seed weight and shoot dry weight to 56% and 30% respectively compared to control. The lowest harvest index (23%) was obtained from 75% depodding. In nitrogen rate of 75 kg/ha, the highest (177 g/m2) and lowest (46 g/m2) seed weight was obtained from 0% and 75% depodding, respectively. This result also was observed in traits of seed number and pod number in this interaction. High N application improved the ability of plant to compensate the pods that removed. All of traits including pod number, seed number, harvest index and shoot dry weight had positive and significantly correlation with seed weight. Pod number (75%) had highest correlation with yield.
ConclusionGenerally, increasing depodding intensity decreased grain yield. But nitrogen fertilizer application decreased the negative effects of depodding in low levels. Among irrigation regimes, supplementary irrigation at flowering and depodding stages was best treatment, therefore under water deficit condition, supplementary irrigation at flowering and podding stages recommend. Under severe stress condition (supplementary irrigation at flowering stage), high nitrogen application did not effect on seed weight. In this condition, favorite yield will obtain by 30 kg nitrogen fertilizer application as starter.

IntroductionChickpea (Cicer arietinum L.), an annual with indeterminate growth habit, is one of the most important food legumes. Loss of foliage due to leaf diseases or environmental hazards are prevalent for many crops. Such loss of foliage affects the yield and also the carbohydrate and protein status of leaves and seeds. The source-sink relationship change during growth stages. Few factors including nitrogen fertilizer and water influence this relationship. This experiment was conducted in order to study the effects of nitrogen fertilizer, supplementary irrigation and defoliation on yield and yield components of chickpea.
Materials & MethodsThe experiment was conducted as split-split plot based on randomized complete block design with three replications in research farm of Faculty of Agriculture, Ferdowsi University of Mashhad, Iran in 2012. Main plot was nitrogen fertilizer including 30, 75 and 150 kg N/ha and sub-plot was irrigation regimes including full irrigation, supplemental irrigation at flowering and supplemental irrigation at flowering and seed filling stages. Defoliation including 0, 25%, 50%, 75% and 100% was considered as sub-sub plot. Leaf and stem dry weight, seed yield, biological yield, pod number per plant, grain number per plant, 100 grain weight and harvest index were all recorded.
Results & DiscussionThe results indicated that all traits excluding harvest index were higher in 150 kg N.ha-1 treatment compared to other levels of nitrogen. Nitrogen rate of 150 kg.ha-1 produced the highest grain yield (135.7 g.m-2). The highest harvest index (40.7%) was obtained at 30 kg.ha-1 N treatment. Full irrigation and supplemental irrigation at flowering and poding stages with average grain yield of 146 g.m-2 were higher than supplemental irrigation at flowering (83 g.m-2). Supplemental irrigation at flowering and poding stages showed the highest harvest index (41.2 %). The highest biological yield was obtained from 150 kg N.ha-1 (413 g.m-2) and full irrigation (415 g.m-2). Nitrogen rate 75 kg.ha-1 at 0% defoliation (control), resulted in the highest seed yield (177 g.m-2). The lowest seed yield (58 g.m-2) was obtained from 75 kg.ha-1 nitrogen treatment and complete defoliation. By increasing of N fertilizer application, the negative effects of defoliation in some traits such as pod number and seed and leaf weight decreased. In 30 and 75 kg.ha-1 nitrogen treatment, 100% defoliation decreased pod number to 50%, but this was 20% in 150 kg.ha-1 nitrogen treatment. Full irrigation with 0% defoliation produced the highest (196 g.m-2) and supplemental irrigation at flowering stage with complete defoliation the lowest (56 g.m-2) grain yield. Defoliation decreased the most of mentioned traits significantly. Complete defoliation decreased grain and biological yield to 46% and 56%, respectively compared to the control. The lowest harvest index (29%) was obtained in complete defoliation. All of traits including pod number, seed number, harvest index and biological yield had positive and significant correlation with seed yield. Biological yield (83%) had highest correlation with yield.
ConclusionGenerally, defoliation decreased grain yield. However, application of nitrogen fertilizer at low levels could decrease the negative effects of defoliation. High N application improved the ability of plant to compensate the leaves that removed grain yield in treatments of full irrigation and supplementary irrigation at flowering and depoding stages was equivalent, therefore under water deficit condition, supplementary irrigation at flowering and podding stages recommend.

In order to study tolerance of durum wheat (Triticum durum) lines to drought stress and also evaluating stress tolerance indices, an experiment based on randomized complete block design with four replications was conducted under two rain fed and supplementary irrigation conditions at Gachsaran station during 2011-2012 cropping season using 20 durum wheat lines. Results of combined analysis of variance for seed yield showed significant differences (p≤0.01) between lines and interaction between lines and environment. The yield based indices were calculated in rain fed and supplementary irrigation conditions. With considering of significant positive correlation between grain yield in the rain fed condition (YS) with geometric mean productivity index (GMP), mean productivity index (MP), stress tolerance index (STI), yield index (YI), drought response index (DRI), drought resistance index (DI), harmonic mean (HM) and modified stress tolerance index (K1STI), these indices were suitable criteria for identification of drought tolerant lines. Also, tolerance index (TOL), yield stability index (YSI), stress susceptibility index (SSI), relative drought index (RDI), abiotic tolerance index (ATI), stress susceptibility percentage index (SSPI) and stress non-stress production index (SNPI) didn’t have important role in the differentiation of lines. Grouping of lines using cluster analysis method showed that the lines 3 and 13 had high yield and were tolerant rain fed condition and the lines 7 and 18 were sensitive to rain fed condition. The results from grouping of lines using three dimensional graphs based on yield in rain fed and supplementary irrigated condition and STI index were same as cluster analysis.

In order to evaluate the effect of supplemental irrigation and nitrogen amounts on yield and yield components of two dryland wheat cultivars an experimental was carried out in a split split plot design arranged in a randomized complete block design with three replications at the farm of Campus of Agriculture and Natural Resources, Razi University, Kermanshah, Iran, during 2008-2009. Experimental treatments including supplemental irrigation as the main plot at 4 levels (no irrigation and irrigation at booting, anthesis and grain filling stages) and net nitrogen as a sub plot at 4 levels (0, 50, 100 and 150 kg ha-1) and two wheat cultivars (Sardari and Cross-Alborz) as sub-sub plots. The result showed that the effect of supplementary irrigation, N rate and cultivar were significant on grain yield. The highest of grain yield obtained in supplemental irrigation at anthesis and booting stages with 362.2 and 352.0 g m-2, respectively. The highest amount of grain protein content obtained at non irrigation treatment. Supplementary irrigation at booting, anthesis and grain filling stages increased relative water content and chlorophyll b. The maximum grain yield (337.0 g m-2) was produced with application of 50 kg ha-1 N. Cross-Alborz relative to Sardari cultivar had highest grain and protein yields. To the results of this experiment, supplemental irrigation at Anthesis or stem elongation stage was important compared to the grain filling stage. Irrigation at these stages and also, use of 50 kg ha-1 N, increased grain yield and physiological charactristics of wheat.

Yield gap analysis is useful method for prioritization agricultural researches and production to reduce yield constraints. To identify options for increasing chickpea yield, the SSM-chickpea model was parameterized and evaluated to analyze yield potentials, water limited yields and yield gaps for 12 regions representing major chickpea-growing areas of Razavi Khorasan province. For model parameterization, a field experiment was conducted in a randomized complete design with 4 replications in the research field of the Ferdowsi University of Mashhad (36. 15° N, 56. 28° E). The chickpea cultivar ILC482 was used in this experiment. Besides the above experiment, data obtained from a large number of field experiments involving varying seasons and management practices at diverse regions in Iran were also used for model evaluation. The evaluation of model indicated that the model predicted potential and water limited yield reasonably well. The results of running the model under different sowing dates scenarios (19 February, March 25 , 4 April and 21 April ) showed that optimum sowing date is 19 February in more counties, the highest and lowest potential yield obtained in Taibad and Mashhad with an average yield of 2736 and 2306 Kg ha-1 respectively. Furthermore, in the optimal sowing dates, the highest and lowest yield was observed in Quchan and Taibad respectively. The highest and lowest yield gap between the potential yield and irrigation levels were observed in Taibad and Mashhad respectively. Overally, the results indicated that 19 February sowing date reduced yield gap which is strategy in semi-arid areas with.