mohammad bannayan aval

Increasing the tolerance to drought and nitrogen stress in tomato cultivars is essential for the sustainable and environmentally friendly production of this product. Also, knowing the morpho-physiological, biochemical and molecular responses to drought and nitrogen stress is important for a comprehensive understanding of plant water tolerance mechanisms and nitrogen limitation conditions in higher plants. Therefore, the purpose of this study was to investigate the effect of different levels of irrigation and nitrogen fertilizer on the quantitative and qualitative characteristics of tomatoes in different Cluster rows under greenhouse conditions.

The experiment was conducted at the research greenhouse of the Faculty of Agriculture, Ferdowsi University of Mashhad, in two years, 2021-02 and 2022-03. The experiment was set up as split-plot layout based on randomized complete block design with three replications. Irrigation levels were considered as the main plot at three levels: 75% (I75), 100% (I100), and 125% (I125) of the crop water requirement. Nitrogen fertilizer was considered as the subplot at four levels: control (no nitrogen), 75 kg ha-1 (7.5 g m-²), 150 kg ha-1 (15 g m-²), and 225 kg ha-1 (22.5 g m-²) from urea as the nitrogen source. Tomato seeds (Newton cultivar) were sown in polyethylene seedling trays with a coco peat and perlite mixture as the substrate. The seedlings were transplanted to the main field at 15 cm height with 3-4 true leaves. In all stages of growth, consistent agricultural practices were applied, including weed control, pest and disease management. Fertilization for tomato plants was based on soil analysis. Initially, after transplanting the seedlings, a complete fertilizer with high phosphorus (NPK 10-52-10) was applied at a ratio of 1.5 kg per thousand plants. In the subsequent stages, complete fertilizers (NPK 20-20-20) and high-potassium fertilizers (NPK 20-20-36) were applied through irrigation. Throughout the plant's growth stages, to prevent potential deficiencies and harm to growth and fruit development, micronutrients were applied as foliar sprays.

 The results for all three Clusters showed that although nitrate accumulation was higher in the first year compared to the second year, in both years, nitrate accumulation was higher at I75 and 225 kg ha-1 nitrogen compared to the other treatments. The highest nitrate accumulation in the sixth (6.12 mg.kg-1) and seventh (6.29 mg.kg-1) Clusters was observed in I75 and 225 kg ha-1 nitrogen treatment in the first year. In the eighth Cluster, contrary to the sixth and seventh Clusters, the highest nitrate accumulation was obtained in I100 and 225 kg/ha nitrogen (6.43 mg.kg-1) in the first year. Chlorophyll decreased with stress but increased with nitrogen levels. In all four Clusters, the highest chlorophyll a content was obtained in I100 and 225 kg ha-1 nitrogen, with values of 3.75, 3.70, 3.30, and 3.85 mg g-1 fresh weight, respectively. The highest fruit number per square meter was obtained in I125 and 225 kg ha-1 nitrogen treatment in the second year (260 fruits), although there was no significant difference compared to the first year. Furthermore, this treatment produced 11% more fruits than the highest fruit number at 100% moisture. The highest single fruit weight was obtained in I125 and 225 kg ha-1 nitrogen treatment in the first year of the experiment (254 g), although there was no significant difference compared to the second year. Additionally, this treatment showed no significant difference in fruit weight compared to the 225 kg ha-1 nitrogen and I100 treatment in the first year but was 11% higher in the second year. The highest yield (65.1 kg m-²) was obtained at I125 and 225 kg ha-1 nitrogen. However, in the control treatment without fertilizer, there was no significant difference in yield at I100 and I125. Furthermore, the highest water use efficiency was observed at I100, followed by I75. In all fertilizer treatments, I125 treatment had the lowest water use efficiency. The highest water use efficiency (285 kg m-³) was obtained at I100 and 225 kg ha-1 nitrogen.

 In general, the results demonstrated that while excessive nitrogen fertilizer increased nitrate accumulation at different irrigation levels, the increased use of irrigation water reduced nitrate accumulation in tomato fruits while improved yield. Moreover, no significant difference in fruit yield was observed between I125 and I100, but optimum yield and favorable water use efficiency were obtained with less water consumption. Based on the results of this experiment, the recommended treatment under greenhouse conditions is irrigation at 100% of the FC and the use of 250 kg ha-1 nitrogen.

Introduction:

Avena ludoviciana L., also known as wild oat, is the predominant grass weed in Iranian agricultural systems. In Iran, the most prevalent approach for managing wild oats is the use of herbicides. Sethoxydim is a herbicide that is specifically designed to be applied after the emergence of weeds and is absorbed by the leaves. It belongs to a series of herbicides called aryloxy phenoxy propionates (AOPP). Sethoxydim has been approved for use on a wide range of broad-leaved crops. Currently, the chlorophyll fluorescence approach is employed as a precise and cost-efficient method in herbicide research. The chlorophyll fluorescence method is a non-destructive technique that is highly sensitive, fast, and easy to detect. It provides crucial information on the photosynthetic mechanism, allowing researchers to promptly assess herbicide efficacy before visible symptoms manifest in plants. An essential aspect of this approach is to reduce the duration of the screening session. While evaluating the impacts of herbicides with non-photosynthetic mode of action may take longer than evaluating herbicides that limit photosynthesis, it still requires significantly less time compared to the previous method. Hence, this study was conducted to examine the variations in the Katsky curve and establish the correlation between the curve parameters and dry weight. The objective was to assess the impact of utilizing vegetable oils on the efficacy of setoxydim in controlling wild oats, while also evaluating the feasibility of employing this approach.

 In order to overcome the dormancy of wild oat seeds prior to conducting the experiment, the outer covering of the caryopsis fruits was removed and the seeds were then placed on a single layer of Whatman no. 1 filter paper in 11 cm diameter Petri dishes. Each Petri plate was supplemented with 10 ml of a potassium nitrate (KNO3) solution with a concentration of 2 grams per liter. An experiment was conducted in 2012 at the Research Greenhouse of Ferdowsi University of Mashhad to discover the early effects of vegetable oils on the efficiency of sethoxydim in controlling wild oat. The Chlorophyll fluorescence parameters were assessed using the PEA Plus instrument at 1, 2, 3, 5, and 7 days after applying the sethoxydim herbicide, both with and without vegetable oils. During the one-leaf stage, the seedlings were reduced to four seedlings per pot and a solution containing 3 grams per liter of N:P:K fertilizer (20:20:20) was given to each pot. The plants were subjected to treatment at the four-leaf stage using a mobile rail sprayer that was fitted with a standard blower nozzle (8004) with an output of 238 L ha-1 and a spray pressure of 200 kPa. The test treatments include of different concentrations of the herbicide cetoxydim, specifically 0, 22.5, 46.8, 93.75, 187.5, 281.25, and 375 g ha-1. These concentrations are applied at ten different levels. 1) Excluding vegetable oil and other types of vegetable oils: The following crops were replicated three times: 2) Turnip, 3) soybean, 4) cotton seed, 5) sunflower, 6) olive, 7) castor, 8) sesame, 9) corn, and 10) rapeseed. To make each vegetable oil, an emulsifier called Cytogate adjuvant was added at a concentration of 0.05%. Each sample of vegetable oils, which contained emulsifiers, was used in a volume of five percent (equivalent to five per thousand). After four weeks after administering the treatments, the above-ground sections of both control and treated plants were taken from the surface of the pots. The dry weight of plants was recorded and used to fit the dose response curves using the R software.

Inhibiting acetyl CoA carboxylase results in the generation of reactive oxygen species (ROS), which cause damage to the electron transport chain between PSII and PSI. The degradation mentioned here affects the chlorophyll fluorescence, perhaps enabling the measurement of herbicide effectiveness by assessing the maximal quantum efficiency of PSII. Chlorophyll fluorescence can serve as a useful tool for detecting the effectiveness of herbicides that have different modes of action, such as acetyl coenzyme-A carboxylase inhibitors, phenoxy compounds, and glyphosate. The overall results indicated a decrease in the values of Fv/Fm, Fvj, and area parameters across all treatments. The treatments were ranked in decreasing order of their diminishing effects intensity as follows: turnip > olive > soybean > corn > sunflower > canola > sesame > castor > cotton > sethoxydim without oil. These findings were in line with the alterations in dry weight caused by the application of vegetable oils. Based on the experiment's findings, the parameters Fv/Fm, Fvj, and Area can be utilized to evaluate and compare the growing effects of vegetable oils on the efficiency of sethoxydim in controlling wild oat.

Chlorophyll fluorescence investigations can serve as a substitute for classical screening approaches, as supported by existing knowledge and experimental proof. This procedure is non-destructive, very sensitive, and rapid compared to standard screening methods. This research showed that the chlorophyll fluorescence approach requires less time compared to standard screening methods. The utilization of the chlorophyll fluorescence approach is likely to be enhanced in future herbicide bioassay investigations. Based on the correlation between dry weight and fluorescence characteristics, it is possible to utilize chlorophyll fluorescence to reduce the time required for analyzing the effectiveness of herbicides.

Bean plant is very sensitive to water and soil conditions and its quality and its yield is damaged even in short periods of stress. Water deficiency has very negative effects on grain yield and bean yield components. Due to the fact that drought stress is one of the most important environmental stresses in the agricultural sector, many efforts have been made to maintain crop yields under drought conditions. Conditions are shortages or high water prices. Therefore, due to the importance of this issue, this study was conducted to investigate the effect of drought stress on yield, yield components and efficiency of radiation consumption in growing different types of beans in Mashhad climate.

To investigate the effect of irrigation treatments on grain yield and yield components and radiation use efficiency in three types of experimental beans in the form of split plots based on randomized complete blocks in three replications in the spring of 2016-2017 and 2017-97 in the research farm. Faculty of Agriculture, Ferdowsi University of Mashhad. Experimental factors include non-stress irrigation (irrigation based on 100% of plant water requirement) and drought stress levels (irrigation based on 75% of plant water requirement and irrigation based on 50% of plant water requirement) as main plot and three types of beans (red, white And Chiti) as sub-plots. Data analysis was performed using SAS software and comparison of means of treatments based on LSD test at a probability level of 5%.

The results showed that the interaction effect of irrigation and bean type on grain yield, biological yield, harvest index, number of pods per plant, number of seeds per pod and radiation consumption efficiency was significant. The highest grain yield, biological yield and harvest index (1421.44 and 4126.6 kg / ha and 35.76%, respectively) were related to red beans and the lowest (872.67 and 2225.5 kg / ha and 52, respectively). / 30%) was related to pinto beans. The highest grain yield, biological yield and harvest index (1602.28 and 4811.9 kg / ha and 39.24%, respectively) were related to stress-free irrigation and the lowest (1093.222 and 3388.8 kg / ha, respectively). 33.06%) was related to drought stress (irrigation based on 50% water requirement). The results of interaction showed that the highest number of pods per plant in non-stress irrigation was red and white beans and the lowest number of pods per plant in pinto beans (with 38.08% reduction) was obtained in non-stress irrigation. The highest number of seeds per pod was obtained in drought stress (irrigation based on 50% water requirement) in red beans and the lowest in pinto beans (with 63.78% decrease) in drought stress (irrigation based on 50% water requirement). The highest 100-seed weight was in non-stress irrigation and the lowest 100-seed weight was in drought stress (irrigation based on 50% water requirement). The highest weight of 100 seeds was obtained in red beans. The highest efficiency of radiation consumption was in non-stress irrigation conditions (1.8 g / mJ) and the lowest was in drought stress treatment (irrigation based on 50% water requirement). Radiation consumption efficiency was higher in red beans (1.9 g / mJ) than white beans (1.6 g / mJ) and pinto beans (1.5 g / mJ).

According to the results, stress-free irrigation and red beans to achieve higher yields, it seems desirable.

Climate change and global warming has increased climatic unfavorable events that could reduce crop yields and endanger food security. 13 agro-climatic indices which are based on the outputs of CMIP5 models and RCP emission scenarios, were used to investigate the effect of climate change on areas at risk of adverse events. Occurrence probability of heat stresses will be increased during the flowering and grain-filling for early and late cultivars at the end of the century so that these stresses will become the dominant adverse events in all areas. The occurrence probability of at least one adverse event is more than 20 and 90 percent for early and late cultivars, respectively in all areas for the baseline conditions, and this probability is expected to increase by more than 40 and 94 percent for early and late cultivars, respectively under future climate scenarios. Proportional to the reduction of water stress for different emission scenarios, the probability of simultaneous occurrence of heat and water stress at the flowering stage will decrease in future as compared to the baseline. In future, areas where are at risk of at least two adverse event occurrences will increase further, as compare to those where are at risk of at least one adverse event occurrence. Toward the end of the century, more areas will be at risk of at least one and two adverse event occurrences.

Adverse and extreme  agro climatic events will disrupt food production and these  changes are expected to increase in the world. The wheat is Iran's dominant diet, especially in the form of bread. It is important as a food product that has an impact on food security. Climate change can affect wheat production in major areas of rainfed wheat production in Iran, with social and economic consequences. Therefore, it is important for policy makers and scientists  to evaluate the effects of climate change on the agricultural sector and food security. Crop models cannot take into account the effects of severe weather events (such as heavy rainfall, heat stresses) on the final yield of the crop. It could be useful to  utilize  agro climatic indices to provide more comprehensive projections of the impact of climate change on  agro climatic conditions. The purpose of this study was  evaluating the  probability of occurrence of adverse and extreme  agro climatic events at different stages of wheat development using  agro climatic indices.

The focus of this study is on main areas of rainfed wheat production in Iran (Kurdistan, Kermanshah, Golestan, Zanjan, Hamedan, and Ardebil provinces). According to the latest statistics and information from the Ministry of Agricultural Jihad, more than 55% of wheat production  achieve in these areas. The evaluations are based on the outputs of seven CMIP5 models and RCP8.5 and RCO2.6 emission scenarios for the period 2045-2065 and 2080-2100.  The equidistant quintile-based mapping method (EDCDF) was applied to bias correct the outputs of CMIP5 models .The proposed method of Allen et al. (1998) was  utilized to estimate daily crop evapotranspiration, soil moisture and relative reduction in crop yield under soil water shortage to describe the major adverse conditions for wheat production;  the set of 13 indicators was used to cover the major causes of low yields of winter wheat.

 The average temperature during the growing season will be increased by 3.1 °C for the late cultivar and RCP8.5 scenario during the period 2080-2100 compared to the baseline. The appropriate sowing dates will occur later for all scenarios relative to the baseline and shift to late autumn. Due to the increased average temperature during the growth period, anthesis and maturity dates will occur earlier relative to the baseline and subsequently the average growth period for all scenarios is shorter than the baseline. Average total crop evapotranspiration (ETc) during the growing season will be reduced in most stations. The average relative reduction in crop yield (YD) and the average total effective solar radiation will be more favorable than the baseline.  Thus, it can be said that these crop yield indicators are better than the baseline. However, increasing frequency of adverse events will be undesirable and the most unsettling possibility is the increase in the likelihood of occurrence of at least one, two and three adverse events during the growing season that can be extremely unfavorable climatic conditions for the production of wheat. The close connection between the likelihood of adverse events  and the duration of growth period (such as moisture and heat stresses) is obvious so that the longer growth period,  is more likely to be exposed to high temperatures and moisture stresses. An early cultivar will be a more suitable cultivar for sowing compare to late and medium-ripening cultivar which can change future climate conditions in favor of rainfed wheat production in most areas, especially cold regions.

In this study, the probability of occurrence of adverse and extreme  agro climatic events during the growing season of wheat was determined, which is usually not well considered in crop models. However, it is well known that the impacts of such extreme events can be substantial. The results of this study showed that, despite high uncertainty in the climate projections within CMIP5 models, the probability of occurrence of at least one (or more) adverse event during the growth period for each cultivar will increase compared to the baseline for the same cultivar. So that, the longer growth period, the greater likelihood of occurrence of at least one (or more) adverse event.

Achieving sustainable practices of mitigation and adaptation to climate change requires accurate projections of climate change in each region. In this regard, Coupled Model Inter-comparison Project (CMIP) over the past 20 years has shown a good performance. Therefore, new CMIP5 climate models are expected to be bases for many climate change studies. These models use a new set of emission scenarios called Representative Concentration Pathway (RCP) to project climate change. Climate change is expected to impact wheat production and food security in Iran. So far, no study has not been conducted to regionally project climate change based on new CMIP5 models and RCP scenarios over the major wheat-producing areas in Iran. Our objective was to evaluate the performance of CMIP5 climate models in simulating temperature and precipitation in these areas. In addition, different combinations of climate models were evaluated to select appropriate models in these areas. According to the latest data, nearly 60% of rainfed wheat is produced within our study area. The mean monthly temperature and precipitation data were provided by Meteorological Organization of Iran for synoptic stations. Period of 1975-2005 was considered as a historical period (baseline period). We evaluated outputs from 21 GCMs from CMIP5 climate models for monthly values of total precipitation and mean surface air temperature. One in ten ensembles of each GCM model was evaluated as available. We used model outputs for two emission scenarios i.e. RCP-2.6 and RCP-8.5, for the future periods of 2045–2065 and 2080-2100 to project temperature and precipitation changes. We assigned the models into two groups, high resolution (models less than 2° latitude/longitude, high-re; 11 models) and low resolution (models greater than 2° latitude/longitude, low-re, 10 models). Output GCM models were used for a grid in which recorded data are available. We applied the equidistant quintile-based mapping method (EDCDF) to correct bias of monthly precipitation and temperature simulated by models in the historical period (1975-2005) and, then in the future periods. We also used the root mean square error (RMSE), the coefficient of correlation and the skill scores (SS) to evaluate the model performance.
Result and Average of all ensembles of an individual model outperformed the other ensembles in simulating the historical climate. This superiority is largely caused by the cancellation of offsetting errors in individual ensembles of a model, and also reduces the effects of natural internal climate variability in simulations. Taylor diagram showed, contrary to a simulation of temperature, simulations of precipitation have great variability than observations and the standard deviation of simulated precipitation values was less than that of observations for most used models. The models simulated temperature much better than precipitation across the region. Contrary to precipitation, the simulated temperature did not show a significant difference among the models. Several combinations of models resulted in an improvement in precipitation and temperature simulations. Therefore, a combination of models can be used in regional climate change assessment studies. The models performance for simulating the historical climate was evaluated based on skill score (SS) and Δ (the Euclidian distance from perfect skill, point (1, 1, 1, . . . , 1)). Many different combinations of 21 GCM models were evaluated, which combination of 7 models as selected models yielded a lower Δ and higher skill scores. For multimodal ensemble (MME) mean (All, high-re, low-re and Selected, models) Δ value was less than that for individual models. SS values in the simulation of precipitation were more than -3 for 75% of models during the high precipitation months. Uncertainty in the simulation of precipitation during the low precipitation months was more than that of high precipitation months and it was even much more in southern areas (especially in August and September). Uncertainties in temperature and precipitation changes projections were affected by the scenario, the time period and models selected. All models showed biases indicating the fact that direct use of such models in climate change studies (without bias correction) is not recommendable. Although the use of statistical methods for bias correction resulted in a significant reduction of nonsystematic biases, systematic biases were not considerably influenced. Precipitation will increase in northern areas toward the end of the century and a higher reduction in precipitation is anticipated in the southern areas. The average, long-term (2080–2100) temperature increase was 5.5°C under RCP-8.5. Further, temperature increase will be greater in the southern regions. Performance of 21 GCMs from CMIP5 climate models were evaluated in major rainfed wheat-production areas in Iran and temperature and precipitation changes were projected under RCP-2.6 and RCP-8.5. Taking into account all GCM’s initial conditions (if they are available) leads to a better performance. Simulations of models exhibited biases, so models output must be corrected before they can be used in regional climate change assessment studies. Although bias correction resulted in a significant reduction of nonsystematic biases, systematic biases were not significantly affected. The MME (All, high-re, low-re and Selected, models) consistently outperformed individual models for both precipitation and temperature suggesting that a smaller group of models can be used in regional climate change assessment. We recognized a subset of 21 models (7 selected models) based on performance that combination of them can provide the best performance and plausible future projections.

Sowing date is the variable with the largest effect on crop growth and its yield (Hundal et al., 1997). Planting the suitable variety at the right time results in flowering phase when the risk for freeze damage is the lowest and before heat stress during flowering and grain filling stages (Khichar & Niwas, 2006). Adequate soil moisture especially in dryland conditions are also important. Correctly matching the time at which growth stages of crop occur with the environmental requirements is key to maximize growth and yield (Hay et al., 1986; Dadashi & Khajehpour, 2004). Thus, producers have to choose the appropriate variety for a specific planting time for the optimum flowering time and thereby, the highest possible yield. Early planting can improve crop establishment but may cause early flowering, which increases the risk for frost damage. Early planting is more prone to pests and diseases. Delayed planting will reduce yield and growth as flowering and maturity stages may occur in hot, dry conditions. Generally, the time of planting varies depending on the climatic condition of the region and the variety to be grown. Different varieties of wheat are sensitive to change in environmental conditions where the crop is being grown. Therefore, it is necessary to study the genotype × environment interaction to identify the varieties which are stable in different environments especially under dryland farming.
Wheat (Triticum aestivum L.) is the third leading crop in the world after rice (Oryza sativa L.) and corn (Zea mays L.). The rising population and the rapid growth of the economy have resulted in an increasing demand for wheat in the following decades.  

This experiment was conducted as split plot based on complete randomized block design (CRD) in with three replications at the Dryland Research Station of North Khorasan, Shirvan during the growing season of 2015-2016. The main and sub factors were allocated to planting methods (2 October (T1), 1 November (T2) and 1 December (T3)) and seven cultivars (such as sardari (old cultivar), Sabalan (old cultivar), Ohadi (modern cultivar), Homa (modern cultivar), Karim (modern cultivar), Azar II (old cultivar) and Cross Sabalan (old cultivar)), respectively. Investigated traits were plant height, days No. to flowering, days No. to maturity, No. of fertile spike per m2, No. of grain per spike, No. of grain per m2, 1000-grain weight, grain yield, biological yield and harvest index.
The treatments were run as an analysis of variance (ANOVA) to determine if significant differences existed among treatments means. Multiple comparison tests were conducted for significant effects using the Duncan test.

Results showed that the simple effect of planting date was significant on plant height, days No. to flowering, days No. to maturity. Plant height, days No. to flowering, days No. to maturity, No. grain per m2, 1000-grain weight, grain yield and biological yield were significantly affected by cultivar. Interaction effect between planting date and cultivar had significant effect on No. of fertile spike per m2, No. of grain per m2, 1000-grain weight and grain yield. The highest and the lowest No. of grain per m2 were observed for Ohadi+T2 with 4149 grain.m-2 and Karim+T1 with 1309 grain.m-2, respectively. The highest biological yield was related to Ohadi with 3465 kg.ha-1. The maximum and the minimum grain yield was obtained in Ohadi+T2 with 1639 kg.ha-1 and Karim+T1 with 297.8 kg.ha-1, respectively.

Growth, yield and yield components of wheat were significantly influenced by planting time and cultivar. Early plantings experienced low early season temperatures which reduced biomass and yield. Conversely, late plantings experienced higher summer temperatures that reduced time to reach maturity. Planting date of 1 November had the highest grain yield to other planting dates. The early or late planting significantly reduced the crop yield and yield components. The maximum yield and yield components was related to Ohadi

Yield gap analysis provides an essential framework to prioritize research and policy efforts aimed at reducing 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 nine regions representing major chickpea-growing areas of Razavi Khorasan province. The average potential yield of chickpea for the locations was 2251 kg ha-1، while the water limited yield was 1026 kg ha-1 indicating a 54% reduction in yield due to adverse soil moisture conditions. Also، the average irrigated and rainfed actual yields were respectively 64% and 79% less than simulated potential and water limited yields. Maximum and minimum yield gap between potential yield and actual yield were observed in Quchan and Torbat-jam respectively. Generally، yield gap showed an increasing trend from the north (including Nishabur، Mashhad، Quchan and Daregaz regions) to the south of the province (Torbat- Jam and Gonabad). In addition، yield gap between simulated water limited potential yield and rainfed actual yield were very low because both simulated water limiting potential and average rainfed actual yields were low in these regions. Yield gap analysis provides an essential framework to prioritize research and policy efforts aimed at reducing 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 nine regions representing major chickpea-growing areas of Razavi Khorasan province. The average potential yield of chickpea for the locations was 2251 kg ha-1، while the water limited yield was 1026 kg ha-1 indicating a 54% reduction in yield due to adverse soil moisture conditions. Also، the average irrigated and rainfed actual yields were respectively 64% and 79% less than simulated potential and water limited yields. Maximum and minimum yield gap between potential yield and actual yield were observed in Quchan and Torbat-jam respectively. Generally، yield gap showed an increasing trend from the north (including Nishabur، Mashhad، Quchan and Daregaz regions) to the south of the province (Torbat- Jam and Gonabad). In addition، yield gap between simulated water limited potential yield and rainfed actual yield were very low because both simulated water limiting potential and average rainfed actual yields were low in these regions.

Saffron (Crocus sativus L.) is one of the native and valuable plants of Iran that proper use of nutrients is particularly important in the development and production. Since saffron is reproduced by corm, so always been considered production of replacement corms through appropriate nutrition; and foliar application is one of auxiliary methods in this crop nutrition. In order to investigate the effects of different maternal corm weight and different levels of foliar concentrations on replacement corm characteristics and flower yield of saffron, an experiment was conducted as factorial based on a complete randomized block design with three replications and 16 treatments at the Agricultural Research Station, Ferdowsi University of Mashhad during growing season of 2011-2012. Treatments were four corm weights (1.1- 3, 3.1- 5, 5. and 7.1- 9 g) and 4 levels of foliar application (0, 6, 8 and 10 per 1000). Variance analysis results revealed that the maternal corm weight had significant effect on studied characteristics of saffron corm and flower. Among the treatments, maternal corm with 7.1-9 g weight had the highest total corm number (408 corms.m-2), corm yield (809 g.m-2) and fresh flower yield (5.25 g.m-2). The number and yield of corm, flower and stigma of saffron were decreased with decreasing in maternal corm weight. The studied characteristics of corm and flower were not affected using foliar application and interactions of corm weight with foliar application. Generally, the results of presented research show that the maternal corm with high weight has significant and positive effects on the studied characteristics of replacement corm and flower of saffron. Therefore, it is recommended to achieve high yield of saffron, as far as possible, large maternal corms with more weight should be used.