فهرست مطالب سید عطاءاله سیادت

Deterioration reduces the quality of seeds. Oilseeds like Nigella are highly susceptible to seed aging. Seed priming enhances the quality of deteriorated seeds by improving germination indices and increasing the activity of antioxidant enzymes. This research aimed to investigate the extent of damage caused by accelerated aging treatment on the germination characteristics and antioxidant enzyme activity of Nigella seeds and the possibility of mitigating the adverse effects of aging through hormonal priming with cytokinin.

This research was carried out in the form of a completely random basic design with four replications in the seed technology laboratory of Khuzestan University of Agricultural Sciences and Natural Resources in 2017. The treatments included hormonal priming with cytokinin at five levels (0 (control), 10, 20, 40, and 80 m/l) for two durations (12 and 24 hours), and aging under 100% relative humidity and a temperature of 45 °C at five levels (no aging, 24, 48, 72, and 96 h).

The analysis of variance results indicated that germination indices were only influenced by main and two-way effects at the 5% and 1% probability levels, while the three-way interactions, including aging, hormone concentration, and priming duration, were significant for plant growth and longitudinal and weight indices at the 1% probability level. Furthermore, it was evident that the priming treatment mitigated the negative effects of aging, with the concentration of 10 milligrams per liter of cytokinin for a duration of 12 h having the most significant impact among the hormone concentrations used on the measured traits. The highest germination percentage (88%) and the lowest germination percentage (63.33%) were observed at concentrations of 10 and 80 mg/l, respectively. The use of cytokinin at optimal concentration improved catalase activity and protein levels. The results showed that in the control conditions, the activity of the catalase enzyme was 0.76 units per mg of protein and the amount of protein was 0.51 mg/g, which reached 0.97 units per mg of protein and 0.79 mg/g with seed priming.

Based on the results obtained from this research, aging led to a reduction in germination indices, the activity of antioxidant enzymes, and seed protein content. The best treatment applied was cytokinin hormone priming for aged Nigella seeds at a concentration of 10 mg/l for 12 h. According to the results, the application of cytokinin at its optimal concentration (10 mg/l) improved the catalase enzyme activity and protein content. Therefore, it can be suggested that hormonal priming with cytokinin helps mitigate the adverse effects of aging in Nigella plants.

Borage (Borago officinalis L.) is an annual plant and belongs to the Boraginasea family, that afford curative properties. This plant has deep roots and can absorb soil, water and nutrients from the depths of the soil, and is therefore somewhat resistant to drought. Increasing people's tendency toward medicinal plants to treat diseases has conduct to and essential the cultivation of medicinal plants globally and in Iran. Water deficit stress is one of the most important non- biological stresses that reduces water absorption by root system. Water deficit is considered as the most important limiting factor for non-living plant growth and yield that, in addition to a negative effect on yield, causes exacerbates other stresses, in particular the stress of the deficiency of nutrients in the plant. Drought stress is one of the most important limiting factors yield in the world. Today, phenolic compounds and plant growth regulator has been proposed, to reduce the negative effects of stress. Thus, this experiment carried out in order to Effects of salicylic acid on yield and nutrient uptake borage (Borago officinalis L.) under interrupting irrigation conditions.

A field study was conducted as a split plot arrengement based on randomized complete blocks design (RCB) with four replications at farm at experimental field of Khouzestan Agriculture Science and Natural Resources University, Iran during 2017-2018 cropping season. Three interrupting irrigation (stress at stemming stage, stress at flowering stage, stress at seed fill stage and control) as main plat and four application of salicylic acid including of 0, 69, 138 and 207 mg.L-1 as sub plots comprised experimental treatment. With reach each of these stages, from stem emergence to flowering initiation, from flowering initiation to seed fill interrupting irrigation and from seed fill initiation to beginning seed harvesting interrupting irrigation was carried out. This continued until the end of the physiological stages. Salicylic acid application was carried out during two stages during vegetative period (stem emergence and flowering initiation) simultaneously with applying moisture stress treatment. After applying the respective treatments, traits were measured at full flowering stage. Grain yield, oil percentages, ash contents of flower and leaf, nutrients of nitrogen, phosphorus, potassium, and sodium in two parts of the flower and leaf of Borage were measured. Analysis of variance and comparison of means was performed by SAS software and test LSD, 5% level probability .Respectively.

The result of analysis of variance showed that interrupting irrigation and salicylic acid had significant effect on grain yield, oil percentages, ash contents of flower and leaf ash and nutrients of nitrogen, phosphorus, potassium, and sodium in two parts of the flower and leaf. Also interaction effect of interrupting irrigation and salicylic acid on flower ash, potassium flowers, and leaf, phosphorus and sodium flowers was significant. Mean comparison test showed that with interrupting irrigation in stemming and flowering stages, only the concentration of sodium and potassium elements and oil percentages increased significantly. Maximum grain yield in the control treatment was 633.43 kg. ha-1. Foliar application with 207 mg.L-1 salicylic acid increased 50% grain yield. Salicylic acid increased all the traits studied, other than sodium. Consumption of 138 mg.L-1 salicylic acid in interrupting irrigation condition increased 36% of flower ash and 38% of leaf phosphorus, due to non-consumption of salicylic acid and drought stress. The highest amount of potassium of flower and leaf were obtained by application 138 and 207 mg.L-1 salicylic acid in interrupting irrigation stress at flowering stage and maximum flowering sodium without application salicylic acid with interrupting irrigation in this stage.

The results suggested salicylic acid application in borage can increase uptake of macro nutrients required for plant growth and reduce the negative effects of drought stress damage.

Crop biomass accumulation is directly related to the amount of photosynthetically active intercepted radiation by the canopy during the crop’s cycle. The slope of this relationship represents the radiation use efficiency (RUE), defined as crop biomass produced per unit of total solar or photosynthetically active intercepted radiation (IPAR). Therefore, above-ground biomass (g m−2) can be expressed as a product of the cumulative IPAR (MJ m−2) during the crop cycle and RUE (g MJ−1). The amount of IPAR depends on the length of the crop cycle over which radiation is accumulated, the fraction of intercepted radiation (FIR) by the canopy each day and the total incident solar radiation. The length of crop cycle is affected by the genotype and/or environmental factors mainly temperature and photoperiod. Indeed, soil constraints such as nutritional deficiencies have shown minor impacts on the crop cycle. FIR depends on the leaf area index (LAI) and the canopy light extinction coefficient (k). Several studies on different crops have shown that IPAR is negatively affected by nitrogen (N) deficiency. RUE is affected by the crop species, environmental conditions and also by management factors such as crop nutritional status. Over the past few decades, one of the aspects of improving crop productivity has been increasing N fertilizer utilization. Nitrogen application is one of the key inputs for crop production that determines the potential of total crops dry matter production through its effect on IPAR, RUE, and/or both. The aim of the present study was to comparatively evaluate in two rapeseed cultivars their responses on IPAR, RUE and related traits under different N availabilities at field conditions. In this study, the effects of N utilization on IPAR and RUE of two spring rapeseed cultivars (Hyola 401 and Dalgan) were investigated. Field experiment was conducted as a split plot in a randomized complete block design with three replications at Agricultural Sciences and Natural Resources University of Khuzestan. N consumption in seven levels of 0, 50, 100, 150, 200, 250 and 300 kg ha-1 was considered as the main factor and the type of rapeseed cultivar in two levels as the sub-factor. The results showed that the response of the above-ground biomass to N supply in both of the studied rapeseed cultivars was related to the change in both IPAR and RUE. The total accumulated IPAR during the growing season under of consumption of 200 kg N ha-1 was about 27 and 35% higher than those of the control treatments in the cultivars Hyola 401 and Dalgan, respectively. In both rapeseed cultivars, IPAR was strongly dependent on LAI and LAD. This means that N utilization with increasing LAI and LAD resulted in an increase in IPAR. Reduction of LAI in response to N deficiency can be explained by (1) changing the phyllochron, (2) decreasing leaf blade area, and (3) the higher rate of loss of old leaves. Utilization of N had no effect on the light extinction coefficient (K) of crop canopy, and this coefficient was estimated to be 0.65 (± 0.02) in the cultivar Hyola 401 and 0.73 (± 0.02) in the cultivar Dalgan. Depending on N level, the above-ground biomass varied from 932 to 2192 g m-2 in the cultivar Hyola 401 and between 853 and 1811 g m-2 in the cultivar Dalgan. Depending on the availability of N, the RUE varied between 2.02 (control treatment) and 3.25 g MJ-1 (200 kg N ha-1) for the cultivar Dalgan and between 1.86 (control treatment) and 3.62 g MJ-1 (300 kg N ha-1) for the cultivar Hyola 401. Reducing RUE in N-limit treatments may be due to reduced leaves nitrogen content, which reduces their photosynthetic capacity. The results of this study showed that the above-ground biomass production by two rapeseed cultivars was related to differences in their growth rates in response to the applying different amounts of N. The physiological traits that explained above-ground biomass responses of both cultivars were the cumulative intercepted radiation during the crop cycle and radiations use efficiency. In both rapeseed cultivars, the K coefficient was not affected by N utilization, which indicates that IPAR responses were the result of changes in LAI and LAD during the crop cycle affecting the fraction of intercepted radiation by the crop.

Accurate prediction of seedling emergence in the field is crucial for the performance of growth models. In order to determine thresholds of seedling emergence response to temperature, two replicated field experiments were carried out at Ramin Agriculture and Natural Resource University of Khuzestan during 2015-2016 and 2016-2017. In these experiments, seedling emergence of two spring canola cultivars (Hyola 401 and Sarigol) was evaluated in a randomized complete block design with four replications in fifteen planting dates (as environment). Thermal-time model was developed based on the Weibull probability distribution function, and thermal thresholds for seedling emergence response of two spring canola cultivars in field conditions was modeled based on this function. Based on model outputs, the base temperature for seedling emergence (Tb) was estimated to be 5.83 °C in the hybrid Hyola 401 and 4.16 °C in the cultivar Sarigol. The thermal-time required to initiate seedling emergence at sub-optimal temperature range (θT(0)) and the thermal-time needed to complete seedling emergence at supra-optimal temperature regimes without significant differences between two cultivars was estimated to be 55.5 and 5.65 °C d, respectively. Maximum temperature for the 50% probability of the thermoinhibition of seedling emergence (Tm(50)) in hybrid Hyola 401 and cultivar Sarigol was estimated to be 33.02 and 33.30 °C, respectively. The optimum temperature for 50% seedling emergence in the field (To(50)) for hybrid Hyola 401 and cultivar Sarigol was determined to be 30.99 and 31.22 °C, respectively.

In order to evaluate the effect of zeolite and vermicompost on Marigold (Calendulaofficinalis L.), a field experiment was conducted in 2017 in the research field of Ramin University, Khuzestan, in split plot as a randomized complete block design with three replications. Vermicompost (0, 3, 6, 9 t ha-1) and zeolite (0, 4, 8 and 12 t ha-1) were investigated as the main factor and sub plot, respectively. Results of variance analysis showed that vermicompost and zeolite had a significant effect on flower yield, biological yield, harvest Index, chlorophylls and carotenoids of leaves, petal carotenoids, nitrogen removal, phosphorus removal, and index of the intensity of the color of the petals. Also, interaction effects of vermicompost and zeolite was significant on all top-mentioned characteristics. The highest flower yield (69.53 g m-2) was obtained at 3 t vermicompost per ha and 12 t zeolite per ha. Maximum biological yield (474.84 g m-2) was achieved at 9 t vermicompost per ha. The highest leaf and petal carotenoids were recorded at 9 t vermicompost per ha and maximum chlorophyll a and b belonged to 9 t vermicompost per ha and 4 t zeolite per ha. The highest soil nitrogen harvest was obtained at 8 t zeolite per ha. Maximum soil phosphorus harvest belonged to 9 t vermicompost per ha and 12 t zeolite per ha. In total, knowing that zeolite is more cost-effective rather than vermicompost, increasing the amount of zeolite consumption can enhance flower yield. In the current research, the best flower performance could be obtained at an optimum amount of 3 t vermicmpost per ha and 12 t zeolite per ha.

In order to study effects of different levels of nitrogen and plant density on yield and components of Sweet corn (hybrid SC 403), a field experiment was conducted at Ramin University of Agriculture Natural and Resources. Experiment was carried out as factorial design arranged in, randomized completely blocks design with 3 replications. The treatments were three levels of nitrogen (100, 150 and 200 kg ha-1) and three levels of plant density (85000, 70000 and 55000 plants ha-1 ) Grain yield, dry matter yield, wet cob yield, kernel number in row, kernel number row, 1000 grain weight, cob length, cob diameter, harvest index (HI), and grain protein. contents were determined The results showed that effect of nitrogen was significant on all traits. The highest grain and wet cob yield (6.39 and 24.78 t per ha-1 ) and the highest of grain protein percentage (14.16%) was obtained with 200 kg/ha-1 nitrogen. The highest kernel number per row, kernel number per row, 1000 grain weight, cob length, cob diameter and harvest index (HI) were obtained with 200 kgha-1 of nitrogen. The effect of plant density was significant on all traits. The highest grain and wet cob yield (5.96 and 24.81 t ha-1 ) were obtaned with 85000 plant per ha but the highest grain protein percentage was obtained with 55000 plants per ha. The interaction between nitrogen and plant density was significant for grain yield, dry matter yield and cob length.

Rice can be irrigated like wheat and corn as an aerobic plant (1 and 3). Studies show that at certain stages of plant development, materials development, production photosynthetic processes are surplus to requirements. This material is for Ghyrsakhtmany compounds in plant vegetative organs such as stems, pods and leaves are stored and to pursue the establishment of a strong physiological destinations, during remobilization to the grain moves (2). Potential remobilization is a physiologically acceptable index to a variety of factors including genotype and lack of water or too dependent (4). With regard to water crisis, it’s essential to increase knowledge level and awareness about water tension loss. This study aims at realization of this purpose and reducing the negative effects of water tension. An experiment Was carried out Study of irrigation regimes on rice genotypes remobilization and grain yield of Khuzestan province in a split-plot arrangement using randomized comlete bloks design with three replication in 2014 and 2015 cropping seasons at Shavoor Agricultural Research Station, Dependent in Research Center of Agricultural and Natural Resources of Khuzestan. For exposing rice genotypes to Four different irrigation regimes (1, 3, 5 and 7 days), and 12 genotypes were randomized in sub-plots. The combined analysis results showed that all of these attributes among different irrigation regimes, genotype and interaction of two factors have significant difference, at the level of five percent and in property remobilization efficiency, between the irrigation regimes and this story was true for other levels and the qualities at one percent level. And only in the interaction of two factors of irrigation regime and total genotype distribution, no statistically significant difference was observed. The amount of remobilization, apart from the leave that saw decrease from Flood irrigation regime to 3-day period, in the other organs saw increase and then by increasing the number of decreasing irrigation intervals, according to the dry matter of organs. Regarding the efficiency of remobilization, apart from the leave that experienced a decreasing trend from flood irrigation regime to 5-day irrigation period, and then in 7-day irrigation period it experienced an increasing trend, while stem experienced a totally an inverse trend. The share of Leaves in redistribution share of three-day irrigation frequency decreased and then increased with increasing and decreasing irrigation, in a way that inverse share of stem and total had the largest share under the condition of increased drought around the plant by seven- day irrigation period. And the ability and difference of leave source could be the reason for its being different from the other organs. Probably due to low tank volume and reduced ability to produce the active tank, the main factor is reducing the amount of supply, efficiency and contribution of remobilization in irrigation regimes. Correlation coefficients show that grain yield with greatest average of 6555.10 kg per hectare in second irrigation regime with three-day irrigation period in the genotype IR 81025-B-327-3. Biggest significant and positive correlation was with panicle redistribution (0.207**), stem (0.136*) and total (0.129*) but the other attributes had negative correlation with the grain yield. According to the results stem maximum value, efficiency and remobilization of dry matter in the main sink plant, The genotypes with greater resistance and frequency of irrigation regimes with one, three and five days filling an important role in providing seed, and this could be one of the reasons for the superior yield of these genotypes is under irrigation

Understanding the interaction between crop-weed competition and herbicide doses may, in many cases, result in a recommendation to reduce the consumption of the herbicide, which is both environmentally and economically important. Nitrogen fertilizer also influences the competitive balance through changes in weed density and biomass, and also contributes to environmental pollution. Hence, the evaluation of the interaction of herbicide doses and nitrogen fertilizer application is necessary for proper management of weeds and achieving acceptable economic yield along with minimizing environmental negative impacts. A field experiment was conducted as split plots in a randomized complete block design with four replications at Ramin Agriculture and Natural Resources University of Khuzestan. Nitrogen fertilizer included five levels of 0, 50, 100, 200 and 350 kg ha-1 of urea was considered as the main plot and the herbicide dose of “iodosulfuron-methyl sodium + mesosulfuron methyl + mefenpyr-diethyl” in six levels of 0, 0.2, 0.4, 0.6, 0.8 and 1 times the recommended dose (1.5 L ha-1) was considered as the sub plot. Half of the nitrogen fertilizer was distributed before sowing and the other half was distributed in mid-tillering stage of wheat. Four weeks after spraying (late of wheat tillering stage), destructive sampling was done using a quadrate with a surface area of 0.25 m2 from four points of each experimental plot. Total biomass of weeds and wheat were weighed in each plot after three days of placement in an oven at 80 °C. The response of weed and wheat biomass to herbicide doses was described, respectively, with dose-response and sigmoid models, and developed in response to an increase in nitrogen fertilizer consumption. Based on the combined model, the dosage required for reducing the weed biomass to less than 50 g m-2 with consuming of 140, 210 and 300 kg ha-1 of urea fertilizer was predicted to be 100, 85 and 60% of the recommended dose, respectively. Also, to achieve about 700 g m-2 of wheat biomass, using 230 kg ha-1 of nitrogen fertilizer plus 100% of the recommended herbicide dose, or applying 270 kg ha-1 of nitrogen fertilizer and 60% of herbicide recommended dose or applying 350 kg ha-1 of nitrogen fertilizer and 40% of the recommended dose of herbicide. Also, application of 230 kg ha-1 of nitrogen fertilizer plus 100% of the recommended herbicide dose or application of 270 kg ha-1 of nitrogen fertilizer and 60% of the recommended herbicide dose or application of 350 kg ha-1 of nitrogen fertilizer with 40% of the recommended herbicide dose led to the achievement of about 700 g m-2 of wheat biomass. Increasing the competitive ability of weeds in response to increasing nitrogen use led to a higher loss of wheat biomass at higher levels of fertilizer application. Application of herbicide at higher levels of fertilizer application, which the competitive ability of weeds in these conditions was much higher than that of low fertilizer levels, led to a greater increase in wheat biomass. Increasing environmental concerns has led to the development of low input systems (low fertilizer and herbicide use). However, our results showed that weeds grown in low nitrogen levels were much more tolerant to herbicide than plants grown at higher levels of fertilizer application.

A range of methods are applied to enhance secondary metabolism in medicinal plants. Treatment of the plants with elicitors is one of these approaches. Salicylic acid (SA) exerts a positive impact on plant growth and yield. The present study, as a biannual field experiment, investigates the response of peppermint (Mentha piperita L.) to different rates of SA under different regimes of nitrogen nutrition during years of 2014-2015. The experiment was made as a random complete block design based on split-plot with three replicates. The treatments included nitrogen fertilization rate as the main factor (0, 70, 140, 210, and 280 kg N ha-1 applied as urea) and salicylic acid, as the sub factor, was spayed at different concentrations (0, 100, 200, and 300 μM). In both years, the highest nitrate reductase activity was found in the roots of the plants treated with 200 μM SA and fertilized with 280 kg N ha-1. Interestingly, the foliar activity of the enzyme was influenced only by nitrogen, whereas the highest rate of activity was determined using 280 kg N ha-1 (2.87 and 2.82 μM nitrite g-1 FW h-1, respectively in the first and second year). Higher concentration of SA caused to increased content of nitrogen and free amino acid in the plants fertilized with higher rates of nitrogen. Nitrate, total phenol, and soluble carbohydrates content of leaf was reduced in both years as the result of high rate of nitrogen and high concentration of SA applied. In the first and the second year, the highest fresh yields (3316.2 and 3480.7 g m-2, respectively), the highest dry yields (811.7 and 855.6 g m-2, respectively) and essence (13.01 and 15.2 mL m-2, respectively) were obtained through annual application of 210 kg N ha-1. Collectively, the application of 210 kg N ha-1 together with SA (200μM) is recommended to achieve desired quantitative and qualitative yield.

IntroductionSome seeds will enter thermoinhibition when imbibed at warm temperature regimes. Seed thermoinhibition is the situation when germination of seeds that have been imbibed at warm temperature is prevented, but the seeds will subsequently germinate rapidly when the temperature is reduced. It is therefore a temporary inhibition of germination that can be alleviated simply by lowering the temperature. This process generally occurs at temperatures considerably lower than ceiling temperature. It may also occur over a small range of temperatures, such that germination can go from 100 to 0 % when the upper temperature limit is exceeded by only a few degrees. This germination behavior is often associated with a winter annual life cycle common in Mediterranean-type climates with wet winters and dry summers, as seeds that are shed in early summer and have subsequently after-ripened nonetheless may not germinate when hydrated at warm temperatures, waiting instead until the fall for cooler temperatures and more certain rainfall before germinating. Patterns of seed germination behavior of different populations in response to warm temperatures can be described using the models based on thermal-time units. In this study, thermal-germination model was developed based on four different probability distribution functions of Normal, Lognormal, Gumbel and Weibull. Seed thermoinhibition in six cultivars of spring oilseed rape (Brassica napus L.) were then quantified using these models.
Materials and methodsExperiment was conducted at the Seed Technology Laboratory, Ramin Agriculture and Natural Resources University, Khuzestan. In this study, germination responses of six spring oilseed rape cultivars (Sarigol, RGS003, Dalgan, Hyola-401, Jerry and Julius) were investigated at constant temperatures. Germination test were conducted in the dark at eleven constant temperature regimes of 8, 12, 16, 20, 24, 28, 32, 33, 34, 35 and 36 ºC with a range of ±0.2 ºC. For each cultivar, germination test was carried out in a completely randomized design with four replications and the entire experiment was repeated three times. The germinated seeds (criterion, radicle protrusion of > 2 mm) were counted and removed at specified intervals. Seeds of all cultivars germinated more rapidly at 32 ºC than at higher or lower temperature regimes. Therefore, the optimum temperature for germination was assumed to be 32 ºC. Above this, oilseed rape seeds showed thermoinhibition of germination. So that, ungerminated seeds of each cultivar at these warm temperature regimes were germinated rapidly at low temperature of 20 ºC. Cumulative-germination curves of oilseed rape cultivars in temperatures beyond 32 ºC were used to perform non-linear regression procedures to assess the relative accuracy of different thermal-germination models in predicting germination response under constant temperatures. The thermal-germination models were fitted to the germination data of each cultivar using the PROC NLMIXED procedure of SAS. Assessment of goodness-of-fit was performed by the Akaike information criterion (AIC).
Results and discussionAssess the goodness of fit indicated that precision of the thermal-germination models was different in describing the germination behavior of early- and mid-maturing cultivars of oilseed rape. Thermal-germination model based on Normal distribution provide the best fit to data of germination progress over time for early-maturing cvs. Dalgan (AIC=-237.5) and Hyola-401 (AIC=-168.8). For mid-maturing oilseed rape cultivars (Sarigol, RGS003, Jerry and Julius), the smallest AIC values were obtained for the Gumbel thermal-germination model, while the model based on Normal distribution gave the worst fit to germination data. The germination responses of early- and mid-maturing oilseed rape cultivars to supra-optimal temperature regimes were different. Early-maturing cultivars showed 5, 50 and 95% thermoinhibition of germination at averaged temperatures of 33.52, 33.99 and 34.37 ºC, respectively. While, seed thermoinhibition in mid-maturing cultivars reached to 5, 50 and 95 % of maximum at averaged temperatures of 33.63, 34.34 and 35.59 ºC, respectively. Based on the model prediction, the germination completely inhibited at an average temperature of 34.54 ºC in early-maturing cultivars and an average temperature of 36.64 ºC in mid-maturing cultivars. Abscisic Acid (ABA) has been reported as the major regulator of seed thermoinhibition.
ConclusionsEarly-maturing oilseed rape cultivars have lower thermal-thresholds compared to mid-maturing cultivars. A different thermal-germination model was necessary for predicting the probability of seed germination in response to warm temperature regimes depending on the type of germination behavior of early- and mid-maturing cultivars. Thermal-germination models proposed here well described the observed thermoinhibition response of seed germination in oilseed rape cultivars.

The study was carried out to assess the effects of humic acid and irrigation cut on yield, yield component and water use efficiency of three fennel ecotypes (Foeniculum vulgare L.) at the reproductive stages. The study was carried out in Agriculture and Natural Resources Science University of Khuzestan in a factorial split plot based on randomized complete block design with three replications during 2016-2017. Irrigation regimes (complete irrigation, irrigation cut from flowering stage, irrigation cut from grain filling stage) and foliar application of humic acid (no application and foliar application of 400 mg.l-1) were placed in main plots by a factorial arrangement, and three ecotypes (Isfahan, Hamadan, Bushehr) were placed in sub plots. The results showed that the highest plant height (157.86 cm) was obtained from complete irrigation and Esfahan ecotype (153.6 cm). The highest number of sub branches (10.14) was obtained by foliar application of humic acid and Esfahan ecotype (10.16). The irrigation cut from flowering stage caused reduced thousand grain weight. The highest umbel per umbrella (24.52), grain yield (1876.95 kg.ha-1) and irrigation efficiency (531.99 grams per cubic meter) were obtained under complete irrigation with foliar application of humic acid. The highest number of umbrella was obtained from Bushehr ectype under complete irrigation conditions. Generally, Bushehr ecotype with complete irrigation and foliar application of humic acid is recommended in terms of higher grain yield, yield components and irrigation efficiency.

To investigate the effect of biopolymer coated urea fertilizer on physiological traits related to yield of sweet corn under deficit irrigation, an experiment was carried out in strip split plot based on randomized complete block design with four replications in Agriculture and Natural Resources Science University of Khuzestan, Iran, in 2016. Irrigationin three levels (100, 80 and 60% water requirement) in length of blocks and urea fertilizer in six levels (without fertilizer as check treatment, pure urea, sulfur-coated urea, starch-coated urea, agar-coated urea and chitin-coated urea) in vertical strips to irrigation in each block were used. The results showed that the effect of irrigation and type of coated nitrogen fertilizer on leaf relative humidity, chlorophyll-a, chlorophyll-b, leaf area index, leaf rolling, ear yield, and interaction of irrigation × fertilizer on chlorophylla and b and grain yield per hectare was significant. The application of coated urea fertilizer increased 29.41, 15.06, 24.88, 34.11 and 14.88 percent on average in leaf area index, relative water content, leaf rolling, ear yield per hectare and fresh forage yield per hectare, respectively, compared to pure urea fertilizer. Also, the highest values of chlorophyll a and b and grain yield per ha were obtained from chitin coated urea fertilizer together with full irrigation (100% water requirement) and their lowest values were from the check fertilizer (without urea)with 60% water requirement. The reduction of 40% in irrigation decreased 15.89%, 31.02%, 42.85% and 40.33% in relative water content, leaf area index, leaf rolling and ear yeild per hectar, respectively, compared to full irrigation. The highest economic ear yield with average of 10238.6 kg/ha and 9853.3 kg/hawas obtained from full irrigation and chitin coated urea,respectively, and the lowest ear yieldwas obtained from 60% water requirement with check fertilizer treatment.

Integrated weed management is based on combination of several management methods, while reducing the rate of the use of herbicides, will result in efficient management and sustainable weed control. Ability of crop tolerance and prevent weed growth are two important traits in weed competition. An appropriate and suitable cultivar, has high yield potential in the presence of weed and under weed free conditions. Such cultivar is weed tolerated and prevent the growth of weed. Therefore this study was conducted to determine the relationships between some morphophysiological traits that affecting on tolerance index of bread wheat cultivars with wild oat in tropical regions condition such as the province of Khouzestan.
In order to investigate the casual relationships between effective morphophysiological traits of tolerant spring bread wheat cultivars to wild oat, an experiment was conducted as strip block includes 4 densities of wild oat (0, 40, 80 and 120 plant per m2) in linear plots and 10 spring bread wheat cultivars (Chamran, Baz, Atrak, Arvand, Maroon, Shoeleh, Chenab, Virinak, Dez and Falat) in horizontal plots based on randomized completely blocks design with three replications in research farm of Khozestan Ramin Agricultural and Natural Resources University during 2011-2012 and 2012-2013 growing season. Each plot consists of 10 lines of wheat planting in distance of 20 cm. Distance between the plots was 50 cm and the distances between the blocks was two meters and the plots were prepared with hand. The rate of wheat seed for cultivars of Chamran, Baz, Atrak, Maroon, Chenab, Virinak, Falat and Dez was 400, Arvand 300 and Shoeleh 250 plants per square meter and wild Oat seed were planted at regular intervals between the wheat lines (for densities of 40 wild oat plant: 12.5 cm; 80 plant: 6.25 cm and 120 plant: 4.16 cm).
The results showed that with increasing weed density, tolerance index of wheat decreased. So with presence of wild oat, the average of grain yield of cultivars decreased by 0.31 percent. Between wheat cultivars, Maroon cultivar with 86.8 percent, had the highest index of tolerance. This cultivar had the highest grain yield and well prevent dry matter accumulation of wild oat. While Virinak cultivar with 69.3 percent had the least tolerance index. This cultivar had the highest accumulation of dry matter of weed and also had the lowest grain yield. Therefore these cultivars based on tolerance index were classified at three groups: 1) tolerant group (Maroon), 2), medium group (some new cultivars such as Baz, Atrak, Dez and Chamran and old cultivars such as Arvand, Chenab and Shoeleh) and 3) weak group (such as Virinak and Falat). Modeling of wheat cultivars tolerance ability index with wild oat showed that different traits such as fertile spike number, harvest index, thousand grains weight, grain number in spikelet and spikelet number in spike cause to increase of wheat cultivars tolerance index ability against wild oat. But none-fertile spike trait, spike upper and under internode length could not strengthen tolerance index. Yield and harvest index of wild oat decreased wheat cultivars tolerance ability index.
Therefore in wheat cultivated areas rich with wild oat, the cultivars are more favorable that to weed infestation, its yield does not decrease too much. Such cultivars, well tolerated to weeds, prevented of its growth and seed production. So these cultivars such as Maroon that is weed tolerant with preventing of its seed production, have ability to control the weed population in subsequent years with actions weed ecological control can be used in integrated control programs.

IntroductionBean (Vicia faba L.) has the great old history of crop cultivation to date would be pushed back to a fairly long day plant, resistant to frost and cool season crop and up to 5 degrees Celsius tolerated. Bean prefers wet and cold conditions. Excessive heat may cause fetal growth problems, loss and reduce the number of seeds per pod bean flowers to the growth of plant and fruit set on low temperature and high humidity environments. Early planting allows more during plant growth and increased performance. Moreover, it is necessary to achieve maximum performance in the bean are balanced in the distribution of nutrients and the roots of the plant. Some studies have shown that many cereal plants can make use of phosphorus in the soil inaccessible. Phosphate makes the plant resistant to lodging, early maturity, higher quality, accelerating plant emergence to the initiation of flowering and pollination, and thus increases the yield.
Materials and Methods In order to investigate the effect of planting date and phosphorus nutrition on growth and performance of faba bean, a field experiment was done in Research Field of Agricultural University and Natural Resources of Ramin, Khuzestan, during 2013-2014. Experiment was done as split plots based on the completely randomized blocks design with four replications. Experimented factors were, five planting dates (2 October,17 October,1 November 16 November, and 1 December) as main plots and phosphorous oxide fertilizer (P2O5) with the amount of (zero, 50, 100,150 kilogram per hectare) from triple superphosphate resource as sub plot.
Results and DiscussionThe Experiment results showed that planting date and phosphorus fertilizer and their interactions had a significant effect on morphological traits (include bush height, pod height from the ground, leaf area index, and number of sub branch). The comparison showed that the highest grain yield obtained in sowing date of 1 November (average production of 2752 kg per hectare) and the lowest yield obtained in planting Persian dates of 1 December (average production of 1903 kg per hectare) and 2 October (mean produced 1943 kg ha-1), respectively. The results of study of more than 100 kg P ha also had no significant effect on performance. The delay in planting bean reduces its performance. But through the power of P can be compensated to some extent the decline in performance so that delayed planting dates (10 December and 25 November) at the level of 100 kg per hectare yield than no fertilizer, respectively, about 55 and 60% increased.
ConclusionGenerally, in the process of growth, with a delay in sowing and increase the average temperature during the growing season and heat stress, all traits such as leaf area index, plant height, number of branches and the height of the first pod reduced. The cold start test at the beginning of the growing season, time to go green rose plant, but with the onset of heat at the end of the growing season and due to its effect on plant growth, all stages of growth were reduced. The results of study of more than 100 kg P ha also had no significant effect on performance. In total, the largest decline in the yield on the culture of 10 December occurred mainly due to reduced plant growth during the growing season as a result of dealing with the heat in the end of the growing season. The best results were obtained from the use of 100 kg per hectare phosphorus. The delay in planting bean reduces its performance. But through the power of P can be compensated to some extent the decline in performance so that delayed planting dates (10 December and 25 November) at the level of 100 kg per hectare yield than no fertilizer, respectively, about 55 and 60% increased.

IntroductionBetween oil seeds, from the quality, quantity and nutrition index point of view, canola has the top level . Because of the solubility of N fertilizers, the time of urea application, is very important and one of the main reasons of the reduction in N application efficiency is utilization of urea in an inappropriate time. By precisely foliar application of nitrogen, the efficiency of nitrogen transformation to the grain will be very high because in this method the leaf is considered the main organ of nitrogen uptake and a low amount of absorbed nitrogen was transferred to the root and entered the soil. The more division of N application in growth stages and in accordance with plant need and foliar application result in increasing nitrogen use efficiency. The delay in sowing will result in the reduction of yield and this is due to low LAI, and thus low radiation absorb in vegetable phase and shorter reproductive phase with high temperature in flowering and subsequent stages that result in low prolific silique and make disorder in transferring stored material to grain. In this experiment using N foliar application to decrease the adverse effect of delay in sowing is objective.
Materials and MethodsThe experiment was conducted in 2013-2014 in Ramin Agriculture and Natural Resource University of Khuzestan. Experiment was conducted as split plots in a randomized complete blocks design with three replications. In this experiment sowing date]optimum sowing (27 November), 17 December and late sowing (30 December) [were assigned to main plots and several time of N-foliar application with 5 percent density from urea (20 liter per ha), ]TO (control), T1 (foliar N application in rosette stage), T2 (foliar N application in budding stage), T3 (foliar N application in flowering stage)[ were placed in sub-plots in randomized way. Fertilizing was based on the results of soil examination. Therefore, 162 kg ha-1 of pure nitrogen (from resource urea) in the way of dusty application (1/3 after appearance of seedling on the soil, 1/3 in 3-4 leaves stage after thinning and 1/3 at the beginning of steam elongation) and 100 kg.ha-1 super phosphate triple in all plot was applied before planting. Each plot was consist of 8 planting line with 20 cm apart from each other and 4 m length. The data were analyzed by using SAS and mean comparison of data based on LSD test in 5% probably level.
Results and DiscussionLate sowing date and nitrogen foliar have significant effect on the yield and efficiency and uptake index of nitrogen. With delay in sowing because the flowering and silique formation stage faced with the heat tension, the vegetative phase, production of photosynthesis matter and growth all treatment like: yield, oil yield, biological yield, oil seed percent, nitrogen harvest index, nitrogen use efficiency, nitrogen utilization of agronomy efficiency and amount of nitrogen uptake, were decrease. But it should be pointed out that with delay in sowing the percentage of nitrogen seed and nitrogen of all bushes was increased.
The highest yield with mean of 3406.6 kg.ha-1 was relevant to first sowing date and least yield with mean 1803 and 1499.1 kg.ha-1 was achieved of second and third sowing date, respectively. In foliar treatment the highest yield was obtained from N foliar in budding and flowering stages and the least yield was obtained from control treatment.
Foliar in budding and flowering stages by increasing the green surfaces of plant, more benefit of sun radiation, increasing in photosynthetic activity were increase and in this way the seed yield and oil yield were increase. As well nitrogen harvest index was increased with increasing of assigned nitrogen to silique in canola and the reduction in wasting of nitrogen will be increased by consume it in appropriate time. With nitrogen foliar application because of availability of nitrogen in appropriate amount and adequate utilization of plant of nitrogen, caused to increase the nitrogen utilization of agronomy efficiency and nitrogen uptake amount.
ConclusionsThe results of this experiment showed that with delay in sowing the flowering and grain formation stages were faced to heat tension and can result in reduction in all treatment. The nitrogen foliar in heat stress caused an increase in seed yield, oil yield, dry mater, nitrogen harvest index, nitrogen utilization of agronomy efficiency and amount of nitrogen uptake. As the result, first sowing date and N foliar application in budding and flowering stages were best treatment in this experiment.

Seed germination is one of the key stages in the life cycle of plants that can ultimately affect their fitness in the environment. The temporal pattern of seed germination is extremely depended on the soil water potential (Ψ) of the germination medium, as this determines the equilibrium water content of the seed. As for temperature, there is a minimum Ψ that must be exceeded in order for seeds complete germination, and seeds in a population vary in the value of this minimum or base Ψ. The germination of a seed population in response to the reduced water potential is modeled using the hydrotime model. According to this model, the time to germination for a given seed fraction (g) is inversely related to the difference between the current seed Ψ and the base water potential (Ψb) for that fraction (Ψb(g)). The hydrotime model functions are well in matching both the timing and the percentage of germination of seed populations in relation to their Ψ environment. In addition, the model outputs which are significant physiologically and ecologically and the parameters of the model can be used to characterize the properties of seed populations. Normal distribution of Ψb among seeds within a population is one of the assumptions of the hydrotime model. However, this assumption may not be met in many species and thus can result in poor predictions. We tried to investigate empirically the validity of this assumption, to compare the fit of alternative distributions and make recommendations to improve germination modeling procedures.
Seed germination of Melilotus officinalis, Sinapis arvensis and Hordeum vulgare were tested across a range of water potentials (0, -0.2, -0.4, -0.6 and -0.8 MPa for M. officinalis and S. arvensis and 0, -0.3, -0.6, -0.9, -1.2 and -1.5 MPa for H. vulgare) and germination responses were described by the hydrotime models based on twelve statistical functions including Normal, Beta, Gamma, Loglogistic, Weibull, Gumbel, Birnbaum-Saunders, Inverse-normal, Log-normal, logistics, Rayleigh and Inverse-gamma. Four replicates of 50 seeds were spread evenly within 9-cm-diameter Petri dishes, each containing a Whatman No 1 filter paper. Each filter paper was moistened with 6 mL of polyethylene glycol (PEG) solutions or distilled water (0 MPa). Osmotic solutions were prepared by dissolving PEG 6000 in distilled water according to the Michel (1983) equation. Germinated seeds (radicle protrusion of>2 mm) were counted daily two or three times for 20 days. All distributions, having been formulated into the hydrotime model, were fitted to data using the PROC NLMIXED procedure of SAS, with the default optimization technique of dual quasi-Newton algorithm.
The results showed that the estimated parameters of the hydrotime model developed on the basis of Beta distribution had more certainty than the other distributions (AICc=-556.60 for M. officinalis, AICc=-847.70 for S. arvensis and AICc=-1034.20 for H. vulgare). Based on the Beta hydrotime model, values of the hydrotime constant (θH) and water potential threshold for beginning of M. officinalis seed germination (δ) were estimated to be 14.01 MPa h and -0.85 MPa, respectively. For S. arvensis, θH and δ estimated to be 22.23 MPa h and -0.98 MPa, respectively. Estimated θH and δ for H. vulgare was 48.69 MPa h and -2.47 MPa, respectively. Results of this research are in contrast to assumption of a normal distribution of base water potential of a seed population. Hence, before using a hydrothermal time model to make predictions, the distribution of base water potential within a seed sample should be examined and an appropriate equation should be selected.. The results indicated that among all three species, the Beta distribution resulting in more accurate predictions than the other distributions. The hydrotime model based on Beta distribution predicts an actual value for the phase of delay germination. In fact, less skewed in predicted germination using beta model can be related to more accurately of this function to predict the onset of germination. Shape parameter gives high flexibility to this model and allows more accurate prediction of delayed germination phase. In addition, the hydrotime model based on Beta distribution was able to prediction germination of species for which the base water potential distribution is symmetrical or unsymmetrical.
In this paper, a model based on the beta distribution is proposed which is not only more biologically relevant, but also provides better predictions of germination compared to the conventional model.

This research was conducted to investigate the effect of growth-promoting bacteria on yield and some traits of maize. This experiment was performed as a factorial randomized complete block design with three replications at research farm of Islamic Azad University, Izeh branch, Iran. The experimental factors included four strains of plant growth-promoting bacteria: Pseudomonas fluorescent 169 (B1), Pseudomonas fluorescent 79 (B2), Pseudomonas putida 108 (B3), Pseudomonas putida 159 (B4) and without bacteria (control, B5) and two corn varieties namely sc 704 (A1) and Bolson (A2). Before planting corn seeds were soaked with liquid inoculation. Plant height, number of leaves per plant and ear, forage yield, dry matter and dry matter digestibility of leaf, stem and ear, crude protein and cell wall without hemicellulose in the leaf, stem and ear were evaluated. Analysis of variances showed that the effects of varieties, bacteria and their interaction on all traits were significant. Plant height, number of leaves per plant and ear, forage yield, dry matter and stem dry matter digestibility were higher in Bolson. Moreover, dry matter digestibility of leaf and ear, crude protein and cell wall without hemicellulose in the leaf, stem and ear of sc 704 were greater, compared to hybrid Bolson. Plant height, number of leaves per plant and ear, forage yield, dry matter and dry matter digestibility of stem and ear were greater in at the presence of fluorescent strains than those of putida strains. The results revealed that bacterial inoculation enhances the grain yield, yield components and quality of forage maize. Bolson seemed potent to outperform sc 704, though this proposition needs further examination in future field trials.

In order to study the effect of the usage of vermicompost and mycorrhiza fertilizer usage on yield quantity and quality of soybean cultivar L17 in water deficit stress condition, an experiment was conducted as plots in a split at randomized complete blocks with four replications in Agricultural Research Center in 2013 in Khoramabad. The experiment treatments including irrigation in three levels (after 60, 120 and 180 mm evaporation from pan class A pan), vermicompost and mycorrhiza in six levels (non-use of vermicompost and mycorhiza fertilizer, inoculated with mycorrhiza fertilizer, consumption of 5 and 10 t.ha-1 vermicompost , consumption of 5 and 10 t.ha-1 vermicompost with mycorrhiza) were respectively as the main plots and sub. The results of experiment showed that the water deficit stress significantly decreased the number of pods per plant, number of grain per pod, number of grain per plant, 1000 grain weight, biological and grain yield. So that the highest grain yield with the rate of 3216.7 kg.ha-1 was obtained from 60 mm evaporation. The use of combined vermicompost and mycorrhiza fertilizer increased the traits except the number of grain per pods. Grain yield in combined treatment of 5 and 10 t.ha-1 vermicompost and mycorrhiza, respectively increased 23 and 29 percent compared to control. By increasing irrigation distance grain oil content decreased and grain protein content increased. Finally, in order to water_saving irrigation and the cost of inputs and ensuring optimal performance in drought condition, we can use combination of 5 t.ha-1 vermicompost with mycorrhiza.

Peppermint (Mentha piperita L.) is an aromatic medicinal plant, that its cultivation is limited due to low soil from organic matter. Therefore choose right amount and type of fertilizer is very necessary to ensure of satisfactory yield. A factorial experiment was conducted at research farm of Ramin University during 2014, arranged in CRD design contain three types of nitrogen fertilizer as the first factor: liquid (urea ammonium nitrate), powder (ammonium sulfate) and granular (Urea) which were applied at five levels: 0, 70, 140, 210 and 280 KgN/ha as the second factor with three replications. Aerial pares of plant were collected in early of blooming, the essential oils were obtained by hydro distillation method (Clevenger apparatus) and were analyzed by GC/MS. Result were showed that the nitrogen had significant effects on vegetative traits, quantity and quality of essential oil and finally on efficiency of nitrogen usage. With increases of nitrogen rate the vegetative traits and its yields of essential oil were increased. The effect of UAN was higher than U and SA, however, the trend of nitrogen usage efficiency was descended with AS of the lowest efficiency at 280 kg.ha-1. The rate and type of nitrogen fertilizers were also effective on essential oil components. The highest content of menthol was obtained in controls (37.16%) with 70 kg.ha-1 nitrogen (38.44%) but with increases of nitrogen application the menthol rate was decreased. Additionally, U and AS were respectively had the highest and lowest impact on menthol content, but in other hands the UAN application had the lowest content of menthofuran (1.17%).

In order to study the effect of drought stress on growth of new hybrids of maize an experiment was carried out at Safi Abad Agricultural Research Center, Dezful, Iran. The experiment was arranged as a split plot in a randomized complete block design with three replications. Treatments consisted of four levels of drought stress (irrigation after 75(±5) (Control), 95(±5) (mild stress), 115(±5) (moderate stress) and 135(±5) mm (severe stress) evaporation from a Class-A pan as main plots and three hybrids of corn (SC704 late-maturing hybrid as local check, Karoon late-maturing hybrid and Mobin medium-maturing hybrid) as subplots. Based on the results, the highest grain yields of 6570 and 6590 kg/ha were obtained under control and mild drought stress conditions, respectively, while the lowest grain yields of 5660 and 4280 kg/ha were obtained under moderate and severe drought stress conditions, respectively. Karoon and SC704 had the highest and the lowest grain yield of 6370 kg/ha and 5160 kg/ha, respectively. Karoon and Mobin hybrids had a greater ability to maintain their yield under drought stress conditions, compared to SC704. Drought led to increase in root depth and Mobin hybrid had the maximum root penetration of 26.6 cm. Drought stress also led to early maturity in the maize hybrids and plants of Karoon hybrid grown under drought were matured 5 days earlier than the non-stressed plants. Increasing the severity of drought led to decrease in dry matter yield by about 56.2 percent compared to control, indicating the key role of water availability in dry matter production. Moderate and severe drought stresses decreased the root dry weight by 4.8 and 9.7 percent, respectively, compared to control. Karoon hybrid had the highest harvest index of nearly 48 percent. Severe drought stress increased the protein content and Mobin hybrid had the highest protein content of 9.34 percent. According to the results, Karoon hybrid was matured 5 days earlier and had greater harvest index and grain yield compared to the control.

In order to study the redistribution response of photosynthetic assimilates of different spring bread wheat cultivars in different densities of wild oat, an experiment was conducted based on a strip block experiment with three replications at the Research Farm of Ramin Agriculture and Natural Resources University, Ahwaz, Iran during 2012. Treatments were four oat densities (0, 40, 80 and 120 plants m-2) in horizontal strips and 10 spring bread wheat cultivars (Chamran, Baz, Atrak, Arvand, Maroon, Shoeleh, Chenab, Veree/Nak and Falat) in vertical strips. Results showed that with increase in oat density up to 120 plants m-2, efficiency and percentage of the assimilates redistribution was increased, but current assimilates contributed less to the grain filling and grain yield. However, dwarf and early maturing cultivars of Veree/Nak and Atrak, with 2400 Kg ha-1 and Chenab with 2200 Kg ha-1 of redistribution appeared to benefit from an efficient transport system against the weed (wild oat). In contrast to the dwarf cultivars, the tall cultivar of Arvand with minimum assimilates redistribution of 600 Kg ha-1 and maximum amount of current assimilates of 3700 Kg ha-1 and also Shoeleh and Maroon were less dependent on their stem reserves at the grain filling stage.

In order to investigate the effect of water deficit on yield and morphological characteristics of four alfalfa cultivars an experiment was conducted as a split plot in randomized complete block design with 3 replications in Agriculture Research Center of Khuzestan, Ahwaz, Iran, during 201l-2012. Main plots included irrigation regimes (normal irrigation, irrigation at 50% available water content (AWC) depletion, 65% AWC depletion and 80% AWC depletion) and subplots were 4 cultivars of alfalfa (Baghdadi, Mesasirsa, Yazdi and Hamedani). The result of 5 cuttings showed that maximum hay forage yield was achieved under normal irrigation in all cultivars. The Baghdadi cultivar produced the highest hay yield at all irrigation treatments, though the hay yield decreased with delay in irrigation. The leaf/stem ratio increased by 22 percent when the cultivars where subjected to 50% AWC depletion. Stem height, LAI and the weight of single stem were decreased by delay in irrigation. Specific leaf area (SLA) decreased in all cultivars due to water deficit, though the extent of the decrease was greater for Baghdadi cultivar. The water deficit affected stem number in a cultivar-specific manner as it increased in Baghdadi and Mesasirsa cultivars and decreased in other cultivars. The Baghdadi and Mesasirsa appeared to be the most tolerant cultivars in Khuzestan conditions.

In order to study the effect of drought stress and soil compaction on corn growth an experiment was carried out in 2012 at Safi Abad Agricultural Research Center. The treatments were arranged in split plot in a randomized complete block design with three replications on 704 single cross hybrid corn. Drought stress was considered as the main plot at 4 levels (irrigation after 75, 95, 115 and 135 mm evaporation from A pan), and soil compaction was as the subplot at 4 levels (no traffic congestion, mild with four times, the average density with 8 times and the intensity density with 12 times of tractor traffic). Based on the results, the drought and soil compaction stresses affected many of the traits. The effects of drought and soil compaction were statistically significant on stem diameter, root deep, number of brace roots per plant, root and shoot dry weight, harvest index, number of ear bearing plants at harvest and grain yield characteristics. The effect of soil compaction stress was significant on root dry weight and reduced it. Only the effect of drought stress was significant on chlorophyll and protein characteristics. Brace roots growth in soil compaction stress conditions was stimulated and was higher than drought conditions. But grain yield was not affected by increasing the number of brace roots. Increase in soil compaction prevented root growth to depth. Conversely, the drought stress cause increased root growth to depth. Stresses weakened maize stem diameter with constant process. The constant processes were observed in reduction of shoot and grain yield dry weight by application of stresses. The drought stress more than soil compaction can affect chlorophyll and protein content of grain. This indicates the important role of water in the field. Drought stress was able to reduce the harvest index, but soil compaction in the most severe condition can reduce it. Both stresses reduced the number of ear bearing plants.

In order to study the effect of limited-irrigation stress on canola cultivars، an experiment was conducted in 2007-2008 at the Safiabad agricultural research center. The design was a split plot in a completely randomized block basis with three replications. Main plots were consisted of 4 levels of limited-irrigation، irrigation based on 60 mm cumulative evaporation (Control)، withholding irrigation in flowering stage، withholding irrigation in pod initiation and irrigation withholding in grain filling period، and subplots were 5 canola cultivars (Hyola308، Hyola330، Hyola401، Hyola420 and RGS003). The mean comparison of interaction showed that the highest (3155. 55 kg. ha-1) grain yield appointed to Hyola420 cultivar in optimum irrigation (control treatment)، and the lowest (1491. 66 kg. ha-1) belonged to RGS003 cultivar at withholding irrigation in pod initiation period. The maximum (161. 42) number of pods observed on Hyola330 cultivar at optimum irrigation (irrigation after 60 mm cumulative evaporation)، and the minimum (78. 1) ones appointed to RGS003 cultivar at withholding irrigation in pod initiation period. Results showed that there was no significant difference among withholding irrigation، cultivars and the interaction effect of them for oil content. By considering the results of this experiment، withholding irrigation at flowering، pod initiation and grain filling periods leads to decrease grain yield by 24. 72%، 14. 33% and 11%، respectively. Reduction of grain yield due to the withholding irrigation during flowering، podding and grain filling stages was along with a decrease in the number of pods per plant and thousand seed weight. By considering the results of experiment، withholding irrigation in flowering stage has to be avoided.

In order to investigate the effect of water deficit on yield and water use efficiency (WUE) of four alfalfa cultivars, an experiment was conducted as a split plot design in randomized complete block with 3 replications in Agriclture and Natural Resources Research Center of Khuzestan during 201l-2012. Main plots were 4 irrigation regimes (a1: traditional irrigation, a2: irrigation in loss of 50%, a3: irrigation in loss of 65% and a4: irrigation in loss of 80% AWC) and subplots were four cultivars of alfalfa (b1: Baghdadi, b2: Mesasirsa, b3: Yazdi and b4: Hamedani). The result showed that alfalfa total fresh and dry forge yield was significantly affect by water deficit, in all of the cultivars the highest of fresh and dry forage yield was in traditional irrigation that decreased with retardation of irrigation. The Baghdadi cultivar had the highest fresh and dry forage yield in all of irrigation regimes (in traditional irrigation: 75. 57 tn ⁄ ha fresh and 17. 5 tn/ha dry forage yield and in a4: irrigation in loss of 80% AWC this cultivar produced 45.86 tn ⁄ ha fresh and 11.15 tn ⁄ ha dry forage yield ).The water use efficiency increased with retardation of irrigation. The highest of WUE in all of cultivars were in a4: (irrigation in loss of 80% AWC) and the WUE in this treatment for Baghdadi cultivar was 1.00 kg/m3/ha , in mesarirsa cu. was 0.820 , in yazdi cu. Was 0.720 and Hamedani cu. Was 0.580 . The lowest rate of leaf/stem in all of cultivars belonged to traditional irrigation and with decreasing of irrigation to a2(irrigation in loss of 50% AWC) the rate of leaf/stem increased about 22% ( mean in all of cultivars).