فهرست مطالب محمدجواد بابایی زارچ

Due to the limitations of freshwater resources, using other sources, such as drainage and seawater, is inevitable for fodder production by halophytes. Salicornia species are the most salt-tolerant plants (Eu-halophytes) that grow directly in seawater. The plant shoots could be used with common fodder plants for livestock feeding. After oil extraction, Salicornia seeds contain 43% protein. The research objective was to select the most suitable Salicornia species in terms of yield and fodder quality in Bushehr Province.

To investigate the yield and nutritional value of Salicornia, this research was carried out on Salicornia bigelovii and four native ecotypes, including Bushehr ecotype (S. sinus persica Akhani), Central Plateau ecotype (S. persica Akhani subsp.Sersica), Urmiai, Gorgan and Markazi ecotypes at the Salinity Research Station of Bushehr Province. The area is characterized by a warm and wet climate with low annual precipitation (217 mm) and high annual average temperature (24.0 °C).A three-replicate randomized complete block design was used. The field was planted by seed sowing and irrigated with Persian Gulf water (60 dS m-1).Aerial plant samples were prepared at vegetative growth to determine the fodder nutritional value of different plant species and ecotypes. Values of aerial ash, crude protein, non-protein nitrogen content (NPN), acid detergent fiber (ADF), neutral detergent fiber (NDF), acid detergent lignin (ADL), and metabolizable energy were measured. At the end of the growing season, an area of one square meter was taken from each experimental unit to determine biomass dry weight. Data were analyzed using SAS software, and mean comparisons were performed using Duncan's test at the 5% level.

Results showed a significant difference in dry biomass between different Salicornia species and ecotypes. Bushehr, Central Plateau, Urmia, Gorgan ecotypes, and S. bigelovii dry biomass amounts were 18.29, 14.64, 4.22, 4.60, and 6.71 tons ha-1, respectively.The highest and lowest values of shoot ash were 54% and 46% of dry matter for Busher and S. bigelovii, respectively. There was no significant difference between species and ecotypes in crude aerial protein. The crude protein content of aerial varied between 6.9 in the Central Plateau and 8.6 in Bushehr ecotypes.The metabolizable energy of fodder was estimated between 5.17 and 5.74 MJ kg-1 of dry matter; the lowest and highest were attributed to the S. bigelovii and Urmia ecotypes, respectively. The highest and lowest cell wall indicators of neutral detergent fiber (NDF), acid detergent fiber (ADF), and acid detergent lignin (ADL) were related to the Gorgan and Bushehr ecotypes, respectively. Fodder gas production for different Salicornia species and ecotypes was significantly lower than for alfalfa during incubation. Among different species and ecotypes of Salicornia, the highest and lowest gas production rates were related to S. bigelovii and Urmia ecotypes.

To provide livestock fodder on the province's coasts, the Bushehr ecotype (Salicornia sinus persica Akhani) is generally recommended for planting due to its high yield and adaptability to the region. However, due to the relatively high ash content of the plant, only a part of the livestock feed could be provided by the plant fodder. Therefore, to properly use the plant fodder in livestock feed, it is necessary to determine the daily consumption of fodder in the ration.

Plants in arid and semi-arid regions are constantly exposed to environmental stresses such as salinity. The sensitivity of different plants to salinity stress at different growth stages is quite different. In many plants, perhaps the most sensitive stage of the plant growth cycle to salinity, is germination and emergence stages. Germination and emergence of seeds are the first important stages in plant establishment which is affected by most environmental stresses. In South Khorasan, which has saline soil and water, conventional millet cultivation is common, and it’s most important weeds are lambsquarters, tumble pigweed and purslane. Since the irrigation of millet fields in this region of the country is performed with saline water, this experiment was conducted out to investigate the emergence response of millet and lambsquarters, tumble pigweed and purslane weeds, under sodium chloride salinity in Hoagland solution.

In order to evaluate the effect of salinity stress on quality and emergence rate of common millet, lambsquarters, tumble pigweed and purslane, four separate experiments were conducted out in a randomized complete block design with three replications in 2017 in the research greenhouse of agricultural faculty at Birjand University. Experimental treatments consisted of 10 salinity levels including Hoagland solution with 2 dS/m as control, 4, 6, 8, 10, 12, 14, 16, 18 and 20 dS/m (created sodium chloride in Hoagland solution). Hoagland formula was used for preparation of nutrient solution and sodium chloride was used for preparation of different salinity levels. After filling each pot with 1.5 liters of acid washed sand, 25 seeds from each species were placed at 1 cm depth from soil surface. Seedling emergence were counted daily. In order to investigate the response of each species to salinity stress, the emergence percentage in each species was analyzed in a randomized complete block design without considering treatments with zero emergence percentage. Data analysis was performed using SAS software. GLM procedure was used for analysis of variance and comparison of mean performed with protected LSD at 5% probability level.

The results showed that common millet, purslane, tumble pigweed and lambsquarters seeds had the ability to germinate up to 20, 16, 12 and 12 dS/m, respectively. The start of emergence for common millet seeds up to 10 dS/m and tumble pigweed up to 8 dS/m was 3 days after sowing. Meanwhile, the seeds of lambsquarters emergence up to 6 dS/m on the fourth day, and purslane in 2 dS/m on the second day after sowing. Millet plants were emergence up to 18 dS/m salinity in the first five days after sowing. The results also showed that for common millet and tumble pigweed, no significant difference were observed for single seedling dry weight at 2 and 4 dS/m. Increasing salinity from 2 to 4 dS/m led to a significant decrease in purslane seedling dry weight but with increasing salinity stress from 4 to 8 dS/m, the reduction in seedling dry weight was not significant. In this study, with increasing salinity stress from 2 to 8 dS/m, dry weight of common millet, purslane, lambsquarter and tumble pigweed decreased by 55, 73.8, 80.7 and 79.5%, respectively. In this study, after ensuring that the seeds did not emerge, to determine the viability of non-emerged seeds, the pots were irrigated with distilled water. Under this condition, non-emerged millet seeds in the pots were not able to germinate at any levels of salinity stress. Purslane had no germination under salinity stress of 18 and 20 dS/m, but there were 34% and 62% emergence percentage respectively, when the salinity were terminated. Under mild stress, the percentage of germinated purslane seeds was 18% after recovery, which decreased with increasing salinity up to 12 dS/m and then increased.

In general, the results showed that salinity stress caused a change in the emergence behavior of millet and purslane, tumble pigweed and lambsquarters weeds. Common millet had the ability to germinate at all levels of salinity stress, but tumble pigweed and lambsquarters had the potential to emerge up to 12 dS/m and for the purslane up to 16 dS/m. Also, with increasing salinity stress from 8 to 16 dS/m, dry weight of seedling of common millet, purslane, tumble pigweed and lambsquarters decreased by 66, 82, 100 and 100 percent, respectively. At the end, the results showed that occurrence of salinity stress and its removal, the purslane seeds had a greater ability to keep their viability, whereas the common millet seeds completely lost their viability.

Many arid and semi-arid agricultural areas are facing with shortages of water and nutrients, especially micronutrients. Drought stress is one of the most important environmental stresses that seriously damage the growth and development of crops, limits the production and productivity of plants more than any other environmental factor. The use of micronutrients can partially alleviate the negative effects of this environmental stress on the growth and production of crops. Iron micronutrient plays an essential role in some biological and physiological processes such as respiration, photosynthesis and chlorophyll biosynthesis and is also effective in diastases as well as in chlorophyll production. According to the above, the main purpose of this experiment was to investigate the growth response of Roshan cultivar to applying iron sulfate fertilizer in different moisture conditions and to investigate changes in the content of some plant elements under these conditions.

In order to evaluate the growth and uptake of iron and other nutrients by wheat, cv. Roshan, a two-factor factorial experiment was conducted in 2012 in the Research Greenhouse of the Faculty of Agriculture, University of Birjand. The first factor was consisted of four different levels of ferrous sulfate (0, 50, 100 and 150 mg.kg-1 soil) and the second factor included two soil moisture treatments including 50 and 100% soil field capacity. After preparing the pots and applying experimental treatments, the seeds were planted and after emergence, the plant density was set to 10 plants in the pot. Moisture levels were applied from the beginning of experiments and watering the pots was done daily based on the weight of the pots and taking into account 20% drainage of soil moisture (in each irrigation treatment). Sampling was done after 8 weeks (early stem elongation stage) and at this time some morphological traits (number of leaves, leaf area, number of tillers and plant height) and the SPAD index and relative water content of leaves were measured. The iron, potassium, nitrogen and protein contents of the plants were also determined for each pot separately. Analysis of variance was performed using SAS software and mean comparison was performed using FLSD test at a significant level of 5%.

As soil moisture decreased from 100 to 50% of field capacity, plant height (5.8%), number of stems (37%), number of leaves (22%), stem diameter (15.8%), leaf area (33%), relative leaf water content (16.8%) and SPAD index (5.45%) decreased. The results also showed that in the control treatment (without iron fertilizer), the highest amount of SPAD index (38.8) was obtained, which with an increase of ferrus sulfate to 150 mg.kg-1 of soil, it decreased by 5.8%. Also, with the increase in soil water content to 100% of field capacity, the percentage of protein, nitrogen and potassium of wheat plants decreased by 9.2, 17.18 and 23.7%, respectively, compared to 50% of field capacity. The iron content of leaf in 100% of the field capacity was equal to 142.7 mg.kg-1 dry matter, which decreased by 27% by reducing the soil water content to 50% of the field capacity. Increasing the iron fertilizer from zero to 50, 100 and 150 mg.kg-1 soil caused the leaf nitrogen percentage to increase by 5, 9.5 and 7.2%, respectively. Leaf iron content in these levels of iron fertilizer was 35.8, 97.8 and 57.8% higher than the non-use of iron sulfate, respectively. Finally, biomass production was reduced by 31% compared to 100% of field capacity and finally water use efficiency was not affected by any of the experimental treatments. Finally, the watering at 50% of field capacity decreased the biomass production by 31%, compared to the 100% field capacity, and the water use efficiency was not affected by any treatments.

In general, the results of this experiment showed that with decreasing soil moisture level, a decrease occurs in the amount of plant dry matter. Increasing the level of ferrous sulfate only led to an increase in the leaf nitrogen and also a 100% increase in the iron content of the leaves, which in turn can play a role in improving drought resistance.

The cultivation of crops in most parts of the world, in addition to competing with different weed species, is affected by a variety of environmental stresses, including salinity stress. The changes in the growth rate and production of crops under the influence of salinity stress and competition with weeds have been extensively studied. However, what is currently less investigated is the competition of several species of weeds with crops and the competition of crops with weeds under salt stress. Therefore, the aim of this experiment was to evaluate the competition between tumble pigweed, common purslaneand and common millet under soil salinity stress. This study was conducted as a factorial experiment based on a randomized complete block design with three replications. Experimental treatments consisted of two rates of soil salinity (3 and 10 dS.m-1), and different ratios of interference of the three species (tumble pigweed, common purslaneand, millet) including 0-0 -100, 0-25-75, 12.5-12.5-75, and 25-0-75, 50-0-50, 25-25-50, 0-50-50, 75-0-25, 37.5-37.5-25, 0-75-25, 0-100-0, 50-50-0 and 0-100-0. The desired density in each pot was constant and equal to 8 plants. After preparing the soil and passing through a 2 mm sieve, fertilizer and saline solutions were added to the soil and the soil was transferred to 5 kg pots. Then all three plants were planted and attained to intended density at the four leaf stage. At the end of the experiment, each plant species was separately harvested from each pot and were weighed after complete drying. Finally, for analyzing the results of the experiment, relative yield indicators, total relative yield (Land Equal Ratio), relative crowding and agressivity indices were used. The results showed that increasing soil salinity decreased the dry matter produced by common millet, tumble pigweed and common purslane by 19.5, 4.7 and 27.8 percent, respectively. Comapring the relative yield of millet with those of tumble pigweed and common purslane and also both weeds together by different ratios of planting showed that these values were more than predicted ones under either 3 or 10 dS.m-1 salinity level, which indicates the weak competitive ability of these two weeds against millet. The results of the relative crowding index of species showed that in the ratio of 75% of millet and 12.5% tumble pigweed and 12.5% of common purslane, the greatest rate of relative crowding index was achieved for millet under salinity level of 3 dS.m-1. Also, the greatest relative crowding index of tumble pigweed and common purslane under either salinity level was observed with the cultivated ratio of 75% for both weeds and 25% for millet, suggesting an increased competitive ability of these two weed species through increasing their density even under a higher level of soil salinity. By evaluating the agressivity index between tumble pigweed and purselane, it was found that this value was negative for purselane under the salinity level of 3 dS.m-1. Therefore, it seems that tumble pigweed is more competitive than the common purslane where both weed species grow together. In general, the results of this study showed that in conditions of salinity of 3 and 10 dS.m-1, common millet had more competitive ability than the two studied weeds, but with increasing salinity level, competitive ability of millet was reduced, while it increased weeds competitiveness. Therefore, in the situation of high weed densities, we may expect a greater damage to crops under salinity stress.

Grass pea is an annual plant which produces adequate yield in unfavorable conditions. South Khorasan is one of the areas where grass pea cultivation has been spread, but due to rainfall rate and high evaporation and transpiration in this region, plants are facing drought stress; On the other hand, Amaranthaceae family weed (pigweed and tumble pigweed) also among the most important weed in farm fields in this region of Iran. Since the studies of multi-species competition provide more detailed information about relationships circumstance between plants, the aim of this study is to evaluate the competitiveness of pigweed, tumble pigweed and grass pea under drought stress using experiments with replacement series. The experiment was carried out in a factorial based on RCBD with three replications. Experimental treatments consisted of two levels of water stress (80 and 50% of soil water field capacity), different weed interference ratios with grass pea (tumble pigweed + pigweed- grass pea) including (0-100, 75-25, 50-50, 25-75 and 100-0%), as well as different two weed interference ratios with each other (tumble pigweed - pigweed) containing (0-100, 50-50 and 100-0). Optimum density of eight plants per pot was fixed. Plants were cultivated after soil preparation and addition of chemical fertilizers and at four leave stage, the desired density was reached. At the end of the experiment, all plants were harvested from each species separately and weighed after drying. Finally, for results analyzing of the experiment, relative yield indices, total relative yield (LER) were used and relative competition Intensity index and aggressiveness index were used. The results showed that grass pea, pigweed and tumble pigweed dry matter, decreased with reducing soil water content of 80 to 50 % of field capacity by 33, 30 and 12 % respectively. Also, the results showed that predicted yield of tumble pigweed was close to the actual yield. The results of relative yields showed that in sowing ratio of 50-50% grass pea and pigweed, 50-50% of grass pea and tumble pigweed, also 50-50% of grass pea and both two weed together in 80% treatment of soil water field capacity, the relative yield of grass pea were 0.33, 0.36 0.39 respectively, that with drought stress increasing to 50% of soil water field capacity, increased by 36, 50 and 31% reached to 0.45, 0.54 and 0.51 respectively. Changes in relative yield curve of grass pea under 80% treatment of soil water field capacity irrigation, in competition with tumble pigweed, pigweed and both weeds together was convex; which indicates that with enough water in the soil, grass pea competitiveness is less than Amaranthaceae family weed. The results of relative competition Intensity index showed that numerical value of this index for grass pea, tumble pigweed and pigweed, in all sowing ratios is a positive value, which shows higher inter-specific competition than intra-specific competition in different sowing ratios. Also the results showed that in the sowing ratio of 50% grass pea with 25% tumble pigweed and 25% pigweed in 50% treatment of soil water field capacity, Grass pea aggressiveness index against both weed separately and together was positive value, which indicates a relative superiority of grass pea under drought stress in competition with these two weed. In generally, the results of this study showed that water stress reduced all three plants growth but, decline in tumble pigweed was lower. The results also showed that the competition formed between these three species was Inter-specific and have negative effects on all three plants. Although the aggressiveness index indicates that the grass pea was beaten in most sowing ratios, but with the increase of drought stress and water deficit, due to inter-specific competition between weed, competition between weed and grass pea has been reached to lowest level.

Salinity is one of the most important abiotic stresses that cause severe effects on crop production around the world. Estimates indicate that more than 800 million hectares of arable lands in the world are affected by salinity. Salinity impacts on various aspects of growth from germination to seed production in plants. Plants′ responses to salinity, however, are different and depend on the toxicity, osmotic potential, as well as the stress duration. Purple nutsedge (Cyperus rotundus L.) is one of the noxious weeds. This weed belongs to sedge family, and is a C4 perennial plant which reproduce by sexual (seeds) and asexual (tubers and rhizomes) means. It can cause tremendous damage on summer crop fields such as onion, potato, maize, sunflower, and so on. Evaluation of weed growth responses to saline condition came about by water and soil can provide for us very important information by which we choose appropriate weed control strategies. Since a few experiments have been evaluated growth characteristics of purple nutsedge under salinity stress, this study was conducted to evaluate the salinity effects on growth characteristics of purple nutsedge.
Material and To evaluate the effect of irrigation water and soil salinity on growth characteristics of purple nutsedge, two separate experiments were conducted in a randomized complete block design with three replications in the greenhouse of Faculty of Agriculture at University of Birjand in 2013. The first experiment contained five salinity levels of water including 0, 3, 5, 7 and 9 dS.m-1 and in the second experiment, there were five salinity levels of soil including 1, 3, 5, 7 and 9 dS.m-1. The salinity levels of water were prepared through solving a certain amount of NaCl in water based on this equation: NaCl (mg. L-1) =EC (dS.m-1)×640.. Following determination of soil electrical conductivity, soil salinity levels were prepared by adding NaCl to the soil based on saturation moisture percent and field capacity. A tuber of purple nutsedge was planted at 2.5 cm depth in each pot. Experiments were terminated at the end of the vegetative growth stage of purple nutsedge (105 days after emergence). Measured traits were plant height, stem number per pot, leaf area, and tuber number per pot, shoot and underground dry weight. After collecting the data, ANOVA was performed using Genstat Ver. 9 and mean comparisons were performed using Fisher's least significant difference test at 5% significant level. In order to evaluate purple nutsedge growth response to salinity stress, an exponential decay model was used; Y=a*exp(-b*x), thta in this model, a and b represents the maximum amount of studied traits and the slope of curve according to the model estimation, respectively.
The results of both experiments showed that the growth characteristics of purple nutsedge (plant height, stem number per pot, leaf area, tubers number per pot, shoot and underground dry weight) were significantly affected under soil (P

In order to evaluate the effect of tumble pigweed competition on yield, yield components and seed quality of six cultivars of sunflower; an experiment was conducted with factorial layout based on a completely randomized block design at the research farm of College of Agriculture, University of Birjand in 2012. The factors were four weed densities (0, 5, 10 and 15 plants/m2) and six cultivars of sunflower (Azargol, Jame Isfahan, Syrna, Farrukh, Progress and Euroflour). The results showed that by increasing weed density, yield and yield components of sunflower were decreased. By increasing weed density from zero to 15 p.m2, grain yield of sunflower was decreased up to 40.2%. Jame Isfahan cultivar produced the highest seed yield (5.789 kg/ha), and Farrukh cultivar had the least percentage of seed yield loss in weed density of 15 p/m2. Generally, Progress, Euroflour and Jame Isfahan cultivars had the most competitiveness and Azargol cultivar showed the least competitiveness against tumble pigweed.

IntroductionDrought stress is one of the most important abiotic stress that leads to decreasing yield of crops, particular cereals, not only in Iran but also around the world. Accessing to sufficient nutrients like potassium is one of the ways that increase crop resistance. Potassium is an essential element to growing plants. This element is a multitasking nutrient in plants that use in activation of enzymes, osmotic control, carbohydrate production and partitioning and anion cation balance. So because of Hulless Barley importance for human, animals and birds feed, drought expansion in Iran and around the world, importance of potassium element to decrease drought stress effects, metabolic process improvement and plant photosynthesis, an experiment to find out the effects of drought stress and potassium on yield and yield components of Hulless Barley conducted.
Materials and methodsTo find out effects of different irrigation regimes and different amounts of potassium on yield and yield components of Hulless Barley, a split plot experiment based on randomized complete block design with three replicates was conducted at the Research Farm of Islamic Azad University, Meybod Branch in 2012. Each block was consist of 3 main plots and 4 sub plots in each main plot. Main plot was consist of irrigation cycles: 7 days irrigation (control), 14 days irrigation (moderate stress) and 21 days irrigation (extreme stress). Sub plot was consist of 4 levels nutrient elements: 0, 100, 200 and 300 kg.ha-1 potassium sulphate. Different potassium levels were applied before sowing. At the end of growing season, grain yield, straw yield, biological yield measured. Also Fertile tiller number, grain number per spike and 1000 grain weight of Hulless Barley measured as yield components.
Results and discussionResults showed that most yeild(3147.5 kg.h-1) and yield components achieved in 7 days irrigation cycle. Yield components decreased 12 and 43 percentage by increasing irrigation cycle to 14 and 21 days. Seed yield was 2761 and 1792 kg.h-1 at 14 and 21 irrigation cycle. Also potassium sulfate application improved agricultural characteristics and decreased negative effects of drought stress. Result showed that increase potassium sulphate application from 0 upto 300 kg.h-1 had significant effect on seed yield, but there was no significant difference between 200 and 300 kg.h-1 application. Maximum harvest index (36.1%) achieved at 200 kg.h-1 potassium sulphate applications. Minimum harvest index (32%) achieved at 0 kg.h-1 potassium sulphate applications. Maximum fertile tillers (1.2) was in 7 days irrigation cycle 200 kg.h-1 potassium sulphate applications and minimum fertile tiller was in 21 days irrigation cycle 200 kg.h-1 potassium sulphate applications. In 7 days irrigation cycle and 14 days irrigation cycle, 100 kg.h-1 potassium sulphate applications caused to increasing fertile tiller number. More potassium sulphate application had no significant effect on fertile tiller number. Also results showed that increase potassium sulphate application from 0 upto 100 kg.h-1 lead to increasing grain number per spike from 26.6 to 31. Among different amounts of potassium suphate application, no potassium sulphate application treatment had the lowest (30.9 gr) 1000 grain weight and 300 kg.h-1 potassium sulphate applications had highest (34 gr) 1000 grain weight.
ConclusionResults showed in no water limitation condition recommended 7 days irrigation cycle for maximum yield. Results showed Hulless Barley can tolerate moderate water stress, so in water limitation condition 14 days irrigation cycle application can suggest for achievement acceptable biological yield of Hulless Barley. According to this experiment results, potassium nutrition can improve yield characteristics in water limitation. There was no significant difference between 200 or 300 kg.h-1 potassium sulphate application, so for reduce negative enviromental effects, 200 kg.h-1 potassium sulphate application can suggest for achievement acceptable yield of Hulless Barley.

IntroductionUsing crop species and cultivars with high competitive ability against weeds is one of the effective strategies for sustainable weed management. Emergence rate, rapid root growth, seed vigor, development rate of leaves, rapid root and shoot biomass accumulation, rapid canopy closure and plant height are important traits in relation to the competitiveness between different cultivars of crops. Competitive ability is measured using two indices including the weed growth prevention ability or weed biomass reduction index and crop tolerance to weed or yield reduction preventing index. The purpose of this study is to evaluate the competitive ability of six oilseed sunflower (Helianthus annuus L.) cultivars and also introducing the most important morpho-physiological attributes affecting their competitive ability with tumble pigweed (Amaranthus albus L.) in Birjand.
Materials and methodsThis experiment was carried out as factorial layout based on randomized complete block design with three replications at the Agricultural Research Station, University of Birjand in 2012. Treatments were included six sunflower oilseed cultivars (Azargol, Jame esfehan, Farrokh, Syrna, Progress, Euroflor) and tumble pigweed densities in four levels (zero (control), 5, 10 and 15 plants per square meter). The number of days and cumulative degree days were recorded from sowing to emergence. Plant height, leaf area and dry matter were recorded at four stages from emergence to 75 days after it. Sunflower seeds were harvested after physiological maturity. Preventing indices were used to evaluate the competitive ability of cultivars, competitive tolerance (Watson et al., 2002) and weed biomass. Data were analyzed with the SAS software and cluster analysis was performed using SPSS software. FLSD test was employed for comparison of the means at the 5% significance level. The graphs were prepared by Excel.
Results and DiscussionAnalysis of variance showed that there was a significant difference between the sunflower cultivars for Competitive Index (P≤0.01). While, different densities of tumble pigweed had no significant effect on Competitive Index. However, the interaction effect between sunflower cultivar and tumble pigweed density was significant on this index (P≤0.05). The highest competitive ability index (1.6) was obtained in the Jame Esfehan cultivar, Followed by Euroflour, Azargol, Progress, Farrukh and Syrna cultivars. Although weed biomass decreased index was not affected by weed density, it increased by 11% with enhancing weed density from 5 to 15 plants m-2. In this study, tolerance index was significant only by the effect of weed density (P≤0.01). In general tolerance index increased by 13.3 and 39.03 percent by increasing the weed density from 5 to 10 and 15 plants m-2. This index for 5, 10 and 15 plants m-2 of weed densities were 127, 144 and 177, respectively. The results showed that rapid emergence and height increasing rate at first 53 days after planting and leaf area development rate between 17 to 53 days after planting were the most important effective factors that increase sunflower competitiveness against tumble pigweed.
ConclusionIn general, Jame Esfehan cultivar had the greatest competitive ability against tumble pigweed due to a rapid emergence, height increasing and leaf area development rates at 24 days after planting. Progress, Azargol, Euroflor and Farrokh cultivars had medium competitive abilities. Syrna had a weak competitive ability due to late emergence, as well as low rates of height increasing and leaf area development
In order to evaluate the competitiveness of some sunflower cultivars against tumble pigweed, a factorial experiment based on completely randomized design was conducted at the research farm of College of Agriculture, University of Birjand in 2012. Experimental factors included four different weed densities (0, 5, 10 and 15 plants m-2) and six cultivars of sunflower (Azargol, Jame Esfahan, Syrna, Farrukh, Progress and Euroflor). The results showed that rapid emergence, the rate of plant height enhancement at 53 days after planting and the rate of leaf area expansion during 17 to 31 days after planting were the most important effective traits for improving the competitive ability of sunflower cultivars against the tumble pigweed plants. In general, Jame Esfahan was the resistant cultivar, Azargol, Euroflor, Farukh and Progress were semi-resistant cultivars, and Syrna was the non-resistant cultivar against tumble pigweed plants.

Using the genetic diversity of crop cultivars to improve crop resistance against various biotic and abiotic stresses is effective way to develop sustainable agriculture. Therefore¡ aimed to investigate the effect of cultivar type as well as introduce the most important traits related to competitive ability of sunflower cultivars against tumble pigweed¡ a factorial experiment with three replications was at the agricultural research station¡ University of Birjand during 2012. Experimental treatment included six cultivars of oily sunflower (Azargol¡ Syrna¡ Farukh¡ Jame Isfahan¡ Progress and Euroflor) and two different densities of tumble pigweed (zero and 15 plant/m2). ANOVA results showed that there was a remarkable genetical diversity among studied cultivars and significant reductions in studied traits values observed where tumble pigweed was present. Moreover¡ there were significant positive correlations between traits such as leaf area index¡ plant height¡ the rate of leaf area and height development¡ relative growth rate¡ seed yield¡ etc. with the tolerance index. Factor analysis also identified 5 factor groups which justified 79% of the variations. Overall¡ Jame Isfahan showed the greatest competitive ability against tumble pigweed compared with other studied cultivars.

Water is one of the most important factors for plants growth and development and both weeds and crops compete for it. To investigate the influence of drought stress on competition between grass pea and pigweed, a greenhouse experiment was conducted as randomized complete block design with three replications based on replacement series arrangement at Faculty of Agriculture, University of Birjand in 2012. Treatments were different planting ratio of grass pea– pigweed (100-0, 75-25, 50-50, 25-75, 0-100%) and four water regimes (100, 75, 50 and 25% soil field capacity, FC). Results showed that a reduction of soil water content from 100 to 25% of FC (pot) caused a 95% (P <0.01) in dry matter production of both species in their pure cultivation. The relative yield index, relative invasion index and relative dominance index of these species indicated that, where both plants were competing, pigweed was more competitive than the grass pea at high soil moisture levels (100 to 50% of the soil (pot) field capacity). Although with further soil water reductions to 25% of field capacity, grass pea showed the superiority over wild amaranth, it seems that growing grass pea is not economically justifiable under these circumstances.

Appropriate selection of donor parent for breeding purposes needs sufficient knowledge about genetic diversity and germplasm classification. In order to investigation and classification of genetic diversity in 35 wheat (Triticum aestivum L.) genotypes، an experiment was conducted in University of Shahed based on randomized complete block design with 2 replications in 2009. In persent study 15 morphological characteristics such as days to 50% of flowering، plant height، number of stems per plant، number of productive tiller، number of internode، length of flag leaf، width of flag leaf، leaves angle، peduncle length، flag leaf distance to spike، spike length، number of grain per spike، awn length، 1000 grain weight and grain yield per plant were evaluated. The analysis of variance for all the traits indicated significant difference between studied genotypes (P<0. 01). Range and correlation analysis between traits، showed considerable genetic variation among studied genotypes. Cluster analysis via Ward method for field data، classified all genotypes in four groups. The ANOVA analysis showed significant difference among the clusters for leaves angle. Factors analysis، extract 5 factors that be able to describe nearly %75 of total variance.

Agricultural production in arid and semi-arid regions always is affected by soil salinity and weeds competition. In order to study the effect of soil salinity on competition between wheat and rye, a factorial replacement series experiment based on completely randomized design with 3 replications was conducted in research greenhouse of faculty of Agriculture, at University of Birjand, in 2012. Four different ratios of wheat-rye (100-0, 75-25, 50-50, 25-75, 0-100 percentage) and 4 levels of soil salinity (2, 4, 8 and 16 dS.m-1) were used as experimental factors. The results indicated significant (P<0.01) effect of salinity on dry matters of wheat and rye. Increasing soil salinity from 2 to 16 dS.m-1 decreased 84% and 90% of the dry matter of rye and wheat, respectively. Competitive ability were more at salinity levels of 2 and 4 dS.m-1 in rye and 8 and 16 dS.m-1 in wheat. Investigation of competition by several indices indicated that increasing of salinity level can decrease competitive ability of rye versus wheat.

Appropriate selection of donor parent for breeding purposes needs sufficient knowledge about genetic diversity and germplasm classification. In order to investigation and classification of genetic diversity in 35 wheat (Triticum aestivum L.) genotypes، an experiment was conducted in University of Shahed based on randomized complete block design with 2 replications in 2009. In persent study 15 morphological characteristics such as days to 50% of flowering، plant height، number of stems per plant، number of productive tiller، number of internode، length of flag leaf، width of flag leaf، leaves angle، peduncle length، flag leaf distance to spike، spike length، number of grain per spike، awn length، 1000 grain weight and grain yield per plant were evaluated. The analysis of variance for all the traits indicated significant difference between studied genotypes (P<0. 01). Range and correlation analysis between traits، showed considerable genetic variation among studied genotypes. Cluster analysis via Ward method for field data، classified all genotypes in four groups. The ANOVA analysis showed significant difference among the clusters for leaves angle. Factors analysis، extract 5 factors that be able to describe nearly %75 of total variance.