Iranian Journal of Field Crop Science
Year:2018 | Volume:48 | Issue:4 |Papers Count:28

In order to study the effect of mycorrhiza and bradyrhizobium on yield and yield components of soybean under different amounts of starter nitrogen fertilizer, a field experiment was conducted at the agricultural research station, Bu-Ali Sina University in 2015 growing season. A factorial experiment based on randomized complete block design was arranged with three replications. Experiment factors included three levels of starter nitrogen fertilizer including 0, 30 and 60 kg ha-1, bradyrhizobium including inoculated and non-inoculated and mycorrhiza including application and non-application. Results indicated that plant height, number of leaves per plant, yield and yield components and biological yield of soybean and mycorrhizal colonization percentage affected by interaction of studied factors. At all levels of starter nitrogen, interaction between bradyrhizobium and mycorrhiza increased number pod per plant and 1000 seed weight. Application of 60 kg ha-1 nitrogen decreased colonization percentage by 20. 22 % compared to no application nitrogen treatment. Application of both bio-fertilizers with 30 kg ha-1 nitrogen gave the highest grain and biological yields (511. 67 g m-2 and 1223. 16 g m-2 respectively). So to improve soybean performance and reduce the nitrogen fertilizer consumption, it is recommended that both fertilizers to be taken simultaneously with 30 kg ha-1 nitrogen as starter.

In order to graphical analysis and estimation of genetic parameters for yield and its components, a oneway diallel cross was applied with seven bread wheat genotypes. In this study, 21 hybrids along with their parents were evaluated in a randomized complete block design with three replications. The results of variance analysis showed significant difference among genotypes for plant height, peduncle length, spike length, the number of seeds per plant, plant grain yield, and 1000-grain weight. The results of Jinks and Hayman primary test showed that assumptions for the number of seed per plants and plan grain yield were authentic, but it was true for spike length, peduncle length, and 1000-grain weight after eliminating one parent and for plant height by eliminating two parents. The results of Hayman analysis showed the role of additive and non-additive effects of genes on the control of traits. Maximum and minimum of narrow-sense heritability were obtained for plant height (0. 47) and the number of seeds per plant (0. 21), respectively. According to the average degree of dominance and the results of the graphical analysis, the gene action for grain yield and plant height was additive effects, while it was over-dominance for peduncle length, the number of seeds per plant, spike length and 1000-grain weight.

The use of superabsorbent polymers is one of the effective solutions to increase water use efficiency and optimal use of rainfall in arid and semi-arid areas. In this study the effect of different levels of superabsorbent STOCKOSORB is investigated on wheat yield and yield components under rainfed and irrigated conditions. For this aim, an experiment was conducted in the Research Field of Agriculture Faculty, Tabriz University, in the growing season of 2015-2016, in which the superabsorbent STOCKOSORB was applied at three levels of 0, 50, and 100 kg/ha. Based on obtained results, application of superabsorbent at 100 kg/ha increased the seed yield and water use efficiency of both rainfed and irrigated wheat farming significantly. The application of 50 kg/ha increased rainfed wheat yield but not irrigated wheat yield, significantly. Results showed that the effect of superabsorbent on yield and water use efficiency in irrigated wheat was larger than rainfed wheat. Also, the effects of superabsorbent application were significant in rainfed conditions at treatment of S1 (increase of water use efficiency equal 25. 9 percent) and in irrigated wheat at treatment of S2 (increase of water use efficiency equal 19. 2 percent). Due to ratio of the increasing benefit as a result of yield increase to cost, application of superabsorbent is not recommended in wheat farming.

Water deficit is one of the most important factors limiting crop production including soybean. In order to evaluate and identify water deficit tolerant soybean genotypes, 40 soybean genotypes were evaluated in a randomized completely block design (RCBD) with three replications. This study was carried out under both normal and water deficit conditions, in 2015 on the research field of Seed and Plant Improvement Institute-Karaj. MP, GMP, HARM and STI indices which demonstrate the most significant correlation with grain yield in normal and water deficit stress conditions were introduced as the best indices for screening tolerant genotype. Based on biplot graph of first and second principal components, the D42×Will82, Spry×Savoy/3, Chaleston×Mostang/12 and Liana×L32/2 genotypes were introduced as water deficit tolerant genotypes with high grain yield in normal condition and GN 2171, GN 2167, GN 2087 and GN 2011 genotypes were selected as sensitive genotypes to water deficit stress. Based on the result of cluster analysis using MP, GMP, HARM and STI indices and grain yield under normal and water deficit stress condition genotypes were classified in four clusters which the most of tolerant genotypes to water deficit stress were located in the first and second clusters and the most of tolerant genotypes to water deficit stress were located in the first and second clusters and the most sensitive were grouped in the third and fourth clusters. The result of cluster analysis can be valuable in order to selection of genotypes with high genetic distance as parents for hybridization and development of segregating population with maximum variations.

This study was conducted to optimizing of in vitro culture of Arbuscular Mycorrhizal Fungi (AMF) on in vitro root and petiole and greenhouse petiole and stem of carrot. Carrot seeds were disinfested and cultured on MS medium and pot. Four weeks old of in vitro root and petiole and 3 months old of greenhouse petiole and stem were inoculated with Rhizobium rhizogenes MSU, 15834 and A4 strains and cultured on MS medium. The effects of bacterial strain and explants type on hairy root production were studied. After the elimination of bacteria, growth rate of hairy roots obtained from each explants were measured in factorial experiment with completely randomized design with three replications and three explants in each replicate. Molecular confirmation of hairy roots induction and bacterial strains were performed using specific amplification of rolC gene in PCR reactions. The results showed that all bacterial strains could initiate hairy root production. Transgenic roots were thicker, more branches and higher growth rate compared to normal roots. 15834 bacterial strain and greenhouse petiole and in vitro root explants demonstrate the highest ability in hairy root production. The highest growth of hairy roots were observed in greenhouse stem explant with MSU bacterial strain.

This study was conducted to quantify germination response of onion (Allium cepa) to temperature. For this purpose, seeds were exposed to various constant temperatures (5, 10, 15, 20, 25, 30, 35 and 40º C) treatments in seed lab, on Tehran university, in 2015. The effects of temperatures on rate and percentage of germination was significant. With temperature increasing from 5 to 30º C, both germination percentage and rate increased, while it decreased with increasing temperature from 30 to 35º C. Cardinal temperatures of seed germination were estimated by using four regression models including dent-like, segmented, beta modified and beta Models. The best model for estimating cardinal temperatures was dent-like and beta modified models that by used dent-like model the base, under optimal, upper optimal and ceiling temperatures were 0. 3, 24. 99, 33 and 35. 89 ° C, respectively, and following beta modified model, the base, optimal and ceiling temperature were 0. 2, 26. 87 and 35. 51° C. For predicting time of germination at different constant temperatures used Thermal-time was used that constant coefficient of Thermal-time was 3191. 43 (° Cd).

In order to evaluate the influence of two different cultivation methods included of Entezari and spring planting a one year study (2014-2015) was carried on in Rozveh agricultural research station (Chadegan-Esfahan) using the split plot, based on a randomized complete block design with four replications. Two methods of planting included of Entezari and spring were considered as the main plot and three new varieties of chickpeas (Hashem, Azad and Arman) and local control were subplots. The yields of Arman, Azad and Hashem varieties in spring planting were 1220, 1070 and 1010 kg ha-1, respectively, which significantly was higher than the native cultivar (702 kg ha-1). Azad cultivar in Entezari planting method with 1709 kg ha-1 grain yield, relative to the native varieties and also than the Arman and Hashem had significantly higher performance. In spring and Entezari planting, water use efficiency was in the range of (0. 39 to 0. 67), and (0. 15 to 1. 5) kg seed m-3, respectively. The use of all three new varieties of chickpea for spring planting and Azad cultivars for autumn planting in the experimental region (and similar areas) was superiority and could have important role in increasing water use efficiency.

Nutrients management, especially nitrogen, influences the weed-crop competition. Thus, to evaluate the effect of nitrogen and weed interference on yield and yield components of winter barley (Hordeum vulgare L. Var. Makoei), a field experiment was arranged as split-plot based on randomized complete block design with three replications at the Research Farm of the Faculty of Agriculture, University of Tabriz, Iran. The treatments included four levels of nitrogen (0, 40, 60 and 120 kg ha-1) and 10 weed interference periods in two sets (weed free and weed infested periods), that allocated to the main and subplots, respectively. Results indicated that increasing nitrogen supply increased spikes per area, grain and biological yields and decreased grain number per spike. Weed interference had significant effect on number of spike per m2, grain number per spike, and grain and biological yields. Increasing duration of weed interference led to significant decrease of spikes per m2, biological and grain yields of barley. Based on the results of this research, spike number per m2 was the most sensitive yield component of barley to nitrogen deficiency and weeds interference. Generally, by application of nitrogen up to 80 kg ha-1 and better weeds management by reducing duration of weed interference in barely, high performance in this crop can be obtained in similar conditions.

To evaluate the effect of pre-planting cover crop and nitrogen application on some qualitative traits and yield of two forage maize varieties, an experiment was conducted at Tehran University to form of split plot in a randomized complete block design in three replications. Assessed factors included pre-planting vetch as main plots in three levels (fallow (or not Planting), planting of vetch as fodder and planting of vetch as green manure), nitrogen fertilizers as sub plots at three levels (zero, 50 and 100 percent of the recommended amount) and maize varieties as sub-sub plots at two levels (Simon and ZP677 var. ), respectively. The studied traits consisted of percent of dry matter digestibility (DMD), water-soluble carbohydrates (WSC), crude protein (CP), crude fiber (CF), ash, NDF, ADF, protein yield (Kg/ha) and dry matter yield (Kg/ha) of forage maize. The results showed that the fallow treatment had significant effect on WSC% in comparison with green manure and fodder maize. The highest and lowest percent of ADF were observed in green manure and fallow respectively. Green manure and fallow had the highest and the lowest impact on NDF percent, respectively. NDF percent in 50% of recommended urea was the highest and zero percent of urea was the lowest. The highest and lowest percentage of CF was obtained in interaction ZP677 cv × pre-plant vetch as fodder and fallow × Simon cv respectively. In relation to the protein yield, interaction green manure × %100 urea and fallow × %0 urea had the highest and lowest amount respectively. Pre-planting vetch can be affected some quality traits and yield of the next crop. In general, application of cover crop along with nitrogen fertilizer for forage corn production can have favorite effects on qualitative traits.

This experiment was done to evaluate the effects of soil tillage methods on chemical and biological properties of the soil along with quantitative traits of silage corn after chickpea as a preceding or companion crop. The experiment was conducted for two cropping years of 2013-15 at farm of Tehran University. The experiment was set up as a split plot in RCBD in four replications. The main factor considered three soil tillage methods (conventional, minimum and no-tillage) and the sub-factor included three varieties of maize (SC704, Zp677, Maxima). The experimental units covered by chickpea residue by at least 30 percent of the surface area. Results showed that the no-tillage and minimum tillage treatments had higher amount of soil organic carbon, pH and number and body mass of earthworm than the conventional tillage treatment. Tillage treatments had no significant effect on total nitrogen, electrical conductivity and sodium of measured soil. Also, the highest maize wet and dry stem weight (691. 5 and 1866. 5 gm-2), Ear dry weight (664. 4 gm-2) and total plants wet weight (4896. 9 gm-2) observed in Zp677 maize cultivar. Conventional and minimum tillage methods had significant effects on leaf and ear wet and dry weights and total plant dry weight traits. Thus, in the 2nd year of this experiment, no-tillage was more effective than other tillage methods. But, there was no significant effect between no-tillage and conventional tillage treatments in the second year. According to the results, both conservation tillage methods is recommended as replacement methods for conventional tillage in maize/chickpea rotation.

For evaluation and grouping of 150 inbred lines of rice based on some morphological and physiological traits, an experiment was conducted using Augment design based on randomized complete block design (RCBD) with four replications in Agricultural College of Guilan University, in 2013. Correlation coefficients between traits showed a significant correlation between grain yield with almost all of traits. Factor analysis showed that four independent and main factors explained 94. 23 percent of total variance in all lines. The first factor with 51. 99 percent of variance was named as the yield components and fertility rate. The second factor with 25. 41 percent of variance was nominated as fertility rate, the yield and the yield components. The third factor with 11. 50 percent of variance was nominated as physiologic traits. The fourth factor with 5. 33 percent of variance was nominated as plant morphologic. Cluster analysis by ward method with a 92. 7 percent of original grouped cases correctly classified four distinct groups for studied lines. Finally, to select high-yielding lines and tolerate to drought stress in rice simultaneously selection can be carried out for traits such as number of total spikelet per panicle, number of filled grain per panicle; spikelet fertility, proline content, chlorophyll a, chlorophyll b, total chlorophyll and relative water content.

Bulrush is one the most important weed of paddy rice. Pot and lab experiments were carried out in order to study some of its ecophysiological characteristics. In the first study, the effects of soil moisture (6, 12, 24, 34 percent based on soil dry weight, and permanent flood as control) on overwintering of bulrush tubers and its growth in following year was determined. In the second experiment, the cardinal temperatures required for tubers germination was investigated. The results showed that survival and overwintering of bulrush tubers in 6, 12 and 24 percent moisture was 10, 30 and 82 percent respectively, and fell sharply in higher humidity. In addition, the number and fresh weight of tubers and also length and fresh weight of bulrush rhizomes in 6% moisture was 100, 58, 70 and 92 percent lower compared to field capacity treatment (24 percent moisture level). The maximum germination occurred at 250C to 300C and the minimum germination at 40° C and the highest germination rate in 30° C. By considering the low survival rate and a considerable reduction in vegetative organs of bulrush in low soil moisture, drainage and tillage of paddy fields after the rice harvesting is a means of reducing overwintering populations and management of this weed. Minimum temperature required for germination of bulrush, compared with rice growing base temperature (12° C), and the growth of bulrush before transplanting rice, indicates well adoptability of bulrush to paddy rice ecosystems and the need to provide appropriate integrated solution for its management.

In order to simulate the effects of soil nitrogen and wheat straw mulch on weed infestation and yield of Dracocephalum moldavica; an experiment was conducted in 2014. The first factor was the amount of nitrogen in three levels including non-fertilization, and adding 50 and 100 kg ha-1 into the soil to create different levels of nitrogen in the soil and the second factor was mulch amount in four levels including: without mulch as a check, mulching with 1, 1. 5 and 2 kg m-2. A plot with hand weeding was also considered as a check. Biomass and density of broad-leaved and total weeds at 70 days after planting, significantly affected by the amount of mulch and interactions of mulch× nitrogen. Both density and biomass of grass weed only affect with mulch amount. At the end of the season sampling, biomass of broadleaf and grass weeds was affected by both factors and their interaction as well. While, for total weeds only mulching effects was significant. At the end of the season, the highest broadleaf and grass weeds biomass was observed when 100 kg N ha-1 used without mulching. Overall, plots without mulch and the use of 2 kg m-1 of mulch had the highest and lowest weed biomass, respectively. Compared to, the biological yield of D. moldavica was decreased from 5495 kg ha-1 in weed free check to 8525495 kg ha-1 in weedy check. Except for weed free treatment, the highest seed and biological yield was obtained in plot with 100 kg N ha-1 and 1 kg m-2 mulch.

To study the effects of different levels of irrigation and nitrogen on yield and yield components of two varieties of red kidney beans, a factorial split plot experiment in a randomized complete block design with four replications was conducted at research farm of College of Agriculture and Natural Resources, University of Tehran (Karaj) in 2015. Three irrigation levels comprised of 60 (normal), 90 (mild water stress) and 120 mm (sever) cumulative evaporation from open pan were assigned as main plots, four fertilizer treatments of zero (control), 50, 100 and 150 kg N ha-1 and two bean cultivars (Akhtar & D81083) compound in as sub plots. The mild and severe water stress commenced after 4th leaf stage onwards. The results showed that water stress significantly reduces the number of pods per plant, seeds per pod, seed weight, seed yield, biological yield, harvest index, number of branches and plant height. Applied nitrogen fertilizer significantly intensified all traits, except pod weight, plant height and harvest index. Two varieties of kidney beans significantly differed in all traits; however, the line D81083 in terms of grain yield, biological and other components performed better than the Akhtar line. The D81083 line at normal irrigation with 150 kg N ha-1 and the Akhtar line at water stress condition with no N fertilizer application, respectively had the highest and the lowest harvest index and seed weight. The interaction of water stress and nitrogen fertilizer on grain yield showed that the treatments of 150 kg N ha-1 in normal irrigation had the highest and the control (not fertilizer) under severe water stress had the lowest yield however, the difference between 100 and 150 kg N ha-was not significant. The results showed that nitrogen supply for crops in water stress conditions can somewhat reduce the impact of drought conditions, but the cultivar yield reaction and other traits in response to rise nitrogen levels at normal condition compared to drought condition was inconsistent more and have created significant differences between different levels of nitrogen.

This study was performed to investigate the effect of water deficit stress on activitiys of some antioxidaive enzymes, photosynthetic pigments and forage yield of sorghum genotypes. This experiment was conducted to a factorial in a randomized complete completely design with three replicates in greenhouse of University of Mohaghegh Ardabili in 2013. Treatments consisted of irrigation at four levels (85, 65, 45 and 25% of field capacity) and three genotypes of forage sorghum (KFS2, KFS6, and KFS17). Catalase, peroxidase and polyphenol oxidase enzymes and soluble sugar content, proline and carotenoids, increased in severe stress (25% field capacity) and decreased chlorophyll a and chlorophyll b. The KFS6 genotype had the highest chlorophyll a, chlorophyll b, and total chlorophyll, however, the maximum biomass, proline, soluble sugars, peroxidase and polyphenol oxidase activity and carotenoids were observed by KFS2 genotype. Also positive correlation were observed between the biomass production and carotenoids and chlorophyll content, proline, soluble sugar, catalase, peroxidase and negative correlation between biomass and polyphenol oxidase. Among photosynthetic indices, chlorophyll a, among adjustment indices, peroxidase activity had maximum contribution to prediction biomass. Also in KFS2 genotype except carotenoid and proline all traits had highest correlation with biomass. In general it could introduced KFS2 genotypes as tolerant genotypes to water stress as compared to other genotypes.

To study the effect of water stress on some physiological characteristics, an experiment was carried out in a simple lattice design with two replications under normal and low irrigated conditions using 49 cumin endemic ecotypes collected from different parts of Iran in the crop year 2011-2012 in college of Aburaihan, University of Tehran. Physiological traits including content of proline, soluble sugars, essential oil, chlorophyll a, chlorophyll b, carotenoids and relative water content were measured beside grain yield. The results showed significant effect of drought stress on all the traits. Drought stress decreased chlorophyll a, b and carotenoids content, grain yield and relative water content about 40, 32, 52, 19 and 9 percent, respectively. Meanwhile, contents of proline, soluble sugars and essential oils increased about 30, 55 and 56 percent, respectively. According to the results of mean comparisons, ecotypes of Kashmar, Chatrood, Ivanaki, Gonbad, Ardekan, Sivand, Qaen and Baneh had the high amount of carotenoids, chlorophyll a, chlorophyll b, relative water content, soluble sugars, proline, essential oil content and grain yield, respectively. In general, cumin as a moderately tolerant plant to water deficit exploit different physiological mechanisms to cope with stress and breeding strategies focusing on physiological aspects can be applied to improve high yield cultivars tolerant to drought stress.

To study the genetic diversity in 77 samples of Silybum marianum consisting 20 ecotypes (from 7 provinces of Iran) and 1 foreign ecotype originated from Budapest, Hungary were evaluated in a randomized complete block design with three replications in Agricultural site of University of Zanjan. Using ISSR markers, the genetic diversity of some ecotypes of Silyb(um marianum along with their classification were studied. Out of 12 ISSR primers, 10 were amplified. Results revealed that the highest polymorphism information content (PIC) value belongs to primers UBC809 (0. 492), UBC842 (0. 487), and UBC826 (0. 443 ), and lowest value was that of primer UBC1 (0. 121). Cluster analysis using UPGMA algorithm divided the lines into 9 separate groups. For molecular analysis of variance of ecotypes a primary classification based on the geographical area used which divided them into 9 groups. Results of molecular analysis of variance revealed that within population variance was higher than between group variance due to its open pollinating nature. Regarding to principal component analysis, the first six components explained 87. 5 % of the total variance and each component accounts for a small percentage of the total variance that emphasizes on good genomic distribution of selected ISSR markers. In general, the results obtained for using ISSR markers showed that this technique is a suitable one to study the genetic structure of the population Silybum marianum.

In order to evaluate seven native broom sorghum populations and determine effective traits on broom yield, an experiment was conducted in East Azarbaijan Agricultural and Natural Resources Research and Education Center, Tabriz, Iran, in 2014 and 2015 cropping seasons based on randomized complete block design. Analysis of variance showed that there were significant differences among population in 2014 for most traits. The resulted population from selected genotypes had superiority in the mean of many traits. High and low heritability-%89 and %41-was observed for shoot diameter and leaf number traits, respectively. Path analysis showed shoot fresh weight, flag leaf lengths and peduncle diameter traits had positive significant direct effect on panicle weight. It seems shoot fresh weight can be considered as very important traits in broom yield selection. Path analysis for panicle yield of broom sorghum in pre harvesting from farm or before flowering condition-no need to measure shoot weight, panicle lengths and peduncle diameter-indicated the most positive direct effect belonged to flag leaf lengths, leaf number, shoot diameter and plant height traits, 0. 559, 0. 231, 0. 191 and 0. 090, respectively. Therefore, it seems in the early stages of selection and to save cost in plant breeding projects, flag leaf lengths can be considered as a practical index for selecting promising broom sorghum genotypes.

In order to evaluation the efficacy of indaziflam on control of purple nutsedge in sugarcane an experiment was conducted in 2015 growing season in a sugarcane field in Shoaeibiyeh, Shoushtar, Khouzestan, Iran. Trial was randomized complete block design with four replications. Treatments were 1-indaziflam (75 g ai ha-1, as preemergence); 2-indaziflam (50 g ai ha-1 as preemergence); 3-Trifloxysulfuron sodium+ametryn; 2, 4-D+MCPA (1687. 5 g ai ha-1); 5-2, 4-D+MCPA+metribuzin (1350 g ai ha-1+1400 g ai ha-1); 6-weeding and 7-weed infested. The results showed indaziflam as 75 g ai ha-1 affected purpule nutsedge growth as dry weight and density reduction percentage of purple nutsedge was reduced 100% until 30 day after treatment (DAT). However, indaziflam efficacy was reduced over time. Other herbicides such as indaziflam as 50 g ai ha-1 and trifloxysulfuron sodium+ametryn indicated good effect in purple nutsedge control compared with 4-2, 4-D+MCPA and 2, 4-D+MCPA+metribuzin. Single stem weight (0. 70 kg m-2), the middle internode diameter (1. 83 cm), number of internode (18. 3 cm) and cane yield (117. 88 t ha-1), were the greatest in indaziflam (75 g ai ha-1). The greatest brix (21. 40%), invert sugar (25. 53%), recoverable sugar (11. 0%) and the lowest fiber content (12. 60 t ha-1) were obtained in indaziflam (75 g ai ha-1).

Barley, considered as a strategic crop, plays an important role in food security in Iran. An experiment was conducted at the experimental field of Agricultural Research Institute of Atomic Energy Organization in Karaj in 2015, as a randomized complete block design with three replications. Treatments included 14 barley cultivars (13 cultivars bred using classical breeding approaches and one gamma irradiated cultivars). Results showed that there were significant differences between most of the studied barley cultivars regarding physiological and morphological traits (P ˂ 0. 05). The newer cultivars (those been introduced during the last decade) and Roudasht showed advantages over older cultivars with regard to leaf area index, radiation use efficiency and crop growth rate. Cultivars Valfajr, Makouee and Bahman had the highest leaf mass fraction (0. 27, 0. 27 and 0. 25, respectively), mostly as a result of being late-maturity cultivars along with having high leaf area index and specific leaf area. On the other side, cultivars Behrokh, Roudasht and Makouee had the highest stem mass fraction (0. 70, 0. 68 and 0. 67, respectively) mainly as a result of their corresponding growth habits (tworows, gamma-irradiated and tall-statured, respectively). Also results showed that cultivars which had the highest stem and leaf mass fractions such as Makouee, Roudasht and Valfajr produced the lowest spike mass fraction and in turn grain yield. Cultivars Lout, Nosrat, Rayhann 03 and Fajr 30 had the highest spike mass fraction (739. 9, 720. 4, 701. 4 and 563. 3 gm-2, respectively) which could be attributed to their six-row habit of spike, early-maturity and lower leaf and stem dry matter at flowering stage. Overall, it could be concluded that tall statured late-maturity cultivars along with gammairradiated improved barley cultivar had the highest leaf and stem mass fractions compared to dwarf and early maturity cultivars. Such advantage, however, translated into lower spike mass fraction and grain yield of the former group.

MicroRNAs (miRNAs) are a group of 17-22 nucleotides that derived from their precursor sequences and represent normally various roles in numerous biological and metabolic processes in both animals and plants. Among several approaches to identify miRNAs, the bioinformatics-based methods are regarded as one of the easiest and cheapest ways to identify miRNAs. In this study, to identify potential miRNAs in Papaver somniferum, the publicly available EST sequences of the plant were obtained from NCBI GenBank and blasted against the previously known Plant miRNAs. Ultimately, seven distinguished potential miRNAs were acquired in the plant. The target genes of the predicted miRNAs included a protein serine/threonine kinase (signal transduction), PPR protein family (edit and stability of RNA) and globulins 7 S (hydration and dehydration cells), phototropin (response to phototropism), protein of serine/threonine phosphatase (glycogen metabolism), TIR protein family (defense against bacteria). These genes play an important role in plant growth and development, metabolism, morphology and determination of flowering time and diverse plant responses against different biotic and abiotic stresses.

Drought stress is one of the phenomena that limited growth and crop yield around the world, especially in arid and semi-arid regions. To investigate the effect of salicylic acid on yield and some physiological parameters of wheat under drought stress, a split plots experiment was conducted in a randomized complete block design with four replications at Agricultural Research Center of Ilam, during 2014-2015 cropping season. Experimental factors included moisture treatments in three levels (control (100), 70 and 40 % field capacity), salicylic acid in three levels (0, 50 and 100 μ M) and two wheat cultivars (Bahar and Pishtaz). The results showed that triple interaction between drought stress, salicylic acid and cultivars on all traits was significant. By increasing drought stress photosynthetic pigments, number of grains per spike and thousand seed weight was significantly decreased, while the use of 50 and 100 μ M salicylic acid in this situation improved these traits. Proline content and soluble carbohydrates were ascending with increasing severity of drought stress, that this trend by use of salicylic acid (50 and 100 μ M) decreased. Although no significant difference between the two cultivars in the grain yield was observed under drought stress, but numerically under drought stress the highest and lowest yield related to Pishtaz, 70 % field capacity by 100 μ M salicylic acid and Bahar, 40 % field capacity by non salicylic acid treatment, respectively. Generally, it seems that application of salicylic acid (50 μ M) under drought stress by improving the plants physiological processes, while increasing plant resistance, lead to greater economic performance.

Wild oats seed is dormant and seeds can persist in the soil for a long time. Factors that influence germination are temperature, seed position and seed coat. Thus, laboratory experiments were conducted at University of Tehran, Collage of Agronomy and Plant Breeding, to study the effect of temperature, seed position and seed coat on seed germination of four population of Avena ludoviciana. The experimental design was a completely randomized design with factorial arrangement of treatments with three replications. Experimental treatments were seed position (lower and upper seeds), temperatures (5, 10, 15, 20, 25 and 30 ◦ c). Response of germination rate against temperature was described with sigmoid function for each population. The results in laboratory showed that the lowest germination percentage (GP) and germination rate (GR) were obtained in Qaemshahr primary and secondary seed without coat, with lowest seed weight (1. 5 gr) among all populations studied. Big seed without coat had higher germination percentages (%80) than small seed (%56) in Qaemshahr. In contrast, Kamyaran with highest seed weight (3. 65 gr) had higher germination percentages and germination rate. In Kamyaran population big seed without coat had higher germination percentages and germination rate than small seed. Marvdasht seed without coat showed higher germination rang (2. 44 and 1. 17 GC respectively in big and small seed) than seed with coat, (0. 72 and 0. 96 GC in big and small seed, respectively). Decreasing in GP and GR in seed with coat compare to seed without coat in Marvdasht and Mahidasht, were observed. However, management plans could be proposed at regional scale according to the approach of modifying the patterns of agronomic to which the local populations have adapted.

Drought stress is the main limiting factor in the arid and semi-arid region of the world. In order to evaluate and determine of drought stress relationship between agronomic characteristics and grain yield, an experiment was conducted in research field of University of Tehran in Karaj in 2016. In this study 102 genotypes of Bean (Phaseolus vulgaris. L) were evaluated in an augment design with three replication along with four control under irrigated and drought stress conditions. Result of simple correlation coefficient analysis indicated a significant positive correlation between grain yield with pod no and pod weight for both normal and stress condition. Stepwise regression analysis showed that pod weight was higher importance, among other grain yield component for normal condition, in determination of grain yield. Whereas in stress condition, pod number and pod weight were the most important. Factor analysis determined five and four factors under normal and drought stress condition that accounted for 77% and 70% of total observed variations of grain yield. Based on result of by-plot analysis, 70, 60 and 100 genotypes were recognized as high-yielding genotypes under stress conditions.

To investigate salinity tolerance in two safflower cultivars and identify the most important traits affecting salinity tolerance in safflower cultivars (Carthamus tinctorius L. ), a greenhouse experiment was conducted as factorial arrangement based on completely randomized design with four replications. Treatments were irrigation water salinity (2, 4, 8 and 12 dS/m) and safflower cultivars (Sofeh and Zendehrud). Plant dry weight in Sofeh cultivar decreased 13, 30 and 58% respectively, while, plant dry weight of Zendehrud cultivar reduced 9, 28 and 40% under salinity levels. The higher concentration of chlorophyll a, b, SPAD, peroxidase and superoxide dismutase activity was found in Zendehrud cultivar under all salinity levels. Enhancement of Na+ concentration in shoot and root, proline and malondialdehyde was greater in Sofeh cultivar compared to Zendehrud cultivar. Linear regression analysis revealed significant and negative relationship between plant dry weight with Na+ concentration in leaf and root and proline content. Plant dry weight was significantly and positively associated with K+/Na+ ratio, peroxidase, superoxide dismutase and chlorophyll a. In general, it was concluded that Na+ concentration in root, shoot (stem + leaf), peroxidase and superoxide dismutase activity can be used as reliable indicators in identifying salinity tolerant cultivars of safflower.