مجله علوم گیاهان زراعی ایران
سال چهل و دوم شماره 4 (زمستان 1390)

The objective of this study was to evaluate some biochemical characteristics of fifty Iranian genotypes of Aegilops tauschii and Kohdasht cultivar which was used as a control. Eight important physiological characteristics that were related to crop yield and resistance to biotic and abiotic stress، was studied in a Completely Randomized Design (CRD) with 3 replications in the University of Tehran in 2009. The results of ANOVA showed significant differences among genotypes in all characters. There was positive correlation between chlorophyll content and carotenoid، but the correlation among enzymes، carotenoid and chlorophyll content were not significant. There was significant correlation between protein and enzymes. Also، the negative correlation was detected between catalase and two other enzymes (proxidase and polyphenol oxidase)، but there was not any correlation between proxidase and polyphenol oxidase. Principal components analysis classified 8 primary variables in to 2 new components that explained 69. 3% of total variations. The first component explained 42% of total variations that mainly included chlorophyll content and carotenoid. The second component explained 26. 4% of total variations that mainly included protein and enzymes. Cluster analysis by UPGMA method classified characters in to 5 groups. The results showed that genotypes were significantly different in all characters; therefore، wild genotypes (especially genotypes with high values of these characters) can be used for transferring desirable traits (such as resistance to drought and salinity) to produce cultivars which are suitable for breeding programs.

In order to study the effect of water level and soil depth on the germination rates of barnyardgrass and rice barnyardgrass, an investigation was conducted at Rice Research Institute of Iran (Rasht) in 2008. Treatments included weed species (Echinochloa Crus-galli and Echinochloa oryziodes), water level (0, 3, 6 and 9 cm) and soil depth (0.5, 1.5, 2.5 and 3.5 cm). The experimental design was a Randomized Complete Block Design (RCBD) with three replications in factorial arrangement. Experiment were laid out in covered outdoor conditions. Results showed that water level and soil depth affected germination rate, seedling mortality, seedling germination, height, dry matter accumulation and radicle length, significantly. Both water level and soil depth affected barnyardgrass more than rice barnyardgrass. Average germination of seeds in 9 cm of water was 80% and 30% for rice barnyardgrass and barnyardgrass 20 day after sowing, respectively. Also increasing soil depth decreased seed germination significantly. Regression analysis showed that by increasing water level and soil depth, the germination rate of barnyardgrass decreased more than rice barnyardgrass. This study showed that rice barnyardgrass is more tolerant than barnyardgrass to water level or soil depth. These results indicate that rice barnyardgrass has more chance to survive in paddy field of Iran.

In order to modeling the output required in corn, an experiment was conducted with a factorial arrangement based on a randomized complete block design with three replications at Research Fields of University of Tehran in 2007. Two factors including four levels of N fertilizer (0, 180, 270, and 360 kg ha-1of Urea fertilizer 46 %) and five doses of Nicosulfuron herbicide (0, 20, 40, 60, and 80 g. ai ha-1) were used. According to the equation fitted on data, to achieve high yield, 250 kg ha-1 N fertilizer and 38 g ai ha-1 Nicosulfuron herbicide dose (i.e reaching to the 50 % of the yield) are needed. Also, the data fitted by line level showed that the highest corn grain yield (almost 11 t ha-1) and corn biomass (8 t ha-1) were observed with 270 kg ha-1 N fertilizer and 80, 60 g. ai ha-1 Nicosulfuron herbicide treatments. Besides, the lowest corn grain yield and biomass yield (3 t ha-1) were obtained in the treatment used no N fertilizer and herbicide dose. The results showed that application of N fertilizer up to 360 kg ha-1 resulted in higher herbicide dose used for appropriate weed control. Consequently, N fertilizer must be applied in farm based on weed density and species.

In order to investigate the relationships among yield, yield components and other important agronomic traits in rapeseed under normal and stress conditions, 135 doubled haploid lines derived from the cross between a Korean spring line "Yudal" and a French winter line "Darmor” along with the parents and seven commercial cultivars were evaluated using a simple lattice design with two replications in University of Tehran, in 2009-2010. Measured traits were days to flowering, plant height, height of lowest primary effective branch, length of main inflorescence, seed yield, 1000-seed weight, seed per silique, silique length, silique beak length, silique thickness and silique density. There was a large variation in the population for different traits. Correlation analysis showed that days to flowering and height of lowest primary effective branch had the highest negative and positive correlation with grain yield, respectively. The regression and path analysis showed that days to flowering, height of lowest primary effective branch and plant height as important components having the highest direct effect on grain yield. Reduction of grain yield and 1000-kernel weight were affected mostly by drought stress. Nonetheless some agronomic traits such as pod thickness, pod length and beak length were not significantly changed under drought stress. Doubled haploid lines were grouped using principal components analysis based on drought tolerance indices. The first two principal components explained 98 percent of data variation.

Sainfoin (Onobrychis viciifolia Scop.) is a perennial forage legume recognized for its feed quality and its tolerance to environmental stress. However, lack of proper genetic variability for some important agronomic traits limits its cultivation. Mutation breeding is a useful alternative for crop improvement. In this research 40 M3 Ethyle Methane Sulphonat (EMS) induced mutant lines along with 39 non-mutant genotypes of Sainfoin were evaluated for 18 agro-morphological traits in the field for two years. Considerable variation was observed in both populations (Mutants and non-mutants) for leaf to stem ratio and powdery mildew susceptibility in the first year and for forage yield, stems percentage, leaf to stem ratio and persistency in the second year. Results of mean comparison showed that mutant genotypes were significantly superior for most of the measured traits especially forage yield, stem percentage, leaf to stem ratio and persistency. Results of cluster analysis also confirmed the high genetic variability in each population. A group of genotypes clustered together in mutant population stayed roset in the first year indicating a possible requirement for induction of vernalization in these genotypes. Finally results indicated that mutation could induce variation for some traits, however their stability should be considered in future generation, so it can be useful for selection of superior genotypes in future breeding programs.

A 2-years (2007-2009) field study was carried out at the college of Agriculture, Shiraz University, to evaluate the influence of crop residues management and nitrogen (N) rates on soil quality and barley grain protein under dryland conditions. The experiment was conducted as strip split plot with four replications. Horizontal plots were three crop residues rates (0, 750 and 1500 kg ha-1), vertical plots consisted of two barley cultivars (CVs) (Afzal and Reyhan), and sub-plots were three N rates (0, 40, and 80 kg N ha-1). The Results of ANOVA showed that there were significant differences for year effects and Y×C×N for total N grain and protein percentage. When the crop residues were completely added (100%), N rates should be added according to residues rates. Increasing crop residue level increased soil organic carbon. Crop residue application had no effect on grain protein percentage. There were no significant differences between two cultivars for Crop residue application. High N increased grain protein percentage significantly.

Seed hardiness in annual medics plays an important role in soil seed bank reserve to ensure ley farming system sustainability. To study the level of seed hardiness in annual medic (Medicago scuttelata var.Rabinson) at different fertilizing treatments and growing conditions (irrigated and dry farming system), an experiment was conducted at two research stations (Sararod, Research Institute and Soil Fertility Research Station in Mahidasht). After the physiological maturity of pods in early July, seed germination tests were conducted at 30 days intervals in consecutive months of July, August, September, October, November, December, January and March. Results indicated that seed hardiness decreased after seed maturity and the lowest of seed hardiness was detected in September. Mean monthly hard seed break down rate was lower under irrigated system compared to dry farming system. The mean monthly hard seed breakdown rate was lower in plots receiving biologic and integrated fertilizers compared to other fertilizing treatments. The monthly hard seed break down rate in Sararoud Station (dryer climatic conditions) was higher compared to Mahidasht Station (more annual rainfall and cooler climatic conditions). The highest hard seed rate in dry farming system was obtained in control treatment. However, the highest seed hardiness in irrigated system was observed in nitrogen fixing bacteria + mycorrhiza and nitrogen fixing bacteria + phosphate solubilizing bacteria treatments, respectively.

Cold stress is considered as a restricting factor in plant production. Recently, many different compounds were applied to minimize the harmful effects of stress. In this study, the effects of foliar application of salicylic acid was studied on some biochemical properties of two different cold resistant canola cultivars. Salicylic acid was sprayed at four concentrations (0, 100, 200 and 400 µM) on RGS (Spring canola, sensitive to cold) and LICORD (Winter canola, resistant to cold). Leaf samples were collected after 24 h after spraying. The effects of salicylic acid and cold stress on the quantity of chlorophyll a, b, total chlorophyll, carotenoid, anthocyanin, flavonoids, proline, lipid peroxidation)MDA) and sugar contents in leaves and root of canola plants were investigated. The results showed that under cold conditions chlorophyll a and b, total chlorophyll, carotenoids and sugar contents decreased in sensitive spring canola but lipid peroxidation in leaves of sensitive spring canola significantly increased. Salicylic acid spray significantly increased chlorophyll a, b, total chlorophyll, carotenoid, anthocyanin, flavonoids, proline and sugar contents but decreased significantly MDA content in both cultivars. Salicylic acid increased photosynthetic pigments and sugars along with reduction in peroxidation of lipids indicated damage reduction caused by oxidative stress. In conclusion, salicylic acid in concentrations of lower than 200 µM had a significant role on mitigation of oxidative-stress damage.

Kochia is a halophyte plant and is a good source of forage for livestock under saline irrigation. In order to investigate the salinity effect on morphological and forage characteristics of kochia, an experiment was conducted. Three saline waters (5.2, 10.5 and 23.1 dS m-1) and three kochia ecotypes (Birjand, Borujerd and Sabzevar) were allocated as main and sub plots, respectively, in a split plot design based on a CRBD with three replications. There were no significant effects on plant height, branch numbers, dry matter yield, forage dry matter, stem and leaves percentage and stem dry matter by increasing salinity from 5.2 to 23.1 dS-1m,. Average of dry matter yield of 9.1 ton.h-1, percentage of dry matter of 29.85 and percentage of stem and leaf of 57.94 were recorded. Fresh forage yield, stem diameter and leaf dry matter yield were reduced by increasing salinity. Birjand showed the maximum plant height, dry matter yield, dry matter percentage, leaf yield, leaf percentage, leaf dry matter percentage and leaf to stem ratio. In conclusion, Kochia had good traits such as plant height, appropriate leaf to stem ratio, large number of branches and acceptable fresh and dry matter yield in saline condition that can make Kochia a suitable candidate for forage crop.

Sainfoin (Onobrychis viciifolia Scop.) is widely grown as forage and pasture legume in Iran and is tolerant to a range of environmental stress. This experiment was conducted to investigate relationship between morphological, physiological and agronomic traits and to identify components affecting forage yield using several multivariate statistical methods on 10 local sainfoin varieties under normal and water stress condition. Drought stress significantly affected most of the measured traits. Results indicated that under normal condition, the correlation coefficients of dry matter yield with fresh matter yield, stem percent, relative water content, number of stem per plant, number of stem per square meter and number of node per stem were significantly positive. However, its correlation with leaf percent and leaf to stem ratio were significantly negative. Under stress condition, the correlation coefficients of dry matter yield with fresh forage yield, stem percent, number of node per stem and relative water content were significantly positive, while those of leaf percent and leaf to stem ratio were significantly negative. Results of stepwise regression for non-stress condition showed that stem percentage, percentage of dry matter and number of stem per square meter explained the highest variation of forage yield, while under stress the majority of variation was explained by stem percentage, percentage of dry matter and plant height. Factor analysis revealed five factors which justified more than 90 and 87 percent of total variation under normal and drought stress conditions, respectively. In non-stress condition, the factors classified as forage production, forage yield components, reproductive factor, photosynthesis and phenological factors while under drought stress condition were classified as forage yield components, photosynthesis factor, reproductive factor, proline content and percentage of dry matter respectively. Results indicated that drought stress changed the relationships of measured traits, therefore, identifying separate selection index for normal and moisture stress conditions could better lead to improve forage yield in sainfoin breeding programs.

This experiment was set to study the allelopatic effect of aqueous and alcoholic extracts of artemisia, coriander, eucalyptus and cumin on growth of red root pigweed and lambsquarters weeds at laboratory and field in the University of Tehran (Karaj-Iran) in 2008. The herbal plant samples were ground and powdered for extraction preparation, and were mixed with distilled water in a beaker. The extracts were shaked for 72 hours at 25°C, then filtered though paper and centrifuged. Laboratory results showed that the extracts of artemisia and cumin prevented the red root pigweed and lambsquarters seed weed germination significantly (p≤5%). This effect was greater on red root pigweed germination than that of lambsquarters. For both weeds, the lowest germination was obtained at %100 concentration of alcoholic herbal extract. According to field observation, the alcoholic extracts of cumin and artemisia prevented the red root pigweed and lambsquarters seed germination. So, the highest pinto bean grain and biological yields and pod numbers per unit area acquired. But, the check (no herbal extract) showed the highest weed emergence and together with using trifluralin + one hand weeding gave the lowest pinto bean yields and pod numbers. Totally, the alcoholic extracts of cumin and artemisia had the most hindrance effects on red root pigweed and lambsquarters growth, which revealed that in future research allopathic products such as herbal extracts can be used as natural herbicide.

In order to study the effect of mallow weed competition and nitrogen (N) rates on grain yield and yield components of wheat cv. Chamran, a field experiment was conducted in 2009. The experiment was designed as a split-plot with three replications and additive series. The N application rates were assigned in the main-plots (50, 100, 150 and 200 kg.N.ha-1) and sub-plots consisted of target common mallow (Mava spp) densities (0, 5, 10, 15 and 20 plant.m-2). Result indicated that, the effect of nitrogen (N) treatments, weed density (WD) and N×WD on grain yield (GY) was significant in 1% probability level. Grain yield decreased significantly as the WD increased. Grain yield reduction in high weed densities was due to lower spike per square meter (Sm-2), grain per spike (GN) and 1000-grain weight. Under the density of 20 mallow plant.m-2, GY, Sm-2, GN, spikelet per spike and 1000-grain weight losses was 27%, 15%, 10%, 6% and 6%, respectively. Wheat grain yield loss attributed to mallow weed ranged from 7 to 32% at 50 kg.N.ha-1 to 9 to 21.8% at 200 kg. N. ha-1. The highest and the lowest weed individual dry weight was belonged to 200 and 50 kg.N.ha-1, respectively. Agronomic N efficiency (ANE) of wheat decreased as the weed density increased. Wheat grain yield in mallow infected plot generally enhanced with N fertilization, while the density of mallow weed increased. Wheat competitiveness, GY and ANE were improved as N rate increased.

To better understand seed dormancy breaking of bread wheat (Triticum aestivum L.RL4137), we examined protein synthesis in dormant and after-ripened seeds.We used six treatments including dormant seed, dormant seed that were subjected to gibberllic acid (GA3) for 10 hours, dormant seed with one, three and six weeks of after-ripening and finally six weeks after-ripened seed subjected to abscisc acid (ABA) for ten hours. Protein synthesis was examined by two-dimensional gel electrophoresis. Almost 600 spots were displayed on gels. Volumes of 13, 40, 18, 15, 38 spots were reduced and volumes of 12, 32, 10 and 39 spots were increased significantly in treatments of GA3, and one, three and six weeks of after-ripeining, respectively. 15 spots in ABA treatment on after-ripened seed, 20 spots in dormant treatment and 23 spots in GA3 treatment were expressed. Germination was increased with after-ripening synchronously. Similar to six weeks after-ripened seed, application of GA3 also increased germination. Moreover, the effect of GA3 on up and down regulation of proteins was similar to six weeks after-ripening. ABA treatment resulted in reduction of germination in six weeks after-ripened seeds. Results of percentage of germination were similar to one week after-ripened treatment. Effect of ABA application on up and down regulation of proteins was similar to one week after-ripened seeds. The result of this study showed that GA3 had the same effect of after-ripening and ABA increased the level of seed dormancy, however, at the level of protein sysnthesis may not be similar.

This research evaluated the effects of gibberellin (GA3) and abscisic acid (ABA) on emergence capability, rate of emergence, vigor index and some physiological characters of chickpea seedling (Cicer arietinum L.) in a field experiment (as split) under dry and irrigated conditions. Seeds were primed with 0, 50, 100 and 150 ppm of each phytohormones. Examined chickpea cultivar was Azad. The results showed that emergence percentage, rate of emergence and number of lateral primary branches were the same in both irrigated and dry conditions. Root fresh and dry weights, seedling growth rate, shoot fresh weight and number of nitrogen fixing nodules increased by hydro-priming. Gibberellin priming improved stem height, root length and seed vigor. ABA priming resulted in maximum emergence percentage, rate of emergence and root dry weight in irrigated condition and the maximum root length and number of lateral shoot in dry condition. The most branchy roots observed in seedling which produced by non-primed seed. Vigor index was increased by 100 ppm GA3 in both irrigated and dry conditions.

WOFOST is a crop growth simulation model which can simulate crop growth and yield components of annual crops dynamically in the various stages of growth period. Some parts of the model outputs (crop yield and crop water requirements) can be used in irrigation planning and management of water resources. In this study, a field research was carried out in a randomized complete block design with three irrigation treatments (Fully Irrigation, 20% and 40% deficit irrigation) in the research farm of Jihad-e-Agriculture and Natural Resources Research Center, located in Mahidasht, Kermanshah. The grain maize (variety 704C) was cultivated in the May 2010. The required phenological stages (emergence, flowering and maturity) for the crop growth model were observed in the field and then thermal time (degree days) required for each of the phenological stages were calculated based on daily weather data. Dry weights of leaf, stem and storage organ as well as LAI were measured eight times during the growing season. The crop parameters of the model were calibrated based on the measured data. The model outputs in the potential situation were compared with the measured data using statistical indicators including the root mean square error (RMSE), coefficient of efficiency (E), index of agreement (d), the maximum error (ME) and the coefficient of residual mass (CRM). The value of these indices were 1174, 0.96, 0.99, 16.67 & -0.02, respectively, for total biomass at the harvest time.

In order to determine the critical period of weed control in black seed, a field experiment was conducted at the Agricultural Research Station of Ferdowsi University of Mashhad, during 2009-2010 growing season. The experiment was laid out in a randomized complete block design (RCBD) with 12 treatments and three replications. In this study, onset and end of Critical Period of Weed Control (CPWC) were determined based on 2.5, 5 and 10% acceptable grain loss using Gampertz and Logestic equations. Two set of weed-free and weed-infested treatments were used to determine the CPWC. At the first set of treatments, weeds competed with black seed until 0, 14, 28, 42, 56 and 70 days after emerging (weed- infested periods). At the second ones, plots were kept free of weeds until the mentioned stage (weed-free periods). The goal of the first and second set of treatment was to determine the onset and end of critical period, respectively. In this study, Stellaria graminea at the onset of growing season and Amaranthus retroflexus, Chenopodium album and Echinochloa cruss-galli at the mid and end of growing season were main dominant species. The results indicated that at 2.5, 5 and 10% yield loss levels, the maximum weed-infested periods (onset of CPWC) were 10/5, 13 and 17/3 days after emergence (86, 108 and 149 growing degree days), respectively. Also based on those 3 levels of grain yield loss, minimum weed-free period (end of the CPWC) were 76/8, 74/8 and 71/1 days after emergence (1005, 960 and 883 growing degree days), from whole black seed growing season (equal to 84 days or 1188 growing degree days).

Wheat productivity depends not only on dry matter accumulation, but also on its effective partitioning to the grains; this is a key factor to yield stability under stress. The aim of this research was to investigate the pattern of dry matter partitioning to aerial parts in 81 Iranian wheat genotypes differing in agronomic traits. Moreover, its relationship with grain yield in drought conditions was studied. The plant materials were evaluated using two simple lattice designs with two replications under irrigation and drought conditions at University of Tehran Research farm (Karaj) during 2008-2009. Drought stress was imposed by withholding irrigation at the heading stage. Samplings were carried out at anthesis as well as at physiological maturity stages. There was a significant difference between irrigated and drought stress conditions in term of grain yield. Wheat cultivars exhibited diferent responses to drought stress. The rate of reduction in grain yield was variable from 7 to 90 percent. At anthesis, stem, leaf and spike had the highest amount of dry matter, respectively. The effect of stress on dry matter partitioning to different plant parts was not considerable at this stage. In stress condition, a kind of remarkable correlation was observed between grain yield and dry weight of leaf at anthesis. At maturity, spike had the highest amount of dry matter and drought stress decreased dry matter partitioned into spike. But the effect of stress was not considerable on the dry weight of leaf and stem. At maturity, there was a negative correlation between dry weight of stem and grain yield under stress condition.

Diallel crosses of eight genotypes of safflower were conducted and F1 and F2 generations were evaluated to estimate genetic parameters for seed-quality related traits including protein contents (%), fiber, ash and oil yeild. Griffing’s methods 1 and 2 for F1 and F2 generations was used, respectively. Sixty four genotypes including 8 parents and 56 F1 progenies, and half diallel crosses of F2 generation were grown using a complete randomized block design. Results of analysis of variance based on Griffing’s method revealed significant general combining ability (GCA) and specific combining ability (SCA) of all studied traits in F1 and F2 generations, implementing the importance of additive and non-additive genetic effects. Significant reciprocal mean squares were estimated by Griffing’s method indicated the importance of cytoplasmic genetic factors for controlling oil yield. Low narrow sense heritability estimates and high estimates of dominance effects for ash content indicated the importance of non-additive genetic efficiency for it. Hence the efficiency of hybrid production method would be high to improve it. High narrow-sense heritability estimates and high degrees of additive effects for oil yeild and fiber indicated the prime importance of additive genetic effects for these traits, therefore, the efficiency of selection would be high to improve these traits. The estimates of genetic variance components proposed the importance of both additive and dominance genec effects which contribute to variation in protein content.

To evaluate the effect of drought stress, biofertilizer and chemical phosphorus fertilizer on yield and seed protein percentage of two lentil cultivars, an experiment was conducted in split factorial based on CRBD design with 4 replications in research farm of University of Tehran (Karaj-Iran) during 2009-10. The main factor including three irrigation levels (irrigation after 70, 90 and 130 mm evaporation from open pan class A) and sub treatments were the different kind of fertilizer (100% super phosphate triple; seed inoculation with biofertilizer; 50% super phosphate triple+inoculation with biofertilizer; no fertilizer & inoculation or check) along with two lentil varieties (namely; ILL6039 & Ziba, susceptible and tolerant cultivars, respectively). The biofertilizer contained pseudomonas (strains number 93 & 187) and azotobactor. The characteristics recorded were plant height, pods number per plant, seed yield, seed protein content (%) and harvest index. The results indicated that irrigation levels had significant effects on all plant traits (p≤0.01). The interaction effects between irrigation and fertilizer, irrigation×variety, fertilizer×variety and the triple interactions had significant effects on all plant traits (p≤0.01). Amongst the triple interactions, the variety×fertilizer under irrigation after 70 mm evapotranspiration from open pan (check) produced the highest seed yield. The effect of integrated fertilizer treatment on seed yield in comparison with 100% phosphorus fertilizer at different irrigation levels was better. Therefore, one can conclude from the view point of fertilizer reduction that the combination of 50% phosphorus fertilizer + inoculation with bio-fertilizer can be recommended.

In order to evaluate the response of emergence rate of oil seed rape seedlings to temperature, a pot experiment was conducted to assess the relationship between emergence rate of three rape seed cultivars (apetalous flower, RGS003 and Syn3) by using a non-linear regression against temperature variation. Six models (tooth shape, segmented, beta, curve, quadratic and cubic) were used and the superior model was selected according to square root of MSE, coefficient of determination, coefficient of correlation and simple linear regression coefficients (a, b) between observed and predicted emergence rates. Results showed that the seedling emergence response to temperature explained by beta function in RGS003, by beta and cure functions in Syn3, and by segmented function in apetalous flower cultivar. Prediction of cardinal temperatures by using the best models showed that the base temperature varied between 7.89 and 10.94, the optimum temperature was between 20.1 and 24 and the ceiling temperature was between 36 and 37.19°C for rape seed cultivars. The biological day estimation for seedling emergence by using segmented and beta models showed that there were significant differences between rape seed cultivars. According to the results of this experiment, beta and segmented models could be used for quantification of seedling emergence response of rape seed cultivars to temperature. It seems that these models and parameters (base, optimum and ceiling temperatures) could be used for prediction of seedling emergence in the field. Cardinal temperatures and its related model could be used for modeling of seedling emergence of rape seed cultivars.