Iranian Journal of Field Crop Science
Year:2016 | Volume:47 | Issue:3|Papers Count:16

Germination is series of biochemical reactions that depends mainly on temperature and moisture. Therefore, seed germination rate of lemon balm (Mellissa officinalis L.) were evaluated in temperatures of 20, 23, 25, 27, 30 and 32ºC and water potentials of 0, -0.2, -0.4, -0.6 and -0.8MPa. According to the results, germination temperature window was not very wide in a way that germination temperature range was 23-32oC. Three non-linear regression models (Dent-like, Segmented and Beta) were used to evaluate cardinal temperatures. According to the indices including RMSE, the coefficient of determination (R2) and correlation coefficient (r), the best model was Dent-like which can better estimate germination rate in response to temperature and water potential. The base, the lower and the upper and the ceiling temperatures of lemon balm were 17.31, 30.26, 31.15 and 35oC in the optimum conditions of water potential, respectively. Biological time for germination ranged from 41 to 137 h in different water potentials. Biological time decreased about 96 h by increasing 1 MPa in water potential. Estimated parameters and the relations can be used to predict time to germination or emergence in lemon balm under wide environmental conditions from normal to drought stress.

Bacillus anthracisas a spore-forming bacterium is the causative agent for anthrax. Three proteins from B. anthracis including protective antigen (PA), lethal factor (LF) and edema factor (EF) are causative factors of this bacteria. To produce plant-based vaccine, fusion protein of PA 4 domain and LF 1 domain via furin cleavage site joined to subunit B Vibrio cholera toxin (CTB) as an inducer of immune system. In this research we used 3’and modified 5’ untranslated regions of cowpea mosaic virus (CPMV) as translation enhancer and silencing inhibitor gene 2b of cucumber mosaic virus (CMV) to construct binary vector and transfer gene. Transient expression of tobacco and lettuce performed via agrobacterium and transient expression was confirmed at the level of transcriptome and proteome through RT-PCR and ELISA assay, respectively.

To investigate effects of temperature and salinity different levels on germination parameters of German chamomile (matricaria chamomilla), an experiment carried out in complete randomized design as factorial with three replication in department of agronomy, college of agriculture on the University of Guilan, in 2014. Treatments were including temperature levels (5, 10, 15, 20, 25, 30 and 35 oC) and different levels of salinity stress 0 (control), 4, 8, 12 and 16 dsm-1. Analysis of variance showed that treatments and their interaction had significant effect on germination rate, germination velocity, germination unity, germination index, time to 50% germination and time to 90% germination. Salinity stress decreased significantly all of germination traits. GR and GP were significantly decreased in lower temperature (≥15 oC), also had not germinated at 35 oC. Maximum of MTG in different salinity levels had occur in temperatures of lower of 15oC. GI had decreased with increasing of salinity levels and in all temperature levels, and had not significant difference between control and 4 dsm-1. In this experiment germination parameter more decreased in higher temperature levels (≤20 oC), with increasing of salinity levels. The levels of 15 and 20 OC discard significantly impact of salinity treatment.

Under condition of limited water supply, determination of minimum water requisite to keep potential yield should be considered as an important target. With this respect, a field experiment was conducted at research farm of university college of agriculture and natural resources, university of Tehran, in 2012-2013, Karaj, Iran. The experiment was conducted in a split plot, based on randomized complete design with three replications. Three wheat cultivars, recommended for conditions similar to the experimental site, (Parsi, Sivand and Pishtaz) and nine moisture regimes (a combination of 3 at vegetative an 3 at reproductive stages) were arranged in main and sub plots, respectively. Increase in irrigation intervals from 70 to 90 mm, based on class A evaporation pot, during vegetative stage did not affect grain yield. Irrigation after 110 mm pot evaporation at this growth stage, however, reduced yield by 14%. At any moisture regimes during vegetative stage, increase in irrigation intervals from 90 to even 110 mm pot evaporation during reproductive stage, did not affect grain yield. The highest WUE were obtained in T79 and T711 treatments. Decrease in moisture regimes, in a range applied in this experiment, increased harvest index. Reduced grain yield was accompanied with decrease in biomass and leaf area under low moisture regimes. Among the cultivars, Parsi showed the highest value of stem reserve accumulation, but lowest value of remobilization. Highest stem reserve remobilization was found in Pishtaz which showed highest grain yield under reduced moisture regimes. Decrease in moisture regimes was accompanied with decline in stem reserves but increase in reserve remobilization.

In order to study the complementary effects of application time of two herbicides sulfosulfuron 75% WG (Apyrus) and 75% sulfosulfuron+5% metsulfuron-methyl (Total) and planting wheat density on wild barley (Hordeum spontaneum koch.) control, an experiment was conducted in randomized complete blocks design with two-factors during 2012-2013 growing season in Zarghan (Fars). The first factor was five levels of herbicide application including application of Apyrus 75 WG (30 g ha-1+Citogate 1 L ha-1) and Total 80 WG (5o g ha-1+adjuvant 1250 ml ha-1) at 2 to 4 leaf stage and second joint stem of wild barley. The second factor was wheat density of Chamran cultivar in four levels including 400 (recommended rate), 500, 600 and seedlings per m2. Results showed that herbicides, crop density and their interaction had significant effect on wild barley traits such as seedling number, biomass, dry weight, spike weight and also crop yield. Apyros and Total, using at second joint stem of wild barley, had the highest effect by 88 and 93 percent respectively. The best treatment for controlling wild barley was the application of Total at second joint stem of wild barley and planting of 400 seedlings of wheat per unit area.

Drought stress is one of the major causes of reduction in crop production. Study physiological and biochemical processes related to drought stress can give better insight about mechanism of drought tolerance. To study the physiological and biochemical processes, three genotypes including K-S-31167, GE-288 and Naz were subjected to 3 level of drought stress based on 25, 50 and 100 percent of field capacity using CRD design with three replication using Factorial arrengment, Droght stress was applied five weeks after planting and lasted for 10 days. Second terifoliate were used for sampling. The results indicated significant changes in the electrolyte leakage (EL), prolin content (PC) and carbohydrates content (CC). Tolerant genotype (K-S-31167) had greater PC but lesser EL compare to relatively tolerant genotype (GE-288) and sensitive genotype (Naz). This indicates that tolerant genotype had higher membrane stability during stress. Results from measurement of soluble carbohydrate and expression ofsucrose synthase and vacuolar invertase genes showed increase and decrease in the expression of these genes resulted in increase and decrease in the activity of the invertase and sucrose synthase enzyme which in turn influences the concentration of soluble materials which acts as metabolic signal in response to stress.

Black seed is one of important ancient medicinal plants with various properties in traditional medicine. In order to evaluate microelements (Fe and Zn) effects on seed yield and yield components of black seed in salinity stress, a complete block design with three replications was conducted in Esfahan Agricultural and Natural Resources Center during 2013-2014. Three water salinity treatments were control (0_, 3.5 and 5 dS/m and three levels of mineral spraying, control, 0.1% and 0.2% Fe+Zn (as 3*3 factors). Fourteen characters of plants were measured and calculated. According to results, the effect of salinity treatments on majority of traits was significant. By increasing salinity stress, seed yield and biological yield decreased (70% and 67%, respectively) and the abnormal seed percentage increased significantly (150%). In this experiment, the effects of Fe+Zn spraying were not clear, because of abundance of these two elements in the soil. Also, emphasis on deficit signs in field is not suitable criterium for microelements spraying in black cumin.

In this study the response of 9 rapeseed genotypes were evaluated at the seedling stage using different irrigation levels (50, 70 and 100% FC). A factorial experiment based on RCBD was conducted in the research greenhouses of Urmia University with four replications during summer of 2013. Some physiological traits such as relative water content, stomatal conductance, transpiration, photosynthesis, water use efficiency, shoot fresh and dry weight; root dry weight and the amount of soluble and insoluble sugars were evaluated. The results of this study showed that with decreasing irrigation levels, relative water content, stomatal conductance, transpiration, photosynthesis, water use efficiency, shoot fresh and dry weight, root dry weight and insoluble sugars decreased, however the amount of leaf temperature, SPAD number and soluble sugars increased. The highest rate of net photosynthesis was observed in Zarfam and Licord genotypes at 100% of field capacity. The maximum decreasing in net photosynthesis was observed in Licord genotype by increasing water stress level (50% field capacity). Under severe drought stress, maximum shoot fresh and dry weight was observed in Zarfam genotype while it was lowest in the Zafar and Licord genotypes. Using cluster analysis in 50% FC, the genotypes were located in two groups of semi resistant (Zarfam, Karaj 2, Okapi and Karaj 3) and sensitive (Sarigol, Opera, Zafar, SLM, and Licord).

In order to study the competition effects of redroot pigweed (Amaranthus retroflexus) and millet (Panicum miliaceum) on maize performance under different rates of N fertilizer, a field experiment was conducted in 2009 in the research fields of Tarbiat Modares University in Tehran as a randomized complete block design with factorial arrangement of treatments and three replications. Accordingly, three factors included nitrogen fertilizer (75% optimum or 138 kg N ha-1, optimum or 184 kg N ha-1 and 125% optimum or 230 kg N ha-1), weed species (redroot pigweed and millet) and weed densities (5 and 25 plants m-1 for redroot pigweed and 7.5 and 37.5 plants m-1 for millet) consisted. Results showed that the highest grain yield (921.89 g m-2) was achieved in treatment 230 kg N ha-1 while the lowest yields (466.72 g m-2) belonged to treatment millet fertilized with 138 kg N ha-1. High densities of millet and redroot pigweed resulted in significant reductions in number of grains per row and the ear length. Differences in N application rates cause significant variations in biological yield and some of the yield components of maize. Overall, results indicated that in fields where a nitrophile species is the dominant, increasing N application rate beyond the optimum not only does not increase maize grain yield but also reduces its yield and causes pollution of environment.

Environmental stresses such as drought have important effects on plant growth and development. In order to evaluate the effect of drought tolerance, 12 chickpea genotypes were treated with drought stress in hydroponic condition in greenhouses. Treatments were a control and two stress treatments -3 and -6 bar that was created with polyethylene glycol in hydroponic condition. Two weeks after the stress treatments on the genotypes, moisture content, osmotic potential, proline and soluble sugars were evaluated in their shoot and root. Results showed that drought stress reduced moisture content in shoot, but moisture content in the root had no significant changes. On the other hand amount of osmotic potential, osmotic compounds and proline increased in response to drought stress in shoot and root. Drought tolerance index in genotypes showed positive significant correlation with amount of the root osmotic compounds in -3 bar treatment. Despite the absence of significant changes in leaf soluble sugars, the amount of root soluble sugars declined in stress treatments compared to control. In addition, the positive significant correlation was observed between the drought tolerance index in -6 bar treatments and root soluble sugars of this treatment. Leaf and root proline levels had not significantly correlation with drought tolerance in genotypes. Despite some correlations between traits and drought tolerance index it seems that osmotic adjustment, moisture content, proline and soluble sugars alone not to be a suitable indicator to evaluate drought tolerance in chickpea genotypes.

In order to study the effects of rate and application time of nitrogen on grain yield of rainfed wheat, water use efficiency of rain (WUE), nitrogen agronomic efficiency (NAE) and soil moisture depletion (SMD), one experimental farm was carried out in Kurdistan province during 2012-2014. Tratments were five rates of nitrogen (N0, N30, N60, N90 and N120) kg.ha-1 as Urea with three application times, consist of T1 (Total in the fall), T2 (2/3 in the fall+2/3 in the spring), T3 (1/2 in the fall+1/2 in the spring) with three replications as split plot arrangments, based on randomized complete block design. Annual precipitations were 256.1 and 294 mm respectively. Soil moisture measured in 0-20, 20-40 and 40-60 cm depths in five growth stages of wheat. Results shown interaction effects of timing and nitrogen rates on grain yield was significantly.The effect of nitrogen rates were significantly on WUE, NAE and SMD at (P<0.01). Fall application of 60 kg.ha-1 nitrogen with increseing grain yield realative check (82%), WUE (15.44 kg.mm-1.ha-1) and NAE (25 kg.kg-1) was the best treatment. Soil moisture depletion was effected by nitrogen, so SMD started initially from tillering to stem extention from soil surface to 40 cm depth, then SMD continued to head visible and flowering of rainfed wheat in 60 cm soil depth, at last in physiological ripening stage, soil moisture was completly depleted in throuought of 0-60 cm soil depth. Nitrogen promoted the synergistic effect between nitrogen uptake and absortion of soil water. Soil mouisture depletion due to nitrogen application in 20-40 and 40-60 cm depth explained increasing of grain yield 12.36% and 27.85% respectively.

In most experiments comparing the cultivars, the interpretation genotype × environment interaction is complex, and environmental and genotypic effects are not separable. Shifted multiplicative model (SHMM) provides a powerful analytical tool for the discriminating of genotypic effects from environmental effects and discriminating of environmental from genotypic effects. In this study 10 elite lines of Grass pea (Lathyrus sativus L.) local landrace with Naghadeh (as a control) in a randomized complete block design with three replications were analyzed using SHMM models. Using cluster analysis based on the proposed distance measure produces four final groups of environments with a SHMM1. The first three years of Gachsaran and the first year of Ilam and tow last years of Lorestan located in one cluster, the first two years of Lorestan located in separate cluster, Ilam’s last two years and Gachsaran last year were grouped in a cluster. The second year of Ilam ranked in a separate cluster as well. In each of these clusters, the genotypes did not show crossover effects with themselves, and SHMM1 model has had adequate fitting in each cluster. The results of SHMM model was confirmed using the graphical method. Results revealed that the least and the highest cross over interactions in different years among genotypes at Gachsaran and Ilam locations, respectively.

Aerobic rice is as useful potential in reducing of water problem. Comparison and investigation of genetic differences between Iranian rice varieties and aerobic rice can be useful in identification of genomic regions influencing in drought tolerance. In the present study in addition to an examination of germination genotypes under osmotic stress, allelic diversity were evaluated in 53 genotypes including 31 aerobic rice and 22 lowland Iranian rice varieties based on 26 SSR markers linked to QTL associated with drought and salinity tolerance. A total of 118 polymorphic alleles of microsatellite loci were produced with an average of 4.54 per marker. The highest calculated PIC level of 0.77 and 0.76 and the maximum range genetic diversity of 0.80 and 0.79 were related to RM10793 and RM493 respectively. Overview of genetic diversity statistics showed that two markers RM10793 and RM493 had higher values the other markers and more obvious role played in genotype differentiation. Grouping of genotypes according to Jaccard similarity coefficient using algorithms neighbor joining assigned them into two groups. This classification had significant compliance with the results of cluster analysis using the WARD algorithm based on germination traits. This may indicate the effectiveness and confirmation of used microsatellite markers in the separation of genotypes for osmotic tolerance.

In order to investigate the yield stability of eight promising rice genotypes, these lines along with Shiroudi and Fajr cultivars as control were sown in three regions of Mazandaran province (Amol, Sari and Tonekabon) as randomized complete block arrangements with three replications in 2012 and 2013. Analysis of variance for grain yield indicated significant differences among the genotypes in all environments (six experiment). Combined analysis of variance with assumption of random effects for year and location and fixed effect for genotype, revealed significant genotype main effect and year x location, genotype×location and genotype x year x location interactions. To determine the yield stability of the genotypes, were calculated several stability parameters including the variance and coefficient ofenvironmental variability, Wricke’s equivalence, Shukla’s stability variance, regression coefficient, variance of deviation from regression, variance within locations, mean rank and its standard deviation. The results showed that the promising lines 27610-33-1-1 and 2765-3-5-1-2 were superior than Fajr cultivar and without significant differences with Shiroudi cultivar in respect of grain yield. Based on the majority of stability parameters, lines 27610-33-1-1, 2765-3-5-1-2 and Shiroudi cultivar were recognized as stable genotypes with average yield of 7531, 6424 and 6501 kg per hectare, respectively.