Iranian Journal of Field Crop Science
Year:2014 | Volume:45 | Issue:3|Papers Count:17

In this study, 110 samples of bread wheat, Aegilops crassa, Ae. cylindrica and Ae. tauschii were investigated to identify Low-Molecular-Weight Glutenin Subunits. Overall, the four alleles in term of the analysis of SDS-PAGE gels were detected. The a allele with 45% had the greatest frequency, and after that, b, c and d alleles were with 38.1%, 11.8% and 9.1% frequencies, respectively; however, in Ae. crassa, b and c alleles were the highest and the lowest frequencies, respectively. The a, c and d alleles were the highest and the lowest frequencies in Ae. cylindrica; nonetheless, In Ae. tauschii, a and d were the highest and the lowest frequencies. In T. aestivum, b was the highest while d shows the lowest frequencies. Genetic diversity (ζ) in populations of bread wheat, Ae. crassa, Ae. cylindrica, Ae. tauschii and total population were 0.6564, 0.5792, 0.6378, 0.6214 and 0.6294, respectively. Furthermore, the average genetic diversity (H) for the total population was 0.6294. The results showed that wild wheat relatives have various alleles that can be utilized them in breeding programs to improve glutenin.

Water deficit, ultraviolet radiation and carbon dioxide enrichment are the most important environmental factors in global climate change. This research was conducted in Tarbiat Modares University, Research Greenhouse and the objective was to study the effects of three levels of carbon dioxide (500, 900 and 1300 ppm), UV-radiation (UV-A, B and C with intensity of 18, 25 and 40 mW.cm2, respectively) and water deficit (common irrigation and 40 percent of available water remain in soil) on grain yield and some quality traits of sweet corn (Zea mays L. var. Sacarata). The experiment was conducted as factorial arrangement in a randomized complete block design with three replications in one year (2009). The results showed that interaction among UV-C radiation, elevated CO2 and water stress had a significant effect on grain yield and Fv/Fm. The highest grain yield was detected in water deficit and 900 (ml/l) of CO2 concentration. The most content of Fv/Fm was obtained under water deficit and 1300 (ml/l) CO2 concentration. Water deficit and elevated CO2 increased proline, and decreased chlorophyll a, chlorophyll b, chlorophyll a+b, carotenoids and flavonoids. Grain protein decreased with UV wavelength reduction. Above result showed that three main environmental stresses reduced plant productivity in the most aforementioned conditions and as a result decreased the performance of corn plant.

In wheat, Na+ exclusion and K+/Na+ have shown to be associated with salinity tolerance, therefore, in order to identify QTLs with additive effects for Na+ and K+ concentration traits in roots and shoots of wheat, 319 bread wheat recombinant inbred lines (RIL F7), derived from a cross between Roshan (salt tolerant) and Falat cultivars (salt sensitive), along with their parents and two control cultivars (Arg and Moghan3) were studied in two separate randomized complete block design (normal and stress) with three replications in greenhouse in 2012. Measured traits included shoot and root Na+ and K+ concentration, K+/Na+ ratio in root and shoot and root to shoot Na+ and K+ concentrations. Linkage map was constructed with 730 markers (709 DArt markers and 21 SSR markers). The linkage map spanned 4505.71 cM with an average distance of 6.17 cM between adjacent markers. A total of 31 additive QTLs were identified by QTL Cartographer program using single-environment phenotypic values. The results indicated that the biochemical pathways for Na+ and K+ accumulation are highly likely to be independent. Also, results indicated that shoot Na+ concentration and root to shoot Na+ and K+ concentrations could be used as selection criteria between tolerant and sensitive cultivars in salt stress condition.

Reaction of canola genotypes to terminate irrigation was analyzed. This experiment was carried out as a split plot in a randomized block design with three replications in the Safiabad Argicultural Research Center for two years. Main plot was considered of different time of terminating irrigation (terminate irrigation at the end of flowering and 10% and 30% ripening of pods in main stem ) and sub plot was included four canola genotypes (SG10-86369, SG19-86369, SG63-86369 and Hyola401). The combined results showed that the effects of year, terminate time of irrigation, genotypes, and interaction of ending irrigation by genotypes were significant on number of pods per plant, number of grain per pod, 1000 seeds weight, harvest index and grain yield. Means of interaction of ending irrigation by genotypes showed the highest number of pods per plant (97.62) at ending irrigation at 30% ripening of pods in main stem belonged to Hyola401 genotype and the lowest amount achieved in SG10-86369 with stopping irrigation at ending of flowering stage. The highest 1000 seeds weight (4.18 gr) detected for Hyola401 genotype with stopping irrigation at 30% ripening of pods in main stem. Genotypes reactions were different to time of stopping irrigation. The highest grain yield (2743.5 kg/ha) belonged to Hyola401 genotype with stopping irrigation at 30% ripening of pods in main stem and the lowest amount (1465.83 kg/ha) appointed to SG63-86369 genotype with stopping irrigation at the ending of flowering. By considering the same reaction of Hyola401 genotype to stopping irrigation at 10% and 30% ripening of pods in main stem, it is recommended that the stage of 10% pods ripening in main stem is optimum stage for terminating irrigation.

In this study, the ability of 32 rhizobium strains (26 strain of Sinorhizobium meliloti (SM)), 4 strains of Rhizobium leguminosarum biovar phaseoli (Rlp) and 2 salt tolerance strains of Rhizobium leguminosarum biovar viciae (Rlv) for use of ACC as individual nitrogen source in RMM media was evaluated. Based on the results, 25 strains were found positive for ACC-deaminse, and strains according to growth in the RMM media containing ACC were categorized into three groups of strong, medium, and weak. In the next step, in 2011 a series of greenhouse experiments were conducted for investigating the effectiveness of two strains from strong group (R281Rlp and R103Sm) and one strain from weak group (R29Sm) with control treatment, for the promotion of growth parameters of canola under the salinity levels of 0, 3, 6, and 9 ds/m in factorial format experiment as a randomized complete block design with three replications. The Results showed that R281Rlp inoculation, even at higher salinity (9dS/m), significantly increased wet and dry weight of root (32 and 62.6%, respectively), wet and dry weight of shoot (22 and 23.5%, respectively), height (49%) and nitrogen uptake (50%) compared to control treatment. Furthermore, at this level of salinity, R103Sm inoculation increased the uptake of phosphorous up to 34.5% compared to control. A positive correlation was observed between ACC-deaminase activity of bacterial isolates and plant growth parameters; especially root biomass, (Pearson Correlation Coefficients > 0.82). These results revealed that the strains containing high ACC-deaminase activity were more successful in improving the growth parameters of canola seedling, which confirms that using of these strains may be suggested as a biologic alternative to the amelioration of increasingly saline stress.

Adverse environmental storage conditions including high temperature and relative humidity could affect seed quality. The objective of this investigation was to quantify relationship between temperatures and seed moisture on seed deterioration and determination viability constants in sorghum. Four storage temperatures (5, 15, 25 and 35oC) and three moisture content levels (6, 10 and 14%) were used. We carry out viability coefficients using Ellis and Roberts equation and were compared by Probit analysis. Process of germination of sorghum seeds indicated that germination percentage decreased as the storage period progressed. Increasing moisture and temperature of storage decreased germination percentage. Germination percentage of seeds with 14% moisture content stored at 35oC after 90 days of storage was 11%. According to the results, seeds with 6% moisture content stored at 5oC had the highest germination percentage and the least deteriorated state even after 200 days. Estimated value of KE, CW, CH and CQ were 2.49, -0.30019, 0.00725 and -0.00057, respectively. Moreover, our results provide convincing evidence that storage in various storage conditions can reduced seed viability. Also the results showed that increasing moisture content and temperature reduced seed longevity especially under high temperature and seed moisture content.

Expansins are cell wall proteins that due to changes in pH, causing the expansion of the cell wall. These proteins are causing deformation of walls through loosening hydrogen bonds between the cellulose and polymer matrix microfibrils. In this study, a root specific gene called AtEXPA18- that directly affect the formation of root hairs and also its role have been proved in other parts of the plant was isolated from Arabidopsis thaliana and cloned into the plant expression vector PBI121 under the control of CaMV 35S promoter and NOS terminator and finally was transferred to Agrobacterium. This gene was then transferred to the tobacco through leaf disks transformation. Plants obtained from regeneration was selected on screening medium containing kanamycin. Plants were transferred to the greenhouse and after growth, molecular and morphological analysis was conducted. To prove the transformation of plants in genome wide, DNA was extracted and AtEXPA18 gene was amplified by polymerase chain reaction technique with specific primers. Also, the results of RT-PCR confirmed the transcription of transgene in transgenic tobacco, after RNA extraction and cDNA synthesis. The transgenic tobacco plants were shown to have significantly larger leaves and longer stems compared to control plants. The results obtained with the other results demonstrate that the role of mentioned gene in cell expansion and recommend it as a public growth regulator to obtain transgenic plants with larger organs.

One of the most common methods for conservation of plant genetic resources is their ex situ storage as seed gene banks. Seeds that are stored in the gene banks must be regenerated due to exchange and seed deterioration; if they are not be regenerated, the potential benefits of infrastructure investments for germplasm ex situ conservation may not be attained. Prediction of seed longevity is based on viability equation that has four constants which are species specific. The aim of this project was estimation of these constants and then using them for predicting the regeneration time of Thymus transcaspicus, T. daenensis, Salvia officinalis, Satureja hortensis, Dracocephalum moldavica, Descurainia sophia, Eruca sativa and Melilotus officinalis. The seeds were placed in three environments with relative humidity of 20, 40 and 60% and their moisture content was measured after equilibrium. Then the seeds sealed in nylon pockets and stored at 30, 35 and 40oC. The TP germination tests with three replications were done monthly. The Excel software was used for estimation of viability constants (i.e. KE, Cw, CH, CQ). The KE was estimated 5.065, 5, 5, 4.46, 3.837, 4.33 and 4.21 for T. transcaspicus, T. daenensis, Salvia officinalis, Satureja hortensis, Dracocephalum moldavica, Descurainia sophia, Eruca sativa and Melilotus officinalis, respectively. The maximum and minimum seed longevity estimated for T. transcaspicus and Eruca sativa, respectively. If viability be 100% at the beginning of the storage, the seeds of T. transcaspicus and E. sativa with 8% moisture content in the active collection (5oC) must be regenerated after 123 and 15 years, respectively.

One of the soil and water management practices in order to delay drought stress under water deficit condition; is superabsorbent application. In order to study the effects of superabsorbent application on yield and yield components, two antioxidant enzymes contents and water relation of two canola hybrids under terminal drought stress condition, a research was carried out under Ahvaz climate condition. A split-split plot experiment using a complete randomized block design with four replications, in 2009-10 cropping season was conducted. Two water treatments (well-water and terminal drought stress), two canola hybrids (308 and 401), and three superabsorbent applications (0, 75 and 150 Kg/ha) were considered as the main, sub and sub-sub plots, respectively. Yield and yield components, and some physiological characters including glutathione peroxidase (GPX), super oxide dismutase (SOD) contents, cytoplasm membrane leakage (CML) and leaf relative water content (RWC) were measured. The results showed that except for the harvest index, effect of water treatment was significant for grain yield, all other yield components and physiological characters. Hybrids differences were significant only for biological yield. The effect of superabsorbent application was not significant for biological yield and thousand grain weight. Interaction effects of hybrids by superabsorbent application and water treatment by superabsorbent application were significant for yield and yield components. Mean grain yield under well-water and terminal drought stress conditions were 2948 and 1345 Kg/ha, respectively. Contents of GPX, SOD enzymes and RWC decreased while CML increased under terminal drought stress condition. According to the comparison of grain yield and yield components and also based on physiological traits which were studied in this research, however, superabsorbent application decreased the water deficit effect under terminal drought stress condition, but it is not likely that superabsorbent application could compensate the terminal water stress damage per se.

Soil and water salinity is a major constraint in arid and semi-arid regions. In order to study the impact of water salinity on physiological characteristics and dry matter production of six linseed genotypes, a 4-replicate factorial randomized complete block pot experiment was conducted. Salinity consisted of four levels: 0 (control), 35 (low salinity), 70 (intermediate salinity) and 105 mM (severe salinity) of NaCl and genotypes consisted of C1, C2, C3, B, 33 and Khorasan. Severe salinity led to 37, 33, 36, 3, and 61% decreases in chlorophyll a (chl a), chl b, total chl, chl a/chl b and carotenoids contents, respectively. Mean proline content of plant leaf and root increased by 6.35- and 1.54- fold under 105 mM, compared to the control, respectively. Genotypes C3 and 33 indicated the greatest (6.4-fold) and smallest (2.8-fold) increases in leaf proline content, respectively. Khorasan indicated the greatest increases (3.81-fold) and C3 the smallest (1.97-fold) increase in leaf soluble carbohydrate content. While mean antioxidant activities increased with salinity, the greatest mean enzymes activities were detected with the intermediate level of salinity. In contrast to the rest of genotypes, Khorasan and 33 indicated increases in their catalase, ascorbate peroxidase and glutation peroxidase activities when subjected to the severe salinity, compared to the intermediate salinity. Mean plant dry mass decreased with increase in salinity, with Khorasan indicating the smallest decrease. It could be concluded that physiological attributes, growth and dry mass production in linseed is negatively affected by NaCl, even with intermediate water salinity. Genotypes Khorasan and C3 seemed to be more resistant to the NaCl salinity due, at least in part, by maintaining or increasing the level of antioxidants activities.

In order to study of the effects of nitrogen sources, operation methods and weed control methods on weed biomass, yield and yield components of corn (Zea mays L.) an experiment was carried out as split plot factorial based on a randomized complete block design (RCBD) with four replications in Shahrood University of Technology. The treatments included weed control methods at four levels (hand weeding at all growth season, weedy, EPTC herbicide at regular dose and 50% regular dose) as main factors, nitrogen sources at two levels (urea and ammonium sulphate) and operation methods at two levels (band and broadcast) as sub plots. Results showed that EPTC herbicide at regular dose and band operation method reduced weed biomass more than EPTC herbicide at 50% regular dose and weedy check treatments. Weed control methods significantly affected grain yield, 1000-seed weight, seed row number per ear, seed number per row, ear length, biological yield and ear weight traits. Nitrogen sources significantly affected only ear length and ear diameter. The interaction of nitrogen sources and weed control methods significantly affected only ear length and ear diameter. Hand weeding at all growth season and EPTC herbicide at regular dose produced maximum grain yield. Grain yield for EPTC herbicide at 50% regular dose and weedy treatments was the same and at the least effect. Seed row number per ear and 1000-seed weight traits were the highest for EPTC herbicide at regular dose and at the least for EPTC herbicide at 50% regular dose and weedy treatments. Interaction of weed control methods and nitrogen operation methods significantly affected seed number per row in corn.

Selection of proper cultivars and lines is affected by genotype-environment interaction dramatically. In order to study genotype × environment interaction in rice, 12 lines with 2 commercial cultivars as check cultivars (Neda and Fajr) was studied in 9 different environments (3 location and 3 years). The experiment was a randomized complete block design (RCBD) with three replications. The differences among genotypes, environments and their interaction were significant. The yield stability was studied by AMMI method. The results showed that two principal components were significant and explain 67% of interaction variance. The results revealed that grain yield was highly influenced by environmental factors. The line 9 had higher yield than mean and with the lowest for the first interaction principal component, thus distinguished as stable line. Biplot of the two first interaction components revealed that line 9 in Sari (2008) and Amol (2008) had specific adaptability. Also Lines 4 and 8 in Tonkabon (2008 and 2009) and in Amol (2010) had specific adaptability. Lines 6, 7, 10 and Neda cultivar in Sari (2009, 2010) had specific adaptability. The lines 1, 2, 3 and 5 in Tonkabon (2010) had specific adaptability. Finlay, the lines 2, 5, 7, 12 and Fajr and Neda cultivars had the highest common adaptability to environments.

In order to investigate the effects of irrigation intervals and harvesting time on yield and yield components of Anise (Pimpinella anisum L.) a field experiment was conducted at the Agricultural Research Station, University of Zanjan in 2010. For this purpose, a spilt-plot experiment based on a complete randomized block design with three replications was used. Three irrigation intervals (every 7, 12 and 17 days) allocated in main plots and three harvesting time, including harvest at soft dough (waxy), hard dough and full maturity stages allocated to sub plots. The results indicated that effect of irrigation intervals on majority of measured traits including number of seed in umbellet, number of seed in umbrella, number of umbrella in plant, seed thousand weight, grain yield, grain essence content and essence yield was significant (P≤0.05). With increasing irrigation interval from 7 to 17 days, majority of measured traits such as grain yield and essence yield decreased significantly but grain essence content significantly increased. Therefore, the highest grain yield (636.07 kg/ha) and essence yield (23.76 kg/ha) was obtained in 7 days irrigation interval and the lowest amount of mentioned traits was obtained from 17 days irrigation interval. Also harvesting time had significant effect (P≤0.05) on some of traits including seed thousand weight, number of seed in umbrella, grain yield, grain essence content and essence yield. By delaying in harvesting time from hard dough to full maturity stage, number of seed in umbrella, grain yield, grain essence content and essence yield significantly decreased. The results also showed that interaction effect of irrigation intervals and harvesting time on grain yield was significant. The highest grain yield was obtained with 7 days irrigation interval and hard dough stage.

To study the effects of salinity on physiological and morphological traits of chickpea two experiments were conducted in 2010 at Faculty of Agriculture and Natural Resources, University of Tehran. Seven chickpea genotypes and 5 levels of salinity stress (Ctrl, 200, 150, 100, 50 mM) were used. Two laboratory and greenhouse experiments were conducted using RCBD design with 3 replications. Some traits were recorded such as germination percentage, root length, shoot length, and vigor index in laboratory. According to the results, mentioned traits had linear response with increasing of salinity stress. The highest and the lowest of germination percentage were obtained in 200 mM treatment for G485 and G456, respectively. G485 had the highest vigor index in response to 200 mM treatment. The biomass of pea genotypes was significantly affected by salinity levels, so the stress level of 50 mM in G485 with 3.8 g had the highest levels of biomass. In the second study, activities of catalase, peroxidase, polyphenol oxidase, total chlorophyll content, carotenoids and biomass were evaluated. G104 genotype had the highest catalase activity (1.75unit) and proxidase activity and for polyphenol oxidase G485 genotype exhibited the highest in 200mM treatment. Also the highest (93%) and the lowest (54%) reduction percentage of chlorophyll content were observed in G643 and G485, respectively. Results showed a high correlation between antioxidant enzyme activities and chlorophyll, so that genotypes with higher antioxidant activity had higher chlorophyll content and biomass. There was positive correlation between salinity resistance at germination stage and seedling stage under greenhouse conditions.

In order to evaluate the effects of atmospheric CO2 concentration increment on rapeseed salinity tolerance, four levels of salinity (0, 5, 10 and 15 dS.m-1) on three cultivars of rapeseed (Okapi, Zarfam, and RGS) at three levels of atmospheric CO2 concentration (350, 700 and 1050 ppm) were studied. The experiment was conducted at the greenhouse of Tarbiat Modares University at 2010 and 2011 crop season. Three levels of CO2 concentrations have been considered as three environments in which two other treatments (salinity and cultivar) carried out in a completely block design in factorial arrangement. Results indicated that photosynthesis rate of canola increased with increasing CO2 concentration (about three times in 1050 ppm) in the air and decreased with increasing salinity (21% in 15 dS.m-1). Three times concentration of CO2 (1050ppm) reduced the impact of salinity on photosynthesis. Elevated CO2 by increasing photosynthesis rate, reducing transpiration and increasing water use efficiency reduced the effects of salinity. Water use efficiency was increased with increment concentration of carbon dioxide and decreased with salinity.