JOURNAL OF AGRICULTURAL SCIENCE AND TECHNOLOGY (JAST)
Year:2015 | Volume:17 | Issue:1|Papers Count:25

In this study, application of Adaptive Neuro-Fuzzy Inference System (ANFIS) in forecasting three perspectives (1, 2, and 4 years) ahead of Iran’s agricultural products export was compared with ARIMA as the most common econometrics linear forecasting method. For this purpose, Iran’s agricultural products export revenues related to 1959-2010, and forecast performance measures such as R2, MAD, and RMSE were used. Results of the models performance evaluation showed that the forecasted test data related to ANFIS designed architects had more correspondence with the real data in comparison with that of ARIMA forecasted out of sample data. Therefore, the non-linear ANFIS model outperformed the linear ARIMA model for all of the considered perspectives.

This study presents a detailed analysis of cost management for intensive cultivation activity in terms of tomato production. The main objective was to provide qualitative and quantitative costs obtained in the intensive cultivation of tomato. This methodology was structured by activity costs (soil preparation and planting, crop monitoring, harvesting, selling, etc.) through a study in greenhouses in Almeria, Spain. According to the results, this kind of management provides a cost analysis of the products, with extensive information on variable costs, produces measures that are used for cost management and operational performance evaluation; helps in the identification and the evolution of costs; identifies the main activities and tasks carried out during the growing season; and quantifies the cost margin, which enables the farmers to position their products strategically in the market with competitors.

Spodoptera exigua (Hübner) was studied in laboratory (25±1oC, 60±5% RH, and 16:8 L:D h) exploring the antibiotic effects of 10 canola cultivars (Sarigol, SLM046, Hayula420, RGS003, Opera, Okapi, Licord, Modena, Zarfam and Talaye) on its demographic parameters. The age-stage, two-sex and the traditional female age-specific life tables were constructed by using the demographic data. The larval period was longest on Modena (17.53 days) and pupal period was longest on Opera (8.96 days). The longest and shortest development time of immature stages lasted 29.96 and 25.82 days on Talaye and Okapi, respectively. Male adult longevity was longest on Okapi (14.93 days) and shortest on Hayula420 (9.14 days), and female adult longevity was longest on Zarfam (18.04 days) and shortest on Hayula420 (8.07 days). Based on the two-sex life table, the net reproductive rate (R0), intrinsic rate of increase (r), and finite rate of increase (l) were highest on Okapi (352.96 offspring per individual, 0.201 and 1.223 day-1, respectively). The lowest value of R0 was recorded on Opera (152.73 offspring per individual) and lowest value of r and on Talaye (0.142 and 1.153 day-1, respectively). The mean generation time (T) took longest time on Modena (36.41 days) and shortest on Okapi (29.06 days). The results of this study showed that ‘Okapi’ was the most suitable canola cultivar for reproduction and population growth of S. exigua, which revealed higher susceptibility of ‘Okapi’ to this pest.

Increased nitrogen applications to crops influence plant-herbivore interactions and potentially increase herbivore population growth. In this research, the impact of nitrogen fertilizations on nutritional quality of three canola (Brassica napus L.) cultivars (Zarfam, Okapi and Modena), and, consequently, the performance of mustard aphids, Lipaphis erysimi Kalt., on them were investigated under green house conditions. Nitrogen fertilization treatments were 0, 75, 150, and 225 kg N. ha-1. The results showed that increased nitrogen fertilization resulted in enhancing plant nitrogen content and decreasing of C/N ratio of leaves. Based on N-content and C/N ratio, Zarfam had the highest nutritional quality for herbivore among the tested canola cultivars. Fertilization generally increased the susceptibility of plants to mustard aphid. Therefore, aphids feeding on plants receiving higher nitrogen levels had shorter nymphal developmental time, longer adult longevity as well as greater fecundity. The highest and the lowest values of aphids’ intrinsic rate of increase (rm) were calculated on Zarfam and Modena cultivars, respectively. Moreover, nitrogen fertilization positively affected rm of aphids on all canola cultivars. According to our results, management of nitrogen fertilization and cultivation of resistant cultivar could be suitable eco-friendly strategies to manage mustard aphid population.

In this study greenhouse tomato production was investigated from energy consumption and greenhouse gas (GHG) emission point of views. Moreover, artificial neural networks (ANNs) and adaptive neuro-fuzzy inference systems (ANFIS) were employed to model energy consumption for greenhouse tomato production. Total energy input and output were calculated as 1, 316.14 and 281.1 GJ ha-1. Among the all energy inputs, natural gas and electricity had the most significant contribution to the total energy input. Evaluations of GHG emission illustrated that the total GHG emission was estimated at 34, 758.11 kg CO2eq ha-1 and, among all the inputs, electricity played the most important role, followed by natural gas. Comparison between ANN and ANFIS models showed that, due to employing fuzzy rules, the ANFIS-based models could model output energy more accurately than ANN models. Accordingly, correlation coefficient (R), Root Mean Square Error (RMSE) and Mean Absolute Percentage Error (MAPE) for the best ANFIS architecture were calculated as 0.983, 0.025, and 0.149, respectively, while these performance parameters for the best ANN model were computed as 0.933, 0.05414, and 0.279, respectively.

Cadmium (Cd), known as a non-essential heavy metal, can cause oxidative stress in plants. In this study, an attempt was carried out to find out whether Cd-induced oxidative and microscopic changes could be observed in the early stage of seedling growth. Seeds of Brassica napus (cvs. Zheda 619 and ZS 758) were germinated in vitro at 0, 100, 200, 300, and 500 mM Cd concentrations in dark for 48 hours. Results showed that the higher concentration of Cd (500 mM) significantly reduced plant growth in both cultivars. However, Cd concentration in both cultivars increased linearly with the Cd concentration, but was more pronounced in ZS 758 than the other cultivar. Moreover, Cd caused oxidative stress in germinated seeds by increasing reactive oxygen species, however, no relationship was found between antioxidative defense capacity including catalase, peroxidase, superoxide dismutase and glutathione reductase activities and Cd tolerance in the two cultivars. Cd toxicity showed significant ultrastructural changes in germinated seed cells, but cell structure in Zheda 619 did not show any difference, while cell structure in ZS 758 was totally damaged under higher concentration of Cd (500 mM). Based on the present findings, it can be concluded that cultivar Zheda 619 showed comparatively higher tolerance and integrity of cell organelles under Cd stress.

Nineteen bread wheat genotypes were selected to examine the effect of glycine betaine (GB, 100 mM) on various photosynthetic gas exchange parameters under drought stress and to study the relationship of these parameters with non-enzymatic antioxidants. Drought stress caused a significant decline in net CO2 assimilation rate (Pn), stomatal conductance (gs), intercellular CO2 concentration (Ci) and transpiration rate (E) among the studied wheat genotypes, with the tolerant genotypes characterized by higher net photosynthetic rate, lower drought susceptibility index (DSI), and higher maintenance of glutathione content (GSH) and ascorbic acid (AsA) levels than the sensitive ones. GB application significantly improved the photosynthetic characteristics, particularly Pn and gs, of studied wheat genotypes which could be due to more utilization of glutathione and increased levels of ascorbic acid in flag leaves under drought stress. But this response was observed to be genotype specific. Positive correlation of AsA with DSI in GB treated plants, and of Pn with GSH under drought stress and GB applied conditions suggested the role of these non-enzymatic antioxidants in sustaining photosynthetic efficiency and yield stability under prolonged field drought stress conditions.

Tarkhineh is one of the traditional foods in Iran and a rich source of probiotic bacteria. The objective of this study was to identify the probiotic bacteria isolated from Tarkhineh using 16S rRNA gene sequencing and molecular typing with repetitive extragenic palindromic–PCR (REP-PCR). In total, 20 different bacteria were isolated from traditional dairy products and Tarkhineh. Molecular identification of the isolates was carried out by 16S rRNA gene sequencing, and DNA sequences of isolates deposited in GenBank. The REP-PCR reaction by REP1R-I, REP2-I and REP1R-I+REP2-I markers was performed for fingerprinting and characterization of the isolates. Unweighted pair group method with arithmetic mean (UPGMA) clustering methods were performed based on Dice similarity. The REP1R-I primer grouped isolates into three, and REP2-I and REP1R-I+REP2-I grouped all isolates into four main clusters in dendrograms. In all analyses, isolates of Lactobacillus casei, Lactobacillus brevis, Lactobacillus plantarum, and Entrococcus facium formed separate clusters. The results of sequencing corresponded to clustering in the dendrogram. According to the results, REPPCR is an accurate technique for determining the genetic diversity of lactic acid bacteria species.

Despite the numerous health effects of the dietary fibers, the amount of the fiber in the diet is generally lower than the recommended value. Therefore, increasing the fiber content of the foods particularly those of high consumption can compensate for the shortage of the fiber in the diet. However, it seems a difficult task since increasing the fiber content can have adverse effects on product acceptability. The main objective of this study was to include oat fiber in the cake recipe and to determine the physical and sensory properties of the resultant product. Therefore, oat fiber at different levels of 0, 5, 10, 15, 20, and 30% (w/w, flour basis) were added in the cake recipe. Increasing the level of oat fiber resulted in the increase in batter density and consistency and cake volume. In addition, cake crust and crumb became darker. Cake hardness and gumminess increased, while cohesiveness and springiness decreased as determined using a texture analyzer. Cakes containing no more than 20% oat fiber had acceptable sensory characteristics. In total, it was concluded that addition of maximum 20% oat fiber to cake can result in a product of acceptable sensory characteristics.

Morphological and RAPD markers were used to investigate the genetic diversity among 21 accessions of pomegranate originating from South Eastern Tunisia. Thirteen morphological traits were studied and results showed significant differences for all morphological characters (P<0.001). Clustering based on fruit traits, using Ward’s method, divided the accessions into three main groups. In RAPD analysis, 6 out of 15 employed random primers showed good amplification and polymorphism on pomegranate samples with a total of 63 bands, of which 56 were polymorphic. The lowest percentage of polymorphism (50%) was observed with TIBMBA-03 while the highest (50%) was observed with primer TIBMBB-03. According to Jaccard coefficient, the lowest (0.29) and highest (0.94) similarities were detected between genotypes. UPGMA clustering based on data from polymorphic RAPD bands resulted in three clusters at a similarity of 0.46. The Stress value for the nonmetric multidimensional scaling plot was 0.071, showing an excellent representation of the data. The comparison between groupings based on the fruit traits and RAPD data did not produce a significant correlation (r=-0.09). Using a stepwise linear regression, significant regressions were found between 13 morphological traits and 63 molecular markers revealing association between RAPD molecular markers and some traits.

Saturated fat consumption increases the risk of both coronary and cancer diseases. Therefore, fat reduction in UF-Feta cheese (»45% FDM) is favorable but, unfortunately, it has some negative effects on the texture and sensory characteristics of the cheese. In this research, response surface methodology was employed to study the probably improving effects of WPC80 (0-20 gr kg-1), lecithin (0-2 gr kg-1) and a mixture of xanthan and guar (0-1 gr kg-1) on sensory and instrumental texture characteristics of low-fat UF-Feta cheese made from 6% fat retentate. Lecithin and xanthan-guar had positive and WPC80 had negative effects on hardness, chewiness, and gumminess of the cheeses. Furthermore, results showed lecithin had negative effects on taste, acceptance, and appearance and positive effects on sensory texture. The taste was improved by WPC and xanthan-guar enhanced sensory texture and acceptance scores. Finally, multiple response optimization method was used to determine optimized formula of low-fat cheese (19.47 gr kg-1 WPC80, 0.5 gr kg-1 xanthan-guar and 0.13 gr kg-1 lecithin). A cheese sample produced based on optimized formula and full fat cheese had similar sensory and instrumental texture.

In this research, rehydration behavior of dried figs was studied at different temperatures (25, 60, 70, 80, and 90oC). The rehydration kinetic was examined using the four most frequently used empirical models, namely, Weibull, Peleg, first-order, and exponential association models. The Weibull model gave the highest coefficient of determination (R2) and the lowest values of root mean square error (RMSE), sum of squared error (SEE), and chi-square (X2) was considered the best. In all models examined, the equilibrium moisture content showed statistically significant differences as compared to the rehydration temperature. The temperature dependence of kinetic constants was described in terms of Arrhenius relationship. The average activation energy for the four models was 24.362 kJ mol-1. During the rehydration process hardness of dried figs decreased, which was further confirmed by microscopic evaluation. Scanning electron microscopy (SEM) images of rehydrated figs indicated porous structure proposing the presence of free water.

Plantation Located in a Semiarid Climate We estimated the rainfall interception loss (I), canopy storage capacity (S), the ratio of mean evaporation rate from the wet canopy (E-) over the mean rainfall intensity (R-) (mm h-1) (E- / R-), and free throughfall coefficient (p) in a Fraxinus rotundifolia Mill. stand located in an afforested Park land in a semiarid region of Iran. For each storm event, I was calculated as the gross rainfall (GR) minus throughfall (TF). S was estimated by indirect methods: the minimum, the mean, and the Gash and Morton. Fifty-five rainfall events were recorded (cumulative GR 197.2 mm), with 31 events occurring during the growing season (total GR 88.0 mm) and 24 events measured during the non-growing season (total GR 109.2 mm). The mean ratio of I to GR equalled 39.2% during the growing season vs.23.9% during the non-growing season. For the growing season, S was estimated to be 0.27, 0.21, and 0.23 mm using the minimum, mean, and Gash and Morton methods, respectively. For the non-growing season, these values were estimated to be 0.17, 0.13, and 0.15 mm, respectively. During the growing and non-growing seasons, E- / R- were estimated to be 0.13 and 0.11, respectively, with the corresponding p values of 0.39 and 0.52. The loss of the leaves resulted in decline in I, S, and E- / R-, and increase in p. For semiarid regions, these values are useful for solving some water management problems.

The accumulation and composition of berry anthocyanin was measured in Vitis vinifera L. cv. Yatomi Rosa using various light qualities provided by polyethylene films (red, orange, green, blue, and white). The anthocyanin has been enhanced significantly by blue light filter film and suppressed by red, orange, and green films compared to white film (control), which suggests that Yatomi Rosa has adapted photoreceptors to UV-A/blue light. We also observed that Yatomi Rosa mainly accumulated glucosides of peonidin (Pn). Significant differences in composition of anthocyanin were observed in different light filter films. Despite the use of different light quality films, similar patterns were observed for phenylalanineammonia-lyase (PAL), cinnamate-4-hydroxylase (C4H), 4- coumarate: coenzyme A ligase (4CL), and chalcone isomerase (CHI) activities, which are components of the anthocyanin biosynthetic pathway. But the activities of PAL and CHI were induced significantly under blue light filter film, which shows that blue light may increase anthocyanin accumulation in V. vinifera L. by stimulating PAL and CHI activities. The present study confirmed the importance of blue irradiance spectrum in anthocyanin biosynthesis in Yatomi Rosa. The increase of blue light under enough effective transmission light conditions in greenhouses can improve the color of Yatomi Rosa and may be used as a solution to overcome poor berry colors in hot and humid regions of Southern China.

Salicylic acid has been found to play an important role in the regulation of plant growth and development in response to environmental stresses. In the present study, the effect of salicylic acid (SA) (0 and 0.1 mM) on growth parameters and some physiological characteristics of two strawberry cultivars ("Kurdistan" and "Queen Elisa") was investigated under drought stress treatments (-0.1 and -1 MPa). Experimental design was factorial based on completely randomized design with three replications. Results showed that drought stress decreased leaf area, leaf dry matter, shoot dry matter, total dry matter, relative water content, stomatal conductance, yield, and fruit weight. Salicylic acid application increased total leaf area and leaf and shoot dry matter in both cultivars. Leaf number, root dry matter, total dry matter, yield and fruit weight were increased by SA application in "Kurdistan" under drought stress. "Kurdistan" cultivar had higher RWC than "Queen Elisa" and SA application increased RWC, proline and soluble carbohydrate in "Kurdistan" compared to "Queen Elisa" under drought stress conditions. RWC, proline and soluble carbohydrate of “Queen Elisa" did not change with SA spray. Total soluble protein was not affected in "Kurdistan" under drought stress, while "Queen Elisa" showed a reduction in total protein. SA application increased catalase and peroxidase activity in both cultivars under drought stress. In conclusion, “Kurdistan” was less susceptible to drought stress than “Queen Elisa” because “Kurdistan” showed less reduction in leaf number and area, crown, and total dry matter compared to “Queen Elisa”. SA application altered some physiological responses of both cultivars under drought stress. The effect of SA was more pronounced in "Kurdistan” than "Queen Elisa".

Poinsettia (Euphorbia pulcherrima cv. 'Premium Red') as an ornamental pot plant is widely grown in peat-based substrates with high phosphorus (P) fertilization. The aim of the current study was to evaluate the P demand of poinsettia according to its P depletion ability during the growth stages by using a mechanistic simulation model. For this purpose, rooted poinsettia cuttings were grown in the medium with 80: 20 (V: V%) peat+mineral component (generally called as clay) and treated with different P levels of zero, 10, 35, 100, and 170 mg P [L substrate]-1. The yield and quality performance of the plants were evaluated thoroughly. Also, depletion of P around the root surface and the effect of buffering power on the depletion profile were assessed by means of mechanistic simulation model. The results showed that, in peat-based substrates, P was transported to the root surface mainly by mass-flow. The simulation approach also revealed that the well supplied plants cultivated in the peat-substrates needed a higher concentration gradient (30-50 mM) to drive the necessary flux and that the amount of plant available P (Cs) was limiting at later growth stages. The optimum yield and quality of poinsettia was obtained at the P application rate of 35 mg L-1 substrate, with Cs of 11-12 and 15-16 mg [L substrate]-1 at planting and 53 days after planting. It was concluded that, to ensure a sufficiently high concentration gradient, P had to be supplemented by frequent fertigation at later growth stages, but not at the early growing stage.

In this research, some of the echo-physiological characteristics of pistachio trees were studied to understand crop response to drought stress and determine the best irrigation interval. This experiment was carried out in an orchard with a sandy loam textured soil and a commercial cultivar of pistachio named Ouhadi grafted on Pistacia vera L. rootstock for three years. The irrigation system selected was surface flooding with intervals of 30, 50, 80, and 110 days. These intervals were chosen so as to resemble common irrigation intervals of pistachio orchards in the region. This enabled a comparison between the best and worst conditions of trees in respect to drought stress. Total irrigation water received was a constant depth of water to all treatments. Quantitative and qualitative yield such as weight of fresh and dry nuts, percent of blank and split nuts, and number of nuts per ounce, vegetative and echo-physiological characteristics were considered and measured. In terms of yield quantity and quality, the results showed vegetative and echo-physiological attributes to be significantly different between the treatments of 30, 80 and 110 days irrigation intervals. This means that with an increase in irrigation intervals and considering soil water holding capacity, soils were not able to provide enough moisture for the plant to carry out its normal metabolic activities. However, in the prolonged irrigation intervals, there were not much differences between treatments i.e. the pistachio tree could adapt itself to the naturally occurring environmental stress conditions.

Virtual water adds a new dimension to crop trades and provides a new way of thinking about water scarcity. A systematic analysis of virtual water flows requires integration of all critical drivers of virtual water flows under a single consistent framework. The aim of this study was to assess virtual water flows related to trades of grain crops (wheat, corn, rice, and coarse cereals) and their influencing factors in Hetao irrigation district, China during 1981-2010. Results indicated that: (1) volume of virtual water export decreased from 2.08×109 m3 in 1981 to 1.27×109 m3 in 2010. Volume of virtual water import fluctuated around 621.48×106 m3 during study period; (2) Cultivated area per capita and total population were the major influencing factors for virtual water export in Hetao irrigation district. Volume of virtual water import was mainly influenced by consumption and retail price index of grain crops. Combination of large volume of virtual water export and severely constrained water resources confronted Hetao irrigation district with great challenges in its sustainable development. Decreasing virtual water export is a mean to alleviate regional water shortage pressure, and may be achieved by measures that constrain continued population expansion.

Basal stem rot caused by Sclerotinia sclerotiorum (Lib.) de Bary is one of the most important diseases of sunflower. Quantitative trait loci (QTL) implicated in partial resistance to two isolates of S. sclerotiorum (SSU107 and SSKH41) were investigated using F9 recombinant inbred lines (RILs) from the cross between sunflower parental lines PAC2 and RHA266. Experiments were conducted in completely randomized design with 3-6 replications under controlled conditions. The reaction of genotypes to basal stem rot disease was evaluated by measuring the percentage of necrosis area three days after inoculation. Combined analysis of experiments showed significant interactions between sunflower genotypes and S. sclerotiorum isolates suggesting that partial resistance to S. sclerotiorum should be isolate-specific in sunflower. QTLs were mapped using an updated high-density SSR and SNP linkage map. The map consisted of 210 SSRs and 11 genederived markers placed in 17 linkage groups (LGs). The total map length was 1,653.1 cM with a mean density of 1 marker per 7.44 cM. A total of 14 QTLs were detected for partial resistance to two isolates. The phenotypic variance explained by QTLs (R2) ranged from 0.10 to 9.85. The sign of additive gene effects showed that favorable alleles for partial resistance to isolates came from both parents. Six QTLs were common between two isolates on LGs 1, 8 and 17, whereas the others were specific for each isolate. Colocalized QTLs on LG 1 were linked to the glutathione S-transferase gene (GST). The colocalized QTLs for partial resistance to basal stem rot isolates could be good candidates for marker assisted selection (MAS).

During a survey, five known species of plant-parasitic nematodes of the families Tylenchidae and Dolichodoridae (Tylenchomorpha: Tylenchoidea) were collected and identified from several locations in Golestan, Guilan, Kurdistan, and Fars provinces. Paratrophurus kenanae, Tylenchus elegans and T. ritae, as new records for Iranian nematode fauna, with the two previously reported species Filenchus butteus and Tylenchorhynchus leviterminalis are illustrated and described. The similarity of several species of Paratrophurus with those of the closely related genus, Tylenchorhynchus, is also discussed.

Bacterial leaf streak (BLS) caused by Xanthomonas translucens pv. Cerealis (Xtc) is an important disease of wheat (Triticum aestivum L.) worldwide. The management methods presently in practice are insufficient to meet current safety and/or efficacy standards. Therefore, use of resistant genotypes is the best approach to manage BLS. The present study was undertaken to identify possible sources of resistance to Xtc in cereal cultivars and germplasm. Twelve strains of Xtc were isolated from symptomatic leaves in several regions in Kerman province. Out of twelve, nine strains produced the expected Xtcspecific 120 bp fragment using PCR and the primer pairs PABr/PBf. Six strains produced water-soaked streaks covered with exudates on wheat cultivars, whereas the three remaining strains incited only chlorotic streaks with no water-soaking on leaves. A highly virulent strain that caused conspicuous water-soaking and necrosis was used for inoculation of 645 winter and spring wheat, barley, and rye accessions to identify possible sources of resistance to BLS. The fourth leaves of test plants were infiltrated with bacterial suspension and scored after seven to ten days. Among all the accessions evaluated, only two rye accessions, namely, 4538 and 4794, were resistant to BLS. These two rye accessions can potentially be used in breeding rye and triticale cultivars for resistance to BLS.

The objective of this study was to investigate the effects of addition of pulses in crop sequences, crop residue management, and application of fertilizer N on soil nitrogen content, soil organic carbon, nutrient uptake, and its consequences for wheat yields. The field experiments were carried out from 2009 to 2012 in the sub-humid and sub-tropical zone of northern India. The treatments were (i) crop residue retained (+Residue) or (ii) removed (-Residue), (iii) 120 kg N ha-1 applied to wheat, (iv) 150 kg N ha-1 to maize, and (v) a control with no nitrogen applied to either wheat or maize. The cropping systems consisted of a rotation of wheat and maize or wheat and green gram. Postharvest incorporation of crop residues significantly (P<0.05) increased the wheat grain and straw yields during 2010-2011 and 2011-2012. On average, crop residues incorporation increased the wheat grain yield by a factor of 1.31 and straw yield by 1.38. The wheat crop also responded strongly to the previous legume (green gram); grain yield increased by a factor of 1.89 and straw yield by 2.05, compared to the control. Application of fertilizer N to the preceding maize crop exerted a strong carryover effect on grain (1.18) and straw yield (1.26) wheat. Application of N fertilizer to wheat increased grain and straw yields by, respectively, a factor of 1.69 and 1.79 on average. The overall conclusion is that an improved crop residue management, combined with application of fertilizer N or incorporation of legumes greatly improves the N economy of cereal cropping systems and enhances crop productivity in soils with a low N content on the short term.