JOURNAL OF AGRICULTURAL SCIENCE AND TECHNOLOGY (JAST)
Year:2012 | Volume:14 | Issue:6|Papers Count:21

Iran's economy dependence on oil revenues has caused some impacts in the form of commodity price fluctuations on current revenues. Accordingly, in the past few years especially in the Second Development Plan, the government included encouragements and reduced the country's dependence on oil revenues in its agenda. Agricultural export, especially livestock and poultry export has a proper status due to its relative advantage. Therefore, this study aims to identify the factors affecting the supply of export animal products. For this purpose, factors affecting the export of livestock products were identified using Co-integration Analysis. Empirical results showed that livestock products export is significantly affected by livestock added-value, changes in price index of export goods, subjective price index of livestock products and climate changes.

Sunn pest is a serious pest of cereals causing severe damage to the crop especially wheat. Its life cycle is comprised of two different phases, one is the growth and development phase and the other is diapause phase which takes place at the adult stage. In this study the effects of juvenile hormone analogue Pyriproxyfen, ecdysone analogue methoxyfenozide and a mixture of Pyriproxyfen plus methoxyfenozide on diapause termination of<24-h-old-, 45day old-, and 90 day old adult Sunn pests were examined using topical application. Pyriproxyfen and a mixture of Pyriproxyfen plus methoxyfenozide induced the growth of the female reproductive organ whilst methoxyfenozide had no effect on adult diapause termination. Also, Pyriproxyfen failed to induce egg deposition in sexually immature adults of Sunn pest. Pyriproxyfen, methoxyfenozide and a combination of the two exerted no effect on the termination of diapause in<24-h-old treated adult Sunn pests. However, Pyriproxyfen alone and a mixture of Pyriproxyfen plus methoxyfenozide successfully terminated reproductive diapause of 45, and 90 day old adult Sunn pests. Treatment of female only with Pyriproxyfen (10,000 ppm) induced termination of diapause and made egg-laying activity appear. However, egg number and percent of hatchability (27.6±7.5 and 9.77±4.89% respectively) were significantly lower than the treatment of both males as well as females with Pyriproxyfen (53.5±4.8 and 33.18±2.7% respectively) (P<0.01). Treatment of the insect with these Insect Growth Regulators (IGRs) i.e. Pyriproxyfen and a combination of Pyriproxyfen plus methoxyfenozide produced significant differences in the egg and haemolymph protein concentrations, too. Thus, it is shown that these treatments affect vitellogenesis in Sunn pest.

This study was carried out to determine the effect of seed growing regions and loading speed on some mechanical properties of castor seed. These properties are used to design and improve related machines such as expeller that are used for extraction of oil from castor seed. Mechanical properties of castor seed were expressed in terms of rupture force and energy, bio-yield force, apparent modulus of elasticity and toughness using material testing machine. Factorial test with Completely Randomized Design (CRD) was used to study the effect of velocity (4 levels: 5, 15, 25, 35 mm min-1) and seed growing regions (Izeh, Dezfoul, Baghmalek, Shoushtar and Urmia). The results showed that the effect of seed growing region on force, modulus of elasticity, bio-yield force and rupture energy was significant. Izeh seed had the maximum rupture force (75.11 N) whereas Dezfoul and Shoushtar seed had the minimum amount of rupture force (approximately 42 N). Also, loading speed had a significant effect on modulus of elasticity and rupture energy. With the increase of loading speed modulus of elasticity of Baghmalek seed decreased significantly from 144 to 65.5 MPa. Finally, interaction effect of seed growing region and loading speed was significant for most properties. In this research work, an extrusion system was designed and fabricated for the extraction of castor oil.

Drying properties of high moisture potato slices with initial moisture content of about 4.06 (db) under thin layer fixed, semi fluidized and fluidized bed conditions were studied. Drying air temperatures of 40, 50, 60 and 70oC were applied in experiments using a laboratory fluidized bed convective dryer. In order to predict the drying behavior of potato slices, seven thin layer drying models were applied from where finally Midilliet al. model was selected as the suitable one, based on comparative indices. Effective moisture diffusivity of the potato slices varied between 4.29×10-9 and 15.70×10-9 m2 s-1 for fixed and fluidized bed conditions, respectively. Moisture diffusivity values of the slices were increased as the drying air temperature levels increased. Activation energy values varied between 15.88 and 24.95 kJ mol-1. Minimum and maximum values of activation energy were obtained at minimum fluidized and fixed bed conditions, respectively. Consumption of specific energy for thin layer drying of high moisture potato slices was obtained between 0.45×105 and 1.64×105 (kJ kg-1). Increase in the drying air temperature in each bed condition caused increase in energy consumption. The maximum value of energy consumption was obtained at fluidized bed conditions.

This study was conducted to determine a relationship between energy input and yield in greenhouse basil production in Esfahan Province, Iran. Data were collected from 26 greenhouse basil producers through a face-to-face questionnaire. The data collected belonged to the production period of 2009–2010 with the following results obtained. A total energy input of 236, 057 MJ ha-1 was estimated to be required for basil production. The share of electricity (75.68% of the total energy input) was the highest form of energy required. The expense was followed by plastic cover (9.69%) and chemical fertilizer spending (7.28%), respectively. The energy ratio, productivity, specific, and net energies were found out as 0.25, 0.11 kg MJ-1, 9 MJ kg-1 and -177377 MJ ha-1, respectively. A determination of the efficient allocation of energy resources was modeled through Cobb–Douglas production function. The results of econometric model estimation revealed that the impact of energies spent in the form of human labour and plastic coverings on yield was significantly positive at 1% level. Sensitivity analysis of the energy inputs revealed that the marginal physical productivity (MPP) value related to human labour was estimated as the highest.

Salinity is among important soil stresses adversely affecting the process of nitrogen (N) fixation in leguminous plants in different parts of the world. It has been indicated that salinity can inhibit the early stages of nodulation process between bacterium and the host plant including the exchange of signal molecules (nod gene inducers). There has not been any research regarding the effects of nod gene inducers on the growth of alfalfa inoculated with Sino rhizobium meliloti under saline conditions. A growth chamber experiment was conducted to determine the effects of pre-incubation of S. meliloti with effective inducers of nod genes Luteolin, Methyl jasmonate and Genistein on the growth and N-fixation of two different alfalfa (Medicago sativa L.) cultivars (Yazdi and Hamedani) under salt stress. Nod gene inducers increased alfalfa growth and N fixation under normal as well as under salt stressed conditions. Yazdi cultivar showed to be more tolerant to salinity than Hamedani with a higher growth rate and N fixation. Luteolin was the most effectivenod gene inducer on plant growth and N fixation under normal and as well under salt stressed conditions. The results suggest that pre-incubation of S. meliloti with effectivenod gene inducers can improve alfalfa growth and N fixation under salinity stress.

Dried figs collected from various exporting companies (2, 461 samples) and local stores (219 samples) were analyzed using reverse-phase high-performance liquid chromatography (RP-HPLC) to determine and compare the incidence of aflatoxins, the effectiveness of the regulation limits and monitoring system to select non-compliant samples and the mean daily aflatoxin exposures. The incidence rates of aflatoxin contamination were higher in the domestic samples (47.5%) than in the samples intended for export (23.6%). According to the European regulation limits (2 ng g-1 for aflatoxin B1 and 4 ng g-1 for total aflatoxin, sum of B1+B2+G1+G2), non-compliant samples were 6 and 24.2% of the dried figs for export and domestic market, respectively. The respective rates of 2.2 and 16.4% were obtained with the national limit. The dietary intakes of aflatoxins through the consumption of dried figs were calculated as 1.27 and 0.2 ng kg-1 body weight×day for domestic market and export, respectively. Dried figs contaminated with high levels of aflatoxins can lead to acute and chronic human toxicities. Reducing contamination and exposure to an acceptable level by the implementation of strict periodic monitoring and application of effective new prevention measures might also help to decrease the significant health and economic risks in exported and domestic commodities.

Yoghurt ice cream (YIC) or frozen yoghurt dessert can be regarded as a healthy alternative to plain ice cream. Also use of soy derived products in food formulations can lead to the development of products of improved nutritional and health promoting values. Yoghurt ice cream was prepared using full-fat soy flour to substitute 55% of non fat dry milk content. Product formulation comprised of 12% SNF, 10% fat, 18% sucrose, 0.4% stabilizer-emulsifier and 0.1% vanillin. The effect of incorporating yoghurt at the rate of 5.3%, 15.9%, 26.5%, 37.1% and 47.7% of the total ice cream mix on the flow behavior, physico-chemical and sensory properties of Yoghurt Ice Cream was evaluated as compared with control, devoid of any yoghurt. The mixes all showed pseudo plastic flow behavior, with the viscosity increasing from 0.7 to 1.57 pa s when the yoghurt content increased from 0 to 47.7%. Higher contents of yoghurt in the mixes significantly improved the melting rate of the yoghurt ice cream where the minimum melting rate (16%) was obtained for the sample of 47.7% yoghurt content. The highest overrun value of 58% was obtained for the sample containing 15.9% yoghurt. However the specific gravity of the product decreased with increasing yoghurt content with the highest specific gravity of 1.108 being recorded for control. In the light of these findings, it can be concluded that yoghurt ice cream, containing full fat soy flour, can be successfully made by incorporating 25.6% yoghurt in the mix with the end product maintaining its acceptable sensory characteristics.

Application of either protein or carbohydrate-based products as fat replacers in low fat ice-creams can improve the properties of these products. However, the type and level of fat and fat replacer utilized are affected by such different parameters as functional ones, namely: viscosity and overrun, hardness and melting rate, nutritional properties (calories) as well as the price of the final product. Throughout the present study, single and multi-objective optimization method as based on the genetic algorithms (GAs) was applied to select the suitable fat-free as well as low-fat ice-cream formulations. The data related to single-objective optimization of selected parameters revealed that the ice creams containing 3.5% Simplesse plus 1.72% fat, and 2.95% Maltodextrin plus 1.87% fat have ended up with the most desirable functional objectives. The application of multi-objective optimization led to a range of solutions of different fat and fat replacer contents out of which the producers can adopt the most suitable choice depending on the needs.

Enzymatic acidolysis of canola oil through caprylic acid was investigated to produce certain medium chain Triacylglycerol (TAG) structured lipids (SLs). Lipozyme TL IM, ansn-1, 3 specific Thermomyces lanuginosa lipase, and Novozym 435, a non-specific Candida Antarctica lipase, were utilized as the biocatalysts in a batch reactor. Reaction conditions were designed according to Taguchi’s approach, considering three levels of fatty acid to oil ratio (1: 1, 2: 1, and 3: 1), three levels of enzyme load (4, 8 and 12%, w/w), three levels of temperature (45, 55, and 65° C) as well as three levels of reaction time (15, 30 and 45 hours). Results indicated that fatty acid composition of canola oil was modified by the above acidolysis reactions. The highest mole percent of caprylic acid incorporation (37.2 mole%) was obtained after 15 hours of incubation in the presence of Lipozyme TL IM at 55° C, fatty acid to oil ratio of 3: 1 and at 12% of enzyme level. However, with Novozym 435 the highest level of incorporation (38.5 mole%) was obtained after 45 hours of reaction at 45° C, fatty acid to oil ratio of 3: 1, and at 8% enzyme level. Novozym 435 was able to incorporate more caprylic acid in the oil than did Lipozyme TL IM. SLs prepared using either Lipozyme TL IM or Novozym 435 differed in terms of their TAG compositions. According to the obtained results, SLs produced by use of Lipozyme TL IM lipase contained higher levels of MLM-type (Medium-Long-Medium) triacylglycerols than those produced using Novozym 435 lipase (21.2 and 9.9%, respectively).

Volatile compounds generated from two types of polymeric laminated films, irradiated by gamma radiation at 8, 10 and 15 kGy, were investigated. Activated carbon was used as a dry food simulant to trace the migrating compounds by Gas Chromatography/Mass Spectroscopy (GC/MS). The resulting data showed that the Polyethylene Terephthalate (PET) /Polyethylene Terephthalate (PET) /Linear Low Density Polyethylene (LLDPE) film was more resistant to gamma radiation as compared to Biaxial Oriented Polypropylene (BOPP) /Cast Polypropylene (CPP) film. Toxic radiolysis products migrated through both laminated films at 8 and 15 kGy gamma irradiation. The toxic products originating from additives formulated in adhesive and in direct food contact layers may be considered as high risk against the safety of dry foodstuffs such as spices.

The aim of this study was to explore the minimum amount of urea formaldehyde (UF) resin content and optimum particleboard density while maintaining boards' quality to reduce production costs. Board density at three levels (520, 620 and 720 kg m-3) and resin content (6, 7 and 8%) were variable parameters. Stepwise multivariate linear regression models were used to evaluate the influence of board density and resin content on board properties and to determine the most effective parameter. In order to obtain the optimum board density and minimum resin content, contour plots were drawn. Regression models indicated that both board density and resin content were included in Modulus of Rupture (MOR) and Modulus of Elasticity (MOE) models based on the degree of their importance. Internal Bond (IB) model only had one step and resin content positively affected it. The results obtained from contour plots revealed that manufacturing poplar particleboards with density ranging from 600 to 650 kg m-3 and 6% resin would result in boards with mechanical properties within those required by the corresponding standard. Thickness swelling (TS) values were slightly higher (poorer) than the requirements. The panels required additional treatments such as using adequate amount of water resistant materials to improve thickness swelling after 2 and 24 hours of immersion.

The Hargreaves-Samani (HS) equation, which estimates reference evapotranspiration (ET0) using only temperature as input, should be most suitable for ET0 prediction based on weather forecasting data. In the current study, the HS equation is calibrated with daily ET0 by the Penman-Monteith equation, and is evaluated to check the possibility of predicting daily ET0 based on weather forecast data. The HS equation is likely to overestimate daily ET0 in the humid regions of China. Coefficients a and c are calculated as 0.00138 and 0.5736 according to local calibration. The calibrated HS equation performs considerably better than the original one. The proposed equation could be an alternative and effective solution for predicting daily ET0 using public weather forecast data as inputs. The error of daily ET0 prediction increases with the increase in the error of daily temperature range (TR) or daily mean temperature (Tmean). This error is likely to be more sensitive to the error inTR than in the Tmean. Ensuring that TR errors are less than 2oC is necessary for perfect estimations of ET0 based on public weather forecast data using the calibrated HS equation.

The authors of the present paper studied some aspects of hydro and agro meteorological phenomena in terms of humidness, dryness and crop growing periods over India. Revised water balance model is used to obtain the above and the results are examined during the two half centuries i.e 1901 to 1950 and 1951 to 1995 in delineating the climate change impacts over India. Palmer Drought Severity Index (PDSI) for All India is related to aridity and humidity indices to understand the dry and wet spells over India. The paper also holds its stand on the analysis and the trends of thermo and hygric components such as precipitation, maximum and minimum temperatures, water need, actual evapotranspiration and soil moisture for All India. The return rates of All India maximum and minimum rainfall and temperatures are obtained for different time intervals using Extreme Value Analysis, that might be useful in assessing the impact and thereby to plan over the risk management for the better environmental and thus the human sustainability.

Shortage of irrigation water is a crucial problem especially in arid and semiarid regions, therefore, application of wastewater in agriculture in such regions seems to be an indispensable solution. A field experiment was conducted in non-agricultural soil to investigate the effect of Treated Municipal Wastewater (TMW) on the yield and fiber quality of cotton (Gossypium hirsutum L.) crop. The treatments consisted of surface irrigation by different mixtures and as well, through different intervals of freshwater plus TMW. Two additional treatments, namely, irrigation with freshwater and with TMW were considered as control. The experimental design was a randomized complete block one with eight treatments and three replications. The results indicated that cotton yield, number of bolls per m2, Leaf Area Index (LAI) and plant height were significantly higher when the crop irrigated with TMW rather than with freshwater. The crop yields in TMW vs. freshwater treatments were about 2, 200 and 780 kg lint ha-1, respectively. There were no significant differences observed between interval and mixture treatments when the same percentages of freshwater and TMW applied. Also there was no significant detrimental effect observed on the characteristics of cotton fiber quality when the crop irrigated with TMW.

Agronomic and physiological traits and protein expression were compared between non-Bt glandless upland cotton variety-Zhong5629 and its Bt-transgenic near-isogenic lines differing incry IAc gene. Results showed that the Bt isogenic line had higher plant height and rate of effective bolls, more internal bolls but lower yield, than the non-Bt line. The Bt isogenic line had lower chlorophyll content and transpiration rate relative to the non-Bt line, but had higher Chl a/b, F0 and Fm. Soluble protein content in the Bt isogenic line was significantly higher at boll setting stage (BSS) but lower at initial flowering stage (IFS) compared with the non-Bt line. The Bt isogenic line had significantly higher concentrations of Ca, Mg, Cu, Zn, Mn and Fe at IFS, and P and Cu at BSS, whereas it had lower in concentrations of P, K and B at IFS, and K, S, Zn and Fe at BSS. The Btisogenic line exhibited less malondialdehyde content at BSS and lower superoxide dismutase activity at IFS and BSS. Furthermore, proteomic analysis of the two NILs detected 20 differentially expressed proteins. The 4 up- regulated proteins in Btvs non-Btisogenic line were attributed to signal transduction, photosynthetic carbon assimilation and defense response, whereas the 16 down- regulated proteins were attributed to signal transduction and protein metabolism.

Terfezia, Picoaand Tirmania, so called desert truffles, are mycorrhizal fungi mostly endemic to arid and semi-arid areas of the Mediterranean Region, where they are associated with Helianthemum and Carex species. The aim of this work was to study the identification, molecular analysis, distribution and hosts of these pezizalean hypogeous fungi in Iran. Among the specimens, Terfezia claveryi, Tirmania pinoyi, T. nivea, Picoa lefebvrei and P. juniperi were identified. Field, laboratory and anatomical studies showed that Helianthemum ledifolium, H. salicifolium, H. lippi and Carex stenophylumhave ectomycorrhizal associations with five species in the studied areas. The results of molecular analysis showed that C. stenophylum roots form mycorrhizal associations with T. claveryi. Hyphal mantle was absent from sections of the mycorrhizas. The results of physico-chemical analyses on soil samples from different parts of the Fars Province in Iran showed that the genusTirmania was more prevalent in soils with high CaCO3 and silt contents than the T. claveryi, P. lefebvrei and P. juniperi. The Canonical Correspondence Analysis (CCA) indicated that soil structure were an important environmental parameter influencing desert truffles distribution.

During a survey of plant-parasitic nematodes in Bamyan and Mazar Sharif provinces of Afghanistan, several species of plant-parasitic nematodes belonging to infraorder Tylenchomorpha were detected and identified. Filenchus facultativus, Filenchus discrepans, Filenchus elegantulus, Boleodorus volutus, Neopsilenchus magnidens, Coslenchus costatus, Ditylenchus myceliophagus, Tylenchorhynchus clarus, Paratylenchus microdorusand Merlinius neohexagrammus are reported here for the first time from Afghanistan. Detailed examination of M. neohexagrammus using SEM microscopy confirmed this species in the genusMerlinius by having a labial disc not marked and with four longitudinal striations on the lip region, amphid apertures located at the lateral edge of labial disc and lateral field at mid-body areolated.

Petri disease is responsible for grapevine decline and occurs wherever grapevines (Vitis vinifera) are cultivated. Phaeoacremonium species are among the principal hyphomycetes associated with Petri disease. During 2009, a field survey was conducted throughout different vineyards in the Fars province of Iran in order to determine the fungal pathogens associated with the vine decline observed in the region. Samples were taken from grapevines showing yellowing, interveinal chlorosis, leaf necrosis, reduced growth, wilting, wood necrosis and streaking, and xylem discoloration symptoms in cross section. Isolations were made from symptomatic wood tissues from cordons and trunks on malt extract agar supplemented with 1 mg ml-1 streptomycin sulphate (MEAS) and potato dextrose agar (PDA) media. Based on morphological and molecular characteristics two species of Phaeoacremonium, Phaeocremonium mortoniae and Pm. inflatipes, were isolated and identified from grapevines showing yellowing, slow dieback, stunted growth, and reduced foliage in Bavanat (Fars province, south-western Iran). Pathogenicity tests were conducted on rooted grapevine cuttings (cv. Askari) under greenhouse conditions. Based on the results of pathogenicity tests, both tested Phaeoacremonium species were pathogenic and caused significant vascular discoloration in inoculated cuttings four months after inoculation. The fungi were reisolated from the margins of the lesion and healthy tissue, completing Koch’s postulates. Based on our knowledge, this is the first report of Pm. mortoniae and Pm. inflatipes causing grapevine Petri disease in Iran.

Fusarium solaniwas isolated from diseased roots of common bean (Phaseolus vulgaris) grown in fields which were severely infected with Fusarium root rot of bean in Markazi Province of Iran. Specific PCR primer pairs were used for the identification and verification ofF. solani (Mart.) f.sp. phaseoli (Burkholder) W.C. Snyder and N.H. Hans. Spore suspensions of F. solani f.sp. phaseoli were subjected to gamma irradiation at 130 Gy using Cobalt-60, and 700 mutants were generated. All 700 mutagenized colonies were tested in the greenhouse for reduced pathogenicity. One mutant (M23) showed the best expected reduction of Fusarium root rot and was chosen to be tested as a biocontrol agent in field experiments. Different concentrations of avirulent mutant (avr-M23) were used against Fusarium root rot in the infested field and their effects on the yield of bean plants were evaluated. The biocontrol effect of avr-M23 on Fusarium root rot was significantly improved with increasing its concentration from 103 to 109 conidia ml-1. Best yields (no. of pods per plant and 100-seed weight) were obtained at concentrations of 106 and 109 conidia ml-1. This study confirms that avr-M23 can be used as a biocontrol agent to protect bean plants from Fusarium root rot under field conditions.

Sustainable management of limited land and water resources is urgently needed to meet the increasing demand for food and to protect the environment. Land suitability analysis is a prerequisite in assessing and proposing sustainable land use alternatives for an area. Soil data are usually available at different levels of detail and stored in various forms, usually soil maps and/or soil observations. Soil data interpretation methods control the reliability of land suitability evaluation results. This has a serious effect on the reliability of the suitability maps, the subsequent land use decisions, and environmental modeling. This study examines the reliability of land suitability mapping using different methods of soil data interpretation–the average of land characteristics for field observations within soil map units (point-in-polygon) and spatial interpolation using field observations only (proximity to points). The degree of agreement between the two methods depends on the type of land utilization–rainfed barley (86%), open range (85%), improved range (75%), drip irrigated vegetables (69%), and drip irrigated trees (59%). This results from the difference in the limiting land characteristic that determines the suitability of each land utilization type and the pattern of spatial variation of each land characteristic in the field. Suitability maps for adaptable (indigenous) crops (such as barley and range crops), which require minimum farming inputs, are generally more accurate because they tolerate a wider range of variability. The interpolation method was more efficient in detecting the spatial distribution and extreme values of limiting land characteristics, resulting in more accurate suitability maps. Therefore, when detailed soil maps are not available, field observations could be used to derive suitability maps using an exact interpolation method.