Journal of Agricultural Science and Technology
Volume:13 Issue: 3, May 2011

The objective of this study was to investigate dehydration kinetics of barberry (Berberis vulgaris L.) at different drying temperatures (60 ºC, 70 ºC, 80 ºC), air velocities (0.3 m s-1, 0.5 m s-1, 1 m s-1) with two types of pretreatment. Drying time and colour quality during dehydration were experimentally determined. Barberries were dried from the initial moisture content of 73.44% (w.b.) to the required moisture content of 18% (w.b.). Dehydration kinetics was monitored by measuring barberries weights at regular intervals. Convective drying curves were obtained for the treated and untreated barberries. The effect of two dipping pretreatments on drying kinetics of barberries was also studied. The two pretreatments were thermal shocking by immersing barberries in hot water, followed by cold water cooling, and dipping in olive oil and food grade K2CO3. Colour of the dried product was altered significantly during drying. The results indicated that the use of low temperatures is adequate for preserving this property. The air temperature significantly affected drying time and hunter colour indices of barberries (P< 0.05). With heat shocking and treatment with olive oil and K2CO3, drying time was reduced to about 40% and 60%, respectively. The total colour change (ΔE) and hue angle (H) increased with temperature. Moisture transfer from the test samples was described by applying the Fick’s diffusion model for calculating the effective diffusivity. The effective moisture diffusivity (Deff) of barberry increased as the drying air temperature increased. The Deff values were higher for the treated samples than the untreated ones. These values were also higher for the samples treated with olive oil and K2 CO3 emulsion than those treated with hot water. The effective diffusivity of the untreated and the pre-treated varied between 2.57×10-13 and 9.67×10-12 m2 s-1, respectively. Higher colour change was observed in barberries treated with olive oil and K2CO3 emulsion. Statistical analysis showed that temperature and pretreatment had the most significant effect on drying time at p<0.01.

The effect of different fertilizing systems and drought stress during grain development on grain minerals of barley (Hordeum vulgare L.) was studied in field experiments on a clay-loamy soil during 2007 and 2008 growing seasons. The treatments consisted of three irrigation regimes (main plots) of: Non-stressed (NS, normal irrigation continued until the end of plant physiological maturity), Moderate Stress (MS, irrigation ceased from the beginning of flowering to the beginning of grain filling stage and Severe Stress (SS, irrigation ceased from the beginning of flowering stage up to the end of physiological maturity) along with six fertilizing regimes consisting of no fertilizer application (control) (NF), phosphorous and nitrogen Biofertilizers (BF), 100% Chemical fertilizer (NPK) (CF), Vermicompost (VC) 5 t ha-1, 50% Chemical fertilizer (NPK)+50% Vermicompost (2.5 t ha-1) (CV), and 50% Chemical fertilizer (NPK)+ Biofertilizer (CB), assigned to the sub plots. Drought stress significantly increased grain minerals of N, Zn and Mn by 12, 27, and 7% as compared with control (NS), respectively. Average grain nitrogen concentration in chemical fertilizer (CF) treatment was significantly more than those in the other treatments followed by integrated fertilizing systems (CB and CV). Phosphorous concentration in grains produced in BF fertilizer medium was significantly higher than those in other treatments. Grain Fe and Zn concentrations increased through vermicompost application. However, Mn concentration was higher in grains fertilized with chemical fertilizer. It can be concluded that in barley production under water deficit conditions, grain mineral quality could be improved through integrated fertilizer application.

In order to evaluate the physiological indices in relation to the screening of spring safflower genotypes for drought tolerance and productivity, seed and oil yields and yield components were measured for five genotypes including Local Arak, Local Esfahan, Sina, KH23 – 57 and Goldasht. The study was conducted in a loam soil in East Azarbaijan, Iran, during three successive years (2005-2007). Water treatments consisted of non-stressed and water deficit imposed from flowering (80% flowering) to maturity. Several physiological indices including relative water content (RWC), stomatal conductance (Kl), leaf temperature, osmotic adjustment, and specific leaf weight (SLW) were measured. Considering the significant decrease of seeds in capitulum, 1000 seeds weight, harvest index (HI), seed and oil yields due to water deficit, it seems that drought decreased seed and oil yields mainly via declining these components of yield. Since RWC and Kl decreased and leaf temperature, osmotic adjustment, and SLW were increased significantly by water deficit, therefore these indices could reflect the stress effects during seed filling period. Among RWC, Kl, leaf temperature and osmotic adjustment, significant correlations were seen. Also significant positive correlations were found among Kl, RWC and SLW with seed and oil yield. Screening spring safflower genotypes by the abovementioned characteristics may lead to economically acceptable yields under water deficit condition. Among the genotypes, Goldasht, with 1,412 and 358 kg ha-1 seed and oil yields, respectively, had the lowest yield, associated with lower values of RWC, Kl and osmotic adjustment. Other genotypes had similar seed and oil yields, while Local Arak had the higher amounts of seed and oil yields, associated with higher values of RWC, Kl and osmotic adjustment. It is concluded that Local Esfahan, Sina, KH23-57, and especially Local Arak genotypes, can be used for cultivation in Khosro Shahr and areas with similar climate (cold and semi-arid in Koppen climate classification) under normal and late season drought conditions.

The impact of climate change in the next few decades will increase risks of wheat production under dryland conditions. Therefore, it is important to find cultivars that are tolerant to these conditions and can provide reasonable yield under future climates. Radiation use efficiency (RUE) is the key factor determining the crop yield and is related to crop biomass and leaf area index (LAI). To obtain a high yield from a given cultivar under dryland conditions, it is necessary to achieve optimum RUE. In this study, the effects of different levels of nitrogen fertilizer (N) and plant growth retardant (chlormequat chloride= CCC) on LAI, dry matter accumulation, biomass yield, and RUE of four dryland wheat cultivars were examined. The field experiment was carried out during 2006-07 and 2007-08 growing seasons at the experimental agriculture research station of Shiraz University, Iran. The results suggested that different cultivars varied significantly in LAI, biomass and RUE under similar conditions and demonstrated the dependency of RUE on LAI and biomass yield. During 2006-07, the highest biomass production (431.2 g m-2) and RUE (0.99 g MJ-1 m-2) were obtained from Nicknejad cultivar, CCC application, and using 80kgN.ha-1. During 2007-08, the highest biomass production (333.5 g m-2) and RUE (0.76 g MJ-1 m-2) were obtained from Azar-2 cultivar, CCC application, and 80 kg N ha-1. Based on the results of this study, application of N and selecting cultivars resistant to late season drought stress could be considered for improving RUE in dryland farming.

A 42-d study was conducted to evaluate the influence of full-fat flaxseed (FS) and canola seed (CS) on broiler performance, fatty acid (FA) profile of meat, and the oxidative stability of meat during frozen storage. A total of 324 one-day old broiler chicks were randomly attributed to 6 experimental groups and fed iso-energetic and isonitrogenous diets as follows, C: control (soybean-corn); CS1: 7.5% CS; CS2: 15% CS; CS-FS: 10% FS+10% CS; FS1: 7.5% FS; FS2: 15% FS. Negative effect on performance parameters were found by diets containing FS and CS i.e. feeding oil seeds resulted in significantly (P< 0.01) lower body weight gain and higher feed conversion ratio, compared to the control. However, no significant differences of feed consumption were shown (P> 0.05) among treatments. Inclusion of FS and CS significantly increased (P< 0.01) the concentration of omega-3 fatty acid (α-Linolenic acid= ALA) and decreased the content of the arachidonic acid (AA). Total omega-6 to omega-3 polyunsaturated fatty acid (PUFA) ratio was significantly lower for all FS and CS fed groups compared with the control (P< 0.01). Inclusion of FS and CS decreased the oxidative stability of raw meat (breast and thigh) during frozen storage period based on thiobarbituric acid (TBA) values (P< 0.01). In conclusion, by adding vegetable sources of omega-3 to the broiler chicken diets, the omega-3 fatty acid content of broiler meat can be increased, which may have beneficial effects on human health.

This experiment was conducted to evaluate the effect of barley green fodder produced by hydroponics system on the performance of feedlot calves. In a completely block randomized experiment, 24 cross bred (Holstein×Local) male calves were assigned randomly to one of the two treatments (diets) that were either control (grain barley) or hydroponic barley green fodder (BGF) that was included to provide 22.8 percent of the total diet on dry matter basis. Seed grade barley was grown in a hydroponics chamber system where the growth period was adjusted for 6 days. Body weigh gain was not significantly different between the treatments, but the animals that had received the control diet had higher (P< 0.05) dry matter intake than those fed BGF diet. There was a tendency (P= 0.199) toward differences in feed efficiency due to dietary treatments. From economical point of view, feed cost increased up to 24 percent when the calves were offered BGF, because of the costly production of hydroponics green forage. Although the mass production of fresh fodder was about 4.5 times per kg of barley grain, this was due to water absorption during germination and growth period. Nevertheless, the dry matter obtained was less than the initial barley grain and further dry matter losses were found in the green fodder. These findings suggest that green fodder had no advantage over barley grain in feedlot calves, while it increased the cost of feed.

Effects of three pressure reduction rates (PRR) of 103 Pa s-1, 197 Pa s-1, and 347 Pa s-1 on temperature distribution and variation, moisture content, and sensory quality of steamed stuffed buns were investigated after vacuum cooling. The distributions and variations of surface temperatures were determined by the thermal infrared imaging method. The temperature profiles presented significant differences in the average cooling rates of the different parts, depending on the PRR. Results showed that the greatest mass loss of 8.1% and the shortest cooling time of 288 seconds were found with the quickest PRR of 347 Pa s-1, while the least mass loss of 5.96% and the longest cooling time of 955 seconds were observed in the case of the slowest PRR of 103 Pa s-1. The pressure reduction rates had little influence on the changes of moisture contents in the crumb and stuffing. The sensory quality scores of vacuum-cooled buns at 103 and 197 Pa s-1 were higher than those at 347 Pa s-1.

In order to provide the data needed for the design of saffron processing equipment, physical properties of its flower were investigated. These properties included dimensions, mass, true and bulk densities, porosity, static and dynamic coefficients of friction, and terminal velocity as a function of moisture content. The average range of these properties for the three different parts of saffron flower was about 0.03 to 0.16 gcm-3 for bulk density, 0.55 to 1.56 gcm-3 for true density, and 85.2 to 95.5% for porosity. Also, the coefficients of friction were measured for three flower parts by using three surface materials including plywood, iron, and galvanized steel sheets. The minimum and the maximum values of static coefficients of friction were found on galvanized steel sheet. They were 0.8 and 2.14 for anther and stigma, respectively. The dynamic coefficient of friction ranged from 0.45 for anther on iron to 1.14 for petal on galvanized steel sheet. The variation range of terminal velocity for three different parts of the flower was recorded between 0.9 and 2.38 ms-1. The results of friction coefficients and terminal velocity measurements suggest that, based on these properties, design of a separator for saffron flower parts is feasible.

Total energy, protein content and digestibility, antinutritional factors, and total and extractable minerals of normal sorghum (Type II) and four newly developed lines of sorghum (Eri-1, SHK-ABA-4, SHK-ABA-6 and SHK-ABA-10.) were studied before and after fermentation. Phytic acid and Tanin contents of raw flour of the normal sorghum were, respectively, 41.73 mg 100 g-1 and 170.54 mg 100 g-1, while the same values for the four lines ranged from 16.07 to 38.64 mg 100 g-1 and from 31.90 to 184.25 mg 100 g-1, respectively. Polyphenols content of raw flour of the normal sorghum was 604.56 mg 100 g-1, exceeding the values found for the four lines in the range of 476.46 to 544.44 mg 100 g- 1. According to our results, fermentation of normal sorghum flour and that of the new lines significantly (P
0.05) decreased the antinutritional factors i.e. phytate, tannins, and polyphenols. The total energy of raw flour of the normal sorghum was 369.87 Kcal 100 g-1 while it ranged from 367.23 to 372.57 Kcal 100 g-1 for the new lines. In all cases, this energy slightly decreased after fermentation. Protein digestibility of normal sorghum was 22.60% and, for the new lines, it ranged from 37.00 to 57.19%. After fermentation, protein digestibility and the total and extractable Ca, P, and Fe increased significantly (P
0.05) for all genotypes studied.

We assessed the size and composition of the soil seed bank and above-ground vegetation in 52 relevés representing a range of habitats within an old- growth, temperate deciduous forest at Hyrcanian region, northern Iran. We identified 63 taxa in the seed bank, with an average density of 4202 seeds/spores per m2 by seedling emergence method. Hypericum androsaemum, Cardamine impatiens, and Rubus hyrcanus, with Athyrium flix- femina and Pteris cretica as two ferns, were the most abundant species in the seed bank and spore bank that made up to 92 % of the seeds/spores recorded in the soil seed bank. Totally, 107 species were recorded in the vegetation and soil seed bank of the study site, of which 33 % were common in both seed bank and vegetation and 26 % and 41 % were found only in the seed bank or in the vegetation, respectively. The dominant tree species with many woody understory species found in the above- ground vegetation were absent from the persistent soil seed bank. Jaccard’s similarity coefficient revealed that the correspondence between the species in the vegetation and the same species in the seed bank were consistently low (average of 24.3%) based on presence/absence data. Yates- corrected c 2 test showed that sites present significant differences (P<0.001) in seed bank and vegetation species composition. DCA ordination of the above-ground vegetation and soil seed bank flora displays a clear pattern, with two distinct groups on the basis of the above-ground vegetation and soil seed bank floristic data. Our results explain the low similarity between soil seed bank and vegetation of the Darkola oriental beech (Fagus orientalis Lipsky) forest only to a limited extent, but confirm that most of the species of the above-ground vegetation do not depend on the persistent soil seed bank. Therefore, it may be concluded that the persistent soil seed bank is not capable of restoring the extant vegetation of the studied site.

Enzyme electrophoresis was used to measure genetic variation within, and divergence among, three generations of recently bred synthetic alfalfa generations (Syn1, Syn2, and Syn3) originating from a polycross of 12 selected parents and several cultivars. Three isozyme loci, exhibiting tetrasomic inheritance in 10-day seedlings, were detected from five enzymatic systems analyzed by polyacrylamide slab gel electrophoresis for about 100 individuals of each alfalfa population. Very high levels of heterozygosity (ranging from 0.521 to 0.699) were observed within alfalfa populations, using polymorphic loci. The reduction in heterozygosity was about 5% from Syn1 to Syn2 and from Syn2 to Syn3. The last open pollinated generation was found to be in W-H equilibrium as well as Gharayonja, a native ecotype under examination, using c2-test. Application of Wright's Fstatistics revealed that the estimated overall inbreeding coefficient, (FIT), of 9.4% was mainly related to inbreeding or double reduction in alfalfa (FIS= 8.61%) rather than random genetic drift or population differentiation (FST= 1.6%). Therefore, due to very large intra-population diversity, the breeding program of the synthetic alfalfa did not generate a large variety differentiation. However, the use of seedling allozymic loci can be applied successfully for estimation of the population genetic parameters.

During 2007-2008, 58 strains of P. syringae pv. syringae (Pss) were isolated from various Prunus species and other hosts such as sugar beet, pear, quince, oat, millet, wheat, barley, and rice in Fars, Isfahan, Kohgiloye and Boyer Ahmad, Chahar Mahal-o-Bakhtiari provinces of Iran. The strains were tested for pathogenicity, the presence of the syrB gene and BOX PCR (BOX A1R primer). All tested Pss strains were pathogenic on peach seedlings regardless of their original hosts. A total of 58 isolates of the Pss and Pss IVIA 773-1 amplified a 752-bp fragment with the syrB primers. The results of analysis of the BOX fingerprints from P. syringae pv. syringae strains showed that the strains isolated from stone fruits, graminous hosts and pome fruits formed a relatively distinct cluster, which were separable from the strains isolated from the other hosts. Results of this study indicate the existence of a relative degree of host specialization within the heterogeneous pathovar Pss.

The incidence of grapevine virus A (GVA) is reported from almost all of the major grapevine growing regions in Iran. Grapevine is vegetatively propagated by rooting of cuttings or grafting. In such plants, viral diseases are transmitted from stock plants to the progeny. Therefore, the control of grapevine viruses can be achieved primarily through production of healthy stock plants. In the present research, cryotherapy and electrotherapy were employed for elimination of GVA from naturally infected vine (Vitis vinifera L. cv Black) and their efficiency was compared. In cryotherapy, 59% of the shoot tips survived and regenerated into whole plants, of which 42% were free of GVA detected by RT-PCR. In the electrotherapy, the effects of electric current value and treatment duration were investigated on plant survival and virus elimination. The best results were obtained by using 30 milliamps (mA) for 15 minutes. With this treatment, survival and virus-free frequencies were about 62% and 40%, respectively. This is the first report of electrotherapy of grapevine shoot tips as a potential tool for GVA elimination. The results showed that cryotherapy was a more efficient and convenient protocol than electrotherapy for elimination of GVA from infected grapevine.

Accelerated soil erosion is an undesirable process that adversely affects water and soil resources. Rainfall erosivity is an important factor in water erosion models. Accordingly, the present study was conducted to estimate the rainfall erosivity throughout Iran based on the latest available detailed rainfall data while considering its temporal and spatial variations. To accomplish this, the data from 18 synoptic stations of the Iranian Meteorological Organization, known to have reliable data and hyetographs with a 23 year common period, were accordingly analyzed. The kinetic energy of rain for each storm event was calculated based on Wischmeier and Smith’s original model, i.e. the USLE, and many of its modifications. Later, the rainfall erosivity factor was calculated on a monthly, seasonal, and annual basis using the calculated kinetic energy. The results revealed that the greatest risk of erosivity occurred in March, December, and November, as indicated by R factors of 0.228, 0.201, and 0.147 MJ mm ha-1 h-1, respectively, while June and August had the lowest erosivity factors, as indicated by R factors of 0.017 and 0.027 MJ mm ha-1 h-1, respectively. Furthermore, analysis of the spatial variations in R verified that the Anzali and Babolsar Stations, located in northern Iran, had the maximum erosivity values, with R factors of 11.518 and 4.260 MJ mm ha-1 h-1, respectively. Conversely, the Bam and Semnan Stations, located in the central and eastern Iran, had the minimum erosivity values, as indicated by R values of 0.201 and 0.212 MJ mm ha-1 h-1, respectively. The long term mean annual rainfall erosivity factor of Iran was ultimately found to be 1.226 MJ mm ha-1 h-1.