Journal of Agricultural Science and Technology
Volume:15 Issue: 4, Jul 2013

Functional response of the female ladybeetle, Hippodamia variegata (Goeze) (Col., Coccinellidae) to varying densities (5, 10, 20, 40, 60 and 80) of third instar nymphs of Aphis gossypii Glover was assessed in a growth chamber (25˚C, 65± ­5% RH and a photoperiod of 16L: 8D h), on the black eyed bean, Vigna unguiculata (L.), in an open patch design. The logistic regression showed a type II functional response for female ladybeetles with the parameters (using Rogers’ model) as follows: a= 0.083±0.011h-1 and Th =0.197±0.040h. The mean time for the predator to be settled in a patch was 36.1±9.25, 26.8±5.81, 17.18±4.71, 8.5±2.12, 3.3± 0.88 and 0.8±0.35 minutes at densities of 5, 10, 20, 40, 60 and 80 third instar nymphs of A. gossypii, respectively. The settlement time decreased as prey density increased. The maximum theoretical predation (T/Th) for the females was 121.475. The proportion of female H. variegata that remained at the end of the experiment and their voracity were dependent on prey density. This may give an indication for the ability of the predator to persevere in the high pest infestations, and thus a high level of control could be expected.

Development, reproduction and life table parameters of Tetranychus urticae Koch were determined on leaves of peach (G. H. Hale cultivar) at different temperatures, ranging from 13 to 33°C under laboratory conditions. No development was observed at 13°C. Egg-to-adult developmental time decreased gradually from 17 to 27°C and increased at higher temperatures (27 to 33°C). An average of 136.43 degree-days was required to complete development above the lower threshold temperature (13.79°C). Mean total egg productions per female were 40.09, 18.74, 8.03 and 21.33 at 25, 27, 30 and 33 °C, respectively. Mean longevities of the females were 12.91±1.65, 5.92±0.55, 3.56±0.54 and 6.53±0.56 days, respectively at the above mentioned temperatures. The intrinsic rate of increase (rm) at different temperatures ranged from 0.108 to 0.213 day -1, with the highest value recorded at 27 °C. The highest and the lowest values of the net reproductive rate (R0) were obtained at 25°C (16.87) and 30°C (4.18), respectively. Doubling time (DT) varied significantly at different temperatures and the shortest and longest values of this period were obtained at 27 and 30°C, respectively. The results suggested that T. urticae was able to develop and reproduce within a wide range of temperatures, and that temperatures from 27- 30°C are the most suitable conditions for the development, survivorship and reproduction of the mite.

Internationally, employability has recently become an increasingly controversial issue in higher education. The emergence of knowledge-based economies, accompanied by the by-products of globalization, has forced agricultural higher education systems all around the world to think twice about the quantity and quality of their courses. On one hand, there has been a surplus of highly educated graduates seeking a career, while on the other hand, potential employers complain of a skill-mismatch phenomenon. Employability is defined as the perceived ability of conquering sustainable employment appropriate to one’s qualification(s). This study evaluates factors influencing the employability of senior agricultural students at the level of Bachelor of Science (BSc) using a descriptive-correlation survey methodology. A sample of 274 out of 979 senior agricultural students was selected from agricultural faculties of five universities located in the western provinces of Iran through a stratified random sampling technique. Students showed moderate employability levels, which were significantly different depending on their field of study. The path analysis technique revealed that social class, university obligations, mastery in generic competencies, and agricultural background were the most important factors affecting students’ perceived employability, respectively.

This paper aims at analyzing farmers’ responses on quality of agricultural information services provided by public and private sources. The study is based on primary survey of 461 farmers in eight districts of Uttar Pradesh, India, using a structured questionnaire. Farmers’ responses on quality of agricultural information services from public and private sources were analyzed using Analysis of Variance (ANOVA) technique. Findings of the study indicate that private sector information delivery sources provide significantly better quality information to the farming communities as compared to public sector information delivery systems. The results have far reaching implications for designing successful information and extension delivery models by the public, private or by collaborative efforts of the public and the private sector for better extension services delivery.

Biodiesel fuel, which is produced by transesterification reaction between alcohol and vegetable oil/animal fat is proposed as a clean alternative to petro diesel fuel. Today, one of the new technologies to produce biodiesel is using ultrasonic energy that makes production faster, with improved quality and less expensive. Various factors that affect the design of ultrasonic reactors are ratio of vibrating rod diameter to reactor diameter, reactor height, depth of horn penetration into fluid and chamber characteristics (material and shape). In this paper, two parameters namely the ratio of vibrating rod diameter to reactor diameter and reactor height were studied in order to increase the reaction efficiency. In all performed tests, the horn diameter of 14 mm, molar ratio of alcohol to oil of 5 to 1, catalyst concentration of 0.7% wt?? oil, depth of horn penetration into fluid of 15 mm and a cylindrical reactor were used. Experimental design involved the use of Central Composite Design (CCD) and the statistical Response Surface Methodology (RSM). Considering the empirical model, a significant relationship was found between independent and dependent variables with a regression coefficient of 0.99. Taking into account the desirability of increasing the efficiency, the optimal function of reactor diameter and reactor height were 63 and 110 mm, respectively with a reaction yield of 87%. In order to verify the model, function responses in the defined area were tested with five replicates and the average efficiency of the reaction was 87.2%. The obtained model suggests the simultaneous reverse effects of reactor diameter and height on the reaction efficiency.

This study suggests a new effective chemical pretreatment to hydrolyze rice straw for efficient ethanol production. It introduces a new yeast strain that ferments rice straw hydrolyzate more efficiently than Saccharomyces cerevisiae. The results proved the effectiveness of alkali application before HCl to delignify rice straw and to make it more appropriate for hydrolysis. The application of the hydrolyzing enzymes (cellulase and pectinase) resulted in hydrolysis of pretreated rice straw up to 94.3%. The total sugars released due to pretreatment-enzyme system was about 624 mg g–1 dry mass and the glucose fraction was 198 mg g–1. The results indicated that Pichia guilliermondii is more effective to ferment rice straw hydrolyzate than S. cerevisiae. P. guilliermondii produced larger amounts of bioethanol (7.72 g L–1) than S. cerevisiae (6.13 g L–1) under the same conditions. Our results suggest an appropriate pretreatment system (the cold dilute alkali-acid) and a new effective yeast strain to ferment the rice straw hydrolyzate to produce large amounts of bioethanol.

To understand the effects of salinity stress on four different growth stages of sorghum, a greenhouse experiment with 10 treatments, considering all possible combinations of salinity stress and salt- free periods was carried out. The four growth stages for stress application included: emergence until growing point differentiation, growing point differentiation until half bloom, half bloom until soft dough, and soft dough until physiological maturity. Treatments were arranged based on randomized complete block design with 3 replications at the Research Greenhouse of theFerdowsiUniversityofMashhadin 2010-2011. Salinity stress during early growth and panicle differentiation declined the plant height and tiller number. The highest biological yield was obtained from the control treatment, but it was the lowest when plants were salinized throughout the growing season. When plants were stress-free at 2-3 early stages and then subjected to salt stress, reductions in total dry matter were remarkably less than those experienced when salinity was imposed in later growth stages, especially if salinity occurred at a late individual stage. Continuation of salt stress from emergence to both blooming and soft dough stages led to remarkably adverse effects on grain yield. The effect of salinity appears to be most effective on yield components that are growing or developing at the time the salt stress is imposed. The critical period of salinity stress for biological yield was more distinct than that of the grain yield. This indicates that sorghum is not sensitive to salinity at seed setting and seed filling periods.

Twenty spices were employed to preserve the cooked and uncooked fillet of Puntius sarana (Hamilton) and Puntius ticto (Hamilton). IC50 values of 2,2’-diphenyl-1-picrylhydrazyl (DPPH) based free radical scavenging activity ranged from 0.1123 μg ml-1 in turmeric to 13.035 μg ml-1 in roman coriander. Phenol content ranged from 0.365 μg g-1 in onion to 5.67 μg g-1 in clove. The raw and cooked fillets of P. sarana, and the cooked fillet of P. ticto, treated with garlic recorded the highest rates of thiobarbituric acid (TBA) reactivity (P< 0.05). For raw P. ticto, both the control and garlic treated fillet recorded higher rates of TBA reactivity (P< 0.05). Fillet of both fish species recorded higher TBA reactivity under raw condition, compared to cooked fillet. This condition was similar for the spice treated fillet. The exceptions were garlic, green and black cardamom, roman coriander and onion for P. sarana and garlic, cumin, field mustard, black pepper and poppy seed for P. ticto, where TBA reactivity was higher in cooked condition. It is recommended that spices with active phenolic antioxidants be used to inhibit the lipid oxidation in P. sarana and P. ticto. However, application of garlic extract for fillet preservation should be avoided until further documentation.

Xylitol is the first rare sugar that has global market due to having beneficial health properties and being an alternative to current conventional sweeteners. Biotechnological production of xylitol by Candida tropicalis DSM 7524 as an alternative to chemical method for the fermentation of xylose to xylitol was studied. Banana peel was used as a substrate for xylitol production. Hydrolysate was detoxified by neutralization, activated charcoal treatment and vacuum evaporation. Effect of pH was tested for C. tropicalis at three different levels and pH value of 2.5 was found to be the best; producing 24.7 g L-1 xylitol. Rusks were prepared by replacing sucrose with xylitol at different levels. Physicochemical analysis of rusks at different intervals of storage i.e. 0, 10, 20 and 30 days was carried out. Hardness decreased significantly (P< 0.05) from the treatment having 100% sucrose(4,950.6 g) to 100% xylitol (3,090.3 g) upon replacing sucrose with xylitol, while fracturability value increased from 71.90 to 74.26 mm for the treatment containing 100% xylitol.Color value and water activity of rusks increased significantly with the replacement of sucrose with xylitol. The increase in moisture content and decreasing trend in other parameters with storage were observed in rusks. Xylitol has low calorific value as compared to sucrose so it can be incorporated into dietetic foods which may help in controlling sugar level in diabetic patients.

To obtain an optimum formulation for stabilizers–emulsifier in ice cream, different combinations of three stabilizers, i.e. basil seed gum, guar gum, and carboxymethyl cellulose, at two concentrations of 0.15 or 0.35% with or without E471 emulsifier were studied using a simplex-centroid mixture design. The regression models for physical properties and texture smoothness of samples were also established. Generally, increasing ratios of basil seed gum in gums mixture increased the apparent viscosity of ice cream mixes and smoothness of texture, but decreased the melting rate. Increasing proportions of guar gum enhanced overrun of samples. Results suggested that the combination of 96.94% basil seed gum and 3.06% guar gum at the concentration of 0.35% with 0.15% emulsifier produced the optimum ice cream. Subsequently, the interaction of the obtained optimum formulation with κ-carrageenan as a secondary stabilizer was studied at two levels of 0.01 and 0.02%. The pH, draw temperature, overrun, hardness, and melting rate were measured through physical methods. Rheological and sensory analyses were also performed. Inclusion of κ-carrageenan in formulations decreased the values of instrumental hardness and improved the smoothness of the samples; while it had no significant effects on other properties such as draw temperature, overrun, sandiness, and foaminess.

In this study, the effects of moisture content and corn variety on the physicochemical properties of popcorn were investigated and modeled using response surface methodology. Each of the two corn varieties (Hybrid corn KSC 600 PC and American) was prepared with a range of moisture (six moisture levels ranging from 10 to 20%) and popped by a hot air popper. Variety and moisture content affected the density, air bubble diameter as determined from electron micrographs, textural hardness and color parameters. The lowest densities for American and hybrid corns were obtained at moisture contents of 14 and 18%, respectively. As water content deviated from the optimum levels the popcorn density significantly decreased. For both corn varieties, with increasing water content, the lightness of the samples increased while b (yellowness-blueness) values decreased. For American popcorn no significant impact of the moisture content on the hardness was observed, however in hybrid corn, hardness of popcorns significantly decreased with increasing water content, and the lowest density and hardness were observed at moisture content of 18%. Experimental models are presented for the prediction of density, color parameters, air bubble diameter and hardness of popcorns at different moisture contents for American and hybrid corns.

In the last few years, public awareness has been on the increase about short- and long-term effects of forest roads construction on the environment. Therefore, forest road managers have to be concerned about the negative impacts and mitigate them as much as possible. This research conducted multi-criteria analysis techniques in a useful way to define the effective criteria and propose a model for forest road network planning and assessment so that both economic and environmental costs are minimized. The model was used for evaluating the alternatives and a sensitivity analysis was then performed to verify the model. Results of sensitivity analysis showed that, there were two alternatives out of nine, with the lowest negative impacts. As a result, analytic hierarchy process and sensitivity analysis (AHP-SA) revealed that the criteria slope, soil texture and landslide susceptibility had the highest weight values, respectively, and the criteria soil texture and distance from stream networks and distance from faults were especially sensitive to the changes. In addition, the sensitivity analysis proved that the model proposed in our analysis was almost reliable and stable, and only the first and second priorities were replaced in priority levels when the weight values of criteria were changed. Results showed that the methodology was useful for identifying road networks that met environmental and cost considerations. Based on this work, the authors suggest future work in forest road planning using multi-criteria evaluation and decision making be considered in other regions and that the road planning criteria identified by the experts in this study can be useful.

In production of tissue paper, the adhesion of a liquid adhesive creping aid, compound polymer, as creping aids on the Yankee dryer surface was investigated. A compound polymer was prepared based on mixing ratio of poly (amideamine)-epichlorohydrin resin (PAE) as an adhesive agent, polyvinyl alcohol (PVA) as a modifier agent, and cationic fatty acid (CFA) and ethylene glycol (EG) as release agents. In order to simulate the Yankee dryer cylinder, the adherence of paper to the substrate that was coated by the compound polymer solution was measured using a peel strength test. Results indicated that increasing the percent of total solid content of compound polymer would increase peel strength of paper. Peel strength of paper increases if EG as a release agent is used. The amount of PVA/PAE resin in the formulation of creping aid was critical for building a flexible and tough coating layer on to the substrate and to provide adequate adhesion of paper in peel strength test.

In order to evaluate salt (NaCl) tolerance in alfalfa (Medicago sativa L.) half-sib families, a factorial experiment on the basis of completely randomized design, with 20-25 individuals in pot (replicates) was carried out under field conditions at the Research Station of University of Tabriz. Electrophoretic analyses were performed by using 7.5% slab polyacrylamide gels. Two antioxidant enzymes including superoxide dismutase (SOD) and peroxidase (POX) and one common isozymic system namely esterase (EST) were stained and for each isozymic band the “density × area” scores onto gels were evaluated by MCID software as enzymatic activity. Plant materials consisted of 12 half-sib families that were obtained from a “polycross nursery progeny test” in the same station, a few years ago. The applied salt stress (9±0.2 ds m-1) reduced plant height, dry weight, leaf weight and stem weight about 31.7, 37.5, 33.7 and 34.7 percent, respectively. Significant correlations were observed between plant height and some antioxidant isozyme activities. Salt stress increased activities of some SOD and POX isozymes but it was ineffective on the activity of EST. Among the families, Ranger cultivar and Zaghl-aghaj and Taze-kand landraces which displayed maximum height and other characteristics exhibited the highest increments in respect of isozyme activities, indicating that antioxidant analysis by gel electrophoresis could be a useful tool for salt stress tolerance studies.

In this study, 120 accessions of Aegilops crassa collected from various geographical areas of Iran were analyzed with respect to genome size and protein markers. A flow cytometry survey of these accessions revealed that one hundred and thirteen of the accessions were tetraploid and seven were hexaploid. Moreover, these accessions revealed variations in high molecular weight glutenin subunit compositions. In most accessions, subunits showing electrophoretic mobility similar to that of Dy12 were present. Eleven allelic variants were observed in Glu-D1 locus with the highest (30.90%) and the lowest allele (0.5%) frequencies in 3+12 and 2+10 variants, respectively. Among 17 bands selected for MALDI-TOF-TOF-MS analysis only 6 bands were identified with high probability and 11 of them had no MS/MS data. The results showed that Iranian accessions of Ae. crassa formed an interesting source of favorable glutenin subunits that might be very desirable in breeding programs for improving bread wheat quality.

Different competitor weed fungi Rhizopus stolonifer, Penicillium glabrum, Fusarium oxysporum and Coprinopsis kimurae were found to have associated with the fruit beds as constant contaminants of Pleurotus sajor-caju and Lentinula edodes. Several antagonists, plant extracts and chemicals were tested against the weed fungi to screen the most effective ones and to have an integrated combination for better management of the disease. Among the chemicals used, Baynate and Bavistin at the dose of 0.5% provided highly significant inhibition of all the competitors. Different plant extracts were treated against the weed fungi and it was found that garlic (Allium sativum) preparation exhibited the best result followed by Cycas revoluta and Azadirachta indica. Among the antagonists, Trichoderma viride was proved to be the most efficient one. Out of the various compatible combinations, the T. viride, garlic extract and Bavistin combination was found to be the most potent integrated combination providing more than 97% growth inhibition of the weed fungi in vitro. Under in vivo condition, biological efficiency of the combination of T. viride, T. hamatum, bavistin and garlic preparation was found to be significantly higher than untreated beds of both edible mushroom species.

To study molecular evolutionary characteristics and genetics of beet necrotic yellow vein virus (BNYVV) isolates population from Iran, nucleotide sequences of p25 and coat protein (CP) were determined and the amino acids sequences thus deduced were analyzed using phylogenetic and population genetics methods. A survey of BNYVV in Iran indicated the infection of 288 collected samples out of 392 samples in most beet growing areas and that most of the isolates (92%) were of the A-type and the rest of isolates (8%) were P-type. Our molecular evolutionary analysis showed that CP was highly conserved but allowed to assign all isolates to three distinct groups. Different parts of p25 coding regions were under different evolutionary constraints. The most positive selection was detected at the position 68, the second amino acid of the tetrad motif. Iranian isolates were found to cluster with European isolates into three distinct clusters based on p25 sequences. Population genetics analysis revealed that BNYVV populations have low differentiation (Kt= 3.97145) and low diversity (πT= 0.006, Hd= 0.860) with frequent gene flow indicating lack of phylogeographic structure between populations.

Leaf blotch disease of barley, caused by Rhynchosporium secalis is a major disease of barley in Iran. Its worldwide occurrence and economic importance in barley production has motivated studies on the population genetic structure of this pathogen. Random Amplified Polymorphic DNA (RAPD) method was utilized to investigate the genetic diversity of populations of R. secalis isolated from barley leaves. A total of 94 isolates, representing five geographically distinct populations, were collected from diverse climatic regions in Iran. Genetic diversity was studied using eleven RAPD primers. Out of a total of 119 fragments generated by random decamer primers, 89 (75.1%) were polymorphic with an average of 8.1 polymorphic fragments per primer. Cluster analysis of RAPD data using UPGMA and simple matching coefficient method distinguished 33 main groups at 75% similarity level. The similarity between isolates ranged from 0.62 to 0.89. In total, 42 molecular phenotypes (haplotype) were distinguished among the 94 isolates by 11 RAPD primers. Haplotype one was found in all the five regions of Iran surveyed. Some haplotypes were specific to a single region while others found in several regions. There was little correlation observed between genetic vs. geographical distance suggesting that they were independent of each other.

Australian grapevine viroid (AGVd), an apscaviroid of the family Pospiviroidae, was recently identified in vineyards of southern Iran. It had a relatively wide host range and caused stunting, leaf deformation, mottling and vein clearing in experimental hosts upon mechanical inoculation of nucleic acid extracts or agroinfiltration of the viroid infectious cloned DNA. Predicted secondary structure of the AGVD-Ir showed a difference from the predicted structure of the type isolate in the viroid pathogenicity domain. Mutational analyses showed sequence changes introduced into that domain of the AGVD-Ir clone decreased the viroid’s replication efficiency in planta but did not show any effects on its movement.