JOURNAL OF RESEARCH IN AGRICULTURAL SCIENCE
Year:2011 | Volume:7 | Issue:1 (12)|Papers Count:8

Acanthiophilus helianthi Rossi (Diptera: Tephritidae) is a pest of safflower and managing it because of its fecundity and concealed larval habitat is a challenge. Potential components of an integrated pest management program for A. helianthi were investigated at the Gachsaran Agricultural Research Station, in southern Iran from November 2008 to July 2009. For the life cycle studies, the infected flower heads were collected from an experimental field plot and were developed from egg to adult under laboratory conditions. The results showed that the first adults emerged gradually in mid April 2009. Female A. helianthi had a pre-oviposition period of 5.8±1.0 days and the average fecundity was 27±3.2 eggs. The eggs were laid in the bracts of flower heads singly or in clusters of 3-18. The Incubation period was 3.8±0.6 days under field conditions and 3.4±0.6 days under cage conditions.Three larval instars occurred, and the larval phase was 7-10 days. Males emerged earlier than females, but the longevity of the adult females (12±3.0) was significantly greater than that of males (8±1.0).Analysis of aggregated male and female sampling data showed that the gender ratio was 1: 1.28. To evaluate the efficiency of different methods of fruit fly control on safflower, a field experiment was carried out. Five diverse methods, insecticides, baiting, cultural, Integrated Management and no treatment were assessed on weight of one thousand seeds, percentage of oil, percentage seed damage and harvest/ha. Integrated Management and insecticide control indicated best results with harvest potential of 1850 and 1723 kg/ha with a least damage of 5 and 8%, respectively. Since use of selective insecticides is one of the most important methods for pest management, the efficacy of six insecticides against A. helianthi infesting safflower were evaluated. Among the treatments Endosulfan 35% EC at 0.03% proved more effective followed by Chlorpyriphos and Monochrotophos.

Before fabrication of any system, development of its simulation model can improve designer' s understanding about strengths and weaknesses of the system. As a result, fabrication phase can be done without trial and error method. In this study a simulation model for alfalfa hay yield monitoring system on the baler was developed. Simulation of the yield measuring section led to the numerical solution of a first order differential equation. Dead reckoning method was used for simulation of the coordinates determination section. According to the results of this study: In the model of yield measuring section, the retardation time was shown. This retardation time is considered to take into account the required time for reaching crop from the ground to the baling channel. There were jagged shapes in the simulated data which coincide with changes in type of data variations. Therefore when the measured data faced a sudden change, a jagged shape will result in the simulated data. It was recommended to use each bale bulk density measuring system on the baler. In order to increase the accuracy of the coordinates determination section, it was essential to use ballast or spring pressure on the ground wheel.

Hypericum perforatum L. is among important herbs worldwide, which growing wild in Iran various areas and altitudes particularly north of the country. However, according to different regional and genetic reasons, its secondary metabolites differ in its growth vegetative. Therefore, in order to define its best vegetative area, the most important biochemical components in five regions and three altitudes and four samples from each regions (60 samples all together) were sampled and analyzed. Experiment revealed that the highest values of hypericin (0.251% DW) and total phenols (412 mg/l) were obtained in Jannat Roodbar region in a height of 1218 m and the highest amounts of flavonoid (73 mg/ml) and carotenoid (0.13 mg/ml) were observed in Pole Zangoole region in a height of 2300 m. Regression equations have been demonstrated to have a positive linear relationship between hypericin and total phenols contents. While among hypericin and flavonoid as well as carotenoid, this relation forms a second degree equation. The relationship of hypericin and total phenols contents was a negative correlation as well.

In order to study the impacts of nitrogen fertilizer and plant density management on growth, dry matter remobilization and yield of durum wheat, Seymareh cultivar, a split plot experiment based on randomized complete block design with three replications was conducted at Agricultural Research Station, Islamic Azad University, Ardabil Branch, Iran in 2009-2010 cropping year. Main plot included three plant densities (300, 350 and 400 seed m-2) and sub plots contained four nitrogen levels (0, 70, 140 and 210 kg ha-1 N). Results showed that with increasing nitrogen levels, length of the vegetative growth period increased and dry matter remobilization from the plant to grain and its impact on grain yield decreased. Also, the highest length of generative growth and ripening periods and grain yield were obtained using 140 kg ha-1 N and excess rates, decreased grain yield. With increasing plant density, all measured traits were increased. On account of increase in remobilization and grain yield, prevent of environmental pollution and decrease in fertilizer application as excess cost, application of 140 kg ha-1 N in 400 plant m-2 density (with conditions of this research), is recommended.

To evaluate the effect of different levels of salinity on antioxidant enzymes activity of leaves and plant physiological characteristics of canola as a marker of resistance to salinity, an experiment was conducted in greenhouse of Research Center of Agriculture and Natural resources in East Azarbaijan in 2009. Treatments included combinations of five different levels of salinity (0, 50, 100, 150, and 200 mM) and four cultivars of brassica included (Elite, Licord, SLM046 and Okapi). With increasing salinity, stomatal conductivity, transpiration and leaf relative water decreased in all cultivars. Effect of salt stress on antioxidant enzymes of leaves was significant, and changes in the amount of super oxided dismutase enzymes, catalase and glutathion reductase was observed. Enzyme activity in the period of growth increased and in plant maturity decreased. Comparison between canola cultivars showed the strong correlation between leaf relative water and enzyme super oxide dismutase activity.SLM046 showed the least changes in leaf relative water level and the highest enzyme activity and was resistant cultivar and Elite were the most sensitive cultivar to salinity.

Samples of different solid organic wastes (SOW) including cow manure (CM), pistachio wastes (PW), cotton residues (CR) and date wastes (DW) were collected from different regions of Iran and converted to various vermicomposts. Each vermicompost had an iron-enriched counterpart produced by gradual addition of ferrous sulphate to organic wastes during the vermicomposting. Samples of a loamy soil were mixed with various proportions of prepared vermicomposts and pistachio seedlings were grown in 3 kg pots filled with them, for six months. During the period of experiment, some growth indices such as seed germination percentage, leaf area index, leaf chlorophyll content, leaves number, stem diameter and photosynthesis rate were measured for each treatment. After growing period, shoot and root dry weights and also macro and micro elements were measured. After vermicomposting, there was a substantial decrease in organic carbon content, total K and electrical conductivity of organic wastes. However, the contents of ash, N, P, Ca, Mg and some micronutrients including Fe, Mn, Zn and Cu increased in vermicomposted organic wastes. The pH of organic wastes shifted toward neutrality and their bulk densities were changed. There was a significant increase in seed germination, leaf area index, shoot dry weight and stem diameter in pots treated with 10% pistachio and cow manure vermicomposts in comparison with control and other treatments. Due to fungi growth and seed infection, germination did not occur in pots treated with date vermicompost so this organic amendment was not a suitable component for potting media. Vermicomposts enriched with ferrous sulphate increased chlorophyll and Fe contents of leaves.

Aflatoxins are one of the most important toxic metabolisms that are produced byAspergillus flavus andAspergillus parasiticus on contaminated feed. Consuming of the contaminated feed by the dairy cattle may result reducing dry matter intake, decreasing milk yield, blindness, walking in circle, ear twitching, teeth grinding, frothing at the mouth, photosensitive dermatitis, keratoconjuctivitis, diarrhea, abortion, and some other reproductive problems. More recently, other problems such as lameness and ovarian cyst have been related to aflatoxicosis in the dairy herds. Since aflatoxins are considered as potential mutagens, their metabolisms excreted in the milk, which was considering during the last decades. A number of quantitative methods were applied to measure the aflatoxin metabolites in biological samples and feedstuff that was consisting of thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC), gas chromatography (GC), and immunochemical method such as enzyme linked immunosorbent assay (Elisa). In the present study, measuring of the aflatoxin was implemented in two groups: 1) the feeds of dairy cattle, which was exposed to four types of aflatoxin (B1, B2, G1 and G2) 2) the milk samples, which exposed to aflatoxin M1, were collected from dairy farm in the province of Esfahan. Two methods, HPLC and Elisa, were used for this purpose. It was concluded that there was no significant difference between the values obtained by the two procedures. However, sensitivity and specificity of HPLC was higher than the Elisa method.

The objective of this study was to estimate genetic parameters coupled with genetic and phonotypic trends for age at first calving (AFC) and first and second calving interval (CI1 and CI2) in Iranian Holstein cows. Records of reproduction from 1983 to 2007 for AFC, CI1 and CI2 were 261116, 163234 and 92661, respectively. Single and two trait animal model was used to estimate genetic parameters by restricted maximum likelihood procedures using Average Information algorithm in ASREML software. Estimates of heritability were 0.19±0.005 for AFC, 0.04±0.003 for CI1, and 0.04±0.004 for CI2. Genetic trends for AFC, CI1 and CI2 were -0.75±0.11, 0.004±0.02, -0.02±0.01day per year and phonotypic trends were -2.35±0.38, -1.13±0.39, -0.28±0.23 day per year, for AFC, CI1 and CI2, respectively. The genetic, phonotypic and environmental correlations were -0.049, 0, 0.002 for AFC and CL1, 0.014, -0.004, -0.004 for AFC and CL2, and 0.877, 0.081, 0.043 for CL1 and CL2, respectively.