Showing papers in "Journal of Agricultural Science and Technology in 2010"

Chemical Characteristics and Oxidative Stability of Sesame Seed, Sesame Paste, and Olive Oils

Abstract: Raw (intact) sesame seed showed a high content of oil, protein and ash: respectively, 52%, 24% and 5%. Studies were conducted on some quality characteristics of sesame and olive oils. The following values were obtained from raw sesame, sesame paste and olive oils, respectively: unsaponifiable matter 1.35, 1.46, and 1.50%; total phenols 14.21, 16.82, and 53.33 mg kg -1 oil; chlorophylls 0.04, 0.09 and 1.88 µg g -1 ; carotene 2.62, 3.66 and 19.10 µg g -1 ; refractive index 1.47, 1.47 and 1.47; saponification value 186.6, 185.75, and 97.94; iodine value 113.35, 91.34, and 81.23, acidity along with of 1.64, 1.10, and 1.12 mg KOH g -1 oil. Fatty acid profiles of raw sesame, sesame paste and olive oils showed a predominance of oleic acid (41.68%, 41.94%, and 52.14%, respectively) followed by linoleic-acid (38.29%, 37.48%, and 17.82%). Storage effect at 65°C of raw sesame, sesame paste and olive oils were later on studied. Results showed that the oxidative stability of raw sesame oil was higher than that of sesame paste oil. Due to its all favorable properties, sesame oil could be used in either food or cosmetic products.

Nutritional potential of longhorn grasshopper (ruspolia differens) consumed in siaya district, kenya

Abstract: The longhorn grasshopper (Ruspolia differens) forms a major part of the food culture of communities in the Lake Victoria Region of East Africa. The aim of this research was therefore to assess the nutritional potential of this insect to the human diet in the region in combating nutritional deficiencies that are of public health concern. The green and brown coloured grasshoppers were studied. They were found to contain a protein content of 37.1% and 35.3%, fat content of 48.2% and 46.2%, ash content of 2.8% and 2.6%, a fibre content of 3.9% and 4.9% for the green and brown grasshoppers respectively. Among the macro minerals, potassium (K) was the most abundant with a value of 370.6 mg/100g and 259.7 mg/100g, phosphorus (P) 140.9 mg/100g and 121.0 mg/100g while calcium (Ca) levels showed overall means of 27.4 mg/100g and 24.5 mg/100g in the green and brown grasshopper respectively. Iron (Fe) was the most abundant among the trace minerals with a value of 16.6 mg/100g and 13.0 mg/100g while zinc showed a mean value of 17.3 mg/100g and 12.4 mg/100g in the green and brown grasshopper respectively. The insects showed a retinol concentration of 2.1 μg/g and 2.8 μg/g, α-tocopherol 201.0 μg/g and 152.0 μg/g, riboflavin 1.2 mg/100g and 1.4 mg/100g, 2.1 mg/100g and 2.4 mg/100g of niacin for the green and brown grasshopper respectively. Lipid analysis revealed that the insects’ oil comprised of high amounts of polyunsaturated fatty acids, 89.4% and 84.3% neutral lipids, 7.4% and 9.3% phospholipids, 3.2% and 6.4% glycolipids for green and brown grasshopper respectively. These values suggest that Ruspolia differens has potential for exploitation to combat nutritional deficiencies that are of public health concerns. The insect could form a base for new food products of considerable nutritive value.

Chemical compositions of essential oils of Artemisia dracunculus L. and endemic Matricaria chamomilla L. and an evaluation of their antioxidative effects.

Abstract: The present study explores the chemical constitution and antioxidant activity of the essential oils of the aerial parts of Artemisia dracunculus L. and the flower heads of Matricaria chamomilla L. GC-MS analysis revealed the presence of ( Z)-anethole (51.72%), (Z)-�-ocimene (8.32%), methyleugenol (8.06%), limonene (4.94%) and linalool (4.41%) in Artemisia dracunculus and ( E)-�-farnesene (24.19%), guaiazulene (10.57%), �bisabolol oxide A (10.21%), �-farnesene (8.7%) and �-bisabolol (7.27%) in M. chamomilla L.. The antioxidant activity (AOA) of the essential oils was investigated using DPPH • (2, 2 �-diphenyl 1-picrylhydrazyl) free radical scavenging and �-carotene/linoleic acid methods. The essential oil EC 50 values were determined as 3.19±0.13 and 5.63±0.20 mg ml -1 for A. dracunculus and M. chamomilla , respectively. Further, the A. dracunculus L. essential oil (ADEO) and M. chamomilla L. essential oil (MCEO) were able to reduce the oxidation rate of soybean oil under accelerated conditions at 60 °C (oven test).

Combining Ability and Heterosis in Rice (Oryza sativa L.) Cultivars

Abstract: Quantitative valuations of observed heterosis for 11 traits of 15 F 1 hybrids generated by half diallel crosses of six diverse rice cultivars (Domsefid, Hashemi and Binam, three Iranian local cultivars; Dorfak, Kadous and IR30, three improved cultivars), were made in this study. Fifteen F 1 hybrids and their parents were evaluated in a randomized complete block design with three replications at the Research Farm of the University of Guilan at Rasht, (Iran) in 2006. The studied traits were growth period, reproductive period, flag leaf area, plant height, panicle length, number of panicles per plant, number of grains per panicle, 1000-grain weight, grain yield, brown grain length and brown grain width. The significance of specific combining ability (SCA) and general combining ability (GCA) for all studied traits revealed that both additive and non-additive gene effects contributed to the inheritance of the traits. Assessment of standard heterosis based on check variety Dorfak showed that there was significant heterosis for all the traits studied in the 15 hybrids. For grain yield, the Dorfak ×Domsefid cross had the highest heterosis. This hybrid had good heterosis values for many traits such as growth period, reproductive period and 1000-grain weight and was recommended as the most promising combination for developing high yielding hybrid rice varieties.

Application of ATR Infrared Spectroscopy in Wood Acetylation

Abstract: Acetylation is a chemical modification of wood to enhance its properties. IRspectroscopy is a useful technique for proofing chemical bondings in wood and the Attenuated Total Reflection (ATR) Infrared Spectroscopy technique was applied as an easier technique over other IR-spectroscopies. In this research, different degrees of acetylation, weight percentage gains (WPGs) in beech and pine mini-stakes were achieved by using acetic anhydride. Acetylated samples were analyzed by applying an Attenuated Total Reflection (ATR) Infrared Spectroscopy technique. Comparison of the acetylated samples with non-acetylated woods showed that hydroxyl groups (O-H) were diminished at wave numbers of about 3,354-3,328 cm due to the substitution of hydrophobic acetyl groups in cell wall polymers. A strong peak appeared at wave numbers of about 1,733-1,728 cm in beech and 1,737-1,728 cm in pine due to the carbonyl (C=O) stretching of acetyl groups. The magnitude of the bands increased with raising the weight percentage gains (WPGs). The methyl deformation of the acetyl groups induced at wave number 1369 cm caused by the stretching of C-H in polysaccharides. There was also a clear increase in the magnitude of the wave numbers at about 1234-1226 cm in beech and 1236-1226 cm in pine due to the stretching of C-O and carbonyl deformation in the ester bonds during the acetylation of lignin.

Antibacterial Effect of Effective Compounds of Satureja hortensis and Thymus vulgaris Essential Oils against Erwinia amylovora

Abstract: Use of essential oils as pesticides or fungicides is safer than chemicals, but it requires plenty of the plant to be effective. Hence, finding the effective compounds of essential oils and their synthesis decreases the problem of preparing the natural compound. The antibacterial effect of Satureja hortensis L., Thymus vulgaris L. essential oils, and their major constituents were determined using the disc diffusion method. These essential oils prevented Erwinia amylovora growth (that causes fire blight disease). The essential oils were fractionated using preparative column chromatography (Silica column) and all fractions were tested for their antibacterial activities on this bacterium. Effective fractions were analyzed by GC-MS. Results showed that carvacrol is the effective compound in Satureja hortensis essential oil and has strong antibacterial effect. The effective compounds in Thymus vulgaris essential oil are thymol and carvacrol. Thymol and carvacrol showed a strong antibacterial effect against E. amylovora in the disc diffusion method. These compounds prevented the growth of E. amylovora in sucrose and nutrient agar media.

Isolation of Phosphate Solubilizing Bacteria from the Rhizosphere of Faba Bean of Ethiopia and Their Abilities on Solubilizing Insoluble Phosphates

Abstract: Native phosphate solubilizing bacteria (PSB) were isolated from four areas (Ankober, Keyt, Mehalmeda and Molale) of Ethiopia to study their effect on releases of soluble phosphorus from insoluble P sources. The highest bacterial number was found at Keyt (2.6 ×10 3 g -1 soil) and the least at Molale (15 g -1 soil). Five efficient PSB were selected for further study based on their ability in forming a higher clear zone diameter than the other isolates. These isolates were identified based on phenotypic characters as Pseudomonas sp. Anb-105, Meh-008, Meh-101, Meh-303 and Meh-305. The phosphate solubilizing efficiency of these five isolates along with Jim-41 isolate from the National Soil Research Centre were studied using different P sources [Tricalcium Phosphate (TCP), Egyptian Rock Phosphate (ERP), Bikilal Rock Phosphate (BRP) and Old Bone meal (OB)] in an incubation study. The results revealed that all the PSB isolates significantly (P ≤ 0.01) solubilized a higher amount of TCP, ERP and OB over the uninoculated control. The highest amount of solubilization was achieved for TCP with Meh-305 (39 mg per 50 ml) followed by ERP with Meh-101 (31 mg per 50ml) at pH 3.82 and 3, respectively. Although Meh-008 and Jim-41 isolates solubilized significant amount of BRP during the 20 days of incubation, the soluble P obtained was very small as compared to other P source tested.

Estimation of leaf moisture content by measuring the capacitance

Abstract: Water is one of the most vital constituents in plants. In this research, for an estimation of leaf moisture content, the variation of capacitance was employed. The variations were measured via designed and manufactured capacitive sensors. The objective of the research was to estimate leaf moisture content by measuring its capacitance for five agronomic crops. Experiments for measuring leaf capacitance were performed on maize, sorghum, capsular bean, white bean and sunflower at two frequencies of: 100 kHz and 1 MHz. The results showed that in all cases the best fitted curve for variations of the capacitance in relation to leaf moisture percentage was in the form of an exponential function namely: y= ae bx (where y is capacitance, x is leaf moisture content, a is the linear coefficient, and b is the exponential coefficient). Parameters a and b for different plants of each crop and each frequency were not significantly different at 1% probability level. However, these coefficients were significantly different among different crops. Coefficients of determination were higher at 100 kHz than at 1 MHz. It was also observed that the higher the leaf moisture the more the data points scattered around the best-fit line, although the scattering was more uniform at 1 MHz.

Economic Analysis of Rice Consumption Patterns in Nigeria

Abstract: This study examined the nature and patterns of rice consumption in Nigeria, using Kwara State as a case study The study methodology comprised a two stage sampling technique which was used to survey 110 rice consumer households across two villages and six towns in Kwara State Analytical tools used in the study include descriptive statistics and the multinomial logit model The major factors that significantly influence household preferences for either a combination of local and imported rice or the imported rice only to the local rice were the income of the head of household, household size and the educational status of the heads of household, the price per unit kilogramme of rice, however, was not a significant factor This study therefore recommends that an effort should be made to increase rice production coupled with the provision of standard processing facilities This will help to make the local rice sufficiently more competitive thereby increasing its demand

When Is Metafrontier Analysis Appropriate? An Example of Varietal Differences in Pistachio Production in Iran

Abstract: Estimates of technical inefficiency in agricultural production are suspect so long as variations exist in production technology among the sampled farmers. Traditional methods of dealing with these technological differences risk attributing "technology gaps" to technical inefficiency between farms, pointing to the need to undertake a metafrontier analysis that allows technology gaps to be distinguished from technical inefficiency. Using farm-level data on the production of three different varieties of pistachio trees in Iran, we outline two criteria to justify its use: an inability in farmers to switch between production technologies except in the long term, and satisfaction of statistical tests on metafrontier coefficients. The application of metafrontier analysis enabled technical efficiency scores to be corrected for differences in production capacity imposed by tree variety. Results reveal that there is very little difference in technical efficiency between farms growing the different tree varieties. But they show that ignoring the production constraints imposed by variety choice could overstate the scope for farmers to improve their technical performance by adopting better farming practices. The results also indicate that it is misleading to compare the performance of different tree varieties on the basis of yield per hectare alone.

Simulated In-transit Vibration Damage to Watermelons

Abstract: Vibration generated by vehicles during road transport has an important effect on the agricultural products damage process, particularly vegetable and fruit. Modulus of elasticity is one of the most important mechanical properties of fruits and its variation can be described as one of the damage criteria during transportation. This research was conducted to evaluate the effects of vibration parameters (frequency, acceleration and duration) and fruit position in the bin, on watermelon damage. At first, vibration frequency and acceleration were measured on the different points of a truck-bed in order to obtain the range of vibration frequency and acceleration distribution during transportation. Second, a laboratory vibrator was used to obtain some factors influencing damage during watermelons transportation. The damage was described as a difference in the modulus of elasticity of the watermelon (flesh and hull) before and after the test. According to the results measured on the truck-bed, the vibration frequency mean values were 7.50 Hz and 13.0 Hz for 5-10 Hz and 10-15 Hz frequency intervals, respectively. Furthermore, vibration acceleration mean values were 0.30 g and 0.70 g for 0.25-0.50 g and 0.50-0.75 g intervals, respectively. Vibration frequency and acceleration mean values were used for vibration simulation. Vibration durations were 30 and 60 minutes and damage was measured for watermelons at the top, middle and bottom positions in the bin. Laboratory studies indicated that, vibration frequency, vibration acceleration, vibration duration, and fruit position, which were taken into consideration as controlled variable parameters, significantly affected the damage (P< 0.01). Damage to the watermelon flesh was higher than watermelon hull. Vibration with a frequency of 7.5 Hz, acceleration of 0.70 g, and duration of 60 minutes caused higher damage levels. Fruits located at the top of the bin showed more damage than those in middle and bottom positions (P< 0.05).

Mathematical Modeling of Forced Convection Thin Layer Solar Drying for Cuminum cyminum

Abstract: This paper presents mathematical models of thin layer forced convection solar drying of Cuminum cyminum using two drying methods (mixed and indirect) at different operating conditions. The average initial moisture content of the seeds for all tests was about 43% d.b. and the drying was performed continuously, in each test, for a uniform period of 90 minutes drying time in a solar cabinet dryer to obtain an average final moisture content of 8% d.b. Three airflow rates (0.084, 0.127 and 0.155 m 3 s -1 ) were adopted and the experiments were run each sunny day from 11:30 to 13:00 with an average solar intensity of 750 W m -2 (±50 W m -2 ), ambient air temperature of 27°C (±1°C) and relative humidity of 30% (±1%). In order to find the most suitable form of thin layer solar drying model, eleven different mathematical models were selected using the experimental data to determine the pertinent coefficients for each model by applying the non-linear regression analysis technique. The goodness of fit was evaluated by calculating and comparing the statistical values of the coefficient of determination (R 2 ), reduced chi-square ( � 2 ) and root of mean square error (RMSE) for any model and for the two drying methods. The best results were found for the approximation of diffusion model with R 2 = 0.995, 0023 . 0 2 = χ and RSME= 0.0199 in mixed mode type, and the Midilli model with R 2 = 0.994, 0.0045 2 = χ and RSME= 0.0225 in indirect mode type thin layer solar drying.

Characterization of Acid and Salt Tolerant Rhizobial Strains Isolated from Faba Bean Fields of Wollo, Northern Ethiopia

Abstract: Density of Rhizobium population in faba bean (Vicia faba L.) fields of Wollo area (Asketema, Gashana, Kotem, Major and Sekota) northern Ethiopia was studied. The highest population of rhizobia was found at Major and the least at Sekota regions. The native rhizobial strains isolated from the northern parts of the country tolerated a higher salt concentration (5% NaCl) than the exotic rhizobial strains (Tall 1402 and Tall 1397). Both native and exotic strains failed to grow at pH 4 and 4.5 levels in the laboratory conditions. In the soil adjusted to pH 4-7, all the native rhizobial strains persisted while those of the exotic strain failed to survive at pHs below 5.5. The native strains were more versatile than the exotic ones in utilizing different carbohydrates as a sole carbon source and were found to be more resistant to many antibiotics (streptomycin, chloramphenicol, rimfampenicillin, oxytetracycline, penicillin and tetracycline) than the exotic strains which are found resistant to chloaramphenicol only. Percentage of nitrogen fixation is also higher for native rhizobial strains these isolates being found to be superior to the exotic strains in stimulating growth, dry matter yield, nodulation and nodule wet weight of faba bean in pouch culture.

Susceptibility of Microorganisms to Myrtus Communis L. Essential Oil and its Chemical Composition

Abstract: The antimicrobial effects of essential oil isolated from Myrtus communis L. against Escherichia coli, Staphylococcus aureus, Streptococcus faecalis, Pseudomonas aeruginosa, Klebsiella pneumoniaee, Bacillus subtilis, Bacillus licheniformis, Candida albicans and Saccharomyces cerevisiae were studied. The disc diffusion method was used to evaluate the zone of microbial growth inhibition at various concentrations of the oil. The minimal Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC) of the oil were determined. The oil was found to have an antimicrobial effect. Kinetics of microbial destruction exhibited that the oil could kill microorganisms within 45 minutes of exposure. GC and GC/MS analysis of the oil revealed 32 components. The major components were α-Pinene (29.4%), Limonene (21.2%), 1,8-Cineole (18%), Linalool (10.6%), Linalyl acetate (4.6%) and α-Terpineole (3.1%). The high monoterpenes hydrocarbons such as αPinene and Limonene seem to contribute to the strong antimicrobial activity of Myrtus communis L. Further research on antimicrobial effects of essential oils with a view to substituting the common chemical compounds is promising.

Population density and spatial distribution pattern of thrips tabaci (thysanoptera: thripidae) on different soybean varieties

Abstract: Population density and spatial distribution of Thrips tabaci Lindeman on seven soybean varieties (Williams, Tellar, Sahar, Dpx, L 17, Sari and Zane) and one genotype (Ks3494) were studied in Tehran region, during 2007 The highest population density of the thrips per leaf was recorded on Dpx and on Ks3494 (081 ± ± ± ±005 and 080 ± ± ± ±005, respectively) The lowest population density was observed on L 17 and Tellar (062 ±004 and 064 ±003, respectively) To estimate the spatial distribution pattern of this pest, data were analyzed through index of dispersion, Lloyd's mean crowding, Morisita's index as well as through regression models (Taylor and Iwao) The index of dispersion and Lloyd's mean crowding indicated an aggregated pattern for the spatial distribution of this insect in all the varieties and the genotype of soybean Spatial distribution of T tabaci using Morisita's index was aggregated in most of the sampling dates In Taylor's model, regression between log S 2 and log m was not significant for Dpx varieties (P> 005), but the b values of Taylor's power law on Zane, Sahar, Williams and Tellar varieties exceeded 1, indicating aggregated distribution However, the other varieties had a b value equal to 1, indicating random distribution Iwao's patchiness regression indicated that the spatial distribution of T tabaci on Sari, Zane, Williams and Tellar varieties as well as on Ks3494 genotype was aggregated, but on the rest of varieties the pattern was of a random one It is concluded that soybean varieties affect the population density and spatial distribution of T tabaci Spatial distribution parameters of this species can be employed to outline a sampling program as well as to estimate the population density of T tabaci

Optimization of Extraction Conditions of Phenolic Compounds from Pistachio ( Pistachia vera ) Green Hull through Response Surface Method

Abstract: Phenolic compounds, especially those of plant origin, constitute an essential part of the human diet, and are of considerable interest due to their antioxidant properties. In this study, Ultrasound-Assisted Extraction (UAE), Microwave-Assisted Extraction (MAE), as well as Maceration Extraction (ME) methods were applied for phenolic compounds’ extraction from pistachio green hull. Response surface methodology was employed to optimize the extraction conditions as regards the yield of the compounds. A Central Composite Design (CCD) was employed to investigate the effects of three independent variables, namely liquid-to-solid ratio (8-20 times), temperature (25-65 °C) and time (5-45 minutes) on the dependent variable (level of total phenolic compounds). The results indicated that within the same extraction time, the extraction yield through UAE was higher than those in ME and MAE methods. Correlation coefficients (R 2 ) of the models for UAE, MAE and ME methods were 0.95, 0.96 and 0.94, respectively. The optimal conditions for extraction of phenolic compounds from pistachio green hull through ME, UAE, and MAE methods were 20(v/w), 65°C, 45 minutes; 20(v/w), 65°C, 25 minutes; and 20(v/w), 65°C, 45 minutes, respectively. Under optimized conditions the experimental values well agreed with the values predicted by the proposed models.

Spatial Variability of Soil Erodibility Factor (K) of the USLE in North West of Iran

Abstract: The soil erodibility factor varies spatially according to variations of some soil properties on the surface. This study was carried out to compare spatial variability of the soil erodibility factor as estimated and measured using the USLE. The study was conducted in an agricultural zone with an area of in 900 km 2 in Hashtrood, northwestern Iran. In the study area, 36 square grids with a dimension of 5 km were considered. In each grid, three unit plots were installed on the southern aspect with a slope of 9%. The soil erodibility factor was estimated using the USLE nomograph and measured as mean rate of soil loss from the unit plots per unit rainfall erosivity factor on an annual basis. The results indicated that the difference between the measured and estimated soil erodibility factor was significant (P< < < < 0.001) and correlation between the two was very poor with r 2 = 0.21. The spherical simulations were the best models to explain spatial variations of both the estimated and measured erodibility factors. The effective range of the spatial variations of the measured soil erodibility factor (2.43 km) was smaller than that in the estimated value (11.51 km). There was a considerable difference in the effective range (P< 0.001) of spatial variations between the estimated and measured soil erodibility factor on the study area. The map of the proportion of the estimated values to measured values of the soil erodibility factor was nearly uniform (between 7.4 and 9.6) on the study area. The study indicated that use of the USLE nomograph would considerably lead to over-estimation of the soil erodibility in the entire the study area.

Fatty Acids Changes during Frozen Storage in Several Fish Species from South Caspian Sea

Abstract: Changes in the fatty acid content, during frozen storage at -24 °C of Caspian kutum (Rutilus frisii kutum ), golden grey mullet ( Liza aurata ), common carp ( Caprinus carpio ), pike perch ( Sander lucioperca ) and common kilka ( Clupeonella cultiventris caspia ), caught from south Caspian Sea were studied in the present work. Changes in saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs), polyunsaturated fatty acids (PUFAs), ecosapentaenoic acid plus docosahexaenoic acid/palmitic acid (EPA+DHA/C16), n3 PUFA/ n6 PUFA ( n3/ n6) and polyunsaturated fatty acids/saturated fatty acids (PUFA/SFA) were investigated during a six month period. Results indicated that due to the decrease in unsaturated fatty acids particularly PUFAs (9.25-23.03%), and lower ratios of n3/ n6 (2.02-6.06), EPA+DHA/C16 (polyene index; 0.21-0.65) and PUFA/SFA (0.18-0.64) the poststorage nutritional values of these species significantly decrease.

Analysis of Grain Yield Stability in Hexaploid Wheat Genotypes Grown in Temperate Regions of Iran Using Additive Main Effects and Multiplicative Interaction

Abstract: Eighteen wheat breeding lines were evaluated along with two check cultivars across nine locations of temperate zone of Iran during two crop seasons (2003-2004 and 20042005). Field records were taken for some important traits especially grain yield. Combined ANOVA for nine locations in the first season and for seven locations in both seasons was undertaken. In each case, additive main effects and multiplicative interaction analysis (AMMI) was employed and the biplot of the Interaction Principal Components (IPC) were evaluated for stability and adaptation relationships among genotypes and locations. IPC1, IPC2 and IPC3 accumulatively defining 78.4% of genotype×environment (G×E) interaction variation were found out as significant in the first crop season. Biplot of first two IPCs identified at least two sub-regions among the locations. Some genotypes (M-82-7 and M-82-17) showed specific adaptation toward one of the drought-prone subregions. For the combined data of both seasons, only IPC1 was significant defining 41.5% of G×E interaction variation. Thus, plot of IPC1 along with grain yield means were employed for an interpretation of adaptation relationships. Entries M-82-8, M-82-9, M82-11 and M-82-15 showed specific adaptation to Mashhad station which was interactive and particular in behavior. The results indicated that AMMI is an informative method of stability and adaptation analysis to be employed in practical plant breeding and subsequent variety recommendations.

An Estimation of Individual Leaf Area in Cabbage and Broccoli Using Non-destructive Methods

Abstract: Accurate and nondestructive methods to determine individual leaf areas of plants are useful tools in physiological and agronomic research. A determination of the individual leaf area (LA) of such species in Brassicaceae family as red cabbage ( Brassica oleracea var. cappitata L. f. Rabra), cabbage ( Brassica oleracea var. cappitata L . F. Alba) and broccoli ( Brassica oleracea var. Italica L.) involves measurements of leaf parameters including leaf length (L) and width (W), or some combination of these parameters. This research was carried out during 2008 (on eight cabbage, six broccoli, and three red cabbage genotypes) under open field conditions, to see whether an equation could be developed to estimate leaf area of cabbage and broccoli across their genotypes. Regression analysis of LA vs . L and W revealed several equations that could be used for estimating the area of individual cabbage and broccoli leaves. A linear equation having W as the independent variable provided the most accurate estimate of red cabbage as well as ordinary cabbage LA . The linear equation (LA= a+b W 2 ) exhibited a high accuracy and precision in estimating red cabbage and non-red cabbage LA . For broccoli a linear equation having LW as the independent variable provided the most accurate estimate of LA , but required twice the time needed for leaf area measurement.

Land Surface Temperature in the Yardang Region of Lut Desert (Iran) Based on Field Measurements and Landsat Thermal Data

Abstract: Due to the hard climatic conditions of the yardang region in the Lut Desert, not much information about land surface temperatures of this region, one of the extremely arid climatic zones of Iran, has been extracted. Therefore, in this study in order to obtain some information about important surface features of the Lut Desert (marl, grey sand, bright sand and salt affected land), field temperature measurements were taken and remotely sensed data processing were made. Temperature was measured eight times from 6 a.m. to 8 p.m. during a 15-day period in October 2000. In addition to field measurements, Land sat satellite TM thermal data dated on the 25th of June, 1989 and other sources of data and maps were used. Thermal remote sensing analysis was applied for mapping surface temperatures in the south-eastern part of the Lut Desert in Iran. In this research, the methodology comprised : 1) field temperature measurements, 2) the relationship between the temperature of different soil surfaces and land cover types, 3) diurnal variations in the surface temperature of land cover types, 4) primary image processing and fieldwork, 5) image processing and calibration,6) image classification and accuracy assessment, and 7) land surface temperature mapping. The results obtained have shown the differences between the surface temperatures of the studied features. The significant differences between surface temperatures were discussed. The results obtained have also shown the importance of thermal sensor selection from the viewpoint of satellite overpass time. The results obtained from thermal data and field temperature measurements have shown the time of Landsat satellite overpass has to be considered for image interpretation. As a result, the temperature lowers, respectively, in regions such as yardangs, desert pavement, salty lands, and wetlands; however, it increases in sandy regions.

Optimizing Storage and In vitro Germination of Date Palm (Phoenix dactylifera) Pollen

Abstract: Iran is one of the main date ( Phoenix dactylifera ) producing countries in the world. however, little information is available on the pollen viability and favorable storage conditions of Iranian male date cultivars. This study was conducted to estimate the best in vitro pollen germination of three male date palm cultivars, ` Ghanami ’, ` Samsmavi ’ and `Gheibani ’ using various doses of boric acid (0, 50, 100 and 200 mg L -1 ), calcium nitrate (0, 200 and 300 mg L -1 ) and sucrose (15% and 25% (w/v)) in a Modified Brebaker and Kwack (MBK) medium. The results showed that the best germination was achieved with 50 mg L -1 boric acid, 200 mg L -1 calcium nitrate and 15% (w/v) sucrose. Once the optimal in vitro germination medium had been established, pollen viability (% germination) of these three cultivars stored for up to 200 days at room temperature (dark and light), in a refrigerator (4uC), freezer (-20uC) and in liquid nitrogen (-196uC) was compared. For all the tested cultivars, germination declined as storage temperature increased and, by 200 days, the highest survival rate was obtained with cryostored pollen. Long-term storage of date pollen using an ultra-low temperature (-196uC) can be used without any deteriorating effect on pollen viability, while room temperature storage significantly reduced pollen germination.

Drying Rough Rice in a Fluidized Bed Dryer

Abstract: The objective of this study was to examine the effects of the fluidized-bed drying method on the final quality of two varieties of Iranian rice, medium- and long grain. The results were compared to that of paddy drying using a traditional method. Rough rice was treated in the fluidized bed drier at 140oC for 2 minutes. Similar samples were dried for 8-10 hrs by the traditional method. Dried samples were dehusked and polished. Quality factors, including trade quality (head rice yield percent and whiteness), cooking quality (amylose content, gelatinization temperature, gel consistency, aroma and flavor) and nutritional quality (thiamine and lysine contents), were then measured for each sample. Finally, the data was analyzed. Results show that paddy drying in a fluidized bed dryer would reduce the quality factors except for rice whiteness for which conventional drying is more acceptable. Therefore modification of fluidized-bed drying technique is recommended.

Effects of crop rotation and tillage depth on weed competition and yield of rice in the paddy fields of northern Iran.

Abstract: Crop rotation is one of the essential practices in sustainable agricultural systems, because of its effects on soil fertility and other benefits including a reduction in weed competition. A field experiment was conducted at Chaparsar Rice Research Station, Tonekabon, Iran, from 2002 to 2003 to assess the influence of crop rotation, time of planting, and tillage depth on rice (Oryza sativa L.) yield and density and the biomass of three important paddy weeds. Treatments included the crop rotations of continuous rice and rice-soybeanrice, in combinations with planting times and no tillage, minimum tillage, and chisel plowing. Crop rotation had a significant effect on the growth of barnyardgrass (Echinochloa crus-galli), arrowhead (Sagittaria sagittifolia), and water plantain (Alisma plantagoaquatica) weeds. Continuous rice planting produced the highest density of barnyardgrass, arrowhead, and water plantain weeds, compared with a rice–soybean-rice rotation. Weed biomass and weed densities were lower in the rice-soybean-rice rotation than in continuous rice. There were a 62.5 and 80% reductions in the weed density and weed biomass respectively, in the rice-soybean-rice rotation compared with continuous rice planting. Fewer barnyardgrass, arrowhead and water plantain growth were observed in no-tillage treatments than in minimum tillage and chisel. Therefore, rice yield in rotation treatments increased by 17 and 21% in 2002 and 2003, respectively, compared to continuous rice planting.

Population Density and Spatial Distribution of Aphis gossypii Glover (Homoptera: Aphididae) on Cotton in Gorgan, Iran

Abstract: The seasonal abundance patterns of the cotton aphid, Aphis gossypii Glover, in cotton fields at Gorgan in northern Iran were studied during two growing seasons of 2002 and 2003. The spatial distribution of different developmental stages and morphs of the aphid was described by fitting data to Poisson (random) and negative binomial (aggregated) distributions, and calculating the dispersion indices. A sequential sampling plan was also developed using the fixed-precision method of Green for estimating the density of the adult, nymph and total population. The first aphid colonies appeared on plants during late June and early July and peaked in early September when cotton plants were at the boll maturation and opening stages. Aphid populations, especially nymphs and apterous females, were aggregated during most of the growing season and negative binomial models fit data sets better than the Poisson series. The percentage fit for alate morphs showed a slight tendency to the Poisson distribution. With respect to sampling cost or required sample size, the developed fixed-precision sequential sampling plans showed an acceptable performance for estimating aphid density at the precision level of D= 0.25. The optimum sample size was flexible and depended upon the aphid density and desired level of precision, and generally ranged from 10 to 513 and 62 to 3,206 at the precision levels of 0.25 and 0.10, respectively. The sequential sampling plans developed could be recommended to estimate the aphid density in integrated pest management programs.

Prevention of Salmonella Colonization in Neonatal Broiler Chicks by Using Different Routes of Probiotic Administration in Hatchery Evaluated by Culture and PCR Techniques

Abstract: The effects of various methods of probiotic administration in hatchery and on prevention of Salmonella enteritidis ( Se ) in broiler chicks was investigated. A total of 150 Salmonella free day old chicks (Ross 308) were assigned to five experimental groups including control and four in-hatchery probiotic administration method groups comprised of: in ovo injection, oral gavage, spray and vent lip application. Each group was comprized of 30 chicks. The chicks were challenged by 8 Log CFU Se using oral gavage on 2 days of age. At 1 and 7 days of post-challenge (PC) 15 birds per experimental group were sampled for Se recovery through either one of culture or culture based PCR techniques. Administration of probiotics reduced the number of Se colonized chicks, compared with control as evaluated through either culture or PCR method. These reductions were significant for all the administration routes (P 0.05). Furthermore probiotics were capable of reducing the number of colonized chicks from day 1 to day 7 PC. Vent lip method was evaluated as the most effective route of probiotic administration in prevention of Se colonization, not significantly different from either spray application in day 1 of PC group or from other administration methods in the day of 7 PC (P> 0.05). PCR method was more reponsive in detection of Se as compared to traditional culture method. Administration of probiotics in hatchery finally resulted in reducing the colonization of Salmonella in the alimentary tract of chicks.

Stability Comparison of cytb and β-actin Genes Expression in Sea Cucumber(Apostichopus japonicus)

Abstract: Analysis of gene expression commonly uses internal control gene for normalization.The mRNA levels for cytb and β-actin genes were detected by using RT-PCR at 11 larval development stages of sea cucumber(Apostichopus japonicus)including unfertilized egg,fertilized egg,cellulous stages,blastula,gastrula,early auricularia,auricularia,late auricularia,doliolaria,pentactula,juvenile and in different tissues of young sea cucumbers including body walls,coelomocytes,intestines and respiratory trees.The results showed that cytb gene expression was stable at all development stages and in the four tissues.The mRNA levels for β-actin gene showed significant differences at different development stages,but were stable in the tissues of body walls,intestines and respiratory trees.Moreover,cytb mRNA showed no significant changes in expression after a LPS challenge at the stages of gastrula,early auricularia,auricularia,late auricularia,doliolaria and juvenile or in the four tissues of young sea cucumbers.The expression of β-actin gene was also stable in the tissues of coelomocytes,intestines and respiratory trees after a LPS challenge.This study provides information for the selection of cytb gene and β-actin gene as suitable internal control gene in target genes expressions research of sea cucumber.

Natural Deoxynivalenol Contamination of Corn Produced in Golestan and Moqan Areas in Iran

Abstract: Deoxynivalenol contamination was determined in corn produced in Golestan and Ardabil (Moqan) Provinces, Iran, in 2004-2005. Samples were collected from different stages of production, including before harvest, at harvest, post harvest as well as after drying. Ground sub samples were extracted with water; each extracted sample was cleaned up through an immunoaffinity column. Deoxynivalenol was estimated through reversed-phase High Performance Liquid Chromatography (HPLC). The linearity of standard curve for 50 -10,000 ng ml -1 of standard solutions was proved (R 2 = 0.9999). Detection limit was 10 ng g -1 . Recovery of the method for 1,000 and 500 ng g -1 spiked samples was 73.5% and 93.5% (n= 5). Deoxynivalenol contamination was found in 76.7% of samples in the range of 54.4-518.4 ng g -1 . The mean of contamination was 116.25 ng g -1 . This is the first report of natural DON contamination of corn from Iran.

Karyological and Nuclear DNA Content Variation in Some Iranian Endemic Thymus Species (Lamiaceae)

Abstract: Thymus is a medicinal plant which contains one of the world's top ten essential oils, exhibiting antibacterial, antioxidative, food preservative and mammalian age-delaying properties. This work was aimed at identifying between-species variations requiring for selecting appropriate parents for hybridization. Six Iranian endemic Thymus accessions belonging to Thymus daenensis , T. eriocalyx and T. migricus were studied. Root tips were examined for karyological studies and fresh young leaves of the standard reference (Parsley, Petroselinum crispum , 2C DNA= 4.45 pg) and the Thymus samples stained with propidium iodide (PI) for flow cytometric (FCM) measurements. Two ploidy levels (diploid and tetraploid) and 3 chromosome numbers (30, 56, 60) were recognized. The latter chromosome number is being reported for the first time on T. daenensis accession. FCM measurements showed that 2C DNA contents varied from 1.02 to 2.42 pg, verifying more than 2-fold variations and showing a genome size range of 499 to 1182 Mbp, correspondingly. The mean amount of 2C DNA/chromosome and mean of monoploid genome size were not proportional to ploidy. 2C-values were correlated with, and linearly regressed upon somatic metaphase, considering either total chromosome volume (TCV) or total chromatin length (X).

Occurrence of Mould Counts and Aspergillus Species in Iranian Dried Figs at Different Stages of Production and Processing

Abstract: The present study was carried out to investigate the occurrence of total mycobiota and Aspergillus species at different stages of fig production and processing in Iran. In the meantime, the potential of different culture media for isolation of fungal species from figs was also investigated. The mycobiota of 389 samples of dried fig were studied. Total fungal counts ranged from <2 to 6.74 log10 CFU g -1 . In general, the predominant species were Aspergillus niger aggregate, Aspergillus flavus, Acremonium spp. and Mucor spp. in percentages of 90.9%, 63.7%, 54.6% and 36.4% infection, respectively. Other Aspergillus spp. and Mucor spp. Corresponded to 36.7% and 28.3% infection, respectively. The lowest contamination was observed in dried figs. The predominant fungi were Alternaria spp. and Penicillium spp. (9.1% infection). On average, Aspergillus spp. comprised 34.4% of the total fungal population. Aspergillus niger aggregate was detected in 99%, and A. terreus was present in 11.3% of total samples. The results revealed that poor hygienic conditions in fig harvesting, drying procedures, collecting sites, sorting and packaging plants caused higher mould contamination and risk of the A. flavus growth in dried fig production in Iran. As the result obtained from this study, using more than one culture media for isolation of A. flavus is recommended.