IRANIAN JOURNAL OF AGRICULTURAL SCIENCES (JOURNAL OF AGRICULTURE)
Year:2007 | Volume:38 | Issue:4|Papers Count:27

Maternal effects on body weight at 8 weeks of age (BW8W), egg weight (EW), egg number (EN) and age at sexual maturity (ASM) from 13 generations of Mazandaran native fowl were investigated. The data were analyzed using restricted maximum likelihood procedures and animal model with DFREML software. With or without using maternal effects, six different animal models were fitted. Likelihood ratio test wase employed to determine the most appropriate model. For all traits, maternal additive genetic and environmental effects together with the covariance between direct and maternal additive genetic effects were important. Direct heritability (h2a) ranged from 0.130 (for EN) to 0.506 (for EW). These estimates for maternal heritability (h2m) and maternal environmental variance as a proportion of the phenotypic variance (c2) varied from 0.008 (for EW) to 0.034 (for ASM), and 0.020 (for EN) to 0.047 (for BW8W), respectively. Also for all traits c2 was higher than h2m. The correlation between direct and maternal additive genetic effects (ram) were all negative and -0.737, -0.692, -0.590 and -0.396 for EN, EW, ASM and BW8W, respectively. The results indicated that ignoring maternal effects in the analysis of BW8W tended to overestimate direct additive genetic variance and heritability, but for EW, EN and ASM ignoring the covariance between direct and maternal additive genetic effects caused a decreased in those estimates.

Sugarcane is cultivated in extensive areas in Khuzestan It is irrigated through hydro-flume and in furrows. For an evaluation of the effect of deficit- irrigation on sugarcane yield, this experiment was conducted. The treatments consisted of the conventional irrigation method (blank), variable, every other irrigation, (by alternative furrows) and invariable every other irrigation (by fixing the furrow). Results indicated that shifting every other irrigation required the lowest amount of irrigation water in comparison with other treatments. Highest water use efficiency, quality and quantity of sugarcane belonged to the variable every other irrigation (0.72 kg of sugar per m-3 irrigation water). Conventional irrigation method consumed highest irrigation water and produced lowest quantity of sugarcane production and water use efficiency (0.48 kg of sugar m-3 irrigation water). Invariable every other furrow irrigation had a sugarcane production egual to the conventional treatment but water use efficiency was 0.14 kg m-3 more than in the common treatment. From total irrigated waters entering the furrows, about %46.4 and %53.6 were reserved in non- irrigated as against the irrigated furrows respectively.

A variety of process-based soil erosion models have been developed to simulate and predict water erosion in the recent decays. Most of these soil erosion models are Claimed to be based upon processes effective in soil erosion Water Erosion Prediction Project (WEPP) is one of the most famous process-based models, in which differentiation has been made between interrill and rill processes in calculating soil detachment and transport. Three contrasting soil types were subjected to simulated rainfall using a 1×1×0.1 m drainable flume at varying slopes. Rainfall was applied using a rainfall simulator with a single sweeping nozzle located 4 meters above the soil surface that sprayed drops with a mean diameter of 1.5 mm. Results indicated that WEPP-recommended equations for predicting interrill erodibility using soil properties are not applicable outside their US database and therefore a model calibration is indispensable. Neglecting the water depth effect on interrill erosion is probably one of the most important problems concerning WEPP model. Indeed, contribution of flow driven erosion processes in interrill areas especially at steep slopes and high rainfall rates in conjunction with eventual interaction between flow and rain driven processes are causes of the model bias. In the other words, WEPP model tends to overpredict the values on the lower end of the scale, and underpredict those on the upper end.

Saffron (Crocus sativus L.) is a valuable spice, drug and export crop that is used without much need for processing. The worldwide fame and desirability of this crop has always beloed to the origin of this crop, Iran. Saffron has been grown in limited regions in Iran, and a study of the adaptability of this crop to other new climates; will , extend the cultivation area and increase the production of this crop. For this purpose, three saffron ecotypes from three different regions of Khorasan province (Torbat, Kashmar and Ghaen) were selected and cultivated in three regions in Ardebil area in a randomized complete block design with four replications. The number of flowers/m2, stigma dry matter/m2 (gr) and yield (kg/ha) were recorded during four years (2002-2005). The number of corm/plant and mean weight of corms in each plant were also measured at the end of the 4th year. Analysis of variance for each trait in each region (split plot in time), combined analysis as well as stability analysis were carried out. The results showed that significant differences exist among the yield in the three ecotypes. Ecotypes yield differently in years and regions (ecotype environment interaction). Kashmar ecotype with a total mean yield /ha of 4.95 Kg had a significantly higher production yield in comparison with the tow others. The regional C.V of Kashmar ecotype was also higher than that of the others two , but the differences were not significant.

Whole body vibration can deteriorate health bringing about or back pain or spinal column injury, resulted from continuing exposure to vibration. Also exposure to vibration can cause disorder in central nervous system and adversely influence vascular and skeletal systems. In this research, the vibration of Universal 650M tractor seat and its effect on the operator in five levels of engine speeds: 1000, 1200, 1400, 1600 and 1800rpm, in a vertical direction and while driving on asphalt road was evaluated. Also RMS (Root Mean Square) of acceleration and VDV (Vibration Dose Value) were measured. The experiments showed that the dominant frequency of vibration in all speeds on the seat, were related to revolutions of the engine and piston stroke. Seat vibration frequency was increased with increase in the number of motor speed. RMS of acceleration in speeds from 1000 to 1800rpm was 1.93, 2.26, 2.4, 2.5 and 3.65m/s2, respectively. The VDV values in speeds from 1000 to 1800rpm were 2.34, 2.49, 2.74, 3.1 and 4.29m/s1.75, respectively which showed that were proportional to the engine speed. The results indicated that allowable time to achieve standard values of 15m/s1.75 (ISO 2631) in speeds 1000, 1200, 1400, 1600 and 1800rpm, were 20.8, 11.1, 7.47, 4.72 and 2.1 hours indicating that exposure time, in high speeds, must be reduced.

In this research a stochastic method was employed to simulate litter size data under the assumption that the phenotype of the trait of interest is categorically distributed with a liability of normally distributed background effect. Analysis was conducted through DFREML for phenotypic data set. For the phenotypic categorical measurements, normal distribution of liability was assumed. Also MATVEC was employed for the analysis of phenotypic data assuming a threshold model for the trait. In the simulation process, different true background heritabilities were applied in combination with different points of threshold. Results indicated that by a a departure of the points of threshold from the population mean towards the two tails of the distribution and also by increasing the true heritability, the differences become greater between estimated heritability and true heritability. When comparing heritability estimates obtained through MATVEC with those obtained using DFREML it evident that the linear model had always underestimated true heritabilities but, while threshold model of MATVEC not showing a consistent trend. While threshold model may be trusted at higher levels of true heritability, it does not behave consistently at lower heritability levels. It is possible to use estimates to obtain a confidence range for true heritability when there is enough information about approximate location of threshold and aboutestimates of heritability obtained through linear model.

To find the nutritional condition of plants as related to the tatus of soil nutrients, also for an evaluation of soil solution toxicity and nutrition of plants in salt affected soils, it is preferred to study the activity of these elements rather than their concentrations. To calculate the ionic strength of a solution the concentrations of all cations and anions are needed which is very time consuming to be determined. This research was carred out to investigate the relationship between ionic strength and ECe in salt-sodic soils in Hoze-e-Soltan, Qom. In 40 soil samples, such physical and chemical properties as texture, pH, saturation moisture, gyps, lime, cation and anions in soil solution (Na, K, Ca, Mg, Cl, Co3, HCo3, So4) were assessed. Following a determination of ionic strengths, equation I=1/2 SCi Zi2 was employed for making calculations. Results showed that the values of ECe and pH in studied soil samples varied from 12.90 to 146.40 ds/m and 8.20 to 8.90, respectively. Relationship between ECe and ionic strength was exponential and 92% of IS variations being resulted from EC. Also, there exists a significant linear agreement (r2=0.92) between IS (using Griffin-Jurinak model) and IS, using the concentration of the cations and anions measured in soil samples.

Micronutrient elements Zn and Mn, like other micronutrients, are important for optimum plant growth. It has been reported that zinc and manganese deficiencies are the most common deficiency cationic micronutrient elements in calcareous and alkali soils. Most sugarcane cultivated soils in Khouzestan, Iran bear a high level of CaCO3 (<40%) along with a pH greater than 7.0. Hence, the profess and availability mechanisms of Zn and Mn to maintain the level of these elements in soil coloidal surfaces are important. One of the important that has not been investigated in these soils is the adsorption phenomenon of these elements. Eight surface (0- 30 cm) soil samples were collected from the sugarcane cultivated soils from two sugarcane Agro Industry Units and were used to study the Zn and Mn adsorption characteristics in these soils. The adsorption data were fitted to Freundlich adsorption isotherm equation and respective coefficient calculated. The results showed that Freundlich equation can be employed to explain the adsorption of Zn and Mn in sugarcane cultivated soils. The regression between the coefficients of Freundlich equation and some physical and chemical properties of soils showed that element Zinc had A significant positive correlation with Caution Exchange Capacity as well as with clay percentage. As for Mn element it also exhibited a significant positive correlation with clay, CEC and organic matter, but a significant negative correlation with calcium carbonate percentage, in sugarcane cultivated soils.

The effective factors of forward speed, cylinder rotation, and clearance between a combine’s cylinder and concave on wheat kernel breakage and seed germination were studied in Karaj area using a 955 model John Dear combines. This study was conducted on three levels of adjustment for each of the variables, 1.2, 1.8 and 2.5 Km/hr for forward speed, 800, 900, 1000 rpm for cylinder rotation as well as 15, 20 and 25 mm for the clearance between cylinder and concave. Results indicated an increase in kernel breakage and a decrease in seed germination to arise from a decrease in forward speed, increase in cylinder rotation and decrease in clearance between cylinder and concave. The interaction between forward speed and cylinder rotation indicated a least kernel breakage of 5.47% along with the most seed germination of 96.61% arising from a forward speed of 1.8 Km/hr together with cylinder rotation of 800 rpm. Also, an interaction between cylinder rotation, and cylinder concave clearance indicated a least kernel breakage of 5.38% at 900 rpm and 25 mm for the former and latter variables respectively. A maximum seed germination of 96.6 % was observed for the same condition of cylinder rotation and clearance between cylinder and concave. Interaction between forward speed, and cylinder concave clearance was observed to be non-significant (p<5%). Also, non-significance was observed in interaction among forward speed, cylinder rotation, and cylinder concave clearance (p<5%). The results revealed the adjustments 800-900 rpm, 1.8 Km/hr and 25 mm for cylinder rotation, forward speed, and cylinder concave clearance respectively, while using a 955 model John Deer during wheat harvest in Karaj.

In order to study the seasonal population fluctuations and density of aphid species (vector of potato viruses) in Hamedan province during 1999–2003, four important potato-growing areas (Hamedan, Kaboudarahang, Asadabad, and Ghahavand) were studied using, yellow water traps. Among collected aphids, four species belonging to Aphididae and one to Drepanosiphidae were identified in potato fields. In all the study areas Therioaphis trifolii was dominant species with 65 – 91% of total population present through out the years. Other species including Acyrthosiphon pisum, Myzus persicae, Macrosiphom euphorbia, and Aphis frangullae gossypii were reported as vector of important potato viruses in potato fields. Based on collected data, there were differences in species variation and density as well as in duration of presence in different study areas. These differences were employed as criteria to set the studied areas in three groups of: suitable, intermediate and unsuitable. The lowest species number and the shortest duration time of presence of aphid were found for Kaboudarahang location. Therefore this location was recommended as a suitable place for potato seed production. Because of species richness, high density of aphids and the longest period of presence time, Hamedan were distinguished as an unsuitable area. The other locations were set in an intermediate group.

Growth in plants is defined as irreversible increase in volume and size. These changes are varied depending on stage of growth and physiological activity of the fruit tree. This research was conducted to determine the duration period of fruit growth and development and to come up with a mathematical model representing the relationship between fruit diameter, volume, and fruit fresh and dry weight. Two experiments were carried out using four mid- (KS13, KS14) and late season (KS8, KS12) maturing fruits of Asian pear (Pyrus serotina Rehd.) genotypes grown in Research Orchard, Department of Horticultural Sciences at Tarbiat Modarres University (TMU), Iran. In the first experiment, 24 fruits from the middle canopy zone of trees were tagged and fruit diameter measured in time intervals up to fruit harvest. In the second experiment, 3-5 fruits were destructively harvested from each genotype. These fruits were randomly sampled at 15 day intervals from 35 days after full bloom until fruit harvest (ripening). Fruit diameter, length, volume, fresh and dry weights were measured on destructively harvested fruits. Results indicated that simple and complete fruit sigmoid curves were existent for all four genotypes, even though the period of each phase of fruit growth was different for the studied genotypes. Slow growth phase of the curves for mid season genotypes between 120 – 180 days after full bloom (DAFB)while for late season maturing fruit genotypes between 150 – 200 DAFB. In addition, mathematical models were presented based on the correlation existing between fruit diameter, volume and weight. These models are important and can be used in such orchard management systems as irrigation, applying fertilizers and estimation of fruit harvest and yield.

Non-starch polysaccharides (e.g.: wheat based diet) which are supplemented with enzymes. could have a high potential in nutrient ingestion, digestion and absorption, However, response to the enzyme is dependent on chicks age, as well as genetic status of both the cereal and the chick. This study was conducted in a completely randomized design in 2´4 factorial arrangement to study the efficiency of xylanase and protease enzymes with wheat based diet on broiler performance. One thousand and two hundred of commercial chicks (Ross 308, both sexes) were randomly allocated into 8 dietary treatments with three replicates of 25 birds each. The diets were balanced separately for starter (1-10 d), female grower (11-24 d) and male grower (11-28 d), female finisher (25-49d) and male finisher (29-49 d) stages. The diets contained 0, 20, 35, and 50% wheat, replaced with corn, with or without enzyme. The enzyme containing diets 300-500 gr/ton of enzymes as well as all diets in each stage were isocaloric and isonitrogenous, fed ad libitum. Body weight, feed consumption and feed conversion ratios were measured at the end of the growing period. Two birds from each replicate were selected at the end of experiment, carcass weight, abdominal fat, excreta dry matter and pancreas weights were determined. The result indicated that weight gain, feed intake and feed conversion ratios were dramatically affected by different levels of wheat and enzyme supplementation (P>0.05). There were significant differences observed among groups in carcass weight, percentage of abdominal fat and excreta dry matter (P>0.05).

Field capacity, fuel consumption and drive wheel slippage in Massey Ferguson (MF399) tractor with standard and liquid ballasted (630 kg) axle load and at 4WD mode was evaluated and compared. The tests were conducted at the Experimental Station, College of Agriculture, Shiraz University, in a field with clay loam soil at average moisture content of 18% d.b. The experiment was of a randomized complete block design with a 3´3 factorial of three replications. The treatments consisted of a MF399 tractor at three conditions (2WD mode either with standard or liquid ballasted tires and 4WD mode along with standard axle load) and three levels of plowing depth; shallow (15-20 cm), medium (20-25 cm) and deep (25-30 cm) using a semi-mounted 4-bottom moldboard plow. The assessed parameters included; field capacity, wheel slip as well as fuel consumption. The results demonstrated that by water ballasting the rear drive wheels of MF399, its wheel slippage during medium and deep plowing decreased from 20% and 59% to 16% and 34.6%, respectively. This slippage rate stands at the threshold of acceptable range for medium depth plowing but is still extremely high for deep plowing. In the 4WD mode, the average wheel slip page during moldboard plowing for medium and deep plowing was reduced to 12.24% and 15.6%, respectively,both of which were in the acceptable range. The fuel consumption during deep plowing was reduced from 31.52 to 27.42 l/hr through water ballasting of the rear drive wheels and further reduced to 22.84 l/ha by shifting to 4WD mode with no wheel ballasting. Considering the overall results of this experiment, including values of wheel slippage, fuel consumption and field capacity, it would be wise to suggest using MF399 tractor with standard load rear axle drive, water ballasted rear wheel drive and standard load (4WD mode) for conducting shallow, medium and deep plowing, respectively.

Collected data in Animal Breeding Center of Iran from 1983 to 2003 was used to estimate the genetic parameters of milk yield in Iranian Holstein cattle. Genetic parameters were estimated, using single and three trait animal models. Records of three lactations were divided into thre esub groups according to average milk yield, climitical regions and herd sizes. All variance components in the three lactations for dry desert region were the highest and for the humid region the lowest. Heritabilities and variance components increased in three lactations for three herd sizes, by increase in the herd size. In the three milk yields, within the first lactation, additive variance was the highest for average milk yield and residual variance the highest for high milk yield, but in the high milk yield (within the second and third lactations), all variance components were in their highest amounts. In the first lactation, heritability for the high milk yield was the lowest and for the average milk yields the highest, but in the high milk yield within the second and third lactations, heritability was in its highest amount. The results of single trait and three trait analyses showed that there was not a considerable difference among the estimates of three trait analysis and single ones. Genetic and phenotypic correlations among the subsequent lactation periods were higher than those in the far apart ones.

Necessary conditions for callus production from leaf and stem explants of Norfolk Island pine (Araucaria excelsa L.) have been studied. MS and BM culture media containing 0.2, 0.5, 1, 2 and 5 mg/l NAA, IBA, 2,4-D and picloram supplemented with 30 g/l sucrose were used. Callus was initiated in both culture media only in the presence of picloram and in the dark, but BM culture medium produced more callus than MS and its amount was more in the stem explants as compared with the leaf explants. In order to originate somatic embryos, calli were transferred to MS and BM culture media containing low concentrations of NAA, IBA, 2,4-D, and picloram (0.1 and 0.2 mg/l each) and without auxin supplemented with 30 g/l mannitol, 30 g/l ABA, 4 g/l PEG and 80 g/l of sucrose, but no somatic embryos were originated from the calli in the above media.

Effects of various NaCl levels on shoot content of macro elements, in seedlings of five citrus species namely:Bakraei (Citrus reticulata X C. limetta), Volkamer lemon (C. volkameriana), Sour orange (C. aurantium), Sweet lime (C. limetta) and Mexican lime (C. aurantifolia), were studied in a glasshouse, using a randomized complete block design with factorial arrangement of four replications. one-year old seedlings of each species were grown in pots, containing calcareous native soil (pH=8.2) . They were then irrigated with water supplemented with 0 (control), 20, 40 and 60 mM NaCl. At the end of the experiment (90 days later) the amount in shoots of N, P, K, Ca, Mg, and Na were determined. The amount varied among species, even in control plants. Salinity had different effects on shoot content of macro elements. Salinity reduced N, Ca and Mg content (in shoot) all species. It also reduced the amount of P in shoots of all species, except for Mexican lime. Na content increased in shoot for all species. The amount of K in shoot of all species decreased whit increase in salinity level, except for sour orange, in which it tended to increase.

Genetic parameters and trends for milk and fat yields as well as for fat percentage were estimated from 35,438 milk production records (305d, 2X) of 17,971 Holstein dairy cattle in 133 herds during the period of 1990-2003 in Khorasan Province. Variance components were estimated using restricted maximum likelihood statistical method applying univariate and repeatability animal models. For the univariate animal model, the heritability estimates for milk, fat yield, and fat percentage were 0.28, 0.23 and 0.26 respectively while for the repeatability animal model the heritability estimates were respectively 0.23, 0.19 and 0.26. For the traits, repeatability estimates were 0.46, 0.36 and 0.42 respectively. Based upon predicted breeding values, the estimated annual genetic trends estimated for sires were 14.33 Kg, -0.11 Kg and -0.061 % for milk fat yield, and fat percentage respectively while, the corresponding respective figures for daughters were 11.06 Kg, -0.076 Kg and -0.005 %.

To study the sexual fertility and for a dermination of the mating types of the cause of rice bakanae disease and foot rot, samples of infected rice were collected from different regions of Guilan Province in during 2004.One hundred and thirty and three single-spore isolates were obtained from Khazar while nine isolates from local cultivars. Morphological identification was carried out employing the valid morphological identification keys. For fertility test, crosses were carried out among local isolates on Carrot Agar medium, four pairs of which resulted in fertile crosses. Sixty isolates were crossed with six standard isolates representing three mating populations and six mating types (MATA-1, MATA-2, MATC-1, MATC-2, MATD-1 and MATD-2). Of those isolates 23, 17, and 38% belonged to mating populations A, C and D, respectively. Aall, local isolates with fertile crosses were, included in mating population D. Furthermore, the ascosporous isolated from field perithecia, stood in mating population D. For pathogenicity test, 142 isolates were inoculated to Khazar seedlings nine of which showed no disease symptoms. The results of the study revealed that indicated three mating populations, A (F. verticillioides), C (F. fujikuroi), and D (F. proliferatum) are the cause of rice bakanae disease and foot rot in Guilan province, north of Iran Province.

It’s nowadays Proved that one can, from among many strains of rhyzobium species, find those which, in addition to high efficiency in N2 fixation, can positively affect such processes as plant growth (e.g. through production of plant growth hormones). Such strains can be useful not only to their special host, but also to other plants as well as to strategic products as grains. Soil biotechnology, one of the functions of which is to follow the production potential of biofertilizers to improve the quality of agricultural products. Proper soil fertility level and prevention of life sources contamination is highly dependent on the use of rhizobia as a good substitute for chemical fertilizers. Several researches have been performed concerning Iranian rhizobia since a decade ago in N2 fixation efficiency. So the ongoing researches were planned with the aim of evaluation of plant growth hormone as one of the abilities of PGPR group of rhizobia native to Iranian soils and evaluation of application of better inoculation on legume (alfalfa) and non legumes (wheat and corn) plants and for gaining former goal, two laboratory and green-house stages have been performed as follows: Three hundred and fourteen isolates were initially selected from different rhizobial genera microscopic and biochemical tests being done on each. Fresh inoculants of each strain were prepared from stock culture, adjusted to 5´108 cfu.mL-1, and isolates evaluated on their potential production of auxin hormone (IAA and its homologues) by Brick (1991) on LB solid medium which was improved with TRP. Application effect of IAA+ super strain inoculants on growth index and alfalfa, wheat and corn yield were evaluated. The results indicated that indigenous rhizobia carry the potential of Indole auxins production (IAA and its homologues).Two hundred and ninety seven isolates (97%) from all of the isolates (314) could grow on LB-TRP medium. Among 297 isolates with the capacity of being grown on LB-TRP, 220 isolates (74.1%) could produce this hormone. The most IAA+ abundance (>90%) were seen in Sinorhizobium and the least observed in Mesorhizobium ciceri. Depending on ANOVA results, significant difference (P<0.001) has been observed in rhizobial groups and also within strains of each rhizobial group with respect to IAA production capability. The strongest rhizobial groups were Rlp, Rlv and Sm. On the other hand Rlt and Bj groups didn’t show any IAA production. Results from the application of superstrains (IAA+++) inoculants in alfalfa plant showed that IAA+++ strain had a significant increase in biological yield and N content, however, inoculation of IAA+++ rhizobial superstrain in wheat and corn didn’t show any significant increase in any of the growth features in comparison with control (treatment without fertilizer, negative control). Even a significant decrease was observed (p<0.001) in biological yield and wheat spike, dry matter; and plant height, in the case of corn.

Cutting blades are exposed to abrasion and breakage during operation. Therefore a comparison of such mechanical properties as hardness among different blades is necessitated. In this research, the hardness of three Iran made blades (Khooshe-Talaei, Iran-Derogar and Combine-Sazi) and two foreign (Germany and U.S.A) manufactured ones were evaluated and compared with the standard Figures. The results showed that, maximum and minimum mean values of blades’ edge hardness’s were 77.81 HRA and 75.78 HRA respectively for American and German blades. There was no significant difference observed between edge hardness in Iranian and American blades. Blades edge hardness’s for all producers matched the standard values. In a comparison of blades’ middle layer hardness, the maximum and minimum mean values were 55.88 HRA and 52.29 HRA respectively for American and Iran-Derogar made blades. None of the samples met the standard middle hardness requirement.