Journal of Agricultural Sciences and Natural Resources
Year:2007 | Volume:14 | Issue:3 |Papers Count:24

Organism activities in soil can cause different physical and morphological changes in soil. In the studied soils cicada have been active for a long time and their activities have been formed some specific soil phenomena which is called krotovina. Krotovinas are a kind of pedotubule which are due to cicada activities in soil. The term of krotovina is commonly used for channels, voids and nests of different soil organisms which are filled and compacted by soil materials. Krotovinas are classified based on their shapes, internal fabrics and separability from horizon soil matrix. In this study, physical, chemical and micro morphological properties of krotovinas were studied. Krotovinas were classified based on their characteristics and their formation was also studied. The results showed that krotovinas were heavier in texture, higher in bulk density and also they were different in electrical conductivity, acidity and calcium carbonate percentage compared to soil. Morphologically, different isotubules, steriotubules and aggrotubules were recognized. However, most of krotovinas were named as "Weakly adhesive, Circular, Single, Isotubules" in the studied soils.

In order to evaluate the effects of terminal drought stress on seed vigor of harvest seeds in wheat, a greenhouse experiment was conducted using a factorial arrangement in a completely randomized block design with three replications in Gorgan University of Agricultural Sciences and Natural Resources. The factors consisted of four genotypes (para2//Jup/Bjy/vee/42*kauz, veelkoel//weaver, vee#7/lkauz, kauz/star) two drought stress periods (pre and post pollination drought stress), and control treatment (full irrigation). The results have shown that germination percentage after accelerated aging test and seedling growth in vee#7/Ikauz genotype were increased by pre and post pollination drought stress and control treatment. This genotype has needed lesser time until germination start to reach 10% of maximum germination and has the most maximum germination. Germination percentage after accelerated aging test, seedling growth and time until germination start and to reach 10% of maximum germination and maximum germination were decreased by pre and post pollination drought stress condition.

To study the affection of feed energy on growth and body composition of rainbow trout (Oncorhynchys mykiss) the fishes with initial weight of 93.110±0.470g were stocked and reared in polyethylene tanks with capacity of 600 liters. The fishes were fed with diet containing %35. 750 crude protein and 4 levels of energy 3300, 3600, 3900 and 4200 kcal/ kg in base of biomass determined every 15 days. During the period of culture, water temperature 15± 2°C, pH 7.700-8.600 , DO 6.500 - 8.100 , EC 25270 - 25640 qm/cm and salinity 15.600 g/l were reported. Results showed that with increase of feed energy, growth factors (growth rate, protein efficiency ratio, specific growth rate, Net protein utilization) and fat of carcase increase, although cost price of feed, feed conversion ratio, ash, protein and moisture of carcase decreased (P<0/05). Commercial analysis showed that use of high energy feeds for rainbow trout reared in brackish water is more effective and commercially.

The activities of some digestive enzymes were measured in order to assess digestive capacity in parr and smolt Caspian brown trout (Salmo trutta caspius). The results showed that pepsin activity assessed exclusively in the stomach, was significantly higher in parr than in smolt (P<0.05). Trypsin and chymotrypsin activity assessed in the pyloric caeca and intestine showed that they were significantly higher in parr intestine than in smolt intestine (P<.0.05). Trypsin activity was higher in parr pyloric caeca than in smolt pyloric caeca but significant differences wasn,t detected (P>0.05). Chymotrypsin activity was significantly higher in parr pyloric caeca than in smolt pyloric caeca (P<0.05). a-amylase, lipase and alkaline phosphatase activity were also assessed in the pyloric caeca and intestine, the results showed a noticeable increase in each enzyme activity in smolt than in parr (P<0.05). Results of assessment showed used food can be had important role in enzyme activity.

A study was conducted to determine suitable characters for separating 2 Shemaya (Chalcalburnus chalcoides) populations of Haraz river and Shirud river in spring 2004. Using cast net, 70 speciemens were collected in 2 rivers (i.e; 32 in Shirud and 38 in Haraz). Twenty seven morphometric, 10 meristic and 15 proportional morphometric characters were used. PCA in SPSS, version 10 software was used to determine the best separating (isolating) characters of populations and its separation distance. Within the morphometric characters, three factors accounted for about 84% of variation within individuals of the two populations including; head width, head depth, pectoral fin length, predorsal length, preanallength, eye diameter, interorbital length, mandible length and pecto-ventral length. In the case of meristic characters, three factors accounted for 61% of variation within populations including; caudal peduncle scales, lateral line scales, scale rows above lateral line and dorsal fin ray. As far as proportional morphometric characters are concerned, four factors accounted for 84% of variation within populations including 11 characters. The results showed while morphometric and proportional morpnometric characters were not useful for separating the two populations, the meristic characters could almost separate these two populations.

Wheat is a strategic and valuable cereal in nutrition diet of human being. In order to increase the germplasm of agronomical 6x wheat, a wide range of new wheat genotypes i. e: Tritipyrum lines, have been produced by interspecific hybridizaton. An experiment was conducted to evaluate their baking quality traits in comparison with promising triticale lines and bread wheat varieties. The field trail was swon as a randomized block design with four replications. The physical, chemical and baking quality characters of Tritipyrum and Triticale lines along with wheat varieties were studied. The following traits were measured on each plot: a) Physical traits of grain including; 1000-grain weight (gr), grain hardness, grain moisture (%), bread volume, sedimentation volume and water absorption (%). b) Chemical traits of grain including; protein amount (%) by Zeleny and S.D.S, a-amylase enzayme activity, gluten index, dry gluten and wet gluten. c) Bakihg quality traits of dough by Farinograph method including; water absorption (%), arrival time to 500 brinder, maximum height at 500 brinder, breakdown time from 500 brabender and stability time of Farinograph curve to 500 brabender line, mixing tolerance index and valorimetery value. The results indicated highly significant differences between Tritipyrum genotypes with Triticale lines and bread wheat varieties. Although Tritipyrum lines had non-glassy seed and low gluten index, they showed high difference in protein (%), bread volume and flour yield. The mean comparison by Duncan test showed that Tritipyrums lines had low baking quality than the promising triticale lines and bread wheat varieties. Therefore, by now the Tritipyrum flour only can be used in food industy and production the semi- flat bread by mixing its flour with the flour of other bread wheat varieties. There was a significant correlation (a=%5) between most of the baking quality characters in three amphipods indicating a particular variation between Tritipyrum lines which is very important for breeding of this new cereal.

An experiment was conducted using 360 male chicks for 42 days, and the effect of Protein and Protexin levels on broiler Performance were studied. The experiment was done in a completely randomized design with 2 x 3 factorial arrangements with two Protein levels (NRC and 90% of NRC) and three levels of Protexin (without Protexin, recommended level and 120% of recommended level).  All of the rations were Isocaloric except for Protein and were consisted of NRC recommended levels of nutrients. The results indicated that, Protexin significantly increased weight gain of chicks in growing as well as the whole Production period. (0-42 days) (P<0.05). Feed conversion ratio of chicks fed with 120% of recommended protexin level was significantly better than the control group in the whole Period (P<0.05). Protexin had no significant effect on feed consumption, carcass Percent, abdominal fat Percent and feed consumption cost. Feed cost decreased with decreasing Protein levels (P<0.05). 120% recommended level of Protexin reduced feed cost Per Kg of live body weight gain, significantly (P<0.05).

Eight multiparous Holstein Dairy Cows were utilized in balanced change over design (2x2) in four periods of 21 days to examine the effects of supplementation niacin, Ca salts of long-chain fatty acids and their interaction. Treatments were control (no supplements), Ca salts of long-chain fatty acids (3% of dietary DM without niacin), niacin (12 g/d without Ca salts of long-chain fatty acids), and a combination of niacin and Ca salts of long-chain fatty acids. Each period of experiments included 2 weeks for adaptation to diets and one week for sampling and taking records. Cows were fed as TMR. The results showed that average milk and 4% FCM yields, milk lactose percentage, milk SNF percentage, total solid milk percentage and urea were not affected by Ca salts of long-chain fatty acids and niacin levels (P>0.05). Dry matter intake, milk fat percentage and milk protein percentage in cows fed by diet with 0 and 3 percent fat prouder were 24.63 and 24.44 Kg, 3.08 and 3.54 percent, 3.22 and 2.99 percent respectively, that were significant differences between the both levels fat powders in these regards (P<0.05). Percentage of milk protein in cows fed 0 and 12gr niacin were 3.01 and 3.20 respectively that difference was not significant (P>0.05). Concentration of triglyceride was increased in treatment containing the Ca salts of long-chain fatty acids (3% of dietary DM) (P<0.05). Concentration of glucose was elevated in treatment containing the niacin (12 g/d) (P<0.05). In general the results showed that using diet with 3% fat protein and 12gr niacin can be useful in dairy cattle.

This investigation was carried out in order to study of the effect of Saccharomyces cerevisiae yeast on fattening performance, carcass characteristics, blood metabolites and economic efficiency of Atabai fattening lambs. The experiment was conducted using 28 Atabai lambs with average body weight of 31.37±5.09 and 5-6 months age in a completely randomized design with balances rations formulated according to NRC (1984) recommendations. The applied treatment were: I)Basal diet (control); 2)Basal diet+2gr yeast per lamb per day; 3)Basal diet+4gr yeast per lamb per day; and 4)Basal diet+6 gr yeast per Jamb per day. Lambs were weighted every two weeks before the morning feeding. For measuring glucose and urea of blood serum, 3 lambs were randomly selected in each treatment and blood samples were collected from jugular vein of the lambs, 4 hours after morning feeding. Same lambs were slaughtered at the end of experiment for analysis of carcass characteristics. At the and of experiment, rations were economically calculated. The results showed that effect of yeast S. cerevisiae on average daily gain, average daily feed consumption, feed conversion, blood serum glucose and urea, carcass characteristics and feed cost per Kg of weight gain and carcass gain of lambs was not significant (P>0.05).

A cytogenetic study was conducted on 30 Sarabi cattles in Sarabi Cattle Research Center in Shabestar. Under completely sterile conditions, whole blood samples were collected from jugular vein using sterile syringes. About 5-6 drops of whole blood were cultured in 5 ml of RPMI1640 which was supplemented with 20% F.C.S. 1% antibiotics (penicillin, streptomycin), 2% phytohemagglutinin M (PHA-M), and 1% heparin. F.C.S. and phytohemagglutinin M were used as growth parameter factor and mitotic activity stimulator, respectively. Samples were cultured in the incubator to accomplish for 69-71 hours at 37°C. For normal staining, 10% Giemsa solution was used. But for GTG – banding staining, the slides were first treated by 0.25% trypsin and then with 4% Giemsa solution, and finally the slides were dried. The analysis revealed that Sarabi cattle like many species belongine to genus BQS had 60 chromosomes which consisted of 29 pairs of autosomes and one pair of sex chromosems. All autosomes were acrocentric and all the sex chromosomes were submetacentric. X chromosomes were greater than Y chromosomes.

Puccinellia distans are perennial, salt tolerant forage that belongs to Geraminea family. This research was plane for the increment of salt tolerance of Puccienellia distans with silicon and calcium nutrition and their interaction. The experiments accomplished in two growth stages including germination and vegetative stages. Germination experiment performed in peti dishes and paper towels under five salinity levels including 0, 50, 100, 150 and 200 mM NaCl. Vegetative growth stages tests done in three experiments. Design of experiment 1 was completely randomized with two factors, salinity including 0, 100 and 200mM NaCl and silicon including 0, 0.5 and 1mM silicon (as a sodium silicate). The second experiment had two factors consist of salfnity including 0, 100 and 200 mM NaCl and supplemental calcium nutrition including 0, 1/5 and 3mM calcium chloride. Experiment three run with two factors including silicon and calcium simultaneous (respectively including 1 and 1.5 mM) and salinity including 0, 100 and 200 mM NaCl. Plants were cultivated in sand culture in greenhouse and irrigated with Hoagland nutrient solution. Salinity reduced germination percentages, rates and uniformity significantly. Also, salinity decreased the length of radicles and hypocotyls in seedlings. Salinity reduced dry mass of plant shoot but silicon nutrition could alleviate effects of salinity and caused a significant increase in shoot and total dry mass under salinity. Silicon nutrition reduced Na+ concentration in plants under salinity and consequently, alleviated salinity effect in plants. The reduction of Na+ uptake and concentration could at least partly be explained by the inhibitory effect of silicon on the transpiration rate of plants under salinity. The supplemental calcium nutrition (1.5 mM) under 100 mM NaCl increased dry mass shoot and root. Supplemental calcium nutrition (1.5 mM) under 100 mM NaCl reduced sodium concentration in plant tissues that might be resulted higher growth of plants. Comparison of treatments according to dry mass under salinity indicated that sole silicon and calcium plus silicon treatments had certain advantage to sole calcium treatment. Alleviation of salinity by simultaneous calcium and silicon nutrition is lower than each one solely. It might be related to calcium and silicon antagonism on uptake and transportation and competition of them for cell wall sites assimilation. Further experiments I farms and range is essential for confirmation of these results.

Lack of adequate information regarding genotypic diversity within populations of plant pathogenic fungi is one of the most critical factors limiting breeding programs. During the growing seasons of 2003-2004, twenty two Fusarium solani isolates, the casual agent of wilting and dry rot of potato were obtained from fields and storages of Razavi and Northern Khorasan provinces. The pathogen city tests were carried out by soil-infestation, root-dipping, injection of spore suspension into tubers and tuber inoculation with a piece of media covered with mycelia on susceptible cultivar, Agria. In order to study the variation of the rDAN gene cluster, PCR-ribotyping was done on 22 isolates of Razavi and Northern Khorasan provinces and six isolates of Tehran, Hamadan and Ardabil provinces. Also the amplification of ITS-rDNA was subjected to digest by EcoRI and ReaIII enzymes. The results revealed that dry rot occurred by all isolates, soft rot by 28% and wilting symptoms by 76% of the total 22 isolates used in this experiment. The amplification of rDNA-ITS divided all isolates into ITS1 and ITS2 types. ReaIII showed the polymorphism in number and length of digested fragments better than EcoRI. In this study, there was no obvious evidence of any correlation between geographical origion, pathogenicity and ITS types of isolates.

This study was carried out to determine the presence of Eggplant mottled dwarf virus (EMDV) and its natural host range in Northern and Razavi Khorasan provinces between June 2003 to September of 2004. For this purpose plants showing, leaf malformation, dwarfing and vein clearing symptoms were collected from different cultivars of solanaceae and cucurbitaceae, from areas such as: Mashhad, Neishabour, Torbate-Jam, Jim-Abad, Fariman, Sarakhs, Chenaran, Ghochan and Bojnord. Each sample was individually prepared for serological tests including ELISA and double diffusion in agar, using special antiserum of the virus. The efficiency mechanical transmission and host range studies were preformed on 16 different plant species under controlled environmental condition in a greenhouse. The results showed that Northern and Razavi Khorasan provinces were both infected with Eggplant mottled dwarf virus. In Northern Khorasan the natural host range of this virus was only limited to eggplant whereas in Razavi Khorasan, in addition to eggplant, potato and tomato were also infected. In this state, Neishabour had the highest infection rate while there was no infection in Sarakhs and Torbatejam. The results of double diffusion test for isolates from different regions and hosts reveled the existence of just one active virus serotype in Northern and Razavi Khorasan provinces.

Maerophomina phaseolina, isolated from various host (alfalfa, bean, corn, cotton, cowpea, melon, safflower, sesame, sorghum, soybean, olive, pine, sunflower, watermelon) were assayed in reaction to potassium chlorate during 1999-2004. The isolates were grown on Minimal Medium with 25gr/lit potassium chlorate. The experiment was done 2 times, and each time included 20 replications. After 10 days in 25°c and dark, the cultures were investigated in comparison to controls. The results showed that isolates were separated into 2 groups. Bean, corn, cotton, cowpea, melon, sorghum, olive, pine, watermelon isolates were chlorate resistant and grew in dense phenotype, producing numerous microsclerotia on medium containing potassium chlorate. Whereas, alfalfa, safflower, sesame, sunflower and soybean isolates were chlorate sensitive. Sensitive isolates in soybean could be divided into two classes on the basis of growth on chlorate containing medium. One class grew sparsely with a feather like microsclerotial pattern. The other was completely restricted. The dominant phenotype differed between soil and root isolates for each host and among different hosts. These observations suggest that isolates of M phaseolina from various hosts differ in their ability to use certain nitrogenous compounds. Such differences might reflect to metabolic abilities that could lead to host specialization within this fungus.

Biological evidence for occurrence of sibling species in Sycophila mellea (Curtis) (Hymenoptera: Eurytomidae) in U.K, parasitoids of Tetramesa spp (Hymenoptera: Eurytomidae) in Poacea. The taxanomic status of Sycophila mellea (Curtis) species complex (Hymenoptera: Eurytomidae), reared on Tetramesa linearis (Walker) and T brevicornis (Walker) feeding in the grasses: Elymus repens (Viv) and Festuca rubra (L.) respectively, were investigated using mate-choice experiment study. The results of mate choice experiments show that there was an important reproductive barrier between S. mellea (ex: T linearis and ex: T.brevicornis) and mating between members of S. mellea (ex: T linearis and T brevicornis) was shown to be non random and demonstrated highly developed discrimination. In conclusion, the results of mate choice study strongly suggest that members of S.mellea (ex: T.linearis and T. brevicornis) represent different taxa.

One of the main methods for the mass production of callus is the use of the technique of the plant tissue culture. The purpose of this study was the production of Chinese elm callus Ulmus parvifolia Jacq. by application of coconut milk. Samples of tip shoots and shoots with buds, after surface disinfection with ethanol and sodium hypochlorite were cultured on the Murashige & Skoog (MS) and Gamburg (Bs) media culture. The effect of different compounds and coconut milk was compared in these two media on growth of calli. The trial was established in the randomized complete block design with 14 treatments and three replications in vitro. Treatments were two basic media culture of MS and B5 which contained coconut milk with 2,4-dicholoro phenoxy acetic acid (2,4-D), Benzylamino purine (BAP), Kinetin (Kin), Naphthalene acetic acid (NAA) and control were without MS and B5 media cultures plant growth regulator. The results showed that coconut application within MS media culture increased significantly weight of calli (2.37g) 35 days after incubation while there was not significant (p=%5) differences between various treatments in B5 media culture. Among of calli, callus were grown on MS containing coconut milk had significantly greater weight (%31.7) than treatments without coconut milk. Morphological characters of callus in agar media culture with coconut milk were produced yellow cell tissue, hard and intensive tissues. In the treatments containing only 2, 4-D callus weight decreased significantly. This study is the first report that investigated on this species in Iran and Asia.

Pathogencity of Ophiostoma ulmi and Ophiostoma novo-ulmi isolates against Ulmus parvifolia Jacq., was studied in greenhouse condition of the college of Crop Sciences, Pardis area of Gorgan University. Pathogen city rate of Ophiostoma ulmi and O. novo-ulmi isolates, isolated previously from north forest areas was evaluated on various ages of Chinese elm seedlings U parvifolia. Treatments were six months young elm seedlings, one year old and two years old elm seedlings. Wilt percentage of elm seedlings ten weeks after inoculation showed, that Chinese young elm tree is susceptible to aggressive isolates of O. novo-ulmi than O. ulmi. The highest percentage of wilting was observed on six months old seedlings and the lowest level of wilting observed significantly on two years old seedlings. The results indicated that oul isolate of O. ulmi and onu3 isolate of O. novo-ulmi showed significantly the lowest and highest percentage of wilting, respectively. Using of this elm, as resistant species against Dutch elm disease in country, to replace high susceptible species such as; Ulmus glabra and U carpinifolia and U carpinifolia var. umbraculifera by Ulmus parvifolia, and using in elm breeding programs for obtaining hybrid elms with favorite resistances is discussed.

The main cause of concern about the stability of bridge foundation is the occurrence of scour around the piers. Therefore, there is an interest in finding reliable ways to reduce and control local scour depth. The use of slot through a pier is one of the new proposed methods for controlling and reduction of local scour at bridge piers. This study examines the effect of using rectangular slots through the pier groups at clear water condition. The results of experiments show that in pier groups, reinforcing effect causes that the scour depth at front pier is more than that at a single pier. Also, sheltering effect causes that the scour depth at rear pier is less than that at a single pier. The presence of a slot in a two and three pier groups causes the reinforcing effect increases and sheltering effect decreases. The efficacy of a slot in rear pier is more than that in front pier and single pier for three and two pier groups with S=4b. It was also found that the efficacy of slot for two and three pier groups with S=2b for all piers are almost similar and similar to the single pier. Efficacy of slot in reduction of scour depth, increased with increasing pier spacing.

In this research, the rate of vertical infiltration was evaluated and compared using cylinder infiltrometer method to determine the coefficients of 5 infiltration models, called Kostiakov,-Green- Ampt, Horton, Soil Conservation Service (SCS) and Philip. In 82 regions, in addition to agrology profile, soil physics properties and required parameters, infiltration was also performed 3 times by using cylinder infiltrometer. Infiltration parameters (such as time cumulative infiltration, infiltration rate, and average infiltration rate) were estimated by using above mentioned infiltration models and compared to measured amounts. The model with the most explanation coefficient (R2) and the least variance (S2) were introduced as the best model. The study of infiltration on 3 types of soil texture as clay, loam and clay loam showed that Kostiakov was the most suitable model for estimating cumulative infiltration and infiltration rate in all conditions. By increasing the duration of infiltration test, results showed that the coefficients of Kostiakov model had more fluctuation in comparison to other models and using the coefficients of Horton and Kostiakov models which were the basis of experimental data in a short duration had a considerable error for estimating cumulative infiltration in a long duration. So, it was found that Philip and SCS models were more suitable in a long duration.

Limiting water resources for agricultural and non agricultural usages pose some difficulties for the present and also for the future. Rainfall is the most important water resource. Therefore, for optimal allocation of water resources, forecasting rainfall for a region is of special importance. Time series analysis seems to be a suitable tool for such forecasting. Four stations of Fazelabad, Gorgan, Maraveh- Tappeh, and Torshakly with different climates were selected for this study. SARIMA model were fitted to 26 years data, using MINITAB software, and rainfall was forecasted accordingly for the period from years 1379-1382. Two different time horizons of 10-day and monthly were adopted for modeling. Forecasted monthly-rainfall was discritisized to 10-day intervals based on the distribution of month in a similar year. In overall, monthly and annual rainfall were determinated by summing 10-day and monthly values, respectively. The forecasted rainfalls were compared to actual observed data. The results showed that for forecasting 10-day rainfall, using 10-day time horizon in SARIMA model formulation is more suitable. While, for monthly and annual forecasting purposed it is preferred to precede with monthly values.

Effective rainfall is one of the processes of the hydrologic cycle that has been studied very extensively. The various models proposed for description of this process are usually applicable to small plots, subjected to rainfall intensities that are higher than the infiltration capacity of the plots. In this paper we try to introduce a model which presented by Diskin and Nazimov. The model presented here in is not restricted to infiltration capacity only. It can also be used for computing the variations in the infiltration capacity rate and the production of rainfall excess for any given rainfall hyetograph and a specified value of the initial moisture content of the upper soil layer. The model comprises two elements, a linear reservoir and a regulating element. The definitions of the two elements require three parameters: minimum and maximum rate of infiltration capacity (fc, fo) and the maximum value of moisture storage in upper soil layer. In order to calculate the amount of rainfall excess, the model used in Kechik watershed, Golestan Province. The results show that the value of the rainfall excess during a selected rainfall was about 55.9 mm.