فصلنامه دانش کشاورزی
سال شانزدهم شماره 4 (پیاپی 64، 1385)

The stochastic property of inflow to the reservoir system makes the forecast of operation rules in reservoirs to have great importance for irrigation of farmlands. The aim of simulation technique is to develop a mathematical model to predict a behavior of reservoir system in future operation periods. Decision makers make a good management for system operation by application of different scenarios. Aras Baran reservoir with 25MMC active volume was constructed for the purpose of irrigating the 3200 ha of Keleyber farmlands. In this research Monte Carlo technique was applied to generate the synthetic inflows by the use of local historical data for the purpose of system behavior prediction. Using the generated data the decision variables (Reservoir storage, precipitation, evaporation and spill) were determined and operation policy of reservoir was identified. The results show that in the 15 percent of times storage volume in the reservoir greater than form reservoir total capacity and therfore excess water will spills.

Canola is compatible with climatic condition of many regions in Iran, and for this reason its cultivation is developing to provide the needs of edible oil. In the field experiment, two stage harvesting at different grain moisture and one-stage harvesting were compared with regard to grain yield, losses, percentage of breakage, immaturity and impurity of kernels and field capacity in Marvdasht county in Fars province. This experiment was carried out by two methods. In the first method canola was harvested by hand at four grain moisture ranges (15-20,20-25, 25-30 and 30- 35%) and maintained in the field for a few days and picked up at about 10-12% grain moisture by combine. In direct harvesting, canola was harvested by combine at 10-12% grain moisture. The treatments were arranged in a randomized complete block design with four replications and their means were compared by Duncan’s multiple range test. The results showed that, there was no significant difference between treatments for grain yield. Direct harvesting had the lowest cost than other treatments, but economic analysis showed that two -stage harvesting method at 15-20% grain moisture can be recommnded if yield increases 25.8%, under the situation when canola is harvested and taken out from the field.

With regard to the importance of reforms in traditional agricultural methods, usage of modern technologies and need of training farmers, modern techniques, the effect of farmers’ technical knowledge on grape production in Baloo village of Urmia in 2000 - 2001 was investigated as a case study. It was found that experience, training, and use of cordon method had significant and positive effects on amount of production. But variables like age, education and being farmer as a main job, did not have significant effects. This indicates that share of traditional knowledge is more than other variables in the production process and the importance of training farmers by modern technologies was therefore, suggested.

Considering present problems in the production of grafted walnut trees and the role of them in the production of uniform and quality nuts, this experiment was conducted with 11 different grafting methods and times including: cleft, earth up cleft, bark, tongue, shield budding at three times (spring, summer and fall), patch budding (spring, summer and fall) and chip budding. Treatments were arranged in a randomized complete block design with four replications in 2005. Also a preliminary experiment was conducted with the abovementioned treatments systematically in 2004. Results showed that there was a significant difference among treatments on the grafting percentage. The highest grafting percentage (93.3% and 83.75%) obtained from the bark grafting operated at early May of 2004 and 2005, respectively. In the second rank, spring patch budding and earth up cleft grafting resulted in the 60% and 40 % grafting percentage, respectively. However, grafting success in the case of ordinary cleft grafting in both years was about 20%. In other methods and times of grafting the union of scion and rootstocks did not occurred successfully, although the graft union two weeks after operation was green. In conclusion the suitable time of grafting was limited to the early spring. Therefor, it could be recommended to propagate walnut by bark grafting and spring patch budding provided that scions has been stored at refrigerator.

Crust formation leads to development of a dense and hard layer on soil surface which effectively retards water intake and enhances erosion. Various remedies have been proposed to overcome this difficulty. The purpose of this study was to examine the effects of polyacrylamide (PAM), pumice and wheat straw, used as amendments, on soil infiltration and hydraulic conductivity under sprinkler and flooded conditions simulated for soil columns at laboratory. The soil columns were prepared by evenly packing (Db=1.4 grcm-3) of soil (Coarse loamy, mixed (calcareous), mesic fluventic) in PVC tubes with 15 and 25 cm long and 15 cm diameter. Pumice at the rates of %1 and %3 and wheat straw equivalent to 2.1 and 5 tonha-1 were well mixed with 0-5cm layer of the soil in the apprporiate columns. PAM was dissolved (50 and 100 mgl-1) in tap water of EC=0.5 mS/cm and SAR=2.2 and was applied to the soil surface equivalent to 20mm depth, 24 hr before exerting irrigation treatments. The columns were irrigated either by rainfall simulator(100 mmhr-1) or by continuous flooding of soil surface with 1 cm head of water. Infiltration volumes were measured every 5 min. until steady state intake was realized. The soil surface then allowed to eventually dry out and to crust. Crust hydraulic conductivity then were measured using the method of Helalia and Letey (1988). Irrespective of kind and application rates, amendments significantly increased cumulative infiltration (Ic) from 8.5cm in untreated soil to 14.1cm averaged over the two watering methods. PAM 50 mgl-1 led to highest Ic of 16.24 cm; it was increased about 100% comparing to the control. Increase in Ic was more pronounced under sprinkling than flooding. Except pumice %1, all amendments elevated steady infiltration rate about equally and significantly (P<.01) comparing to the untreated soil. Crust hydraulic conductivity (Kc) behaved similar to steady infiltration rates. PAM 50 mgl-1 raised Kc from 44.2 in the control to 88.9 mmhr-1 which was an increase of more than %100. Eventhough PAM indicated greater improvement in soil infiltrability and hydraulic conductivity, but the duration of its effectiveness and the risk of soil pollution from PAM accumulation and its break down to acrylamide may be questionable and needs investigation. From the availability and economic aspects pumice seems a suitable soil amendment.

Adaptability and stability of eight promising rice lines (genotypes) were determined by conducting a randomized complete blocks design with four replications at three locations (Rasht, Roudsar and Talesh) and in three consecutive years (2001-2003). The agro-morphological traits such as grain yield, panicle number, 100-grain weight, plant height, panicle length, days to 50% flowering and grain quality characters such as amylose content, gelatinization temperature, gel consistency and milling recovery were measured adopting standard methods. Analysis of variance based on each location revealed that the cultivars were significantly different for all the observed traits. However, for panicle length (in Rasht) and milling recovery (in Roudsar) the differences were not statistically significant. Combined analysis over three locations and years revealed highly significant differences for all characters among the eight genotypes studied. The differences of locations were significant only for hundred grain weight. Highly significant F were observed for genotype × location × year interactions for traits such as grain yield, 100 grain weight, plant height and panicle length. Overall, mean yield comparison over three locations and three years showed that the lines 837, 838, 840, and 841 were the highest yielding among genotypes ranging from 5.85 to 5.94 t/ha. Stability analysis revealed that the cultivars 838, 840 and 841 are the most stable genotypes, showing lower coefficient of variation and also within location mean square. However, lines 840 and 841 having superior grain quality are comparable with Iranian traditional land races and are recommended for immediate release in Giulan province. These two stable high yielding cultivars are also resistant to blast disease.

Remobilization of internal resources is an important mechanism enabling plants to be partly independent of environmental conditions and external nutrient availability. Therefore, in this study the enhancement of nonstructural carbohydrate remobilization of two barley (Hordeum vulgare L.) cultivars, Walfajr and Reihan, was assessed by pre-anthesis nitrogen usage and a controlled drought stress during grain filling stage. The experiment was conducted as factorial split plot based on randomized complete blocks in both pot and field experiments. Three levels of nitrogen 60, 120 and 180 kgha-1) and three irrigation levels (>80, 55-65 and 35-45 percent of field capacity) were applied at heading and 10 days after anthesis respectively. Soil water was controlled by pot weighing and determination of soil moisture, in pot and field experiments, respectively. Maximum nonstructural carbohydrate (NSC) at anthesis, NSC residue at maturity, NSC translocation, and NSC translocation efficiency measured in leaf, sheath, peduncle, two internodes under peduncle, and stem base. Then, the contribution of these parts to grain filling was determined. Pre anthesis carbohydrate reserves were increased in the high nitrogen condition, but NSC reserves translocation, and translocation efficiency from anthesis to maturity were decreased. In severe soil drying condition, NSC reserves translocation and remobilization efficiency were increased. Two internodes under peduncle and stem base had greatest carbohydrate translocation efficiency. Evaluation of each part indicated that NSC reserves in two internodes under peduncle had the highest contribution to grain filling. No considerable differences were observed between the two cultivars (Walfajr and Reihan).

This investigation was accomplished to study the quantitative and qualitative changes of leaf total soluble protein amounts in a spring (Line 518; cold sensitive) and a winter (Bezostaya; cold tolerant) genotypes of common wheat (Triticum aestivum L.) exposed to a period of a vernalization temperature (4°C). Seedlings were grown in a controlled growth chamber for 14 days at 20°C and then transferred to 4°C for 32 days before returning them to 20°C (cold treatment), or else they were maintained continuously at 20°C (control treatment). Over the experimental period day 14-58, plants were randomly sampled at 4-day intervals for total leaf fresh weight (3 ´ 1 g) measurements. Total leaf soluble proteins were extracted and their concentration was either determined by a colorimetric method using Bradford assay, or size-fractionated on SDS-PAGE. The protein quantity data were analyzed using a factorial experiment on the basis of completely randomized design in three replications. Genotype, temperature treatment and sampling time with 2, 2 and 12 levels, respectively were considered as the factors. The analysis of variance showed that the main effects and their interactions were highly significant (P<0.001). Additional statistical analysis showed that a drop of 16°C caused obvious cold-induced accumulation of proteins during the low temperature treatment in the winter wheat but not in the spring wheat. The results of SDS-PAGE showed that new cold-induced polypeptides were started producing on 4 days following 4°C. The most detected cold-induced polypeptides were 40, 57, 66, 90, 100, 180, and 200 kDa expressing in the leaves of both wheat genotypes (except 40 kDa for spring wheat). A polypeptide of 23 kDa was tailed off in the spring genotype under cold stress.

Sugar beet pests and diseases are the main factors decreasing root yield and sugar content. Sugar beet wild relatives especially section Procombentes have some resistance genes against pests and diseases, and therefore are important in sugar beet breeding programs. Interspecific hybridization between B. vulgaris and these wild relatives is a routine approach to obtain resistant varieties. In this research, interspecific hybridization was carried out between a tetraploid B. vulgaris as female and two species of Procumbentes section as male parents. Embryo rescue technique was used to develop hybrid plants. RAPD markers were used to identify the hybrids. Genomic DNA extracted from parents and hybrids and followed by PCR reactions using random primers OPX15 and OPX2. The sequences of these two primers are recognized to be specific for the Procumbentes genomes. The results showed that there are some bands to identify real hybrids. These hybrids had three common bands with their parents in PCR reactions products with OPX15 primer. Two bands (700 bp and 2600bp) came from Procumbentes and one band (1100bp) from B. vulgaris. PCR product of OPX2 primer showed that hybrids have two common bands (600bp and 990bp) with cultivated and wild parents, respectively. A third band (1900bp) was common in all parents and hybrids. Molecular studies showed that hybrid plants have similar bands to both wild and cultivated species and, therefore, are interspecific hybrids. This indicates that this technique can be useful to identify different species within beet germplasm and their inter-specific hybrids.

In order to investigate the competition effect and yield of two soybean cultivars in pure stand and intercropping systems, a factorial experiment based on randomized complete block design with three replications was conducted in field, 22 kilometers from Gorgon-Sari in 2002. Factors were: soybean cultivars Pershing and Williams with three densities (40, 50 and 60 plants m-2) and six levels of planting patterns of Pershing-Williams(0:100, 20:80, 40:60, 60:40, 80:20, 100:0). The competition models of reverse productivity for Willims and Pershing in pure stand was Cayera equation and for intercropping were Shenozoki and Cayera equations. The reverse productivity of single plant in pure stand in both cultivars had a linear relationship with plant density. The results showed that productivity of Williams single plant was equal to 1.2385 of Pershing and the single plant productivity of Pershing was equal to 0.9212 of Willims. The intracultivar competition in Willims was more than intercultivar competition, while in Pershing it was vice versa. The differences between inverse productivity of single plant of Williams in pure cultivation and intercropping was very low. But in Pershing this difference was relatively high, which shows that Willims cultivar is more competitive than Pershing. The highest yield was obtained at the ratio of 40:60 with 50 plantsm-2 and land equivalent ratio of 1.21.

In order to evaluate the competition in common vetch and pearl millet (nutrifid variety) intercropping, an experiment based on randomized complete block design with three replications was carried out in the Research Field of Faculty of Agriculture, University of Tabriz. Treatments included a plant density of the millet (15 kg seed/ha) and three plant denstities of vetch 50, 70 and 90 kg seeds/ha) and three combinations of the two crops. The millet with low density of vetch showed highest relative yield total. The relative crowding coefficient and aggressivity of millet on vetch at all treatments were negative. Vetch was dominant to millet. The competition index of vetch increased with increasing of vetch density. Therefore, the millet and vetch yield per plant drastically decreased as compared to isolated single plants.

Sainfoin with deep root, high level of drought tolerance, digestibility and lack of bloating is one of the important forage crops in Iran. The present study was designed to assess the 15 sainfoin landraces cultivating in east and west Azarbijan provinces in three plant densities (200, 400 and 600 plants/m2). The trial was carried out as factorial using complete block design with three replications during three years. There were significant genotypic differences for all of the studied characters in the first and third years of experiment except for leaf to stem ratio which was not significant in the third year. Whereas in the second year, significant differences among landraces were observed only for plant height, dry weight of 15 plants and dry forage yield per plant. Combined analysis of variance revealed significant differences among genotypes for all of the characters. Mean comparisons and ranking of landraces based on mean of all characters in each year and combined over three years, indicated that Osko and Arbat Osko landraces are the genotypes with high production potential. Particularly, the Osko landrace with high dry forage yield and someyield components showed significant differences with other landraces in all of the three years. Gharechaman landrace in spite of having low yield as compared to the two above mentioned landraces, can be used as a valuable genetic resource in breeding programs due to high forage quality.

In order to determine the critical period of redroot pigweed control in green bean, two experiments were conducted in experimental field of Islamic Azad University of Tabriz, Iran, during 2004 and 2005. The experimental design was randomized complete block design with three replications. The treatments included weed infested and weed-free conditions in the same periods. In the both years, in weed-infested experiment, redroot pigweed was seeded immediately after green bean planting and removed after 0, 2, 4, 6, 8, 10 and 14 weeks after green bean emergence (WAE). In weed-free experiment, redroot pigweed was transplanted in green bean plots at 0, 2, 4, 6, 8, 10 and 14 WAE. Results indicated that years had significant effects on all of the traits except pod yield at the first and second harvesting time. All measured traits were affected by different interference regimes, significantly. The early 4 weeks redroot pigweed infestation and weed-free until 10 WAE didn,t decrease green bean above ground biomass. At boths years, the highest yield loss obtained in the full season weed infestation condition. The critical period of redroot pigweed control based on 5 and 10% green bean yield loss were determined as 13 to 60 and 19 to 55 days after emergence, respectively.

The effect of genotype, age and sex on the apparent metabolizable energy (AME) and nitrogencorrected AME (AMEn) was studied using male and female chickens of two different genotypes (RIR and Cornish) in 4 and 8 weeks of age. The experiment was carried out for the purpose of better understanding the effect of age and sex of both genotypes on dietary AME and AMEn of corn and fish meal feedstuffs. The results indicated that the different levels of corn (40 and 80 %) and fish meal (4 and 8 %), feedstuffs were not significantly different for metabolizable energy (P>0.05). The effect of different genotypes on the metabolizable energy values obtained for the feed ingredients (corn and fish meal) were not significantly different (P>0.05). This study showed that female chicks may be able to mobilize or retend nitrogen (FN+UN) more than male birds of Cornish (meat type) and RIR (layer type) strains.

One of the inhibitors of polymerase chain reaction (PCR) in detecting fruit tree viruses including grapevine viruses is the presence of phenolic compounds and polysaccarides in the plant tissue. These inhibitors degrade the extracted nucleic acid and inactivate polymerases during PCR reaction. In this study, two protocols were examined to extract total RNA from the grapevines suspected to be infected by Grapevine fanleaf virus (GFLV). One protocol was based on phenol chloroform extraction but the other did not use such solvents. In optimization of the RT-PCR reaction, synthesis of first strand cDNA was initially performed by either a virus-specific primer (S2515 or 3300) or oligo d(T)16 and subsequently PCR was undertaken with two primer sets CP433V/ CP91 C or S2515/A3300. RT-PCR on phenol-chloroform extracted RNA did not result in any amplification from grapevine samples although the expected DNA fragments were amplified from GFLVinfected Chenopodium quinoa plants. Presumably, the phenol-based protocol was not able to remove the preventive substances from the extraction and they inhibited the RT-PCR reaction. However, RT with oligo d(T)16 on the RNA which was prepared without using phenol or chloroform from the grapevines and subsequent PCR with CP433V/ CP912C or S2515/ 3300 resulted in amplification of the expected 480- or 810- bp DNA fragment, respectively. This study, for the first time, revealed the extent of GFLV distribution in vineyards of East Azarbaijan and Ardabil provinces in north-west of Iran plus providing ground for molecular characterization of the virus isolates.

The effects of two fungicides, benomyl and carbendazim, on control of Trichoderma green mould disease of white button mushroom were investigated. Six concentrations of each fungicides were tested on four Trichoderma species including T. harzianum, T. longibrachiatum, T. virens and Trichoderma sp. The concentrations were 10, 25, 50, 100, 150 and 500 ppm. Mean growth of each species of Trichoderma was measured after five days. This study was conducted as food poisoning method and the inhibition percent of Trichoderma species mycelial growth was measured, using the Vincent (1947) equation. ED50 index was used to compare the effect of two fungicides on disease causing agent. After measuring the inhibition percent of Trichoderma mycelial growth, probit analysis was done. The results showed that the inhibition of mycelial growth of Trichoderma species by these fungicides did not have sigmoid curve. There was significant difference between two fungicides for their effect on Trichoderma species. Also there was significant differences among the Trichoderma species in sensitivity to different concentrations of these fungicides. Based on the results, it can be concluded that the carbendazim is more effective than Benomyl. The sensitivity of each Trichoderma species against the fungicides were estimated. The effects of these fungicides on controlling green mould and mushroom yield also were studied. The use of each fungicide increased the yield as compared to control. Furthermore, carbendazim increased the yield more than benomyl.

In this study an algorithm, based on artificial neural networks (ANNs), for classifying four different varieties of Iranian pistachio nuts, Kaleghouchi (Ka), Akbari (Ak), Badami (Ba) and Ahmadagaee (Ah) is presented. To develop the ANN models a total of 3200 pistachio sound signals, 800 samples for each variety, were recorded. Features of pistachio nut varieties were extracted from analysis of sound signal in both time and frequency domains by means of fast fourier transform (FFT), power spectral density (PSD) and principal component analysis (PCA) methods. Altogether forty features were selected as input vector to ANN models. Network output vector consisted of four neurons for classification of varieties. In developing the ANN models, several ANN architectures, each having different numbers of neurons in hidden layer, were evaluated. The optimal model was selected after several evaluations based on minimizing the mean square error (MSE), correct separation rate (CSR), and correlation coefficient (r). Selected ANN for classification was of 40-12-4 configuration. CSR of the proposed ANN model for four pistachio varieties, Ka, Ak, Ba, and Ah were 96.97%, 97.64%, 96.36%, and 99.10%, respectively. Net weight average of system accuracy was found to be 97.51 %.