فهرست مطالب شهرام شاهرخی

The rose-grain aphid, Metopolophium dirhodum is one of the most important species among wheat and barley aphids and its population trajectory in field is characterized by rapid boom. In the present study, three datasets from M. dirhodum population in a wheat field in Varamin (Tehran) from 1999 to 2001 and two datasets from a barley field in Aleshtar (Lorestan) in 2017 and 2018 were used for modeling the aphid population dynamics. We demonstrate that Normal and Hyperbolic Secant Squared models presented a much better description of M. dirhodum population dynamics in the whole season for all datasets from wheat and barley fields than the Exponential or Logistic Growth models. The Normal and Hyperbolic Secant Squared model analysis of data showed that the models were useful representations of the data, gave biologically reasonable descriptions of rose-grain aphid population dynamics, and were statistically powerful basis for the analysis of experimental data obtained in this research. The parameters of two mentioned models are the predicted peak size, Nmax, the predicted time of peak, tmax, and an approximate per capita birth rate, all of which are of interest in practical applications. Overall, the results of this study showed that the Normal and Hyperbolic Secant Squared regression models were shown to fit diverse abundance curves adequately and the parameters of the mechanical model can be estimated by the parameters of these models.

In order to study the response of soil properties and sweet corn traits to different levels of organic and chemical fertilizers of nitrogen, a greenhouse-laboratory research was carried out as factorial based on a completely randomized design with three replications in Miyaneh Branch, Islamid Azad University. Experimental factors included poultry manure at three levels (0, 20 and 30 ton.ha-1) and nitrogen fertilizer at three levels (0, 100 and 200 kg.ha-1 from urea source). Results showed that application of poultry manure in soil increased soil pH, EC and organic carbon. Also, it had a significant effect on chlorophyll content, plant height and leaf area of sweet corn plants. Application of 20 and 30 ton.ha-1 poultry manure resulted in higher values of the studied traits. However, there was no significant differences between 20 and 30 ton.ha-1 poultry manure in most cases and so, application of 20 ton.ha-1 poultry manure was enough for achieving optimal sweet corn growth in greenhouse. According to the results, combined application of 20 ton.ha-1 poultry manure and 100 kg.ha-1 nitrogen from urea source could be recommended for optimum nitrogen supplying in sweet corn cropping system.

Cabbage aphid, Brevicoryne brassicae is one of the major pests of Cruciferae plants, especially cabbages and canola. In order to investigate the effect of plant essential oils to control of cabbage aphid, the contact effect of essential oils of laurel, Laurus nobilis and eucalyptus, Eucalyptus camaldulensis leaves was evaluated on apterous morph adults of cabbage aphid. Bioassay experiments were carried out with essential oil concentrations causing 20-80% mortality to determine LC50 by Topical application. The experiment was done in a Germinator with 25±1ºC, 60±5% RH and photoperiod of 16:8 (L­:­D) at five replications and 10 aphid adults were placed on cabbage leaf disc in each Petri dish as one replication. According to the results, essential oils derived from the studied plants had contact effect on cabbage aphid. LC50 of laurel andeucalyptus essential oils on cabbage aphid wereestimated as high as 11563 and 16835 ppm, respectively, and so laurel essential oil was more effective than eucalyptus one. Results of the experiments conducted as completely randomized design with five replications also revealed that tested essential oils reduced the aphid's fecundity and longevity in comparison to the control, but laurel essential oil was more effective. Application of laurel essential oil caused up to 45.47% and 32.78% reduction in fecundity and longevity of cabbage aphid, respectively. Repellency activity of essential oils of laurel and eucalyptus was evaluated using an Olfactometer (model RZR). An increased repellency percentage was observed at higher concentration of the studied essential oils. Repellency of laurel’s essential oil was more than that of eucalyptus, so that repellency percentage was 86.67% for laurel and 10% for eucalyptus essential oils in LC50. Plant essential oils were extracted by Distillation method and their compounds were identified by GC-MS. Results showed that 1,8-cineole (a component with insecticidal effect) was the major component in L. nobilis (25.5%) and E. camaldulensis (35.14%) essential oils, respectively.

Regarding the importance of medicinal plants and the lack of sufficient study concerning the evaluation of different sources of fertilizer on evergreen medicinal plant, an experiment in a randomized complete block design with 3 replications and 6 treatments were performed in Meshkin shar, Ardebil in 2013. The experimental treatments include: wermicompost 3 t/he, Nytroksyn 3 L/he, phosphate fertilizer 10 L/he, combination of vermicompost 1,5 t/he, phosphate 5 L/he, nytroksin composition 2 L/he, phosphate treated 3 liters per hectare and control (with on fertilizer). The measured traits include essential oil percentage, oil yield and percentage. The plants under vermicompost fertilizer had the most performance with the rate of 6033 kg/ ha). Harvest index and extract percentage were not used unter treat effects. The maximum diameter was gained Nytroksin phosphate composition. Most of the treatment with a combination of essential oils Nytrvksyn - phosphate, respectively, the highest yield of essential oil in the treatment combination Nytrvksyn - phosphate and vermicompost treatments were observed. Finally, the result showed a positive effect of biological and bio fertilizers on the most studied treatments.

Sequential sampling plans of rose-grain aphid, Metopolophium dirhodum (Walker) were developed in wheat fields of Jalilabad region of Varamin, Iran. The aphid population was weekly sampled during 2000-2001. Each sample included 50 wheat stems, which were chosen randomly and the number of aphids was counted. This data was used to describe spatial distribution pattern of M. dirhodum by Taylor’s power law (TPL) and Iwao’s patchiness regression methods. The results indicated aggregated dispersion pattern of rose-grain aphid population in wheat fields, based on both methods. The TPL provided a better description of the aphid’s spatial distribution. Estimates of two mentioned models led to development of sequential sampling plans, using Green and Kuno methods at precision levels of D = 0.20 and D = 0.30 in terms of confidence interval, respectively. In both sequential sampling plans, the higher sample size obtained as population density decreased and it decreased when precision level increased from 0.30 to 0.20. The required sample size for the estimation of mean aphid density was approximately identical at 0.8 and 8 aphids per tiller in both Green’s and Kuno’s plans. Green’s plan was more efficient than Kuno’s model for both lower (≤ 0.8 per tiller) and higher (≥ 8 per tiller) aphid densities due to its small sample size required and less time needed for sampling. Kuno’s model required fewer samples at the intermediate density range (0.8-8 aphids per tiller) and is considered more effective than Green’s plan at this aphid's density range. However, Kuno’s model is not recommended when low aphid population density exists because it requires enormous samples of aphids.

In order to investigating effect of irrigation intervals on yield and yield components of sorghum cultivars, an experiment was conducted at the Research Farm of Islamic Azad University of Miyaneh on May, 2008. This experiment was implemented in the form of split-plot with randomized complete block design in three replicates. The first factor included 3 irrigation intervals (7,14,21) days, and grain sorghum cultivars including Kimya, Payam and broom sorghum called local cultivar Golbous was main and secondary plot, respectively. According to the results, the effect of irrigation intervals and cultivar on many of the studied traits such as plant height, panicle length, stem diameter, number of leaves, grain number per plant and grain yield was significant and intraction between irrigation intervals and cultivar on plant height, panicle length, grain number per plant was significant. The comparison of means indicated that plant height, panicle length, grain number per plant and grain yield decreases as the irrigation intervals increased. This comparison also suggested payam cultivar is superior to Kimya and local Golbous in terms of the grain number per plant and grain yield. Plant height had a positive and significant correlation with all of the studied characters unless seed number per plant.

Broomcorn is extensively cropped in Miyaneh region for traditional broom production and occasionally included in rotation with barley by local farmers. The research objective was clarifying of broomcorn allelopathic potential on barley germination and initial growth. Allelopathic properties of 2.5, 5, 7.5, and 10% of broomcorn roots and shoots aqueous extracts sampled 1, 2, 3, and 4 months after planting, also root exudates using equal compartment agar method and 5 and 10% of intact and burnt crop residues aqueous extract on barley germination and initial growth were evaluated. Also, 2.5, 5, 7.5, and 10% of 3-month broomcorn foliar extracts on barley seedlings growth was evaluated in greenhouse condition. Broomcorn root extracts was less allelopathic on barley seed germination, also 3-month foliar was the most allelopathic studied plant organs on seed germination and growth of barley. Also, broomcorn root exudates were more toxic on barley plumule than radicle. Residue burning decreased allelopathic effect of broomcorn residue up to 77%. Irrigating with broomcorn extracts had less allelopathic effects than direct bioassay on barley seedlings in laboratory. Considering remarkable allelopathic potential of broomcorn on barley, its residue management should be concerned in broomcorn-barley rotations.

In order to Effect of Mepiquat chloride the agriculture in stages on cotton (Gossypium hirsutun L) experiment was conducted in parsabad- Moghan with two factors included cotton cultivars Maher Vermin Sherpan-Oltan and topping at 30 day after flowering, Pix spraying at 30 day after flowering, Pix spraying at 15 the after flowering without pix and topping as control. Measured traits in this experiment was stem height, seed yield and total yield. For Analysis of variance total was used MSTAT-C soft ware. Results indicated that, effete of treatments on stem height of cotton was significant. Treatments of Vermin cultivar Pix spraying at 30 day after flowering with 70.33 cm stem height lowest height. Total yield no significant.

The effects of drought stress and potassium application on yield and yield components of chickpea were studied in Northwest of Miyaneh city. The experiment was carried out as factorial based on a randomized complete block design. The experimental factors were irrigation at four levels (0, 50, 75, and 100% of chickpea plant water requirement) and potassium sulfate fertilizer application at two levels (0 and 100 kg.ha-1). The recorded characteristics were number of lateral branches, days to ripening, pod numbers per plant, biomass, thousand kernel weight, yield and harvest index. Irrigation treatments had significantly different effects on potassium fertilizer use efficiency. The highest fertilizer use efficiency was observed at 75 and 100% plant water requirement levels. The number of lateral branches, number of pods per plant, biomass, yield and harvest index were decreased by irrigation levels decrement. The most pod number per plant, grain yield and harvest index were obtained in 100% water consumption along with potassium fertilizer application. The lowest values of the mentioned characteristics were observed in non-irrigated and no potassium application. The yield and biomass in fertilizer application and 100% irrigation were 69.12 and 33.11% more than non potassium and non-irrigation treatments, respectively. The application of potassium slightly compensated the negative effect of drought stress on yield.

The flight and walking activities of the second, forth, sixth and eighth generations of Trichogramm brassicae reared on Sitotroga cerealella eggs were compared under laboratory condition. The parasitoid wasps were obtained by collecting egg masses of Naranga aenescens from rice fields and Sitotroga cerealella egg traps. The experiments of flight and walking activities was carried out using black P.V.C. tubes and the percentage of inactive, flying and walking wasps to light were calculated. Results showed a reduced flight and walking activities and increased percentage of inactive wasps with the increasing number of generations. In second generation, 41.9±2.88, and 36.7±2.65 of wasps population had flight, and walking ability, respectively, and 21.4±2.45 of them was not able to fly and walking. The highest percentage of inactive wasps were observed at eighth generation, whereas wasps showed significantly better flight and walking activities at second generation. Based on the results, flight and walking abilitiies of T. brassicae were gradually decreased at continuous laboratory rearing.

Broom corn is cultured in broad areas as one of th most important agricultural crops in Miyaneh region, Iran. Greenbug, Schizaphis graminum, an injurious cereal aphid, reduces the yield of the crop and so pestichdes Oxydemeton methyl and Thiometon were usually applicated - times to prevent aphid damage. In order to select effective pesticides for reducing application times, economic yield production and environmental safety, the effect of commen pesticides in broom corn fields (Oxydemeton methyl and Thiometon) was compared with Imidaclopride, Primicarb and Malathion on green bug. Results revealed that Imidaclopride, Primicarb and Oxydemeton methyl were the most effective pesticides on S. graminum. High Relative Potential Reduced Concentration (RPRC) of Imidaclopride, Primicarb and Oxydemeton methyl were duo to their low LC50 values on the aphid population, and indicated that their field recommended doses most probably can kill more than 50 percent of aphid population in the field condition. The highest Relative Potential Reduced Concentration value was observed in Imidaclopride with. 56. Besides, Iranian formulations of Thiometon and Oxydemeton methyl were less effective than others and systemic pesticides were more effective than Malathion contact pesticid.