For evaluation and determination of genetic capacity of existing apricot genotypes in Iran, an experiment was performed in RCB design with seven treatments and three replications on August 2004 in Sahand Horticultural Research Station. Selected promising genotypes with numbers of 177, 190, 390, 414, 416, 464 and 269 were compared with Ordubad 90 cv. (as control) for a period of seven years. The results demonstrated that there was no significant difference between yielding and full blooming dates of the genotypes and control. The range of fruit maturation between the most early and the most late maturity genotypes was 45 days. Genotype 414 had the maximum fruit weight (57.6g) and the highest fruit to stone weight ratio (30.3). From the viewpoint of fruit flesh thickness, the lowest difference was observed between control and genotype 464, and the highest significant difference was detected between control and genotype 269 (p£0.05). Despite relative height of stigma to anthers in genotypes 269, 414, 464 and 177, no problem was observed in fruit setting of them. Based on the biochemical traits results, the highest significant differences were observed between TSS value of genotypes 416 and 177 with 7.7% and also between total organic acids content of genotypes 390 and 177 with 1.2% (p£0.05). Difference between fruit active acidity (pH) of genotypes was not significant. There was also a negative and significant correlation (r2=0.8) between total organic acids content and pH of the genotypes fruit. Based on all results, genotype 177 was recognized for fresh consumption, genotypes 464 and 390 for processing and genotypes 190, 414 and 269 for dual.

In spite of highly economic importance of white mushroom (Agaricus bisporus) and its world wide production, the breeding difficulties for yield improvement of this edible mushroom which is due to its biology is still under consideration. In this research the ways of improvement of the mushroom for yield by employing hetrosis phenomenon of interbreeding crosses was investigated. Spore prints of six commercials exotic and two cultivated domestic strains were prepared and after 15 to 25 days, 100 different spawn produced. In the above stages basidiospore variation in terms of growth rate and type of colony on PDA medium and wheat spawn was carefully investigated. Fruiting test was conducted to isolate homokaryons from hetrokaryons. One hundred Isolates were classified into four groups of high, medium, low and zero in terms of yield. The relationship of these yield classes with the type of colony was studied. Those isolates with zero yields were used in interbreeding crosses to produce hybrids. Some hybrids performed significantly better both in PDA culture medium and in the wheat spawn. RAPD markers used to briefly investigation of variation between some isolates of A15, showed high and positive correlation between number of bands and yield for each isolate. Key words: Agarics bisporus, Hybridization, Spawn, Fruiting test, RAPD.

Today, the use of energy-dissipating system such as yielding metal damper in structures can improve the seismic performance of structures. One of the characteristics of metal yielding dampers is the ability to dissipate high energy and increase the ductility of the structural system, which can improve the ductility and energy absorption characteristics of the metal frame equipped with braces and prevent the brace from buckling during an earthquake. The purpose of this research is introduce a new form of yielding dampers called honeycomb yielding damper (HYD) with different dimensions and thickness along with evaluating and comparing the force-displacement diagrams and investigating the seismic parameters of this type of yielding damper. All modeling and validation of numerical samples were done by Ansys software. Non-linear analysis method is used in this research. The hysteresis curves are obtained under in-plane cyclic loads. The mechanical parameters such as ductility ratio, initial hardness, effective hardness and damping coefficient can be determin. The results of this research showed that the effective stiffness increases by increasing the length and thickness of the sample. The ductility ratio decreases by increasing the height of the sample. the effective stiffness decreases by increasing the height of the sample. The ductility ratio increases by increasing the height of the sample. Also, the effective damping coefficient decreases with the increase in the height of the samples, the effective damping coefficient increases with the increase in length and thickness of the samples.

One of the most widely used and applicable solutions for limiting the damages of earthquakes to steel structures is using Metallic Yielding Dampers as a type of passive devices to dissipate the received energy. Maintaining a proper balance in the design of these devices is a delicate matter as each of the different types have advantages and disadvantages. In this research, different types of metallic dampers are compared using finite element simulation which is performed by means of ABAQUS package. Modeling process is described and verified by comparing the results to a previously published experimental paper on the subject. For assuring more accuracy a mesh convergence analysis is performed to determine the suitable mesh size. Afterwards, cyclic and pushover analysis are performed on each damper and results are presented and discussed. Effective stiffness and damping of each damper, both general and average, is extracted using proper equations and finite element results. Finally, for deeper understanding of dampers behavior, internal forces of the dampers are derived and compared. It was shown that design equations are fairly accurate. As the height of the dampers increases, their effective stiffness and damping reduces and the dampers behavior leans towards flexural behavior. Based on cyclic and pushover analysis, Steel Plate Dampers (SPD) have the highest stiffness and energy dissipation. Also, SPD and Double Pipe Dampers (DPD) are the most suitable to reach a demanded stiffness, damping and have the most stable performance. At the end of the paper, a list of conclusions is presented.

Several crosses have done between local rice cultivars and improved varieties in order to improve and releas high yield withing cultivars with suitable quality characteristics during lastthree decates in Iran. A hybridization breeding program with high emphasis on quality started in 1985. In that program, two groups of riice cultivar (localaromatic cultivars and high yielding improved ones) werecrossed in all possible mating systems (complete dialllel crosses). Suitable crosses were sellected and segregating generation were handled based on the pedigree method. Quality analysis of the selected sigle plant and lines were done in each generation. Finally six promisiing high yielding lines with good cooking and eating qualities were obtained from Sang Tarom and Hassan sarai with Amol 3. One of them D2-12-54, showed superiority in sense of yield and quality, comparing to others improved cultivars as well as Amol 3 and Nemat cultivars. Quality and some important agronomy characteristics of D2-12-54 (Neda c.v.) are as follows: Amylose content 26.2 percent; gelatinization plant heigh 100 cm; panicle length 26cm; 1000 grain weight, 30gr; maturity length 130 days; average yield 8384 Kgha-1; resistant to blast and tollerant to stem borrer.

Steel shear walls have different systems and models, each of which has different fields for investigation and design. Steel shear walls can be classified in categories with or without opening, and each of these models can be placed in steel shear wall systems with or without stiffeners. The steel shear wall system can also be implemented in composite. In this research, it is intended to improve the seismic behavior of this system by adding yielding steel dampers, which is discussed below. For this reason, in this research, it is intended to "Cyclic analysis of steel shear walls with peripheral yielding dampers" in order to evaluate the performance of bending steel frames with steel shear wall system under nonlinear dynamic load. In this research, the studied samples were numerically loaded under cyclic load analysis using ABAQUS v-21 software, and the results of stress, strain and displacement values at the moment of maximum load and at the end of loading were compared with each other for the samples in question, and after evaluating the results of the samples from their analysis, the best performance was determined. As seen, the use of Amo's peripheral yielding dampers on the wall plate when the peripheral dampers are only connected to the beams has led to improved performance and reduced displacement outside the wall plane, increased elastic displacement of the frame, reduced stiffness of the frame and reduced drift of the frame. On the other hand, the use of peripheral yielding dampers in line with the wall plate when the peripheral dampers are only connected to the beams has led to improved performance and increased elastic and plastic stiffness of the frame, increased force absorption in the elastic and plastic area of the frame during the load process