فصلنامه دانش کشاورزی
سال نوزدهم شماره 1 (پیاپی 73، بهار 1388)

One of the structural problems of agriculture in many regions of Iran, which cause high production cost, low yield and the loss of resources, is the land fragmentation and small-scale of producing farms. To this end, in this study the effect of farm size and land fragmentation on yield and production costs in cotton producing farms in Garmsar is conducted where these problems are widespread. By surveying the econometric and statistical criteria of some flexible production functions a suitable function, i.e. the translog function was employed. Data were collected by using and filling a planned questionnaire from some cotton farmers who were selected by using a twostage sampling techniques. In this production function farm size, the number of blocks, chemical fertilizer levels, and human labour as independent variables and the yield level is dependent one.The estimated elasticity of explanatory variables of farm size, the number of blocks, chemical fertilizer and human labour at 0.146, -0.00129, 0.383 and 0.056 respectively, show an increases of 1 hectare in farm size, the corresponding yield, will increase 505.39 kg.; the addition of one unit of labour and 100 kg of chemical fertilizer will lead to the increases of 193.6 and 13.22 kg in yield respectively. Moreover, an increase of one block to farm blocks will leads to the reduction of 4.5 kg in the yield. To show the effects of the farm size and land fragmentation on the production costs the variance analysis test, as well as Duncan ’s multiple rang test was applied. The farms were grouped on the basis of their size and on the number of fragments, and then the above-mentioned tests showthe difference of average cost between groups significant i.e., the average cost of one hectare in the farms with different sizes and different numbers of fragment are not equal. The least production cost was obvious in farms with 4-5 hectares and by increasing the number of farm fragments beyond 4 blocks, the production costs increases.

In the process of non-petroleum exports expansion of Iran, target markets determination is very important. Pistachio is one of most important non-petroleum exports of Iran. Main objective of present research is to investigate the market structure of pistachio and ranks of exporting target markets of Iranian pistachio in order to catch increased export earnings for the country. The investigation period is 2002 through 2006. For determination of market structure Herfindahl Index, Concentration Ratio, Entropy Index, Mean Logarithm Deviation were applied. Also to rank the exported target markets,Riddling approach and Numerical taxonomy analysis were applied. The results of market structure show Irans’ export structure changes from close oligopoly to open oligopoly through the studied period; and the UAE, Hong Kong, Germany, Spain, Italy and Russia were the biggest commercial partners of Iran. Worldwide structure of pistachios’ exports during this period always followed a dominant firm condition for Iran as she, solely owned 60 percent of the world exports of pistachio.Finally, the results revealed that Hong Kong, Lebanon, Portugal, Ukraine, South Korea, Jordan, Hungary, Italy, Greece, and Poland were selected as Irans’ pistachio exports target markets priorities respectively.

Capital is one of essential elements in agricultural production process and the bank system is the most important resource for meeting this need, but with respect to investment limitation that our country and producers are facing, efficient usage of capital resources that are given to farmers is tremendously important Because it will result in meaningful increasing in production and setting a developed and proper production system. According to what is mentioned, studying farmers` efficiency in using production element, specially capital can be of use. The goal of this project is searching into efficiency of capital using by farmers of Sarab. According to that we applied Cobb-Timer approach which used a Cobb-Doglass frontier production function and extracted capital efficiency. As it turned out, capital efficiency of under-studying area was 71.62 % and farmers applied 164937.47 Rials extra capital resource. It means that any improvement in efficiency and management in production process, can increase productivity and yield.

The feasibility study to extension privatization of agriculture in areas of East Azarbaijan province with the view of farmers implemented and review of the literature showed that agricultural extension privatization in the areas is possible with grain culture or crops with post harvesting industries. To get a statistical sample first these regions in the province selected and then using cluster sampling method was. Most cultures of these two types of product for each region were wheat and grapes, so the contacts between these groups were selected. Statistical analysis showed that in general, these regions for acceptance of private services by farmers is not so ready (M=2.93) and two regions of sample, in terms of establishing the possibility of private extension level, haveno difference together. The distance from agricultural areas to extension center to the possibility of privatization does not affect (r=0.83) and what extent of land a farmer is more, more willingness to use private services has been shown (r=0.103); Public extension services is more accessible to large farmers that as a barrier to the possibility of privatization was considered for these farmers. Farmers literacy rate also had no affect but familiar experience for this services, had positive effect (r=0.19).Membership in the organization of rural farmers (X2=49.88) the type of exploitation of farmers (X2=38.3) influenced the possibility of privatization and everything farmers to extension (r=0.653) and its function (r=0.529) and to private extension (r=0.441) have a better view, more is possible privatization. The income of farmers (r=0.112) plays an important role.

In general, the policy set of Iranian government is to chase the principles of sustainability on the way to protect the environment and to achieve sustainable agriculture. But in some cases the onfarm operations are finished as such that the environment tolerates some damages. Hence, to increase production efficiency with some welfare effects, more serious pursuing of the principles of sustainability on farm and village levels by authorities is necessary. The applicability of sustainable agriculture operations mostly depend on the adoption by farmers. The aim of this research was to determine the magnitude of the effect of factors on adoption levels of sustainable agriculture operations within dry-farmed wheat farmers of Marand County. The required data and information was gathered through the completion of designed questionnaire from a sample drawn by two stagerandom sampling method by on-farm visiting of 185 dry-farmed wheat farmers in 2006-2007 production year. In this research logit regression models were fitted with the use of maximum likelihood method. The results show that, education levels of the farmers, participation rates in extension classes, insuring of products, total annual income, had positive significant and agricultural occupation had negative significant effects on the adoption levels of sustainable farm operations. Thus the development of product insurance systems gnducting, more extension and education classes, more long-term grants, lower interest rate credits, and setting some relevant infrastructural backgrounds for income augmentations in non-wheat enterprises is recommended to pursue by planners for the development of sustainable on-farm operations.

This experiment was conducted to study the method of seed reserves partitioning and its effects on the early vigor of seedlings of five winter wheat cultivars (Azar-2, Sabalan, Sardari, Alvand and Zarrin) in a completely randomized design during 2004. Results revealed that, seed dry weight (SDW) decreased through the time in all of the cultivars and approximately 7.7-9.7 % of total seed weight (TSW) was formed by structural compounds. Reduction of SDW was continued up to 15- 18.25 days after soaking and later on, the seedling dry weight got an enhanced trend as the seedlings reached to the autotrophy phase. Furthermore, wheat cultivars followed similar style in root/shoot and TLW/TDW ratios. Also, the cultivars were similar in the amount of seed reservesconsumption (89-92%), but were different in the rate of seed resources consumption. Moreover, leaf emergence affected seed reserves partitioning to the other organs. Accordingly, by leaf emergence a peculiar portion of the reserves allocated to this organ. In addition, results showed that the conversion efficiency of seed reserves to the seedling structure ranged 32-68 % in all the cultivars, in which, the maximum and minimum conversion efficiency achieved for Azar-2 and Alvand cultivars, respectively. The noticeable difference among the cultivars from this point of view could be due to the method of reserves allocation to growth and/or maintenance respiration. Also, thegrowth and maintenance respiration of the studied cultivars ranged from 21.9-44.7% to 55-78.1 %, respectively. Based on the results, it could be stated that, there is a direct relationship between conversion efficiency and growth respiration. However, cultivars with the highest growth respiration were usually produced strong seedlings. Among the cultivars, Azar-2 had the highest conversion efficiency, which was significantly different from the others at 5% probability level.Strong early vigor in cereals would cause reduction of herbicide application, enhancement of water use efficiency as well as improvement of transpiration efficiency and finally the yield increase. Among the cultivars tested in this study, Azar-2 showed better early vigor. However, to attain the optimum yield, evaluation of other wheat cultivars is recommended.

In order to investigate genetic variance components of agronomic traits in sugar beet, five o-type monogerm lines were crossed with 15 CMS monogerm lines on the basis of design II and 75 F1 hybrids were obtained. 75 hybrids were divided to three sets with 25 hybrids in each set and were evaluated in a randomized complete block design with four replications in Abdol-Rasoul Motahhari Research Station, Karaj. In this study, root yield, sugar yield, white sugar yield, sugar content, white sugar content, potasium, sodium, nitrogen, potasium/ sugar content ratio, sodium/ sugar content ratio, nitrogen/ sugar content ratio, alkalinity, purity, molases, root length, root diameter, crown length and crown diameter were calculated. Genetic analysis showed the significant efect ofmales for sugar content, white sugar content and nitrogen traits at 1% probability level and for sodium and purity triats at 5% probability level. Males×Females was significant for white sugar content at 1% probability level and for white sugar content, sugar yield and sugar content in 5% probability level. Additive genetic variance was only significant at 10% probability level for purity and at 12 % probability level for sugar content, white sugar content and nitrogen. Also, dominance variance was significant for white sugar content at 5% probability level and for white sugar yield and sugar content at 12% probability level. Narrow sense heritability of sugar content, white sugar content and nitrogen was significant at 12 % probability level and the rest of traits had low narrow sense heritability. Results of this study revealed that the amount of additive and dominance variances in monogerm germplasm of sugar beet was not large and for impoving genetic basis ofagronomic traits in monogerm gelmplasm, we should use new monogerm germplasm or multigerm genotypes.

(CRM) and N fertilizer on yield and yield components of canola. Field experiment was carried out on Farm Research Station, College of Agriculture at Shahid Chamran University, during 2006-2007 and 2007-2008. Wheat crop was planted in first year and followed by planting canola in second year. The experiment design was a randomized complete block with 3 replications as a split plot. Crop residue management (incorporation, removal and burning of wheat residues) was main plot and N- splitting (the source of nitrogen was 150 kg/ha urea) was subplot including: (1) 50% pre- planting + 50% at twelve leaf stage, (2) 25 % pre- planting + 75% at twelve leaf stage and (3) 25 % pre- planting + 50%at twelve leaf stage + 25 % pre- stem growth. Plant parameters including plant height, peduncle height, pod weight/m2, number of secondary branches, pod length, pod number/m2, seed number/pod, 1000 seed weight, seed yield, biological yield, harvest index, oil percent, protein percent, and oil and protein yield were measured. The findings in the present study showed that yield and yield components have able to perform better when the plants grown on the soil contains incorporation treatment as compared to the other treatments. A highly significant effect was obtained at N- splitting of 25+50+25 when compared to the other N- splits. The highest (4630.5 kg/ha) yield was achieved from the plants sown on the soil receiving 25+75 of N-splitting with incorporation treatment, while the lowest (1964.7 kg/ha) yield was obtained under the burning of residues from the soil having 50+50 of N-splitting. Whereas, the highest oil percent (43.15%) was extracted from seeds of the plants which were grown on the soil receiving 50+50 of N- splitting incorporation treatment and the lowest oil percent (37%) appeared to be gone from seeds of those plants grown on the soil having 25+75 of N- splitting with no residues treatment. In general, incorporation of management technique plus N- splitting exhibited a positive impact on yield and yield components of canola when compared to other treatment.

In order to evaluate the effect of different levels of irrigation and plant density on growth and grain yield of chickpea cv. Kaka, a field study was conducted at Research Field Station of Faculty of Agriculture, Mohaghegh Ardabili University during 2006 growth season. Treatments were arranged as split plot on the basis of randomized complete block design with three replications. Differentirrigation levels (full irrigation, irrigation to flowering stage, irrigation after flowering stage a nd noirrigation) were assigned to main plots and sub-plots comprised of plant densities of 16, 32 and 64 plants/m2. Results showed that dry matter accumulation (DMA), crop growth rate (CGR) and relative growth rate (RGR) were considerably decreased as water deficit increased. The treatments of full irrigation and no-irrigation had the highest and the lowest of these indices, respectively. Also the values of these indices for irrigation to flowering stage were more than that irrigation after flowering stage. In all irrigation levels, the highest DMA and CGR were obtained at 64 plants/m2, but the highest RGR was achieved at 16 plants/m2. At various irrigation levels, differences between densities were higher at early stages of growth for RGR. However, this difference for RGR gradually decreased with increasing days after planting. Grain yield per unit area also was significantly reduced due to water deficit. Grain yield in full irrigation and irrigation to flowering stage were more than that other irrigation levels. Increasing plant density resulted in increasing grain yield per unit area as grain yield at 64 plants/m2 was significantly more than other densities.Interaction effects indicated that the highest and the lowest grain yield were achieved in 64 plants/m2 with full irrigation and 16 plants/m2 with no-irrigation, respectively. However, there was no significant difference between 64 and 32 plants/m2 in treatment with no irrigation. It was, therefore, concluded that according to water limitation in Iran, irrigation to flowering stage and 64 plants/m2 can be used to produce reasonable grain yield under the conditions of this study.

This study was conducted to evaluate the effects of sowing date and density on forage sorghum yield in 2006 at Agricultural Research Centre of Jahad-Keshvarzi, Ardabil. The factorial set of treatments was arranged by a randomized complete block design with three replications. Factors consisted of sowing date at three dates of 8, 15, and 22 May, and density at three levels of 6, 12, and 18 plants/m2. Results showed that sorghum can be harvested twice in the environmental conditions of Ardabil during growth season. Sorghum forage yield was significantly affected by harvest, time sowing date, density, and harvest time × density. Forage yield at the first harvest was more the second harvest than. The highest and the lowest forage yields were related to 15 May with 12plants/m2, and 22 May with 6 plants/m2. It canbe probably attributed to suitable seed germination and seedling emergence in 22 May, and less intraspecific competition and more produced tillers at 12 plants/m2 as comparied to 18 plants/m2. Plant height was increased as Plant density increased. At the first harvest, it was more than the second. As sorghum density increased, % stem weight and stem diameter were inceased and reduced, respectively. Also, % leaf weight was decreased by increasing sorghum density.

To evaluate the response of hulless barley promising lines to water deficiency stress, 15 genotypes were assessed under three irrigation regimes (complete irrigation and water stress at booting and grain filling stages) at field and greenhouse conditions using split-plot design arranged in randomized complete blocks with three replications. The result of analyses revealed significant differences among the genotypes for all of the studied characters. Based on the combined data mean comparison, genotypes 1, 2, 3, 5, 6, 11 and 12 showed the highest yield. However, among these genotypes, the minimum yield reduction under the stress conditions compared with the normal irrigation was observed in lines 3 and 10. Therefore, these lines can be used as promising genotypes in breeding program for improvement of drought tolerance and as parental lines for mapping of genes involved in drought tolerance. Genotype ranking based on the characters evaluated at the field and greenhouse revealed the highest ranks for genotypes 1, 3 and 5. The result indicated that these lines have other desirable characters such as harvest index, biomass and tiller beside high yield.

In order to study the relations between yield and yield components of maize, seven inbred lines and seven hybrids progenies of crossing between them and four open pollinated F1 hybrids: SC 301, SC 604, SC 647 and SC 704 were grown in an unbalanced grouped design with three replications. The analysis of variance showed significant difference among groups for most of studied characters that indicated the existence of genetic variation among varieties. Genotypic correlation coefficients indicated that grain yield had a significant positive correlation with kernel number per row, number of kernel rows per ear, kernel depth, and plant height as well as with % oil. Also, grain yield had a significant negative correlation with % protein. Considering grain yield as a dependent variable, while using stepwise regression analysis, 92.2% of grain yield variation was attributed to two traits, kernel number per row and row number per ear and the model was significant at 1% probability level. Path coefficients analysis showed that the kernel number per row had highest direct effect. This trait had negligible indirect effects through kernel row number. Genotypes and traits were classified in three clusters by cluster analysis. In conclusion the most important traits contributing to grain yield in corn were kernel number per row and row number per ear which could be used for indirect selection of grain yield.

To evaluate the effects of planting date and cultivar on qualitative and quantitative yield of soybean for forage as a summer cropping, an experiment was carried out in factorial, based on randomized complete block design with three replications. The planting dates (22 Jun, 1Jul and 11Jul) and cultivar (Williams, Telar and TNS). Were constituted the experimental factors. Seeds were planted in experimental field of university of Tabriz on 2004. The results showed significant difference among planting date and cultivar for dry matter (DM) and percent of stem DM, pod DM and leaf DM. The results showed that the highest amounts of dry matter yield were obtained from 22 Jun and cultivar Williams. Maximum percent of pod DM belonged to Williams and planting date 22 Jun. Maximum percent of leaf DM was obtained from planting date 11 Jul, by cultivar TNS. However minimum percent of stem DM was obtained from 11 Jul (the same with 1 Jul) and cultivar Williams (the same with Telar). The planting date * cultivar interaction was nonsignificant for all the traits.

In order to study the effect of tillage methods on crop yield and soil physico-chemicalcharacteristics in wheat-sunflower rotation, this research was conducted in Kalpoush region of Shahrood for four years. The experimental design was RCBD with five replications and four treatments. The treatments were no-tillage (T1), minimum tillage (T2) and conventional tillage with and without gathering residue (T3 and T4). Wheat (Alvand) was planted at autumn 2002 and 2005 and sunflower (Progress) at spring of 2005. Combination analysis of soil moisture content at various soil depths showed that soil moisture content at the 10-20cm in reduced tillage was higher than conventional tillage (at 5% level). At the 50-70 cm, soil moisture content in T1 was significantly (p<.01) lower than other treatments. Wheat yield difference in 2003 was significant (at 5% level) among the treatments. Maximum and minimum crop yield belonged to T3 (3880 kg/ha) and T1 (3170 kg/ha), respectively. Sunflower yield and seed oil percent differences were significant at 1% and 5% levels, respectively. Maximum and minimum yield was obtained at T2 (1683 kg/ha) and T3 (1279 kg/ha), respectively. Sunflower yield difference in T1 and T2 was not significant. Maximum and minimum sunflower yield belonged to T2 and T4, respectively. The results indicated that cone penetration resistance was affected by tillage methods. At the depth of 0-20 cm, minimum and maximum penetration resistance rate was revealed for T3 and T2, respectively. Regarding high soil fertility in the area under study and wheat yield during 2003 and 2005 in reduced tillage treatment, it can be recommended that moldboard plough can be replaced by disk harrow.

In order to study the effect of seed specific gravity on characteristics such as seed germination, yield, yield components, biological weight and harvest index in four dry land wheat cultivars, Sardari, Sabalan, Azar and Azar 2, a test for separating the seeds based on the specific gravity and two field and laboratory tests were accomplished as a factorial experiment with 12 treatments (4 cultivars & 3 specific gravity) in 4 replications. The results of laboratory test showed that specific gravity of seed had effect on percentage and speed of germination and the effect of cultivar, specific gravity and interaction effect of specific gravity and cultivar on these two properties was significant. Azar cultivar had the highest and Sabalan cultivar had the lowest percentage of germination. Azar cultivar had also the highest and Sabalan cultivar had the lowest speed of germination. In all cultivars except Azar, heavy seeds had more speed and percentage of germination than light seeds. The results of farm test showed that specific gravity of seed had noeffect on characteristics such as number of spikes on unit area, number of spiklets per spike, number of seeds in spikelet, biological weight, thousand seed weight, yield and harvest index.

To determine chromosomal regions controlling important agronomic traits in rapeseed, eight winter rapeseed cultivars along with their F1 hybrids resulted from a complete diallel cross were evaluated using simple lattice design with two replications. Significant difference was observed among genotypes for all the studied traits. General combining ability was significant for all the traits except percentage of oil and specific combining ability was only significant for 1000 grain weight. Parental polymorphism evaluation by 78 polymorphic microsatellite markers resulted in 359 alleles with allele number ranging from 2 to 9 and an average of 4.22 alleles per locus. Polymorphic information content ranged from 0.21 to 0.84 with an average of 0.60 and gene diversity showed variation from0.24 to 0.86 with an average of 0.65. Based on molecular data, the highest and lowest similarities were observed between Orient and Geronimo and Sunday and Geronimo cultivars, respectively.Genetic distance between parental lines was separated into general and specific genetic distance based on Griffing’s method, mixed model B. Analysis of phenotypic and genotypic data relationships revealed significant and positive correlation between general molecular distance and general combining ability for pod number per main branch. Stepwise multiple regression analysis identified one to eight informative markers for the studied traits and chromosomal region associated with marker Na12-G08 showed the highest additive effect on number of pod in main branch. The most of positive markers detected for yield and yield components showed over-dominance geneeffect.

Water resources are limited in many agricultural areas of Iran and effective use of this scarce resource is very important in this country. Therefore, a split-plot experiment with randomized complete block design in three replicates was conducted in 2007 at the Research Farm of the Faculty of Agriculture, University of Tabriz, to investigate the effects of different irrigation regimes on ground cover and grain yield of three faba bean cultivars (Faranseh, Barekat and Saraziry). Irrigation treatments (I1, I2 and I3: Irrigation after 70, 100 and 130 mm evaporation from class A pan, respectively) and faba bean cultivars were allocated to main and sub plots, respectively. The results indicated that all traits (except grains per pod) were significantly affected by irrigation. Percentage ground cover, pods and grains per plant, biological and grain yield per unit area and harvest index under full irrigation (I1) were higher than those under limited irrigations (I2 and I3).Differences in ground cover among irrigation treatments and cultivars at the early stages of growth were low, but increased with progressing the growth and development of plants. Pods per plant and harvest index did not differ significantly among cultivars, but other traits were significantly affected by cultivar. Barekat with the highest yield per unit area under all irrigation treatments was a superior cultivar compared with Faranseh and Saraziry. This superiority could be attributed to the higher ground cover and biological yield and production of larger and more grains per plant.Percentage ground cover, yield components and grain yield of Faranseh were more than those of Saraziry, although differences in grains per plant and grain yield between these two cultivars were not statistically significant.

In order to investigate the effect of different irrigation regimes on some agronomical characters of three faba bean cultivars, an experiment was conducted in 2007 at the Research Farm of the Faculty of Agriculture, University of Tabriz. The experimental design was a split plot with a randomized complete block arrangement in 3 replications. Irrigation treatments (I1, I2 and I3: Irrigation after 70, 100 and 130 mm evaporation from class A pan, respectively) and cultivars (Aqodolce, Barakat and Zohreh) were assigned to main and sub plots, respectively. The results indicated that grain filling duration, maximumgrain weight, grain yield, yield components (except grains per pod), biological yield and harvest index, were significantly affected by irrigation. Grain filling duration, maximum grain weight, pods per plant, grains per plant, 100 grains weight, grain yield, biological yield and harvest index under full irrigation were significantly higher than those under limited irrigations. However, grain filling rate was similar for irrigation treatments. Grain filling rate, grain filling duration and harvest index were not significantly affected by cultivar. Barakat produced the highest number of grains per plant, 100 grains weight and grain yield per unit area under all irrigation regimes, indicating that this cultivar is comparatively superior under these conditions.

In order to study the relationship of protein diversity with morphological and agronomic traits in Phaseolus vulgaris, 70 genotypes were evaluated. Samples of seed proteins were prepared by two consecutive extractions of 0.2 and 1 M NaCl of salt soluble proteins. Most of the genotypes showed two different protein patterns. Hotteling T2 for comparison of two groups with or without a special band based on agronomic and seed morphological characters showed significant differences for some protein bands. In low salt soluble proteins (0.2 M), genotypes having bands with the Rf of 7, 38 and 40 had higher 100 seed weight whereas genotypes with the bands of 38 and 40 had lowerseed numbers in comparison with genotypes presented Rf of 30 and 32. In high salt soluble proteins(1 M), 54% of genotypes had bands with Rf of 8, 24 and 26 and 46% with the Rf of 7 and 30. In his test, genotypes with lower 100 seed weight and higher number of seeds and pods per plant, had bands with the RF of 8, 24 and 26 and 7 with the RF of and 30 were associated with the genotypes having higher 100 seed weight and lower seed and pod number per plant. The largest difference between the two protein patterns were obtained for 100 seed weight which seems this charactercorresponds to the identification of two centers of diversity for P. vulgaris.

The effects of harvest time on grain yield, yield components and oil content of six rapeseed (Brassica napus L.) cultivars (Option500, RGS003, PF7045/91, Hyola420, Hyola401 and Hyola308) were evaluated in a field experiment during 2004-2005. The experiment was conducted in a Complete Randomized Block Design based Split Plot layout with four replications at Rice Research Institute of Iran, Rasht. At the end of growth season, the seeds of rapeseed cultivars were harvested based on grain moisture content of the siliques of one third of the bottom of the main stem; 1- 40% and higher, 2- 35% and 3- 25%. The results showed that cultivars, harvest times and their interactions had significant effects on grain yield, oil content, oil yield/ha and 1000s grain weight. Silique length, number of grains/silique and plant height were different in rapeseed cultivars, but harvest time and cultivar × harvest time were non-significant. Hyola401 produced the highest grain yield, oil yield, 1000s grain weight and siliques/plant (3470.6 kg/ha, 1318.7 kg/ha, 4.09 g and 259.58 silique/plant, respectively). PF7045/91 produced the highest oil content and plant height (39.93% and 139.25 cm, respectively).

In order to investigate the effects of different management methods on weed density and biomass and potato yield loss, an experiment was conducted at Research Farm, Faculty of Agriculture, Ferdowsi University of Mashhad at 2004. The experimental design was a randomized complete block with a strip split-plot arrangement and three replications. Factors included, two tillage systems (conservation and conventional) and eight weed management practices (herbicide, hand hoeing, cultivator, herbicide plus hand hoeing, herbicide plus cultivator, hand hoeing plus cultivator, reduced herbicide use plus hand hoeing, reduced herbicide use plus cultivator). Results showed that LAI and above ground biomass of potato was greater in integrated treatments until canopy closure

During 2008 a study was conducted for evaluation of the effects of osmotic potential on the growth and macroconidia production of three species of Fusarium including Fusarium semitectum, F. moniliform and F. solani, which were isolated from potato and wheat fields in Golestan province. The experiment was carrued out on soil extract agar media amended with potassium chloride and glycerol in three replicates. The result showed that osmotic potential significantly reduced (p<0.05) mycelial growth rate and macroconidia production in all examined species of Fusarium

Study on the family Sphecidae (subfamilies Sphecinae and Crabroninae) was conducted in East Azarbaijan Province during 2004-2005 which resulted in identification of 19 species. Among the collected species two sphecids Rhopalum coarctatum Scopoli and Ectemnius sexcinctus (Fabricius) and the genus Tracheliodes A. Morawitz are new records for Iranian wasp fauna. Identification as wellas illustrations of keys the species occurring in this province is given.

Population fluctuations of two parasitoid species of alfalfa weevil (Bathyplectes anurus Thom. and B. curculionis Thom.) were studied during 2002-2003 in some regions of Kurdistan province including; Mobarakabad and Karwandan, around Dehgolan, Nesareh around Divandareh, and Agricultural Research Station of Grizeh in Sanandaj. In all arens, B. curculionis had two peak populations, The first was observed at the beginnig of alfalfa vegetative period and the second was occurred one month later. B. anurus had only one peak that was occurred at May or June depending on the area It seems that B. curculionis has two generations, while B. anurus has only one. The maximum parasitismrate (obtained by rearing Hypera postica larvae that were collected weekly from different areas), was occurred after mid-May. Results showed that the lowest and the highest parasitism rates were 9.3 and 10.7% in Grizeh station and 25.8 and 33.3 % in Nesareh, respectively. Adult density as well as parasitism rate in B. curculionis was more than B. anurus, (64.4% versus 35.6%). The efficiency of these parasitoids was determined by caging method in Sadeghabad area. These results showed that the rate of parasitism was about 15% in different treatments but there were not no significant differences setween various treatments and the control group between the numbers of pest.

In order to study the pygmephorid soil mite fauna of alfalfa fields in Northwest of East Azarbaijan province including Soofian, Payam, Zonooz, Marand, Shabestar and Jolfa, soil samples were taken at three different times of the year 2006 (mid-May, mid-July and mid-September). Then pygmephoroid mites were seperated and identified. In this study five family, eight genera and 18 species were identified as fallows, of which six species are new records for mite fauna of world and three genera and 11 species are new records for mite fauna of Iran (indicated with one *). Siteroptidae: Pediculaster n.sp.; Pediculaster mesembrinae (Canestrini,1881)*; Microdispidae: Premicrodispus sp.; Caesarodispus* sp.; Pygmephoridae: Neositeroptes n.sp.1; Neositeroptes n.sp.2; Neopygmephoridae: Pseudopygmephorus* sp.; Scutacaridae: Imparipes longisetosus Willmann,1951; I. tataricus Sevastianov,1964; Imparipes. n.sp.1; Imparipes n.sp.2; Scutacarus (V.) eucomus (Berlese,1908); S. (V.) quadrangularis Paoli,1911; S.(S.) subquadratus Khaustov and Chydyrov, 2004*; S. shvicki Lazauskene and Sevastianov,1974*; Scutacarus n.sp.; Pygmedispus calcaratus Paoli,1911

Trichogramma brassicae Bezdenko is one of the most important species of Trichogramma in Iran that can be easily reared on laboratory hosts such as flour moth Anagasta kuehniella Zeller and cereal moth Sititroga cerealella Hubner. Bollworm Helicoverpa armigera Hubner, one of the most important hosts of this parasitic wasp is a serious pest of crops such as cotton, maize, and tomato. A problem often encounters in parasitoids reared on alternative hosts is declining parasitism rate on target pest following to release. It refers to weakened response of the wasp due to not being familiar to host kairomones. So, in order to overcome the problem, it is recommended that the parasitoidwas reared an additional generation on target pest prior to release. Necessity of such a quality control measure in the wasps reared on any of traditional laboratory hosts i.e. flour moth and cereal moth was investigated in this study. To achieve it, T. brassicae was reared on each of the above mentioned hosts for two sequential generations, followed by two additional generations on bollworm. Quality parameters such as developmental time, longevity, fecundity, sex ratio, and rate of adult emergence were compared among the four generations. It was revealed that wasp response to host change was different in each laboratory host. Adult longevity was the only variable that increased by host shifting from flour moth to bollworm, while fecundity and adult emergence were declined as well following host change from cereal moth to bollworm.

In this research the effect of four various tillage methods on irrigated winter wheat (Alvand variety) on the yield and its components in the Fereidan region of Isfahan was investigated. Tillage methods included: A- heavy offset disk harrow, seed spreader, light disk harrow and furrower, B- chisel plow, seed spreader, light disk harrow and furrower, C- shovel cultivator, seed spreader, light disk harrow and furrower and D-moldboard plow, light disk harrow, seed spreader, light disk harrow and furrower (conventional tillage)

The farm manager must be able to predict repair and maintenance costs. These costs can have significant impacts on replacement decisions. The purpose of this research was to evaluate MLP neural network capability in predicting tractor repair and maintenance costs in terms of with regatta tractor age. The study was conducted using field data on 17 Messy Ferguson tractors from Astan Ghodse Razavi Agro-Industry. In order to train the network, collected data were preprocessed. MLP network trained by both BB and BDLRF learning algorithm. The optimal parameters of the network were determined by a trial and error procedure. Statistical comparisons of actual and predicted test data in the test phase were carried out. The results revealed that the neural network model was capable of predicting the repair and maintenance costs with a mean absolute percentage error of less than 3.37. Also, it was found that BDLRF algorithm in comparison to BB algorithm had a better performance.