JOURNAL OF AGRICULTURAL SCIENCE AND SUSTAINABLE PRODUCTION
Year:2006 | Volume:15 | Issue:4|Papers Count:28

Study of climate and eco-physiological aspects of crops are important factors in crop production. In this case study, long term climatic data of seven meteorological stations were collected and analyzed in the study area (Moghan and Ardabil). The variables considered were: monthly mean temperature, monthly minimum and maximum temperature, potential evapotranspiration (ETP), annual precipitation, growing degree days (GDD), mean temperature of germination period, aridity index, length of growing period, ratio of autumn and spring precipitation to annual precipitation. In addition to climate factors, slope layers were derived from topography data and added to GIS. Abo, for classification of climatic variables and their spatial distribution, digital elevation mpdel (DEM) was created, then correlation between altitude and climatical variables determined. An integrated climate-site model applied to climatic suitability assessments by matching the biological crop requirements to the climate factors and topography data using a GIS (ILWIS software). Four classes of climate suitability were defined, based on published guidelines for winter wheat in the rainfed conditions. In the assessments of suitability for this crop, good management is assumed, including the use of appropriate crop varieties, fertilizers and sowing date. Irrigation and also, social and economic factors were excluded. The results showed that 10% and 33% of the study areas are highly and moderately suitable, respectively, and 33% of areas is marginally suitable and the remaining (24%) is unsuitable.

The success or failure of an aquatic weed control depends upon the concentration of herbicides and the length of time which a target plant is exposed to dissipating concentrations of the herbicide in the water column. The aim of this study was to determine the concentration/exposure time relationships for controlling Eurasian watermilfoil (Myriophyllum spicatum) and Hornwort (Ceratophyllum demersum), which grow in abundance in the Anzali lagoon, with the contact herbicide paraquat and the systemic herbicide triclopyr.The investigation consisted of 31 treatment combinations of paraquat and triclopyr concentration and exposure time. Concentration were 0, 1, 3 and 5 mg l-1 paraquat and triclopyr,and exposure times were 0, 6, 12, 24, 36 and 48 hr. Experimental results showed that paraquat with more than 1 mg l-1 and 12 hour exposure times significantly reduced shoot length and biomass of Eurasian watermilfoil and Hornwort. This experiment showed that triclopyr was more effective than paraquat and needs short exposure times to control these submerged weeds. The reduction of shoot length and biomass in Eurasian watermilfoil was more than Hornwort. The results of this experiment showed that with increasing herbicide concentration the exposure times for decreasing biomass and shoot length is reduced.

In order to evaluate the effects of cultivar and plant density on growth, development and the ratio of tuber dry weight to shoot dry weight in potato an experiment was conducted during 1996 in Bostan Abad located at 55 km east of Tabriz. A factorial experiment with randomized complete block design and three replications was used. Combinations of five cultivars; Alpha, Draga, Cozima, Morene and Auola, with three planting densities; 50000, 62500 and 75000 plants per ha-1 (27, 22 and 18 cm between plants on row and 75 cm row spacing, respectively) were used. The differences among cultivars for the number of days to emergence, tuber set and flowering, number of stems per plant and per square meter at maturity, highest length of stem in one month after emergence and at maturity, dry weight of stem and leaf per plant and per square meter in one month after emergence and at maturity and also ratio of tuber dry weight to shoot dry weight were significant. In cultivars studied, Draga and Morene had highest and lowest ratio of tuber dry weight to shoot dry weight, respectively, but the difference among Draga, Cozima and Auola was not significant. All of traits studied, except number of days to emergence and to tuber set were affected by plant density. The number of days to flowering, highest length of stem in one month after emergence and at maturity, the number of stem and dry weight of stem and leaf per square meter in one month after emergence and at maturity were incerased as plant density increased, but the number of stem and dry weight of stem and leaf per plant in one month after emergence and at maturity were lower with higher plant density. Ratio of tuber dry weight to shoot dry weight was increased by increasing plant density from 50000 to 62500 plants per ha-1, but decreased by increasing plant density from 62500 to 75000 plants per ha-1. However, the difference between plant densities of 50000 and 62500 plants per ha-1 were not significant. With respect to this experiment, planting of Draga cultivar at 62500 plants per ha-1 is recommendable for potato production under climatical conditions of Bostan Abad.  

Soil moisture- matric potential relation which is affected by hysterias is recognized as soil water characteristic curve. This curve is fundamentally important in soil physics because it demonstrates soil structure, porosity, pore size distribution and adsorption effects on soil water retention. In this investigation characteristic curves of three different textures of soils were prepared by pressure plate apparatus. Then these curves were compared to Gupta and Larson, Grigson et al. and Van- Genuchten models, and the most convenient model was identified. The Gupta and Larson model with modified coefficients produced the closest agreement between the predicted and experimental curves comparing to others. The regression coefficients proposed by Gupta and Larson for the prediction of soil moisture content in particular matric suction seems may not be generalized for all soils. Gregson et al. model resulted in satisfactory prediction but only for the sandy soil in particular moisture content and with decreasing moisture content larger deviations between predicted and measured moisture suctions were occurred. Van- Genuchten model by modifying the constant from 1 to 0.7 as n =1/0.7-m, produced better agreement between the predicted and experimental O.7-m curve in the sandy- loam soil. While for the sandy and clay soils, deviation between the experimental and the predicted curve was large.

According to the studies carried out from July to December 2000, the species Megaselia halterata (Wood) is recognized as important pest of button mushroom, Agaricus bisporus (Lange), in Karaj mushroom houses. This species was recorded for the first time from Iran in 200I. Thirty species of this family are recognized in the world in relation to the mushroom and the species M halterata is the most important pest of mushrooms in most regions of mushroom cultivation in the world. The main damage is caused by larval feeding on myceliums in the compost. Biology of the pest was studied in laboratory conditions (20±10c, Rh>80% and 16L:8D photoperiod). The results indicated that developmental time in males and females are 26.33±0.072 and 25.87±0.074 days, respectively. The incubation period, larval period (including three larval stages) and pupal period were determined as 1.82±0.058, 7.80±0.154 and 11.45±0.149 days, respectively. The adult longevity of males and females in food free condition was 1.08±0.039 and 1.25±0.063 days, in peat mass condition 2.53±0.116 and 2.26±0.13 days, in glucose 5% condition 4.57±0.127 and 4.74±0.176 days, in glucose 5% and peat mass condition 4.32±0.126 and 4.83±0.118 days and in natural condition of mushroom cultivation was 5.02±0.109 and 4.67±0.147 days, respectively. The juvenile mortality was 56.55±3.44 percent. Net reproductive rate (Ra) was calculated 8.395 and intrinsic rate of increase was 0.074.

In order to evaluate FAO proposed methods for estimating reference crop evapotranspiration (ET0) in Karkaj area, an experiment was conducted at the Agricultural :Research Station of University of Tabriz in 1997. Grass (Loium perenne) planted as a reference crop and weekly (6 to 8 days) ET0 values were computed using water balance method. Climatic data such as air temperature, relative humidity and etc. were collected from a weather station about three km west of the experiment site, and weekly ET0 were also estimated by using various FAO methods proposed in 1977 and 1998 including adjusted Blaney-Criddle and Penman, radiation, class A pan and Penman-Monteith methods. Comparison between measured and estimated ET0 values were carried out by computing percent of error (E) for the cumulative ET, and root mean square deviation (RMSD) and correlation coefficient (R) for the weekly evapotranspiration. Water balance cumulative ET0 reached to 598.5 mm. Penman-Monteith resulting in 605.2 mm possessed only 1.11% error (E=1.1) in ET0 prediction. Values of E for the adjusted Blaney-Criddle and radiation methods were close to 5%. The corresponding figures for penman (adj.) and class A pan turned to be 20.8 and 24.6 percent, respectively, meaning that these two methods produced the largest error. in cumulative ET0 prediction. Regarding weekly ET0, Blaney-Criddle with RMSD of 10.73 and Penman-Monteith with 10.71mm showed the highest degree of accuracy in ET0 prediction. Class A pan with RMSD equal to 16.9 mm indicated the largest deviations in the weekly ETopredication comparing to the measured values. Highest correlation coefficient (R=0.94) between the two sets of ET0 (measured versus predicted) occurred for class A pan method. The R values for both Penman-Monteith and adjusted Blaney-Criddle was 0.92. Considering the difficulties that encountered in class A pan installation and its maintenance on standard conditions, It seems that Penman-Monteith method would be the first choice and adjusted Blaney-Criddle the second, in predicting both cumulative and weekly ET0 for the area of study.

In order to study of adaptability, yield stability and tolerance to some environmental stresses (drought and heat) of dryland promising durum wheat genotypes, this study was conducted during two cropping seasons (2001-2003) in two separate experiments and three regions of cold dryland area (Maragheh, Sararood and Ghamloo). Experiments included seven promised durum wheat genotypes with one durum as check (Zardak) and three bread wheat genotypes (one landrace, Azar- 2 and Sardari) and conducted in a randomized complete black design with four replications. In the first experiment in each location simple analysis of variance (ANOVA) and combined ANOVA for two years were implemented. Lin and Binns parameter, coefficient of variation, and rank method were used for determination of stable genotypes. Results of combined ANOVA showed that Year (Y). Location (L), Genotype (G) and interaction effects of Y×L and Y×L×G on grain yield were highly significant (P£0.01). The highest grain yields belonged to the first year (1.880 t/ha), Sararood (2.640 t/ha) and after bread wheat varieties Azar-2(2.320 t/ha) and Sardari (2.270 t/ha), line noA (61-130/414-44//...) with 1.960 t/ha had the highest grain yield among durum wheat genotypes. Results of stability analysis with Lin and Binns method showed that lines no. 8, 7, 6 and 3 had the highest stability as compared with the bread wheat genotypes and durum check. Based on the results of rank method all durum genotypes had the lowest ral1k mean comparing with Zardak (check) and the lowest standard deviation of the ranks belonged to line no. 4. Second experiment conducted under rainfed and irrigated (sowing date and spike emergence date) conditions. Quantitative criteria of stress resistance as: stress tolerance index (SSI) and geometric mean productivity (GMP) were used for genotypes response to stresses. Results of the second experiment showed that among the durum wheat genotypes line no. 4 has the highest tolerance to environmental stresses (heat and drought). According to the results, line no. 4 can be recommended for cold dryland areas of Iran.

The seasonal change of population of the pear lace bug, Stephanitis pyri F. (Heteroptera: Tingidae), was studied in Kahriz Horticultural Station of Orumieh by weekly sampling of 100 leaves collected at random from 25 marked apple trees and counting the number of adults and nymphs during 1998-99. The host range, distribution and some biological characteristics of the pest were studied and its natural enemies were identified. The results revealed that the emergence of adults of the pear lace bug from overwintering sites and feeding on newly expanded leaves begins during mid May peaks in late May. Oviposition occurs one week after adult emergence. Eggs begin to hatch in early June with a peak in late June. Adults of the first generation begin to appear in late June. From this time on, adults as well as nymphs can be found on the leaves. The pear lace bug is distributed in orchards of the province. Damage was observed on apple, pear, cherry, sour cherry, quince, hawthorn and almond, the later beeing a new host for Iran. The bug overwinters as adults mainly under fallen leaves. The egg parasitoid Parallellaptera panis Enock, predatory bugs Stethoconus japonicus Schumacher, Orthotylus nasatus Fabricius, Zelus sp., Deraeocoris sp. and Chrysopa sp. were collected and identified as natural enemies of the pear lace bug. P. panis Enock., S.japonicus Schumacher and 0. nasatus Fabricius are new for the Iranian insect fauna.

Repair and maintenance costs of farm machinery are those expenditures necessary to restore or maintain the technical soundness and reliability of the machine. Accurate prediction of the trend for increasing R&M costs is critical to determine optimum economic life and make appropriate decisions for farm machinery. Hence, a study was conducted to evaluate a cummulative relationship between hours of use and R&M costs for 27 active tractors from two different models in Mazandaran Dasht-e-Naz Farm Company. Required data including annual usage in hours and R&M costs in each year over a ten year period and also tractors initial purchase price were obtained. By regression analysis, mathematical prediction models were evaluated along with their parameters for each individual tractor model and whole sample, separately. In all cases, power function had the best fit and performance among all statistical structures. Results revealed that the amount of R&M costs in the current study are lower than estimated costs in all other previous studies, but relatively higher than estimated costs by the prediction model evaluated by Johann Fuls in a similar survey in South Africa. The reason may be related to lower repair and maintenance wages in Iran, high quality of spare parts used and repair operations and probably good machinery management in the location under study.

Pectin due to its gelling properties is a valuable matter in food, pharmaceutical and cosmetics industries. Sunflower heads is a potential source of pectin after removing the seeds. Sunflower pectin is naturally occured as a low-ester pectin which is capable of forming the gel over a wide rang of pH, particulary near the neutral pH, in the presence of little amount of calcium into with or without adding sugar. In this research, somes pectin extraction methods of sunflower carried out by using a completely randomized design. Before pectin extraction, the milled heads of sunflower were washed in hot water to remove pigments and water soluble substances. Extraction of pectins was carried out by using the hydrochloric acid, sodium hexametaphophate (SHMP) and ammonium oxalate (AO). From extracts, pectins was precipited by acidulated alcohol, then the precipitats was washed by alchohol and was dryed and milled. The results indicated that using (SHMP) with 13, 5% yield and (AO) with 11. 6% yield, in low pH is the most effective method to extract the sunflower pectins. The chemical characterization of the obtained pectins showed that they were from a low-ester type with high percent of galacturonicacid and without amide group. The results of gel froming capability studies on pectin samples indicated that all samples were able to form gel even in the prepartions from SHMP, AO , diluted hydrochloric acid and water pectins, effected by 1% pectin, 30% sugar and 25-30 mg calcium chloride, in pH 3. Also the hypocaloric Jellies of grape juice prepared with sunflower pectin samples posses a good quality. Statistical analysis indicated that there was significantly differences at P= 1% between the extracted samples themselves and control.

The association between microsatellite markers and grain quality in rice was studied using 62 advanced backcross lines (BC2Fs) derived from cross between Teqing as recurrent parent and Tarom Molaei as donor parent. The following traits were used: Uncooked kernel length (UKL), uncooked kernel width (UKW), UKL/UKW, cooked kernel length (CKL), cooked kernel width (CKW), CKL/CKW, kernel elongation ratio (KER), kernel length difference (KLD). Two hundred thirty five SSR markers with uniform coverage on all 12 linkage groups were screened for polymorphism in the lines and parents. Amongst them 114 markers showed polymorphism and assigned for genotyping. The map length of 12 rice chromosomes was 1747.3 cM with an average interval size of 15.3 cM. Transgressive segregation was only observed for UKL/UKW, CKL, CKW, UKL. Skewness toward the donor parent was not observed for the traits under study. On the basis of traits related to cooked and uncooked grain, the results of correlation and linkage analysis showed different behavior between shape of cooked and uncooked grain. At least one QTL with additive effect was identified for all traits with the exception of CKW. These QTLs explained significant phenotypic variation of traits. We mapped one QTL for CKL/CKW, UKL/UKW, KER, two QTLs for UKL, UKW and CKL, and three QTLs for KLD.

Certain soil microorganisms during solubilizing low soluble phosphate by production of organic acids or siderophores, may also increase, availability of some micronutrients. The interactive effects of three phosphate solubilizing bacteria (PSB) species and Bradyrhizobium japonicum on yield and P, Fe, Mn, Cu, and Zn uptake of soybean (Glycin max L. CV Harcor) was studied under greenhouse conditions. In the greenhouse experiment treatments consisted of a factorial combination of four levels of PSB (without PSB Mo and three PSB species with relative high potential of solubilizing M1, M2, M3), two levels of Bradyrhizobium (without bacterium B0 and with bacterium B1 and three levels of P (P0=0, P1=29, P2=58 mg triple superphosphate/ kg soil) in a randomized complete block design with four replications. At harvest, shoot dry weight, seed weight and concentrations of P, Fe, Mn, Cu, and Zn in shoot dry matter were measured. PSB increased dry weight. P, Fe, Cu, and Zn concentrations (156%, 30%, 9.3%, 8.3, 6%) compared to the control. Bradyrhizobium had positive significant effect on these variables and also on seed weight. Dual inoculation of plants with PSB and Bradyrhizobium had significant effect on shoot dry weight, P. and Fe concentrations. Increment of phosphorus levels caused increase in dry weight. P concentration, seed weight (14%, 15%, 22%) and decrease in Zn concentration (5.5%) of plant compared to the control. Highest P concentration in plant obtained at P2 level but plant dry weight at P2 level had no significant difference with plants inoculated with PSB at P1 level. Therefore based on decrease in fertilizer applications, it could be concluded that P fertilizer application requirement for soybcan decreases about 50% with bacterium.

River flow estimation has been the interest of hydrologists for long time and several methods have been introduced. Among recent methods, artificial neural networks (ANN) and geographic information system (GIS) have drawn more attention. In this research, GIS was used to calculate the characteristics of watershed, waterways, and flow directions in order to estimate the river flow discharges. Several layers were created in GIS including DEM, flow direction, flow accumulation, flow length and stream grid. In addition, ANN model was used to simulate the nonlinear rainfall runoff phenomena in every subbasin of Gharahsoo river watershed. The outputs of each ANN models in previous section were used as input of ANN model for river flow routing in order to calculate the flow discharge in specific point of the river. In this study, Gharahsoo river was selected to test the proposed methods. The calculated results were compared with observed data and it showed a good agreement.

In order to investigate management systems of cattle-feedlot units, and estimation of their production function (P.F) and technical efficiency (T.E) throughout Iran, 229 feedlot units located in nine different provinces were studied in three group size (<30 hd's, 31-60 hd's, >60 hd's). Through comprehensive interviews & questionnaires ., available data were collected from East Azarbayjan, Esfahan, Tehran, Khorasan, Khuzestan, Semnan, Fars, Gilan & Markazee comprising about 80% of operational feedlot in the country. P.F. was estimated through the COLS method and Transcendental model and T.E. was calculated. Also the effect of different factors on working units efficiency were examined through ANOVA and Duncan's test. In this survey results showed that average T. E. for all units under study was 48%, with 18% min. T. E. and 100% max. T.E. This shows a great potential for promotion of efficiency in management of this production sector. A nonsignificant negative correlation was found between T.E. and active capacity of units. Factors like provinces, occupation of manager in non-related fields and literacy showed significant effect on T.E.

Environmental factors have main effect on growth and development of annual Medicago species. The important factors are air and root zone temperatures. In this research the effect of low air and different root zone temperatures were studied on growth and development, yield and yield components of three annual Medicago species. For this purpose an experiment was conducted in controlled growth chamber. The air temperature of growth chamber was 15/1̊ C day/night during experimental period. Three species of annual medics namely Medicago polymorpha, M radiata, and M. rigiduala, that was supposed to be adapted with cold temperate zones were used. Root zone temperatures at four levels of 5, 10, 15 and 200e were employed. The experimental plan was factorial, based on randomized complete block design with three replications. Results showed that the annual Medicago species were significantly different for dry matter and yield components. M. rigidula had more leaf, stem and root dry matter, plant height, root length, shoot/root, leaf to stem ratio and leaf area and yield than Mradiata and M polymorpha. M. rigidula may be better for ley-farming system in cold and temperate zones. The results also showed that the root zone temperature of 5°C had an adverse effect on the yield and yield components of the annual medics. In conclusion, appplication of ley-farming system is not successful in zones that soil temperature is lower than soe, especially during vegetative stages. Thus, in zones that soil temperature is more than 10°C, annual medics will have normal growth and produce suitable yield. Ley-farming system (cereal-legume rotation) could be replaced with fallow-cereal rotation.

Plant growth is a function of climate, especially temperature. Every year high damages arc occurred due to low temperatures. Prediction of chilling and freezing temperatures both in space and time is very important among the basic researches in agricultural meteorology. In this study minimum daily temperature of Ahar, Tabriz, Jolfa, Sarab, Maragheh and Mianeh Stations in East Azarbaijan were analyzed for a period of 47 years. The probabilities of first fall and late spring freezing temperatures were studied for the above stations. The results showed that first fall freezing occurs in 26th September and late spring freezing occursin 1st May. Nonexceeding probability of 25% for first freezing in Sarab is 26th September, in Ahar 18th October, in Tabriz 4th November, for Maragheh and Jolfa 10thNovember and in Mianeh 13th November, respectively. The results also showed that the occurrence of freezing temperature in this province is delayed from North to South. In relation to late spring freezing with the probability of 25% date of occurrence of this freezing are in April for Ahar, 28th March for Tabriz, 25th March for Jolfa and Mianeh, 1st May for Sarab and 24th March for Maragheh. Number of freezing days in Sarab is 213 days and the minimum number belongs to Maragheh with 134 days. Generally freezing is more probable in Northeastern part of this province.

In order to study physiological characteristics and onion yield of nine onion landraces collected from different regions of Iran (including Sefid-e-Ghom, Sefid-e-Kashan, Germes-e-Azarshahr, Dorcheh-e-Isfahan, Tarom, Germez-e-Kazeroon, Kavar, Sefid-e-Abarkooh and Horand) and one foreign cultivar (Yellow Sweet Spanish)together with the populations obtained from mass selection within each landrace (except Horand) and the foreign cultivar, an experiment was conducted with 19 treatments and four replications using randomized complete block design, in 2000 at the Research Field of the College of Agriculture, Isfahan University of Technology. Results showed that selection had no significant effect on bulb yield and infected impure, thick-neck (onions with thick and solid neck) and double bulbs. Significant differences (variation) were observed among genotypes for most of the measured characters. Among collected landraces, Kavar was earlier and Tarom was later in bulbing time. Yellow Sweet Spanish and Tarom showed the highest and lowest bulbing ratio, respectively. Kavar and Tarom had the lowest and highest percentage of thick-neck bulbs, respectively. Germes-e-Kazeroon showed the highest yield, but was not significantly different from Sefid-e-Ghom, Germez-e-Azarshahr, Sefid-e-Abarkooh and Yellow Sweet Spanish. Yellow Sweet Spanish and Sefid-e-Ghom had the lowest and highest percentage of double bulbs, respectively. Bulbing ratio had a negative correlation with the number of days to onset of bulbing, the number of leaves per plant and plant height. A positive correlation between bulb yield and plant fresh weight was observed as well. Based on cluster analysis, collected landraces were classified in three groups. Combined analysis for the three-year data (due to availability of the data from two previous years) showed that the highest bulb yield belonged to Sefid-e-Abarkooh. Yield stability of this landrace was also higher than other landraces.

To evaluate the role of sorghum density and biomass on soybean yield loss, field experiments were conducted at the Research Station of Faculty of Agriculture, University of Tabriz during 2003 and 2004 growing season. The trials were carried out using factorial experiment based on randomized complete block design with three replications. The experimental factors consisted four levels of soybean(20, 30, 40, and 50) and four levels of sorghum(O,4, 8, and 12) densities. The planting pattern was based on additive series. The results indicated that in both years and in all soybean densities, by increasing sorghum density, the soybean yield loss was increased significantly. Increasing sorghum density from four to12 plants/m2, resulted in soybean yield loss from 30% to 67% in the average of two years. In all densities, the soybean yield loss was higher in 2003 growing season as compared to 2002. The highest and the lowest yield losses were observed in 20 and 50 plants/m2 of soybean, respectively. Increase of sorghum-biomass, also increased soybean yield loss. When sorghum biomass was evaluated from 400 to 1400 gr/m2, the average of soybean yield loss in both years was increased from 28 to 72%. The results revealed that among sorghum density and biomass, the population density was a better criterion for determination of soybean yield loss.

In Vitro culture of plants is one of the excellent tools for screening resistant lines to different stresses. The first step for the production of herbicide resistant lines is introduction of a suitable medium for screening appropriate resistant cell lines. In the medium compounds, sucrose and growth regulators are the most important compounds that are effective for herbicide effects. For this reason, in the first experiment effect of sucrose rates and kind of hormone compounds in the medium on sensitivity of explants to glyphosate and metribuzin, in order to introduce suitable medium, were investigated for screening appropriate resistant ceil lines. In the second experiment, the in vitro sensitivity range of soybean to these herbicides was determined in order to introduce suitable dosage for screening of resistant cell lines. Since this herbicide affect the photosynthetic system, result of the first experiment indicated that the hormone compounds of medium that stimulate chlorophyll production in the explant, will have suitable screening resistant cell lines and in this experiment, the medium with BA stimulated chlorophyll production and the medium with 2, 4-D and kinetin prevented chlorophyll production in the explants. Also sucrose as a supplying source of carbon and energy necessary for explants, affected the sensitivity of explants to these herbicides and reduced the effect of these herbicides and, therefore, one percent sucrose was recommended. In the second experiment, sensitivity range of soybean to metribuzin and glyphosate were 1-100 mgai/l of these herbicides and in order to screen the resistant cell lines, rates of 111.4 and 31.7 mgai/l for metribuzin and glyphosate were recommended, respectively.

Metal pollution has existed since man learned how to use fire, but as a results of the industrial development the production and emission of heavy metals have increased. The major objective of this study was to determine the degree and extent of the heavy metals (Co, Zn, Cu, Pb, Cd, As) pollution in honey, pollen and adult bees in Tehran province. Samples were taken from apiaries of Karaj, Tehran, Talegan, Firozkoh, Oamavand, Ooshan, Maeagoon, Ashtehard and Lavasanat. Samples were oven-dried over night at 105°C. The samples to be analysed by ICP were digested according to the following procedure: 0.5 g. dry samples were weighted and digested in 5 ml of 65% extremely pure nitric acid. The samples were filtered and diluted to 25 ml with distilled water Results showed that samples don't have Pb, Cd, As, and Co. They were under detection limit. However, Zn was min. in the honey of Ooshan (0.033±0.006 ppm), and max. in the adult bees of Firozkoh (2.34±0.057 ppm), Cu was min. in the honey of firuzkoh (0.357±0.010 ppm), and max in adult bees of Firozkoh (0.840±0.005 ppm). The results indicated that the bodies of the adult bees were more contaminated with heavy metals as compared with pollen and the honey samples collected. Therefore, it can be concluded that the contaminating flight area of honey bees can be predicted through estimation of heavy metals in adult bees of that region.

Eight Iranian and foreign rice cultivars were crossed in a half-diallel manner. Parental lines and F1 progenies were sown in a randomized complete blocks design with three replications. After harvesting, six grain quality traits, amylose content, gel consistency, gelatinization temperature, length to width ratio and seed length were evaluated in the laboratory. Analysis of variance showed differences among genotypes. The significant GCA and SCA indicated additive and non-additive gene effects in the genetic control of quality traits. Presence of high additive effects in the genetic control of amylose content and gelatinization temperature, suggested the possibility of successful selection for the improvement of these traits. Seed width was controlled with non- additive genes effects and graphic analysis indicated overdominance gene action. Gel consistency, length to width ratio and seed length were governed by both additive and non-additive genes effects but the additive portion was higher than the non- additive variance.

To study the plant density and planting pattern on yield and its components, harvest index and seed quality in peanut, a field experiment was conducted at the Kianshahr, Guilan province at 2002. The experimental design was performed as factorial based on randomized complete block design with three replications. The treatments include planting pattern at two levels (square 1*1 and rectangular 1*3) and densities at four levels (30, 53, 83, 148 thousands plant per hectar). The square planting pattern increased significantly above ground biomass, pod and grain yield, harvest index and number of pods per plant in comparison to rectangular pattern. Plant density had significant effects on studied traits except 100 grain weight. The maximum pod and grain yield at both planting pattern were achieved at the density of 8.3 plants per square meter. Also, the above ground biomass, harvest index and shelling percent were maximized at this density. In the square planting pattern seed oil percent and oil yield were 5 and 18% greater than the rectangular pattern. Therefore, square pattern with 8.3 plant per m2produced highest grain and oil yield.

Some behavioral characteristics of Trichogramma brassicae Bezdenko were studied on two factitious host species eggs consisted of Ephestia kuehniella Zeller and Sitotroga cerealella Oliver and a natural host species eggs, Helicoverpa armigera Hubner. The experiments were carried out in a growth chamber with temperature of 25±10 C, 50±5% of relative humidity and a photoperiod of 14L:10D hours. The results indicated that T. brassicae preferred E. kuehniella eggs to other hosts, significantly (p<0.01). Functional response of parasitoid wasp to different densities of Harmigera eggs was a type II and to different densities of E. kuehniella and S. cerealella eggs was a type III. The rates of searching efficiency (a) of T brassicae on the eggs of Harmigera, E. kuehniella and S. cerealella were 0.034, 0.125, 0.107 and handling time (Th) were 1.487, 1.336, 0.961, respectively. Parasitoid interference coefficient (m) for eggs of Harmigera, E. kuehniella and S. cerealella were -0.112, -0.256 and -0.198, respectively. The per capita parasitism and per capitasearching efficiency significantly decreased as the parasitoid density increased (p<0.01).

To determine the effects of photoperiod on reproductive characteristics of Indian meal moth, Plodiu interpunctella Hubner, induding oviposition period, percentage of egg hatch and reproduction rate, the insect was reared on three pistachio cultivars (Fried and Fresh) under 12L:12D, 8L:16D and 16L:8D photoperiods under laboratory conditions of 25t1 0C,65±5% RH. The results showed that 12L:12D photoperiod, and also feeding on pistachio cultivar of Fandoghi, in comparison to other cultivars, Kalleh-ghochi and Ahmad-aghaie increased adult female reproductivity rate. Also fried pistachio caused reduction in egg deposition, development and total reproductiion of Inidan meal moth.

In order to study the effect of feeding of larval instars of green lacewing from different immature stages of cabbage aphid, Brevicoryne brassicae, on some biological characteristics of green lacewing, cabbage aphid reared on two canola cultivars, named as Hayola 308 and Hayola 401, at greenhouse conditions of 25±10C, 60±1% R.H. and 16:8 (L:D). Before begining of the main study, cabbage aphid was reared on cabbage, Brassicae oleracea var. capitata, for several generations. 20 first and second nymphal stages of cabbage aphid were reared on each canola plant at the begining of flowering stage. Adult green lacewing were collected from Khalat Pousahan Agricultural Research Station and reared on green peach aphid, Myzus persicae at greenhouse temperature and humidity conditions. Eggs of first generation of green lacewing produced on green peach aphid were used to establish the maine experiment. Petri dishes were used to study the rate of feeding of different larval instars of green lacewing from different nymphal stages of cabbage aphid. Experiment was conducted in insectarium at conditions of 25±10C, 60±5% R.H. and of 16:8 (L:D). Feeding rate of different larval instars of green lacewing on different nymphal stages of cabbage aphid was recorded every 24 hours. Results showed that the type of canola cultivar was effective on the feeding rate of larval stages of green lacewing. From nymphal stages of cabbage aphid fed on two canola cultivars. This effect could be caused by the differences of two cultivars and thereafter, the haemolymph of aphids fed on these two cultivars. Also, the results indicated that the feeding rate of larval instars of green lacewing from different nymphal stages of cabbage aphid was different. Morphological characters of cabbage aphid developmental stages can be a group of factors being effective on the feeding rate of larval instars of green lacewing. Green lacewing larvae and pupal developmental time and also longevity of adults feeding on cabbage aphids reared on Hayola 308 were almost shorter than those reared on Hayola 401. Third larval instar had the longest larval developmental period which was followed by the first and second larval instars, respectively. Adult green lacewing females resulted from the larvae fed on aphids reared on Hayola 308 produced more eggs than those reared on Hayola 401. Mortality rate of immature stages of green lacewing feeding on aphids reared on Hayola 308 was almost less than Hayola 401. Results also showed that the sex ratio of green lacewing adults emerging from aphids which were reared on Hayola308 was more than those reared on Hayola 401.