Journal of Water and Soil Science
Year:2008 | Volume:12 | Issue:45 (A)|Papers Count:34

Freezing is one of the most important climatic factors affecting almond products in Isfahan province. Therefore, it is important to use a rapid method for assessing the resistant cultivars and wild species of these plants. Evaluation of electrolyte leakage (EL) from freezing damaged tissues of almond is an appropriate method for this purpose. In the present work, the effect of freezing on the rate of electrolyte leakage of 10 cultivated almonds (Amygdalus communis cultivars) and one wild species (A. scoparia) was evaluated in Isfahan province. The perfect and mature flowers of all samples were selected at random, and examined under natural (in nature) and artificial (in laboratory) freezing treatments in 3 replicates. All measurements were done using an Ec meter instrument and the mean of obtained data was analyzed statistically via ANOVA and Tukey's tests. In each treatment, increase in the rate of electrolyte leakage of treated samples in relation to the controls was taken as a criterion for comparison. Total Dissolved Solids (TDS) of the flowers of all samples were also measured, with an accuracy of 0.001, under natural freezing conditions. The mean of TDS was 390.8±33.5 mg/L among cultivated almonds (maximum in Safari cultivar with 439±29.3 mg/L and minimum in Kababi cultivar with 355±35.3 mg/L) and 362±55.8 mg/L in the wild almond (a little less than that of the cultivated ones). Linear regression test showed that there was no correlation between TDS and the rate of electrolyte leakage from freezing damaged tissues of the studied samples. Furthermore, the results showed that the cultivars of Tageri (with 7.47% increasing), Azar (with 19.2% increasing) and Rabie (with 22% increasing) are respectively more resistant than other cultivars under natural freezing, and the cultivars of Rabie (with 60.7% increasing), Tageri (with 67.6% increasing) and Hag Mirzaie (with 71% increasing) are more resistant than other cultivars under artificial treatment.These results are in agreement with the experimental observations in the studied area. The freezing tolerance of wild species (with 48.7% and 73% increasing, respectively) was moderate in both natural and artificial freezing treatments.

Remote sensing science and satellite data are widely used by researchers for agricultural studies. Vegetation spectral reflections recorded by satellite sensors have been used extensively for identifying plant types, plant cover, health community of plants and predicting yield. The TERRA satellite, with 5 sensors, provides an opportunity to observe land, atmosphere and ocean characteristics. The Moderate Resolution Imaging Spectroradiometer (MODIS) is on-board TERRA satellite. This sensor with 36 bands by 250m, 500m, and 1000m spatial resolution help us to study our environment. The MODIS vegetation indices are used to monitor photosynthetic activity radiation, change detection in plant communities, planted area estimation and plant health. A statistical analysis was done to analyze Near Infra Red (NIR) (841-876 nm) and Red (R) (620-670 nm) bands of MODIS images for a 16 day period. The images have been used for winter wheat in Mashhad (North East of IRAN) during agricultural season of 2004-05.Some image processing techniques were used to extract the related digital numbers (DN), showing the electromagnetic spectrum reflection for all of the pixels. The analysis shows a positive correlation between R and NIR spectrum (0.70 and 0.69) and decrease in NDVI (0.18 and 0.24) in the first and late wheat growth season. However, there is not such a good correlation in the middle of the season and NDVI increased very much. In spite of having wheat cover in the field, NIR reflection decreased very much in the late wheat growth season (0.5). Therefore the correlation relation between R and NIR band along with NDVI could be used effectively in precision agriculture management such as predicting of phonological stage, wheat yield estimation and wheat health condition.

To improve a complex character such as yield with low heritability, the use of indirect selection through other characters and a selection index based on different effective traits is recommended. This study was conducted to evaluate different selection methods by using 23 F2:4 wheat lines derived from the cross of Virmarin (susceptible cultivar) and Sardari (tolerant cultivar) at Research Farm of Isfahan University of Technology. A randomized complete block design with three replications was used in two irrigation treatments (i.e. irrigation after 70±3 and 120±3 mm evaporation from class a pan). For each irrigation treatment, different selection indices were constructed based on the number of spike per m2, days to heading, number of grain per spike and 1000 - kernel weight. Also direct and correlated responses were calculated for these traits. The results of the response to selection and correlated response indicated that in the same conditions of this study, early heading cultivars with high number of spikes and low number of grain per spike with high 1000 - kernel weight will have more yield potential. Number of spike per m2 and 1000 - kernel weight exhibited positive response in most of the indices and both irrigation treatments, while days to heading and number of grain per spike revealed negative responses. Thus selection based on these indices would result in early heading cultivars with high spike per m2, low number of grain per spike and high 1000 - kernel weight. It was also found that Smith-Hazel and Brim-Williams indices had the highest efficiencies.

Concerning the effects of increasing the species number on the maintenance of ecological stability and agricultural ecosystems sustainability, two field studies were conducted in 2002 and 2003 to evaluate the effects of plant population densities on soybean and sorghum intercropping at the Research Center, the Faculty of Agriculture, Tabriz University, Tabriz, Iran. Cultural pattern was an additive series. The factorial set of treatments was arranged within a randomized complete block design with three replications. The first factor comprised soybean densities of 20, 30, 40, and 50 plants/m2, and the second factor consisted of sorghum densities of 0, 4, 8, and 12 plants/m2. The results indicated that both soybean and sorghum yields were significantly affected by soybean and sorghum densities. Soybean yield increased as density increased up to 40 plants/m2, and then decreased with increasing soybean density from 40 to 50 plants/m2. With increasing soybean density, sorghum yield was decreased. Sorghum and soybean yields, respectively, increased and decreased as sorghum density increased. On the other hand, Soybean and sorghum densities of 20:4 (1.6) and 50:12 (0.8) had the highest and the lowest LER (Land Equivalent Ratio), respectively. It was, therefore, concluded that intercropping of Soybean and sorghum, is more advantageous, compared to their pure cultivation in the same conditions.

In order to study the genetic diversity of 75 Iranian rice genotypes (45 Iranian land race, 25 improved cultivars, and 5 exotic cultivars) with respect to their salinity tolerance at seedling stage and to determine tolerance indices, based on biomass, genotypic code and Na+/K+ ratio a factorial experiment in randomized complete block design with three replications was conducted under control and salt stress (1.2, 4 and 8 dSm-1) conditions at Rasht Rice Research Institute.Root and shoot length, root and shoot dry weight, Na+ and K+ concentrations, and genetic score were studied.Significant differences were detected among genotypes for all traits. Shoot length and K+ concentration had the highest and lowest heritability estimates, respectively. Genetic score under salinity stress showed that Tarom-mahalli, Gharib, Shahpasand Mazandaran and Ahlami-Tarom with more biological yield root and shoot lenghes, and low Na+/K+ ratio were tolerant. Khazar, Speedroud, IR28 and IR29 were the most sensitive cultivars. Tarommahalli, Ahlamitarom, Rashti and Chparsar had low tolerance index, mean productivity, stress sensitive index, geometric mean index, stress tolerance index and harmonic mean for genetic score, whereas Khazar and Speedroud had high values for theses indices. Cluster analysis, based on seedling traits at 4 and 8 dS.m-1 divided the genotypes to three groups. Tolerante group had low genetic score and Na+/K+ ratio, but high root and shoot dry weight, biomass, root and shoot length.

In order to study the effect of planting dates and genistein on nitrogen content and nodulation of three annual Medicago species (Medicago polymorpha cv. Santiago M. rigidula cv. Ragidula, and M. radiata cv. Radiata), an experimental study was conducted during 2004-2005 on the Research Farm of Faculty of Agriculture, Tarbiat Modares University, Tehran (35o431N and 51o81E). The factors were arranged as split-split plot in a randomized complete block design with four replications. Planting dates (February 20, March 1 and 11) were randomized to main plots and three annual medics were located in sub-plots, and genistein (0 and 20 mM) was randomized to sub-sub-plot units. Plant nitrogen contnt, nodulation and other traits were significantly different in species and M. polymorpha was better than other species in view of dry nodule weight, nodule number, nodule number in each cluster, nodule cluster number and nodule diameter.Medicago rigidula had more resistance to cold than other varieties, and its forage yield and nitrogen percentage were better than M. polymorpha. Therefore, M. rigidula may be better suited for cold zones. Twenty mmol genistein had remarkable effect on nodulation and nitrogen percentage of annual medics in comparison with control. The result showed that genistein modified negative effect of low temperature environment on nodulation and nitrogen percentage of annual medics. Nodulation and nitrogen percentage increased in all varieties at the first planting date. This finding emphasizes that genistein has a considerable effect on cold resistance establishment in varieties for improving nodulation and increasing plant nitrogen percentage in farm condition.

Rapeseed (Brassica napus L.) is one of the oilseed crops in the temperate regions and is adapted to different climate conditions. This crop can have an important role in production of vegetable oil, and providing appropriate soil fertility can increase its seed and oil yield. In order to investigate the effect of N, P, K, Fe, Zn and Mn on seed yield and other agronomic traits of rapeseed, an experiment was carried out at the Research Farm of Isfahan University of Technology in 2006. The experiment was arranged as split plot in a randomized complete block design with three replications in which eleven fertilizer treatments and two cultivars of rapeseed (Ocapi and Zarfam) were considered as the main and sub factors, respectively. The results showed that there was no significant effect of fertilizers on days to maturity, but application of NPK+Fe significantly increased the plant height in both cultivars. The fertilizer treatment had no significant effect on the number of pods per plant and seeds per pod. The interaction effects indicated that application of N, P, K, NP and NK significantly increased 1000-seed weight in Ocapi cultivar; however NPK+Fe significantly decreased 1000-seed weight and non significantly increased seeds per pod in Zarfam cultivar. Application of N, NPK and NPK+Fe increased the seed yield by 13, 7 and 43%, respectively. Averaged over two cultivars, N significantly increased seed oil content, but significant interaction between fertilizers treatments and cultivars indicated that application of K and NP significantly reduced the seed oil content in Zarfam cultivar. Fertilizer treatments of N, NPK and NPK+Fe had higher effects on seed oil content and oil yield and means of these traits for fertilizer treatments of control, N, NPK and NPK+Fe were 39.7, 41.7, 39.4 and 39.8%, and 681.1, 816.4, 730.2 and 983.3 kg/ha, respectively which indicate that N and Fe increased the seed and oil yield in both cultivars. However, the application of Zn and Mn had no significant effect on seed yield and seed oil content. In this study, the variation of seed yield and oil yield was mainly due to the variation of number of pods per plant and seed yield, respectively. In conclusion, it seems that in soil and climatic conditions like this experiment, application of N and Fe can be economically important and increase the seed and oil yield in rapeseed.

To study the effects of plant densities and planting orientation on the seed and forage yield of sorghum, an experiment was conducted at Hossein- Abad - Shahcal village - 90 kilometers south of Bam-in 2002. The experiment was a factorial with randomized complete block deisgn and three replications. The treatments were: orientation with three levels (South-North, East - West, Northeast - Southwest) and plant densities with four levels (50000, 70000, 90000, 110000 plants per hectare). Results of analysis of variance showed that planting orientation had significant effects on seed yield, weight of 1000 seeds, number of tillers, dry matter yield, length and diameter of shoot. Mean comparisons, showed that the maximum and minimum amount of the above mentioned traits except for shoot length was obtained under the North-South and East-West orientations, respectively. Significant differences were also found among densities in terms of all the mentioned traits. Results showed that increasing density decreased seed yield, weight of 1000 seeds, number of tillers and shoot diameter. The highest and lowest values (except of seed yield) were recorded for 50000 and 110000 plants/per hectare, respectively. Dry matter yield and the shoot length increased with increasing density. Based on the results of this experiment, the best plant densities to obtain the highest forage and seed yield are 70000 and 110000 plant per hectare, respectively and the best planting orientation is North-South.

In order to study agronomic and morphological traits in maize hybrids in Hammedan, two early (108 and 301), three medium (604, 647 and TWC647) and two late maturing (704 and 711) hybrids were evaluated in a randomized complete block design with three replications in Agricultural and Natural Resources Research Station in Hammedan in 2005. 33 morphological and phonological traits were recorded from 10 plants randomly selected from two central rows of each plot. The maximum and minimum grain yield was obtained from SC647 and SC301, respectively. The grain yield had the highest correlation with dehusked ear weight. Factor analysis of data after varimax rotation identified four factors that accounted for 98.03% of total variance. The scatter plot of hybrids based on the two first factors (the seed yield factor and phenological structure factor) showed that SC704 had the maximum forage yield and the best physiological characteristics and SC647 had the maximum grain yield, cob diameter and number of seed in row.

Improving the drought tolerance of barley varieties through the integrated efforts of plant biotechnology and conventional breeding is an important objective in barley breeding. One hundred and fifty eight doubled haploid lines of barley were mapped with 50 SSR and 93 AFLP markers. Agronomic traits such as early growth vigor, plant height, peduncle length, extrude of spike from flag leaf, spike length and kernel per spike were evaluated at ICARDA research stations, Tel Hadya and Breda, during 1382-1383. Genetic correlation between grain yield and considered traits suggested that important traits for high yield in both stations were rapid early growth, short plant height, more extrude of spike from flag leaf, and more kernel per spike. But peduncle length exhibited a different role in both environments.For plant height, eight Atlas on chromosomes 2, 3, 4, 5, 6 and 7 were identified in Tel Hadya and Breda. Two of these QTLs were shown co-located with peduncle length QTLs. The QTLs which is linked with Bmag13 marker on chromosome 2, explained 42 percent of phenotypic variation for kernel per spike in Tel Hadya. Identification of these QTLs for agronomic traits is the first step to analyse and dissect more complex characters for barley adaptation to drought stress conditions.

To study the effects of planting date and density on yield and its components in chickpea (Cicer arietinum L.) genotypes under dryland conditions of Khorram-Abad, an experiment was conducted during 2005-2006 growing season at the Agricultural Research Station of Lorestan Weather Department. Three sowing dates (March 6, March 21, and April 5) and two chickpea genotypes (Greet and Flip 93-93) with four plant densities (18, 24, 30 and 36 plants m-2) were evaluated using a randomized complete block design with split-factorial design in three replications. Dates of planting were considered as the main plots, genotypes and plant densities were randomly distributed in sub-plots with factorial arrangement. The result showed that delay in planting from March 6 to April 5 significantly reduced number of pods per plant, number of grains per pod, 100-grain weight, grain yield and dry matter. Increasing plant density led to a significant decrease in number of pods per plant, number of grains per pod and 100-grain weight. However, grain yield and dry matter increased firstly with increasing plant density and then decreased. Planting date and density had no significant effect on harvest index, while genotype of Greet produced a larger number of pods per plant, grain yield as well as final dry matter. Also Flip93-93 produced a bigger number of grains per pod, greater grain weight and harvest index. The maximum grain yield was obtained with genotype of Greet at the first planting date in 30 plants m-2 density.It could be concluded that due to thermal and drought stress occurring in late spring, early planting of Greet genotype at 24-30 plants/m2 may lead to a suitable increase in grain yield.

In order to investigate the diversity and relationship between agronomical traits with seed yield components in barley, twenty advanced barley lines were evaluated in a randomized complete block design with 3 replications at Research Center of Agriculture in Sistan in 2006. Each plot consisted of six rows spaced 20 cm apart and 5 meters long. In this research, 24 Agronomic traits were measured on five randomly selected plants in the central rows of each plot. Analysis of variance showed that there were significant differences among the lines for most of the traits. Line No.7 had the highest (406 grs/m2) and line No.5 had the lowest (309 grs/m2) seed yield. There were high correlation between seed yield and number of panicle/m2. Factor analysis results indicated that 7 independent factors explained 82 percent of the total variation. The first two factors, namely yield components and tillering capacity, explained 41 percent of the total variation. Therefore, it can be concluded that the traits are related to seed yield and tillering capacity, i.e., number of seed per main panicle. 1000 seed weight, number of seed per plant, number of days to physiological maturity and days to heading are the most important characteristics in selecting lines with high seed yield. Number of fertile tiller, total number of tillers and peduncle length were also next set of important traits. Number of days to emergence, nodule number and number of panicle per m2 were also important as selection criteria. Seed weight per plant, biological yield, awn length and the traits that were related to flag leaf had lower importance for selection of lines with high seed yield.

The genetic diversity of major crops, including durum wheat, has suffered an overall reduction with time. The knowledge of patterns of genetic diversity enhances the efficiency of germplasm conservation and improvement. In this study, 87 Iranian landraces of Triticum turgidum var. durum originating from different geographical areas of Iran, along with 21 durum cultivars from ten countries were evaluated using ten primer combination SSAP markers.Retrotransposons are mobile genetic elements that transpose via RNA mediation. They have wide distributions in genome because molecular markers have been designed based on them in recent years. SSAP markers BARE-1, Thv19, Tagermina and Tar1 were also used. Thv19\M+ACA primer combination had the most polymorphic band in both landraces and cultivar durum wheats. Approximately 26.7 % BARE-1 bands were polymorphic in landraces. Thv19 showed a polymorphism level of 51.5%, and Tar1 and Tagermina displayed polymorphism levels of 32.8% and 27.2%, respectively. The amount of polymorphism in the studied cultivars for retrotransposons BARE1, Tagermina, Thv19 and Tar1 were 24.4%, 24.3%, 51.5%, 28.5%, respectively. This results show that Thv19 and Tar1 have more transpositional activity in the evolutionary process. Finally, Dendrogram was constructed to use algorithm UPGMA and Dice similarity coefficients.

Field crop landraces are valuable genetic sources. Twenty populations of Persian clover (Trifolium resupinatum L.) collected from different areas of Iran were used in this study. DNA extractions were carried out using minipreparation method with equal amount of leaves from 30 plants of each population. DNA samples from 20 clover populations were evaluated using semi-random (ISJ) markers. Ten primers out of 30 which used IT (intron-targeting) and ET (exontargeting) primers produced repeatable bands. Cluster analysis was conducted using NTSYS software and UPGMA method based on Jaccard's similarity matrix. Primers totally produced 111 bands, of which 93 bands (%93) were polymorphic among clover genotypes. The greatest and least amplification fragments belonged to IT15-31 and ET18-4 primers, respectively. Average band number per primer was estimated 11.1 bands. Furthermore, IT primers produced more polymorphic DNA fragments with higher resolution. Based on cluster analysis and cutting dendrogram in 0.8 similarity coefficients, clover populations were divided into five groups in which Kazerun and Kermanshahi (1) individually formed a separate cluster. According to similarity matrix, the least similarity (%42) belonged to Alvijan and Kazerun and the highest similarity belonged to Chegeni and Haftchin Hamedan. Clustering based on semi-specific PCR method almost substantiated the grouping based on geographical origin. Considering the results, it is concluded that PCR-based semi-random marker technique can be used for genetic diversity study of Persian clover as well as discrimination of its cultivars.

Water deficit, ultraviolet radiation and CO2 concentration enhancement are three environmental stresses that affect nutrition of human in future. This research was conducted in the Research Greenhouse of Faculty of Agriculture, Tarbiat Modares University in 2006, in order to study leaf qualitative traits of durum wheat under different levels of carbon dioxide (400 and 900 ppm), ultraviolet radiation (UV A, B and C) and water deficit (up to %60 of field capacity). Ultraviolet radiation enhancement increased anthocyanin, flavenoids and carotenoids of durum wheat leaf.There was no significant interaction effect between carbon dioxide and water deficit on anthocyanin and carbohydrates.Also, the interaction effects among the three factors were not significant on anthocyanin, carotenoids, chlorophyll a and a+b. Water deficit decreased leaf proteins. Increasing intensity of ultraviolet radiation and carbon dioxide enrichment decreased soluble leaf protein in durum wheat under water deficit conditions. The results showed that three main environmental stresses which reduce leaf pigment and plant protection due to negative effects of these stresses along with soluble leaf protein reduction decrease qualitative and quantitative yield of the wheat variety.

The aim of the study was to examine the effect of CaCl2 on the firmness and post harvest retention of Berry Grape (Vitis vinifera L.) cv. Askari. The experiment was carried out in 2006 in vineyard in the Sisakht region in a completely randomized design with 7 treatments. Experiment includes two parts: 1- spray with 3 levels 0.1, 0.25 and 0.5%. (Two weeks before harvest and repeated one day before harvest); and 2- Dipping clusters in CaCl2 solution with 3 levels 1, 2.5 and 5% post harvest. Grapes were stored at 0oc for 1 month in cold store room. Results showed that the effect of CaCl2 was significant on post harvest abscission berries percentage at 1% level. Minimum post harvest abscission of berries percentage was observed using 5% dipping and 0.25% spray after 30 days storage in cold storage room. Highest abscission of berries was observed in control. Effect of CaCl2 on decay berry was significant at 1% level after 30 days of storage. Minimum decay percentage was observed in 0.25% spray and the highest decay percentage was obtained in control. Effect of CaCl2 on palatability (TSS/TA) was significant at 1% level.

Changes of the main sugars and organic acids content in Asian pear (Pyrus serotina Rehd.) Cultivars ‘KS’9 and ‘KS’13 grown in Tehran were studied from fruit set to maturity. The main sugars and organic acids content in fruits were determined 1 and 2 months before harvest, at the time of harvest and 1, 2 months after harvest time using High Performance Liquid Chromatography (HPLC). Fruits were stored at 2oC and 80-85% relative humidity (RH). There were significant differences between cultivars and time of fruit harvest in terms of sugars and organic acids content. In both studied cultivars, fructose, glucose and sorbitol increased from the first fruit sampling to one month after harvest (1 to 9% FW) and then decreased. Sucrose content decreased from 2 months before harvest to 2 months after harvest time (3 to 0.75% FW). In both studied cultivars organic acids content increased at the time of pick-up and then decreased.The highest organic acids contents in the studied cultivars were malic and ascorbic acids (345 and 41.1mg 100g-1FW in ‘KS’9 and control, respectively). The relationship between low sugar and organic acid content in fruits showed the highest correlation (0.8 to 1) in both cultivars among low flesh firmness, low total soluble solid (TSS), low dry weight and high internal browning determined in this study. Results indicated that high content of sugars and organic acids in fruit led to delayed internal browning. Asian pears with a low ascorbic acid concentration are probably more susceptible to internal browning. High correlation was observed between high sugars content and high fruit colour.

Microsatellite DNA markers isolated from wild species khinjuk (Pistacia khinjuk Stocks.) was used to evaluate the genetic diversity available in Iranian pistachio cultivars. Out of the 27 SSR primers tested initially, 25 could amplify the DNA in different pistachio cultivars, of which 19 primer pairs produced clear bands. Based on the amplification profiles of the genotypes by the remaining primer pairs, eight primers produced a monomorphic product and other 11 microsatellites markers were found polymorphic among the genotypes. The number of putative alleles amplified by each polymorphic SSR locus ranged from two to eleven alleles with a total of 48 alleles. An average of alleles and observed heterozygosity per locus was 3.69 and 0.69 respectively, showing that these microsatellites are highly informative for pistachio fingerprinting. The UPGMA cluster plots based on nei index placed the 20 commercial pistachio cultivars into a major group containing three distinguished subgroups; however, genotypes, namely, Ghazvini zudras and Sarakhs (wild P. vera), were clearly situated into two distinct clusters, distant from the domesticated genotypes studied here. Both Ghazvini zudras and Sarakhs are known as small-fruited genotypes which are grown in restricted regions. Therefore, the distinctness of these genotypes can be attributed to their geographical isolation and morphological characteristics. It seems that Ghazvini zudras probably originated from Sarakhs variety which posses an important role in development of pistachio cultivars. The present study revealed that the khinjuk pistachio microsatellites are well distributed in the genome of P.vera, and are informative for estimating the extent of genetic diversity and characterization of pistachio cultivars.

Effect of different exogenous putrescine concentrations on post-harvest life of strawberry, apricot, peach and sweet cherry fruit was separately studied using completely randomized designs in three replicates. Fruits were immerged in putrescine solutions (0.3, 0.5, 1 and 2 mM for 5 minutes in strawberries, and 0.5, 1, 2, 3 and 4 mM for 10 minutes in the other fruits) and also in distilled water as control. They were then transferred into the fridge. Post-harvest life of all fruits was increased by the use of putrescine. Ethylene production and water loss of the fruits were reduced by this compound. Putrescine also prevented softening of fruit's tissue during their storage period. Titratable acidity was reduced in untreated fruits while their pH was increased. These trends were also observed with the application of putrescine in all fruits, but at a much slower rate compared with the controls. Soluble solids content of sweet cherry fruits was increased by the use of putrescine while it was reduced in the other three fruits.

Pathogens are the most important factors inducing postharvest losses on citrus fruit. Experiments were conducted as a CRD with 4 replications on sweet lime (Citrus limetta) and Valencia orange (Citrus sinensis) in 2003 and 2004.Treatments were pure essential oils of clove and thyme and in 25% ethanol solution at concentrations of 0.1, 0.3 and 0.5% and imazalil (2 ml/l). Results indicated that in the first year, pure essential oils of clove and thyme reduced the decay percentage of blue mold of Valencia orange fruit from 90% (control) to 0 and 12.5%, respectively. Pure essential oils of clove and thyme reduced the decay percentage of sweet lime in the first year of experiment from 95% (control) to 0 and 6%, respectively. In the second year, with the same treatments decay percentage of blue mold was reduced from 90% (control) to 0. Solutions of 0.1, 0.3 and 0.5% of clove and thyme oil extracts in 25% ethanol solution reduced decay percentage of sweet lime fruits form 85% (control) to 65, 41 and 26% for thyme oil and to 60, 30 and 22.5% for clove oil. Comparison of pure clove and thyme oil extract with imazalil showed that pure clove and thyme oil extracts were not significantly different with fungicide treatment. Treatments of clove and thyme oils in 25% ethanol treatment were not as effective as fungicide.

Pistachio (Pistacia vera L.) is an important economic crop, which is mostly planted in saline conditions in Iran.Verticillium wilt disease of pistachio caused by Verticillium dahliae is known as a serious disease for pistachio trees.The causal agent was recovered from shoot and soil samples collected from main pistachio growing areas in Kerman province. The present experiment was carried out to study the effect of salinity on disease using three common P. vera rootstocks including Sarakhs, Badami-e-Zarand and Qazvini and four levels of salinity (0, 1400, 2800 and 4200 mg NaCl per kg soil) in hydroponic culture (1/2 strength Hoagland,s solution). Salt stress was applied before inoculation on ten week old seedlings. The experiment was carried out as factorial in RCD with four replications. Two weeks after salt stress induction, four seedlings were transplanted into pots containing 5 kg sandy-clay virgin soil artificially infested with 40 microsclerotia per gram of soil with equal salinity. In NaCl treatments, Sarakhs showed lower shoot and root dry weight and higher concentration of Na, K and Cl than the other rootstocks. Based on the results, Sarakhs, Qazvini and Badami were found to be susceptible, tolerant and intermediate to NaCl, respectively. In the presence of V. dahliae, salt stress significantly reduced shoot and root dry weight and increased stem and root colonization by the pathogen and Na, K and Cl concentration compared to non-stressed inoculated plants. Sarakhs had higher percentage of colonization of stem and root by V. dahliae and concentration of Na, K and Cl than other cultivars. As a general conclusion, salt stress before inoculation by V. dahliae can increase the severity of Verticillium wilt of pistachio, especially in saltsensitive rootstocks.

Pink root-rot disease caused by Pyrenochaeta terrestris is one of the serious diseases of onion fields in Iran and the world. The use of resistant cultivars might be a good alternative as suggested on the basis of the screening at the near end of growing season. The susceptibility assessment of 43 Iranian onion clones in glass-house condition in Isfahan for the last two successive years i.e. 2003-04 indicated that, the clones react independently with various degrees of resistance to the pink root-rot disease and with a high significant effect. The scoring scale was of 0-3 to determine the susceptibility and/or resistance of the clones to the disease, out of which, the two clones, Ramhormoz-Saffiabad and Balochestan-Sarbaz were the most susceptible clones to the pink root-rot disease, and were placed in 2-3 (0-3) scale.But most of the clones were placed in the scoring scale 1-2 (0-3) indicating that they are in the ranges of tolerance. This could be why they still exist and could tolerate the disease and remain safe. The third and/or the resistant clones are those clones that were placed in the scoring scale of 0-1 (0-3), i.e. Naishabor-Ishaghabad, Sarri-Local, Loosha-Golden, Zanjan-Ghotigheseh, Shahrood- local, Azarbayejan-East, Shahrood-Lasjerd, Kashan-White, Yazd-Marvdasht, Azarshahr-Red and Boshehr-Local, respectively. In fact, the two clones Naishabor-Ishaghabad and Sarri-local are the most resistant ones to the pink root-rot disease of onion in these tests. These results indicate that there are certain clones which can be considered in breeding programs and/or cultivations.

Protein electrophoretic pattern similarity among 21 strains of Xanthomonas axonopodis pv. citri isolated from Hormozgan and Kerman provinces together with the representatives of reference strains of X.a. pv. citri and X. a. pv. aurantifoli and 246 strains of the other Xanthomonas spp. including : X. a. pv. citri, X. a. pv. glycins, X. a. pv. manihotis, X. c. pv. campestris, X. a. pv. phaseoli, X. cassavae, X. vesicatoria, X. c. pv. euphorbia, X. c. pv. arracaciae, X.c. pv. malvacearum, X. a. pv. clitoriae, X. a. pv. citrumelo, X. a. pv. aurantifolii, X. a. pv. alfalfae, X. cucurbitae, X.c.pv. dieffenbachiae, X. vasicola. pv. holcicola, X. melonis, X. hortorum. pv. pelargonii, X. a. pv. poinsettiicola, X. arboricola pv. pruni, X. c. pv. raphani, X. a. pv. ricini, X. a. pv. vasculorum, X. a. pv. vignicola, X. c. pv. armoraciae, X. c. pv. barbareae and X. c. pv. Carotae was compared and analyzed via Gel Compare version 4.2 software. Results indicated 86% of mean similarity among the strains tested. The highest similarity was 100% for strains isolated from Hormozgan and Kerman provinces and X. a. pv. citri LMG 9176 and X. a. pv. citri LMG 9654. The lowest similarity was 84.90% for these strains and X. c. pv. euphorbia LMG 7402 and X. a. pv. ricini LMG 7444. The 100% of protein pattern similarity among the strains isolated from Hormozgan and Kerman provinces and the reference strains from pathotype A (X. a. pv. citri LMG 9176 and X. a. pv. citri LMG 9654) was supported by host range and pathogenicity patterns of these strains obtained from our previous study.

Cultivars or species of different plants through physical and biochemical characteristics or indirectly through food diet of host plant can influence behavioral characteristics and efficiency of a natural enemy. This investigation was conducted to determine percentage of parasitism and functional response of parasitoid wasp, Platytelenomus hylas (Hym., Scelionidae) to different egg densities of stem borer, Sesamia nonagrioides (Lef.) and effect of different cultivars on it. At the first stage, eggs of pest were separately collected from fields in three cultivars of CP48-103, CP69-1062 and CP57-614 and then percentage of parasitism in each cultivar was calculated. For determining functional response of the wasp, collected eggs from fields were reared to adult stage at 29±1oC, 60% of RH,. Then functional response of wasp was investigated at densities of 2, 4, 6, 8, 14, 20, 30, 40, 50, 60, 70, 80, and 90 of the host eggs for 24h. Analysis of data was done using SAS software. Results showed that egg parasitism by P. hylas in cultivars were significantly different (p<0.05). Type of cultivars influences rate of egg parasitism. Comparison of means by Duncan’s test showed that CP48-103 cultivar significantly differed from two other cultivars: CP69-1062 and CP57-614.Functional response in three cultivars was found to be a type III. Comparison of estimated parameters by Holling model in three cultivars showed that searching efficiency on CP48-103 cultivar was significantly higher than two other cultivars but CP57-614 and CP69-1062 were close to each other. Also, handling time (Th) and the maximum rate of estimated parasitism (T/ Th) on the three cultivars were different and on CP69-1062 they were significantly less than the two other cultivars.

In a study of aphids and their parasitoids in wheat fields of Shiraz region, the species composition, distribution and seasonal dynamics of the dominant species were monitored during 2004-5.Collections were made from 1-3 hectare fields in 10 locations within 50 Km radius around Shiraz city. Species density was estimated by counting individuals present on 40 winters wheat tillers taken at random along 2 transects 5 m apart in the fields. Eight aphid and 3 parasitoid species were identified through this survey. Rhopalosiphum padi (L.) and Metopolophium dirhodum (Wlk.) with relative abundances of 33.94 and 31.33%, Aphidius rhopalosipi De Stefani-Perez and Praon volucre (Hal.) with relative abundances of 55.53 and 39.90%, were the dominant species of aphids and parasitoids, respectively. Seasonal dynamics of the above species were also studied in Badjgah, located 15 Km north of Shiraz city. Peak populations of the dominant aphids occurred between late May and first of June 2004-5, and those of parasitoids were seen 1-3 weeks later. A comparison between seasonal parasitism of the dominant parasitoids showed significant preferences of A. rhopalosiphi on R. padi, and P. volucre on M. dirhodum. Since the total parasitism of both wasps was nearly 30% of the two aphid hosts, attention should be paid to chemical control programs of wheat pests (such as Sunn pest) so that it does not disturb the efficiency of the aphid parasitoids.

In this study diflubenzuron as a chitin synthesis inhibitor with a dosage of 25 mg A.I/L, and Pyriproxyfen as a juvenile hormone analogue with a dosage of 0.4 mgA.I/L were incorporated in the wax diets of young and last instar larvae of greater wax moth and reared at different temperatures (25, 30, 35oC). Results showed that these compounds in comparison with control increased larval mortality. Diflubenzuron and pyriproxyfen caused 33.9% and 24.1% mortality respectively. The young larvae showed higher mortality with the mean of 57.8% in diflubenzuron and 31.5% in pyriproxyfen. In evaluation of pupation and emergence of adults, no significant differences were observed between diflubenzuron and control. Pyriproxyfen induced reduction in pupation about 48.4% and adult emergence about 44.8% and caused some abnormalities of pupae. Last larval instar was more sensitive to JHA in this respect. Maximum pupation disruption occurred at 25oC and 30oC in comparison with 35oC which reduced abnormal pupae up to 19.7%.IGRs were effective in last larval instar at 35oC and increased abnormality of adult up to 49.4%. Reproductive potential (egg viability, hatchability) of adults reduced in F1 generation and was 70-90 percent. IGRs have unfavorable effects on biological aspects of larvae; therefore, it is possible to use IGRs alone or in conjunction with other pesticides (Fumigants) in integrated control of these pests.

The biological and behavioural parameters of Anisopteromalus calandrae (Hym.: Pteromalidae), a parasitoid of Callosobruchus maculatus (Col.: Bruchidae) on Chickpea were studied in laboratory conditions at temperature of 25±1oC, photoperiod 16:8 (L:D) and 20±5 % RH. The pre-adult period of the wasp was 19.82±0.038 days and preovipositional period in this wasp was so short that female laid eggs immediately after emergence. Reproductive and post reproductive periods were 25.12±1.98 and 1.75±0.28 days, respectively. Adult life span was 26.69±1.98 days.Total number of progeny produced by a female was 240±28.51. The sex ratio (% females) of the resulting adults on hosts was 0.49. The functional response of A. calandrae was type II. The host stage preference by the parasitoid was investigated in two methods, choice and non-choice experiments. In the first condition, the parasitoid preferred the 4th larval instar to others, but in the second, it preferred both 4th larval instar and pupae. Adult longevity for both female and male parasitoids provided with honey solution (%50), host larvae, host larvae and honey solution (%50), and finally without host larvae and honey solution was 49.00±4.32, 26.69±1.98, 38.90±3.52 and 5.66±0.37 days for females and 10.64±1.5, 6.85±0.34, 8.41±0.52 and 5.59±0.28 days for males, respectively.

The species diversity of bumblebees was investigated in two provinces, Tehran (Fasham, Zayegan) and Qazvin (Alamut, Wikan) in central Alborz during 2005-2006. Three casts of queen, worker and male bumblebees were collected during spring and summer in six dates in the two mentioned regions. Sampling of adult bees in Wikan was done from 26 July 2006 until 19 September 2006, and in Zayegan from 24 May 2006 to 17 September 2006. In sum, eleven species were collected of which eight species were common in the two regions. Data of different species casts at two regions were analyzed by Excel ver. 6 and Ecological Methodology ver. 6. 1. 2 soft wares. Species diversity of two regions was determined and compared with three indices of Simpson, Shannon-Weiner and Brillion, and evenness was calculated with indices of Simpson, Camargo and Esmit-Willson. Species richness of two regions was compared in research. The obtained results showed species diversity; evenness and species richness were more observable in Wikan compared with Zayegan. Consequently, Wikan in comparison with Zayegan was more sustainable. Similarity of two regions was 0/46, showing many differences in terms of the kinds. Also, there were 8 similar species in the two areas.

The pistachio twig borer moth, Kermania pistaciella Amsel (Lep.: Tineidae) is one of the most important pests of pistachio trees (Pistacia vera L.) in Iran. This study was carried out in two pistachio orchards of Rafsanjan area. Periods of pupal cocoon and adult emergence were recorded in two pistachio orchards for four years. Minimum threshold temperatures were calculated according to the least coefficient of variation method for different developmental stages.Cumulative effective temperatures were calculated for different percentages of pupal cocoon and adult emergence.Results showed that minimum threshold temperatures for overwintering larvae to pupal cocoon formation, Larvae to adult and pupal cocoon to adult were calculated 10/ C, 11/ C and 12/ C, respectively. Cumulative effective temperatures for occurrence of 50% pupal cocoon from overwintering larvae with minimum threshold temperatures 10/ C under field conditions were 73.6 degree-day. Cumulative effective temperatures for occurrence of 65% adult emergence from overwintering larvae with minimum threshold temperature of 11/ C under field conditions were 213.8 degree-day.Cumulative effective temperature for occurrence of 65% adult emergence from 5% pupal cocoon, 50% pupal cocoon and 5% adult emergence with minimum threshold temperature of 12/ C was 145.3, 126.9 and 71.6 degree days, respectively.

Due to injuries of pesticides to natural enemies of pests and pollinator insects, especially honeybees, during the flowering periods, it is essential to protect them. Application of chemical compounds along with the pesticides on the plants could repel the non-target insects from the sprayed areas for sometime and lessen the hazards of pesticides to them. In this study, ten repellent chemicals whose repellency effect was proven in the laboratory in previous studies were screened in the field. Among tested repellents including, Acetophenon, Methyl ethyl ketone, Methyl isobutyl ketone, Cyclohexanone, Acetyl acetone, Methylsalicylate, Propionic anhydride, Maleic anhydrate, 2- Ethylhexylamine, and Dibutylamine, it was revealed that amino group compounds including 2- Ethylhexylamine and Dibutylamine and esteric compound, Methylsalicilate had the highest repellency effect on the honeybees under the field conditions.Repellency effect of these compounds was greater at 15 pm than other sampling times. Repellency effects of different concentrations of these three compounds, when mixed with 0.5% concentration of fixative compounds, showed that the mixture of 2- Ethylhexylamine with Benzylbenzoate, Dibutylphthalate and Benzylalcohole with concentration of 0.17, 0.4 and 0.03 % respectively, the mixture of Dibutylamine at the concentration of 1% with Benzylbenzoate and Dibutylphthalate and at the concentration of 0.08% and higher with Benzylalcohole, and also mixture of Methylsalicilate at the concentration of 1.8 % and higher with Benzylalcohole, all have repellency effect of more than 70% under the field conditions.