نشریه علوم آب و خاک (علوم و فنون کشاورزی و منابع طبیعی)
سال دوازدهم شماره 3 (پیاپی 45، پاییز 1387)

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 (35°43′N and 51°8′E). 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 μM) 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 μmol 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 roles 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. Thv19M+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 (exon-targeting) 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 2˚C 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.) were 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 salt-sensitive 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±1 ºC, 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 winter 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, 35°C). 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 35 ºC 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 pre-ovipositional 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 were 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.

In order to investigate the effect of zinc - chelate on drought tolerance of Azadi cross wheat, a randomized complete block design was conducted as split plot with three replicates in the Kherameh during 1383 - 1384. The main plot was four drought levels (control and drought stress in the stages of flowering, seed milk stage and two phases, together), and sub plot was zinc - chelate rates 0, 5, 10 & 15 kg per hectare. The results showed that zinc application under drought conditions increased spike per square meter significantly at the 5% level. Drought stress decreased 1000 - seed weight. Least of 1000 - grain weight was in two phases of flowering and seed milk stage together (29.78 g). The application of 15kg zinc -chelate fixed 1000 - seed weight. Treatments of drought stress decreased seed yield significantly (14.17% in the proportion of control), but zinc - chelate application increased wheat tolerance to seed yield decrease. Zinc - chelate application prevented from seed number decrease per wheat spike under drought conditions that was caused to tolerance of seed yield and harvest index decrease. The application of 15 kg zinc - chelate increased harvest index in comparison of control amount of 22%.

During recent years, several genotypes have been selected from Isfahan land race Kouseh. The performance of safflower selected genotypes was studied in the field conditions, at Agriculture Research Station, Isfahan University of Technology during 2003. The experiment was carried out using a split plot arrangement according to a randomized complete block design with three replications. Planting dates (March 11, April 20, May 22 and June 23) were considered as the main plots and subplots consisted of 20 genotypes of safflower including 19 selections from Kouseh and Arak-2811 genotype. Days from planting to emergence and emergence to stem elongation were reduced as planting was delayed until the fourth planting date. Days from stem elongation to head visible was reduced with delay from the first to the third planting date, and then increased. Days from head visible to 50% flowering was reduced with delay from the first date to the third planting date, but increased in the fourth planting date. Days from 50 percent flowering to physiological maturity was increased with delay in planting. Days from planting to emergence, emergence to stem elongation, stem elongation to head visible and 50 percent flowering to physiological maturity were not influenced by genotypes. Genotype DP7 had the highest and genotype C111 and genotype DP25 had the lowest days from head visible to 50% flowering. The interaction between planting date and genotype in regard to days from stem elongation to head visible was also significant. Seed weight per plant was reduced with delay in planting date. Genotype ISF66 had the highest and genotype Arak-2811 had lowest seed weight per plant. The number of days from emergence to head visible in ISF66, DP5, C128 and Arak-2811 was affected by maximum temperature (Tmax), in genotype DP7 by Tmax2, in genotypes DP17, DP1 and C41100 by Tmin2 and in genotypes DP9, DP25, ISF28, ISF22, and C111 was affected by day length. It seems that development period from emergence to head visible was affected by temperature in the most genotypes. On March 11 planting date, genotypes had the maximum response to temperature and day length and the minimum response was observed in the fourth planting date. The genotype ISF66 had the highest seed yield on March 11 planting date. The result of this study showed that safflower should be planted in late March under condition similar to this experiment for maximum yield production.

This study was conducted to investigate the effects of thirteen fertilizer treatments (as main factor) on agronomic traits of two local cultivars (as sub factors) of sesame (Sesamum indicum L.), "Mobarakeh" and "Ardestan" in Isfahan by using a randomized complete block design with three replications. The results showed that applying fertilizer treatments of N, P, K, Fe, Zn and Mn had no significant effects on yield components, seed yield and oil yield. However, comparing the control treatment, simultaneous application of all fertilizers significantly reduced days to maturity. Significant interaction between cultivars and fertilizer treatments was observed for seed oil content, as application of N, P, NPK and NPK+Fe+Zn in Mobarakeh and application of N+K in Ardestan reduced seed oil content. However, the other fertilizer treatments had no significant effects on this trait. The Mobarakeh cultivar compared to Ardestan had significantly higher plant height, higher seeds per capsule, lower 1000-seed weight, higher seed yield per plant and per hectare and higher oil yield. Seed yield for Mobarakeh and Ardestan cultivars were 1646 and 1169 kg/ha and their seed oil contents were 52.88% and 53.81%, respectively. The correlation coefficients and regression analysis showed that the variation of seed yield was mostly due to the number of capsules per plant and seeds per capsules, thus these two traits were the most important yield components. Oil yield had a very high correlation coefficient with seed yield (r=0.99**), whereas its correlation with seed oil content was very low (r = -0.10ns). Therefore, it seems that seed yield was the main cause of higher oil yield.

Safflower (Carthamus tinctoius L.) is an Iranian native crop that is adapted to different environmental conditions of this country. Sixteen safflower varieties/lines were spring-planted in 6 research stations including Sararood (Kermanshah), Maragheh, Ghamlo (Kordestan), Khodabandeh (Zanjan), Shirvan (North Khorasan)and Khohdasht (Lorestan) with and without drought stress conditions each in a RCBD with 3 replications. Some drought resistante indices including Mean of Productivity (MP), Geometric Mean of Productivity (GMP), Tolerance (TOL), Stress Tolerance Index (STI), Stress Susceptibility Index (SSI) for seed yield and genotypes Cell Membrane Stability (CMS) were calculated. Results showed that STI was the most appropriate index to identify drough resistant genotypes. Estimation of STI from mean of all stations revealed that Gila, CW-4440 and PI-537598 with high STI showed high seed yield in both stress and non-stress conditions. Caculation of STI standard deviation for these genotypes showed that Gila had less STI stability over the locations than other two genotypes so, CW-4440 and PI-537598 are more stable in drought stress resistance. Analysis of variance for cell membrane stability (CMS) of genotypes showed the significant differences in 1% level of probability between genotypes. S-541 had the highest and Kino-76 had the lowest CMS. There were significant and strong correlations between STI, MP and GMP with CMS namely, genotypes with more stable membrane having more drought resistance in field condition. So, cell membrance stability can be a useful and fast method to screen germplasm and identify drought resistant genotypes. Cluster analysis based on STI,MP,GMP, CMS and seed yield in both stress and non-stress conditions divided genotypes into 3 groupes. Results of clustering also identified S-541, Gila, CW-4440 and PI-537598 as 4 superior genotypes and confirmed the results of other methods.

In order to investigate the effects of moisture stress, nitrogen fertilizer, manure and integrated nitrogen and manure fertilizer on yield, yield components and water use efficiency of SC 704 corn (late maturing, non-prolific and dent). In 2005, a field study was conducted in agricultural experiment station of the college of agriculture, Tarbiat Modares University. The type of design was randomized complete block with factorial arrangement and three replications. For the study, four levels of nitrogen fertilizer (0, 92, 184 and 276 kg N ha-1), integrated fertilizer (46 kg N ha-1 + 2/5 ton ha-1 FYM, 92 kg N ha-1 + 5 ton ha-1 FYM and 138 kg N ha-1 +7/5 ton ha-1 FYM ) and organic Farm Yard Manure (5, 10 and 15 ton ha-1 FYM ) along with three levels of irrigation (optimum irrigation (control), water stress 75% optimum irrigation and water stress 50% optimum irrigation) were used as treatments. The results showed maximum seed yield was produced with 92 kg N ha-1 + 5 ton ha-1 FYM and average of seed yield was 7976 kg ha-1. Maximum corn seed yield resulted when optimum irrigation water was applied and average seed yield was 7041 kg ha-1. When water stress was imposed in 50% and 75% of optimum irrigation, seed yield was decreased by 33 and 12%, respectively. The best seed yield was obtained with interaction of 5 ton ha-1 FYM and optimum irrigation. Also, maximum water use efficiency was obtained in using 50% of optimum irrigation. Maximum water use efficiency was obtained with interaction of 92 kg N ha-1 + 5 ton ha-1 FYM and imposition of water stress in 50% optimum irrigation. Results showed that adequate nitrogen fertilizer slightly increased corn seed yield under stress, and integrated (nitrogen and manure) fertilizer increased corn seed yield under stress. But seed yield greatly increased with optimum irrigation. Integrated fertilizer application increased seed yield even with severe moisture stress. Application of integrated chemical fertilizers and manure produced better seed yield and also decreased the amount of chemical fertilizers and improved soil physical and chemical characteristics.

A pot experiment was designed to investigate the effects of full, above and below ground interactions of wheat with wild oat on leaf characteristics and root to shoot ratio. This experiment was conducted as a factorial based on randomized complete design with four replications. The treatments included four interference levels (above ground, below ground, above and below ground and check wheat and wild oat) and four wild oat densities (2, 4, 6 and 8 plants/pot).The effects of full and root interference on wheat and wild oat traits was greater than shoot interference. For both species, full and below ground interaction significantly decreased the number of leaves, flag leaf area and chlorophyll content of flag leaf compared to above ground interaction and control. All traits of wild oat were reduced by above ground interaction compared to control. Number of leaves of wheat and wild oat showed greatest susceptibility to interaction treatments. There was no significant different between full and root interference. When wild oat density increased, the number of leaves, flag leaf area and chlorophyll content of flag leaf of wheat decreased. With strongest competition followed by enhanced wild oat density, root to shoot ratio in wheat and wild oat increased, which indicates more susceptibility of shoot than root to interference mean competition. This ratio for wild oat was more than wheat, thus, it is concluded that wild oat has higher rooting ability compared to wheat.

Soil salinity is an increasing environmental stress on crops in most areas of Iran since farmers use underground saline water for irrigation. In order to investigate the effects of salt stress on germination and seedling growth of safflower (Carthamus tinctorius L.), an experiment was conducted at two stages (germination seedling growth), using four levels of NaCl salinity (0, 5, 10, 15 ds/m), and four cultivars of spiny and non-spiny safflower ( a landrace from Isfahan bred cultivars of IL, LRV and PI). The design was factorial and completely randomized based on 3- replicates (CRD). Germination percentage, germination velocity index, root and shoot length, root and shoot dry weight, root to shoot dry weight ratio and salt tolerance index were measured at germination stage. In seedling growth stage, traits such as, stem length, number of leaves, chlorophyll index, root and shoot dry weight, root to shoot dry weight ratio and salt tolerance index were also measured. Results for both growth stages showed that salt stress decreased all the above mentioned traits, significantly, in all cultivars. Salinity × variety interaction at germination stage was also significant, compared to seedling growth stage. Salt tolerance index decreased significantly with increasing salinity at both stages, but differences between cultivars were not significant. Cultivars PI and IL were characterized as the tolerant ones at germination and seedling growth stages, respectively. It could be concluded that safflower cultivars responded differently to salinity in germination phase compared to seedling growth phase, and that safflower suffers more from salinity during germination stage.

In order to evaluate the interaction effects of nitrogen and organic matter on growth and yield of dryland wheat, an experiment was conducted at the research station of the College of Agriculture, Shiraz University at Bajgah in 2005 and 2006. The experimental design was split plot in which three levels of nitrogen (0, 40, and 80 kg N ha -1) were main factors and additive organic matters including liquorice root residue at 15 and 30 Mg ha -1, municipal waste compost at 10 and 20 Mg ha -1, and wheat residues at 750 and 1500 kg ha -1 (all rates equivalent to 50 and 100%) were sub factors. A check treatment (no additive materials) was also included in the experiment. Results indicated that with increasing nitrogen level from zero to 40 and 40 to 80 kg ha-1, wheat yield increased significantly. Among yield components, number of seeds per spike increased significantly with zero to 40 and 40 to 80 kg nitrogen ha-1, but number of spikes m-2 increased significantly only when nitrogen level was increased from zero to 80 kg ha-1. Compared to check (no additive materials), maximum wheat grain yield (32%) was obtained from 100% compost application. Results of nitrogen and organic matters interaction effects indicated that 100% compost application and increasing nitrogen level from 40 to 80 kg ha -1 had no significant effect on dryland wheat yield. This showed the positive impact of compost application on the reduction of nitrogen fertilizer. Thus, it appears that 50% of the required nitrogen fertilizer could be replaced by compost. Applying organic matter increased soil water in both years, however, among organic matters, compost had a more pronounced effect on increasing soil water.

To study relationship between grain yield and important agronomic traits of rapeseed in paddy fields as second culture, fourteen varieties of spring rapeseed were grown in a randomized complete block design of experiment with three replications at Rice Research Institute of Iran, Rasht, during 2005-2006. Analysis of variance showed that there were significant differences between varieties for most of traits. Broad sense heritability ranged from 0.29 for pod length to 0.99 for days to maturity. Phenotypic and genotypic coefficients of variation for days to maturity and the number of pods in secondary branches were the lowest and highest, respectively. Moreover, genetic advance with 5% of selection intensity varied from 3.68% (0.25 cm) for pod length in main branch to 31.48% (915.58 Kg.ha-1) for grain yield. Results from genotypic correlation coefficients demonstrated that there were positive significant correlations between grain yield and the number of secondary branches, the number of pod in main and secondary branches, pod length in secondary branches, pod diameter in main and secondary branches, 1000-grain weight and oil percentage, and negative significant correlations between grain yield and days to 90% of flowering and days to maturity. Path analysis on genotypic correlations for grain yield as a dependent variable and the other traits as independent variables showed that the 1000-grain weight and the number of pods in secondary branches had the highest direct effects and days to 90% of flowering had low and negative direct effect on grain yield. Therefore, indirect selection for increasing 1000-grain weight and the number of pods in secondary branches are recommended for improving grain yield in rapeseed as second culture in paddy fields.

In order to investigate the effect of sugar plant effluent on shoot solute percentage, yield components and grain yield of two wheat cultivars, a two year field experiment was conducted on a farm near Eghlid sugar plant during 2004-2005. Treatments consisted of two wheat cultivars (Alamot and Zarin) and two irrigated treatment: irrigation with effluent and irrigation with spring water (control). The statistical design was a completely randomized factorial with three replications. The results showed that under effluent treatment, nitrogen, phosphorus and calcium percentage increased in shoot, and Fe, Mn, Zn, Cu and B concentration decreased. However, effluent treatment had not any significant effect on K, Mg and S concentration. The results showed that N percentages in Alamot and Zarin cultivar under control treatment were 2.41 and 2.54% and under effluent treatment were 3.28 and 3.41%, respectively. P percentages under control treatment were 0.42 and 0.47% and under effluent treatment were 0.46 and 0.51%, respectively. Ca percentages under control treatment were 0.29 and 0.32% and under effluent treatment were 0.46 and 0.51%, respectively. In both years, the lowest number of tiller, number of spike, number of kernel per spike, thousand kernel weight, grain yield and harvest index were obtained from effluent treatment in the two wheat cultivars whereas this reduction was higher in Alamot than Zarin cultivar. In Alvand and Zarin cultivars, the lowest number of tiller per plant with 2.33 and 2.50, number of spike per plant with 1.83 and 1.92, number of kernel per spike with 31.67 and 32.50, grain yield with 5233 and 5532 kg ha-1 and harvest index with 32.03 and 33.53% and water productivity with 0.72 and 0.75 kg m-3 were respectively obtained from effluent treatment compared to control. Thus, the results showed that using sugar plant effluent could decrease grain wheat quality and wheat grain yield.

In order to examine the effects of plant density on the morohological traits, yield and essential oil of peppermint, an experiment was conduced in Agricultural College of Tabriz University during 2005 and 2006. The treatments included four plant density levels ( 8,12 ,16,20 plants.m-2) with three replications. The treatments were based on a split plot design in time and result analysis of compound variance was done during two years. The two years’ results of the compound variance showed that the plant density affected the fresh yield, dry yield, the bush essential oil percentage and the essential oil yield, but it had no effect on the bush height and the leaf’s essential oil percentage. In the second year, the maximum fresh yield, dry yield, bush height, the bush essential oil percentage, and the essential oil yield were obtained. In the second year, the maximum essential oil yield in the density of 20 plant/m2 was 21.15 li.ha-1.

In order to investigate the limited irrigation impact on physical characteristics of seed in nine sunflower hybrids, three 3-replicate field experiments RCBC were conducted under three irrigation regimes (irrigation after 60, 120 and 180 mm cumulative evaporation from class A evaporation pan, respectively) at the research field of Seed and Plant Improvement Institute in Karaj, Iran. The results showed that the Maximum length, width and seed diameter were obtained from irrigation after 60 mm cumulative evaporation from pan, and irrigations after 120 and 180 mm evaporation caused to decrease the length by 11% and 16%, width by 21% and 26% and seed diameter by 22% and 28%, respectively. There fore the seed diameter in comparison with width and seed length was most susceptible to limited irrigations levels. The Maximum length was seen in hybrid of A74×R95, and the maximum width, and seed diameter were observed in hybrids of Allstar. Also, A74×R95 under irrigations after 60 and 120 mm evaporation and Azargol under irrigation after 180 mm evaporation had the highest seed weight.

In order to investigate the relationship among seed yield and its components in safflower, path and factor analysis were conducted using the agronomic and morphological traits of 32 genotypes. Genotypes were evaluated on the Research Farm of Isfahan University of Technology, using a randomized complete block design with three replications. The correlation coefficients showed that number of seeds per capitula and number of capitula per plant had the highest positive correlation with both seed yield and seed yield per plant. The results of regression analysis showed that number of capitula per plant explained 43.6%, and along with seeds per capitula and plant height 60% of the phenotypic variations for seed yield. The regression analysis for seed yield per plant also revealed that seeds per capitula, capitula per plant and seed weight in order had more contributions to the variation of seed yield per plant and explained 81.2% of its variation. Path analysis showed that capitula per plant had the most direct positive effect on both seed yield and seed yield per plant however, this effect was decreased by the indirect and negative effect of seed weight. Results of factor analysis recognized 3 main factors which explained 81.81 % of total variation of the data. These factors were named the seed yield and its components, phenological traits and branching. In general, it can be concluded that seeds per capitula, capitula per plant and seed weight in order contributed more to the seed yield of safflower genotypes. In conclusion, these yield components can be used as selection criteria in breeding programs.

In order to study the effect of various amounts of nitrogen (N) and Iranian natural zeolite on the quantitative and qualitative forage yield of winter canola (Brassica napus L.) in light soil, a field experiment was conducted on research farm of Tarbiat Modares University, Tehran, during 2006-2007. Treatments were arranged in the form of RCBD with 3 replications. The experimental treatments were based on factorial various levels of zeolite (0, 3, 6 and 9 t.ha-1) and nitrogen (90, 180 and 270 kg ha-1) in urea form. Seeds of canola (Brassica napus L. cv. Okapi) were sown on October 2, and fresh forage was harvested at the time of silique formation (170 DAP). Results showed that the effect of N and zeolite on forage quantitative attributes including biomass, leaf and stem dry weight and leaf area index were statistically significant. In addition, forage qualitative traits including crude protein percentage and calcium percentage in plant mass were significantly affected by N and zeolite. Increasing application of N fertilizer caused increase in N leaching, and with increasing zeolite application, N leaching reduced. The interaction of two factors for all parameters was not significant. The most increasing effects on forage yield and quality were gained using 270 kg N ha-1 in combination with 9 t. Zeolite ha-1. More detailed studies are strongly recommended to investigate the effects of integrated application of chemical fertilizer and natural zeolite.

To study the effects of different combinations of auxin (IBA, NAA) and cytokinin (BAP, TDZ) regulators, basal salts (MS, WPM, NN) and gelling agents (Gelrite and Plant Agar) on the growth and development of seedless grape explants (cv. Bidaneh Soltani), a factorial experiment was conducted based on a completely randomized design. The number and length of grown shoots were analyzed as two main characteristics. Growth regulators and salts had significant effects (at %1) on the shoot proliferation. The highest number of shoots was observed on MS salts combined with BAP (2.2 mg/l) and IBA (0.5 mg/l) on the 18th days of culture. Compared to Plant Agar, Gelrite had a better effect on the normal growth of the shoots. Based on the new shoots, combinations of MS salts and hormones may be used for micropropagation of seedless grape cultivars in the in vitro condition.

Control of tree size is one of the main problems for which techniques to reduce vegetative growth and increase fruit quality and yield are important in the orchard management system. With this aim in mind, mature peach trees of the cultivars J. H. Hale and Red Skin grown on peach seedling at the Moghan agro industrial orchard were used. The effect of paclobutrazol soil treatments, (0,0.5 and 1.5 gr/tree) on experimental trees during the dormant periods in the 1996-97 was evaluated. The experiment was carried out in a split plot on the basis of completely randomized design with six replications. The effect of paclobutrazol on some vegetative growth and relative water content of leaves was studied. Results showed that paclobutrazol significantly reduced vegetative growth in the first year of application the total dry weight of pruning in treated trees was less than that of controls. The high level of paclobutrazol caused the most growth inhibition. On a commercial scale, paclobutrazol treatment would be able to give substantial benefits to peach growers by saving in pruning costs.

Resveratrol (5,3,4'- trihyroxystilbene) is a valuable polyphenolic compound which prevents cancer, heart and vascular diseases in human. In this research, the compound was extracted from leaf and fruit tissues of two Iranian grape cultivars (Rajabie Sefide Shiraz and Keshmeshie Ghermez) using a general extraction method with some modification, and analyzed quantitatively by High Performance Liquid Chromatography (HPLC). Resveratrol content in leaf and fruit of Rajabie Sefide Shiraz cultivar was higher than Keshmeshie Ghermez and its amount in the fruits of both cultivars was observed to be greater than their leaves. The accumulation of Resveratrol at the early stage of fruit growth (4 weeks after full bloom) was higher than the subsequent stages of fruit growth and development (8 weeks after full bloom and ripened fruit) in both cultivars. This compound gradually decreased from the beginning of fruit set to the complete stage of growth and development and reached the lowest level when the fruits were ripe. Leaves and fruits of both cultivars were treated with methyl jasmonate (1 mM), then the rate of resveratrol was measured after treatments. It was observed that the amount of this compound was significantly increased in treated samples when compared with the control however, the difference diminished later. The fruits of both cultivars responded better to the treatments 4 weeks after full bloom.

Achillea wilhelmsii Koch. is an aromatic plants belonging to Asteraceae family that has relatively wide distribution in different parts of Iran. In this study, we compared essential oil contents and constituents in two wild populations under two different ecological conditions (Fars and Khorasan Provinces, South West and North East of Iran respectively). The blooming herbs were collected and the essential oils of the samples were extracted after drying by “Clevenger apparatus”. Essential oil constituents were determined by GC and GC-MS. Our results showed that “Khorasan” population of Achillea wilhelmsii contains more essential oils than “Fars” population (0.65 and 0.2 % v/w respectively). Thirty components of “Khorasan” population that were 96.94% of total components were determined successfully and the main components were camphore(19.06%), cembrene(10%), 1,8-cieole(8.78%), alpha pinene(8.06%) and linalool (7.47%). Thirty-two components (91.98%) of “Fars” wild population were determined and the main components were isopentyl-isovalerate(9.46%), alpha pinene(8.75%), 1,8-cineole(8.70%), eudesmol(10-epi-gama)(5.56%), spathulenol(4.94%). Cembrene(10%), Germacrene B( 5.68 %) and Sabinene(4.34%) were detected in Mashhad population but not in Shiraz population. 10-epi Gamma Eudesmole(5.65%), Benzaldehyde dimethyl acetal(4.47%) and Ionone (4.29%) were detected in Shiraz population but not in Mashhad population. In conclusion, there are differences between these two populations as far as essential oils content and constituents are concerned.

Seedlessness is the most important characteristic of fruit quality for raisin and table grapes. Grape breeding at University of Tehran, Karaj branch, Iran started in 1999 with crossing some selected seedless and seeded cultivars at the end of evaluation of 90 cultivars in grapevine collection of College of Agriculture in Karaj. Out of 1400 progeny obtained from 26 different crosses, 381 of them which produced fruits were evaluated during growing seasons of 2006 & 2007. Progenies were divided into four groups of completely seedless, semi-seedless, semi-seeded and completely seeded, according to seed trace or seed weight. Results classified progeny to 11% completely seedless, 13.6% semi-seedless, 24% semi seeded and 51.2% completely seeded. Percentages of seedless progeny for four male parents of Askary, Yaghooti, Bidane Sefid and Bidane Ghermez were 15.4%, 10.8%, 9.3% and 10.6%, respectively. Meanwhile, percentages of seedless progeny for female parents of Muscut of Hamburg, Ghezel Uzum, Dizmary, Rajabi Sefied, Ali Baba, Alhaghi Ghermez and Tabariz were 5.4%, 5%, 17.5%, 13.2 %, 1.4%, zero and 36%, respectively. Results also showed that among male parents, Yaghooti and Bidane Ghermez cultivars and among female parents, Tabarze cultivar had better backgrounds to transmit stenospermocarpic seedlessness characteristics.

Leaf chlorosis during both green house forcing and postharvest have been a long standing problem in Easter liliy. The symptoms typically start in the basal leaves and moves progressively upward and reduce flower quality and economic value of crop. In order to delay leaf chlorosis and increase vase life, an experiment was carried out on Asiatic hybrid Lilium cv Canova to study different treatments of benzyladenine (BA) and silver thiosulphate (STS) on pre and postharvest attributs, respectively. The results showed that preharvest application of BA effect the chlorophyll content of leaves significantly, but it s effect on stem and pedicle length and harvest time were not significant. Treatment of 0.44 mM BA on increased chlorophyll content greater than another treatments. In postharvest study, factors of 0.44 mM BA on chlorophyl1 content of leaves and leaf longevity, treatment of 0.88mM BA+ 0.6 mM STS on vase life, total soluble solids and uptake solution had most effect. The results showed that application of STS and BA can be used to prolong vase life, delay leaf senescence and enhance postharvest quality of lilium cut flowers during their transport market.

Because of many small florets and protandry, cross pollination in onion which is a biennial plant, by using polycross method for breeding is suitable and easy. To produce polycross seed, bulbs of 9 self onion genotypes were planted in the shape of equilibrium lattice design for 9 treatments with 10 replications on May 2002. To study some agronomical characteristicss, the polycross seeds produced from free pollination and original self-fed seeds (totally 18 genotypes) were planted in plots as a randomized block design with four replications. Samples were taken from each plot and different characteristics were measured. Results showed that polycross generally increased plant fresh and dry weight, plant height, percentage of off type bulbs and yield, with no effect on bulbing ratio and time to ripening. Although polycross increased most agronomical characteristics and yield in Kashan, Azarshahr and Kazeroon genotypes, in some genotypes little increase or even negative effects resulted due to interaction between genotype and polycross. With more assessment of polycross genotypes, good characteristics will be fixed and seeds with higher qualities will be produced.

Grapevine (Vitis vinifera L.) is a clonally propagated major fruit crop. In grapevine, identification of genotypes with amplographical features is often based on mature plant characteristics that may be affected by environmental conditions. This approach lacks objectivity and reliability. Recently, molecular markers have proved to be supplementary techniques to analyze genetic diversity and examine genetic relationships existing between cultivars in a range of horticultural crops. In this study, twenty genotypes from grapevine (V.vinifera species) grown in Isfahan province were characterized by RAPD technique to understand the extent of diversity and relatedness. Fifty random primers were used for the RAPD study. Of those, twenty four informative primers which generated reproducible polymorphic bands were used for grouping the genotypes. PCR products of the genotypes’genome revealed a total of 315 bands, out of which 282 were found to be polymorphic. Average number of 13 bands was obtained per primer and the amplification produced ranged in size from 300 bp to 3000 bp. The dendrogram constructed using UPGMA cluster analysis differentiated the genotypes into two major clusters, nineteen in one group and Madar-o-Bache genotype has been placed in a separate one, indicating its high genetic diversity compared to the rest of the genotypes. Intra-clustering within cluster A grouped the genotypes in four sub-clusters as expected from their genetic background. The results of the study revealed that the RAPD technique is a relevant technique to determine genetic diversity, genomic analysis and to examine genetic relationship in grapevines.

The purpose of this study was to investigate dairy farmers' attitudes regarding the quality of milk and role of training in improving the quality of milk. The study was implemented in two parts. The first part was survey research and 6200 dairy farmers were the target population for this study in Golpayegan Township, Iran. Dairy farmers were selected using stratified randomization sampling method (n= 130). In the second part, 12 dairy farmers were selected. Plate count and lipid percentage of milk in 12 dairy farms were determined in a completely randomized block design with 2 treatments and 3 replications. The results of the study showed positive and statistically significant relationship between independent variables (sex, educational level, membership in dairy :::union:::s, knowledge and participation in educational programs) and dependent variable (attitude). Results of analysis of variances showed that plate count and lipid percentage in the two treatments were significantly different.

Kernel hardness is one of the most important characterizations on end-use quality of bread wheat and also used for their marketing classification. Kernel texture, mainly controlled by one major locus (Ha) located on the short arm of chromosome 5D. Two tightly linked genes as puroindolin a , and b covered by this major locus and designed as Pina and Pinb respectively. When both puroindolines are in their ‘functional’ wild state, grain texture is soft. When either of the puroindoline alleles is absent or alter by mutation, then the result is hard texture. In this study, 61 Iranian commercial cultivars and 92 landraces were investigated for their kernel hardness and puroindoline alleles using SKCS and, PCR and cleaved amplified polymorphic sequences (CAPS) techniques respectively. Specific primers were used to amplify Pina and Pinb. The results indicated that frequency of hard, mixed and soft genotypes were 65.6, 19.6 and 14.8% respectively, in commercial cultivars and 58.7, 13 and 28.3% in landraces varieties. Among hard type of commercial cultivars, 18 and 5, genotypes have identified as Pina-D1b and Pinb-D1b respectively. Kavir was only cultivar with Pinb-D1e allele. Pinb-D1b allele was identified in two hard types of landrace varieties. Surprisingly, Pinb-D1c was not found in any varieties. Influence of the above proindoline alleles on kernel hardness showed that the SKCS hardness index of Pina-D1b was significantly higher than that of Pinb-D1b. Our knowledge about the genetic basis of kernel hardness could provide useful information in breeding programs of bread wheat.

Drought is a major factor limiting growth and development of crops such as mung bean (Vigna radiate (L.) wilczek) in arid and semi-arid regions of the world. This study was conducted to investigate the effects of different timing and severity of drought stress on physiological traits of mung bean and its relation to grain yield. A field experiment was carried out during 2004 growing season at Experimental Farm of Agriculture College, University of Tehran, Karaj, Iran. The treatments were laid out in a Randomized Complete Block Design (RCBD) with three replications. Plants were exposed to moderate and severe water stresses at either vegetative (VS) or reproductive stages (RS). Physiological traits were measured at the end of vegetative and the middle of pod formation. Generally water stress reduced leaf net photosynthesis rate, stomatal conductance and leaf relative water content at different growth stages. The effects of RS treatments were more severe than that of VS one. Severe VS treatment increased photosynthetic water use efficiency, whereas RS treatments decreased it significantly. However, leaf area index and total dry matter were more responsive in VS compared to RS treatments. VS treatments did not affect harvest index, while RS treatments reduced it significantly. Drought stress also reduced grain yield by 9 and 49 % (relative to control plants) in severe VS and severe RS treatments, respectively. Therefore irrigation is critical during reproductive stage mainly because of the higher demand for photoassimilate. It is concluded that to maximize mung bean grain yield in arid and semi-arid areas, appropriate watering should be practiced across all phenological stages in general, and during reproductive stage in particular.

In the process of agricultural development, sustainability of pasture utilization to ensure sustained production of meat and dairy products has become increasingly important. This article aims to study factors affecting pasture and meat production imbalances in Fars province. For this purpose, the transcendental production function was used. Data was collected by using two stage cluster random sampling from 71 producers. The results revealed that present method of pasture utilization is not compatible with increasing live animal meat production objective. To optimize pasture utilization, the pasture users should be advised to stop overgrazing. In addition, the results indicated that increasing livestock and pasture mismanagement causes damage to pastures and consequently would decrease meat production in the long-run.

This study used a Ricardian approach to measure the impact of climate change on Iranian wheat production and analyzed potential impacts of further climate changes. The study utilized time series data for the period 1984-2004 pooled over 17 provinces. Results showed that climate change has significant nonlinear impacts on net revenue per hectare of wheat in Iran. The results also showed that rise in temperature and reduction in rainfall by the year 2100 will cause the reduction in land value by 41 %, because of increased greenhouse gas emission.

Safflower having oil with high unsaturated fatty acids is a very valuable plant. However the sensitivity of safflower to some pests as safflower fly (Acanthiophilus helianthi), particularly in drought stress conditions has limited its production. In order to evaluate the effect of drought stress on population density and damage of important safflower pests, especially safflower fly, an experiment was conducted in the field using 5 irrigation treatments including 50, 70, 90, 110 and 130 mm evaporation from class A pan in a randomized complete block design with three replications. The local safflower variety used in this study was Isfahan land variety, Kooseh. In each irrigation regime, the half of one plot was locally sprayed by Chlorpyrifos in 2ml per liter of water to be compared with non-sprayed part. During 8 weeks of sampling, population of aphids, Uroleucon carthami, leafhopper, Empoasca decipiens and safflower fly, A. helianthi and also percentage of damaged heads by safflower fly were measured. The results showed that in non-sprayed conditions, the highest safflower fly (2.38 flies per net) and aphid population (165.57 aphids per plant) was observed at 130 mm evaporation regime. Drought stress also decreased (30.23 %) safflower seed yield. Severe drought stress together with non-spaying may increase safflower pests population particularly safflower fly and reduce seed yield. However low level of drought stress (70 mm evaporation from class A pan) may decrease relative number of insects and save irrigation water. Drought stress also decrease the population of leafhopper. In this study, 70 mm evaporation regime was the optimum irrigation treatment regarding lower aphid and fly damage (15.86% damaged heads in non-sprayed condition) and higher safflower seed yield (1687.5 kg/ha in sprayed condition).

Rose is one of the most important ornamental shrubs of the world because of its durability, long period of flowering, different cultivars and its beauty. The rose aphid, Macrosiphum rosae is the most important pest of the rose which causes significant economic damage annually. In order to compare four rose cultivars including Black Magic, Caramba, Noa and Good Life, and a wild rose, Nastaran, infested with rose aphid, a split-plot in time experiment was arranged in randomized complete block design layout with three replications, in Isfahan (Iran) from February 2004 to March 2005. The infestation levels of roses with the rose aphid and its seasonal fluctuations were determined by weekly sampling. Analysis of data showed that there are significant differences (P<0.01) between cultivars. Noa (with pink flowers) has the highest infestation of rose aphid (with average 23.12  ± 0.036 aphids) and Caramba (with yellow flowers) has the lowest infestation (with average 6.46  ± 0.036 aphids). The wild rose, Nastaran, showed low infestation (with average 8.76  ± 0.036) as well. Different sampling times also showed significant differences (P<0.01). There was a significant interaction (P<0.01) between cultivars and sampling date, such that reactions of cultivars to aphid (nymphs, adults and total) were not similar in different sampling dates. Seasonal fluctuations of the rose aphid showed two peaks in a year, in May and December. Activity of the rose aphid in spring which coincides with rapid growth and tenderness of rose foliage causes severe fading and inhibiting of floral opening.

Onion thrips (Thrips tabaci Lind.) is one of the important factors which indirectly restrict the proper yield of onion (Allium cepa L.). Therefore, finding tolerant cultivars to onion thrips is important. Because of many small florets, cross pollination in onion which is a biennial plant by using polycross method for breeding is suitable and easy. To produce polycross seed, bulbs of 9 self pollinated onion genotypes were planted in the shape of equilibrium lattice design for 9 treatments in May 2002. To study tolerance to onion thrips and assess other agronomical characteristics, the polycross seeds produced from free pollination and self pollinated plant seeds (totally 18 genotypes) were planted in a randomized block design with four replications. The main plots were sprayed and not sprayed, and sub-plots were onion genotypes. From August to October 2003, samples were taken from each plot bi-weekly, and number of thrips, and percentage of injury on plants were recorded. As a result of this study, Azarshahr self pollinated genotype showed maximum population density of thrips (22.24) and injury, but Ghom and Abarkooh genotypes showed the lowest amount (2.65 and 5.68 respectively) among all genotypes. Among pollycross genotypes, Ghom and Kashan genotypes showed low population densities (4.3 and 4.24 respectively) and injury, but Azarshahr and Tarom showed high population densities (20.66 and 19.84 respectively) and percentage of injury. Generally, polycross reduced population density of thrips and percentage of injury.