جستجوی مقالات مرتبط با کلیدواژه « ژنوتیپ » در نشریات گروه « گیاهپزشکی »

Fungal species Fusarium pseudograminearum, F. culmorum and Bipolaris sorokiniana are the most economically important pathogens causing crown and root rot of cereals. The use of resistant cultivars can be the most efficient measure to reduce the effect of this disease. As an alternative strategy, screening of resistant wheat genotypes has been emphasized in the recent studies. This research was conducted to evaluate level of resistance of 66 genotypes of bread wheat and durum wheat to B. sorokiniana, F. pseudograminearum and F. culmorum isolates in greenhouse condition. These experiments were conducted based on completely randomized design with seven replications in greenhouse condition. The results showed that, 11 genotypes including C-87-11, C-87-18, BACANORA /3/MASON/JGR//PECOS, 05899G01-2, F06580G2-1, F06659G6-1, McCormick/Trego, VA01W-205/TX99D4628, GA951079-3-5/Neuse, Owl,85224*-3H-*o-HOH/7/T.SPH/2*H567.71//4/CMH79.959/6/Gaspard and AWD99*5725/FL9547 were moderately resistant to diseases caused by B. sorokiniana isolates and its combination with F. pseudograminearum and F. culmorum. Among these genotypes, three genotypes C-87-11, GA951079-3-5 / Neuse and 05899G01-2 were resistant to the combination of all diseases caused by these three fungal species. These genotypes have potential to be incorporated into wheat breeding programs. Cluster analysis of reaction of wheat genotypes to all diseases caused by these three fungal species, as well as to different combination of them were able to separate susceptibe and relatively resistant genotypes from each other. In both dendrograms, genotypes that were relatively resistant to disease caused byB. sorokiniana and its combination with other diseases caused by fungal species were grouped into cluster 3.

One of the most destructive diseases of pome fruit species which causes irreparable damage to gardening products worldwide is fire blight disease caused by Erwinia amylovora. In Iran, it was first observed in pear trees in Alborz province and then spread across fruit orchards in the country. One of the main problems in fire blight management is evaluating causal agent genotypic characteristics. Thus, the present research was conducted to characterize genotypic features of E. amylovora as the cause of fire blight disease in pome fruit species in Hamadan province, Iran.

In this study, the samples with symptoms of canker on shoots and blight blossoms were observed and collected from the orchards in Hamadan province located in the west of Iran. After isolation, the isolates were purified for further studies. Phenotypic, biochemical, and pathogenicity tests were performed due to standard bacterial criteria. Phenotypic and biochemical tests of strains were examined by Ntsys-pc 2.02 software. A total of 15 representative isolates were selected and analyzed due to the size of amplified DNA using primers Ea71 and genetic features of the rep-PCR test using primers ERIC and BOX. For more accuracy and higher reliability of the specific primers results, the 16S rDNA_ gene of two representative isolates was amplified and subjected to sequencing.

Based on the biochemical, pathogenicity and molecular tests, a total of 34 isolates were identified as E. amylovora. Due to the numerical analysis, the data obtained by phenotypic and biochemical tests were similar at 89% level. Therefore, the isolates obtained from a specific host or region was grouped very close to each other. In the PCR tests survey, the isolates amplified 187 base pair expected fragments. The results of determining sequences indicated that both isolates were similar to E. amylovora showing 97% identity to the type of strains in the NCBI database. Due to data from the rep-PCR analysis, the isolates were divided into three groups at the similarity level of 77%.

The results of genetic diversity using rep-PCR showed that there is no significant difference among E. amylovora bacterial isolates from different regions of Hamadan Province. Moreover, they showed high similarity to each other and placed close to each other. Our results confirm other studies regarding phenotypic characteristics of E. amylovora. Our results confirm that the isolates are homogenous in Hamadan province of Iran. To summary, these findings can be applied to breeding programs to better management of the bacterial disease.

Stem or black rust caused by Puccinia graminis f. sp. tritici (Pgt) is one of the most destructive wheat diseases in the world, including Iran. Investigation of virulence factors on wheat resistance genes, identification of resistance sources to stem rust among host genotypes and determination of effective resistance genes in resistant wheat genotypes are the requirements of using genetic resistance (production of resistant cultivars) as the most efficient and healthy way to control this disease. To assess the seedling resistance of 30 wheat genotypes, which produced CIMMYT Center (International Maize and Wheat Improvement Center), and introduced as resistance sources to stem rust was investigated with six different Pgt races base on randomized complete block design with three replications. Race analysis of Pgt isolates was done to identify of their virulence on resistance genes (Sr) of stem rust at the greenhouses of the cereal section of the Seed and Plant Improvement Institute. The results indicated that the races were TKTTF, TTTTF, PKSTC, TTRTF, TKSTF and PTRTF. Genotypes carrying the genes Sr22, Sr24, Sr26, Sr31, Sr32, Sr33 and Sr40 were resistance against all the Pgt races, and are introduced as the differential cultivars with effective Sr resistance genes. Genetic resistance components including infection type and latent period for each genotype were recorded under greenhouse conditions. The results of the genetic resistance components showed the existence of phenotypic variation in the response of genotypes to stem rust races. Resistant genotypes identified in this study (genotypes 4, 5, 6, 7, 8, 9, 11, 13, 14, 16, 17, 18, 20, 21, 22, 25, 26, 27, 28 and 29) can be used as seedling resistance resources in national wheat breeding programs for genetic resistance to stem rust in different climates of the country.

Crown and root rot are important diseases of different small-grain cereals, especially wheat and barley which are caused by soil-borne fungi Fusarium culmorum and F. pseudograminearum. For controlling such diseases, application of fungicides is inadequate, and cause hazardous effects for environment and living organisms. As an alternative strategy, screening of resistant wheat genotypes has been emphasised in the recent studies. This research was conducted to evaluate level of resistance of 66 cultivars/advanced lines of bread wheat and durum wheat to F. culmorum and F. pseudograminearum isolates in greenhouse and field conditions. These experiments were conducted based on completely randomized design with seven replications in greenhouse and randomized complete block design with 4 replications in field condition. The results showed that, 12 genotypes including C61 (C-87-18) and C62 (C-87-11), C38 (F06659G6-1), C43 (POLOVCHANKA/PEHLIVAN), C52 (McCormick/Trego), C37 (F06580G2-1), C35 (Prostor), C54 (VA01W-205/TX99D4628), C50 (GA951079-3-5/Neuse), C58 (Burbot-6), C53 (AWD99*5725/FL9547) and C34 (Gelibolu) were moderately resistant to F. culmorum and F. pseudograminearum isolates. These genotypes have potential to be incorporated into wheat breeding programs.

Barley is one of the world's main sources of nutrients for human and animal, and E. integriceps is one of the most important pests reducing its yield. This study was conducted on different barley genotypes to identify the genotypes that are resistant to Sunn pest. The study was a randomized complete block design with three replications that was conducted in 2016 and 2017 in Neyshabour Agricultural Research Center. The results showed that the highest number of E. integriceps was recorded in genotype 3 and the lowest number of E. integriceps was related to genotypes 2 and 6. Genotype 13, with the important indices of grain yield under non-stress condition (Yp) and genotype 10, with the important indices of grain yield under stress condition (Ys) in the region, were identified to have high yield potential and low sensitivity to E. integriceps. Yp had a positive and significant correlation with the mean of productivity (MP), geometric mean (GMP), and stress tolerance index (STI). YS had a positive and significant correlation with all indices except stress susceptibility index (SSI) and tolerance index (TOL). Therefore, the MP, GMP, and STI were the only indices that showed a positive and significant correlation with Yp and Ys. In conclusion, based on the results of this study, genotype 20 can be nominated as a E. integriceps-resistant genotype in Neishabour region. Genotype 1 can also be reported as a sensitive genotype to E. integriceps with low yield.

Maize is among the world's three most important cereal crops. Weeds are one of the most important factors that reduce maize production. They cause important yield losses worldwide with an average of 12.8% despite weed control applications and 29.2% in the case of no weed control. Weeds compete with crops when they remove a portion of a resource from a shared resource pool, leaving the crop with less of the resource than is needed for optimum growth. Competition may occur for water, creating or exacerbating water stress. It may occur for nutrients such as nitrogen, leading to chlorosis, leaf senescence and yield loss. Increasing the ability of a crop to compete with weeds has been considered an approach to improving weed management in recent years. The importance of weed competition in maize depends on the maize genotype, weed species, crop growth stage, the weed density, the level of water, and nutrient stress. Some crops can significantly suppress weeds by their ability to grow faster than weeds or to endure greater sowing densities. The plant competitive ability can be expressed in the following two modes: First, the crop weed suppressive ability (WSA) that results in the reduction of weed biomass and second, the crop tolerance ability (CTA) to tolerate weed effects and to have high yields at the same time. Crop tolerance to weed interference aims to improve stability of yield and quality in weedy fields, whereas weed-suppressive ability targets the long-term management of weed populations by reducing seedbank size. Several traits, including the growth intensity in the initial developmental stages, rapid development of a high leaf structure, the plant height, maximum LAI, rate of canopy closure, height of LAI, and leaf architecture, may improve weed-suppressive ability and dent maize tolerance to weed interference. Therefore, the objective of this experiment was to evaluating the competitive ability of maize (Zea mays L.) genotypes against weeds under different nitrogen rates.
Experiments were carried out on clay loam soil with low organic matter content (less than 1%) and a pH of 2.9 at south west Iran in 2011-2012 growing season. The experiment site had a hot climate with a moderate winter and dry and hot summer. Treatments consisted of a split-plot with randomized complete blocks design and three replicates. Nitrogen rates (0, 90, 180 and 260 kgNha-1) were the main plots and four dent maize hybrids Sc.704, DKC6589, Mobeen and Sc.640 were planted in sub-plots. DKC6589, Mobeen and Sc.640 are an early-season hybrids, whereas Sc.704 is relatively late-season hybrid. Plots consisted of 6 maize rows (distance between and within the rows 75 and 18 cm, respectively) and 6 m long. Maize hybrids were sown on 1st Jun. Fields received 100 kgPha-1 and 150 kg K ha-1. The P and K were supplied in the form of single superphosphate and potassium sulfate, respectively. Nitrogen treatments were applied in two equal splits as urea (46% N) at two and six weeks after planting by side placement. Each plot was divided into two parts hypothetical. One part was maintained weed-free and another weedy for the all maize duration growth stages. In weed-free parts, weed removal was started immediately after crop emergence and the plots were kept weed-free for different growth stage durations until physiological maturity of maize. The experiment was properly monitored and irrigated whenever water was needed. Weed plants were harvested at the R1 (silking) growth stage of maize using 0.5×0.5m quadrate, and weed biomass obtained by drying tissues at 68 C to constant mass. Weed density and species also, determined. Interference of maize and weed was quantified by calculating weed index (WI), weed interference tolerance index (WITI) and competition index (CI(. Statistical analysis was made using the SAS statistical software. Differences between traits means were assessed using Duncan's Multiple Range Test.
The percent loss of grain yield, 100 grain weight, biological yield and grain number per rows under weed interference conditions were 21.7, 5.3, 24 and 10%, respectively. Grain yield reduction in weedy plots was resulted from decreasing grain number per rows and biological yield. Negative impact of weeds on maize yield was enhanced under higher rates of nitrogen. When maize competed with weeds, the reduction of grain yield at 260 kg N ha-1 treatment was more compared to 180 kg N ha-1maize. Maize genotypes were different in response to weed competition. The highest weed tolerance interference index was obtained in DKC6589 line due to higher grain yield in both weedy and weed-free plots. Competition index was higher in Sc. 704 and DKC6589 than other genotypes. Although Mobeen and Sc.640 hybrids had lower grain yield reduction trend under weed competition conditions, but DKC6589 and Sc.704 showed a high grain yield potential and high ability to withstand weed competition.

Plant resistance to insect pests as a method of pest control in the context of IPM has a greater potential than any other method of pest suppression. Development of crop varieties resistant to insect pests and diseases has been the major research thrust at ICRISAT (International Crops Research Institute for the Semi-Arid Tropics) for sustainable crop production. The most attractive feature of host plant resistance (HPR) is the simplest seed-based technology for which farmers do not need any extra skills concerning the application, and any additional cash investments. Sugar beet root aphid Pemphigus fuscicornis Koch (Hem.: Aphididae) is one of the most important pests of sugar beet, Beta vulgaris L. in many countries. Variability in response to root aphids by commercial varieties is demonstrated by Campbell and Hutchison (1995). Sugar beet variety trials in the western plains region have shown that sugar beet varieties vary greatly in the level of resistance to sugar beet root aphid feeding. Correlative data from these trials in Nebraska, Wyoming and Colorado indicate that varieties being susceptible to root aphids had the yield reductions as much as 30% compared to those varieties with a high level of resistance. Cultivars resistant to root aphid, Pemphigus spp. have been highly successful and the resistance has been stable for more than 30 years in Texas or other areas. Several seed companies have had trouble developing resistant cultivars and even those companies with resistant parental lines required an evaluation of new hybrids.
In this research that was carried out during 2010- 2011, the responses of Pemphigus fuscicornis to 12 sugar beet genotypes (19610, OtypeA37.1, Simin2, 19584, Jit13, Polyrave, OtypeA1, Shirin, Zarghan, OtypeC2, Chinock, Branco) were examined under the laboratory conditions. The sugar beet seeds were planted in the field, and plants were grown to 6 true leaf stages, then were transplanted into a peat-vermiculite mix (50:50) in pots. Four young adult aphids were placed in the root mass before placement into the pot. The plants were irrigated weekly and the incubator was set at 20±2ºC and 16 h in the artificial light. Sixty days after root infestation, the aphid populations were evaluated by floating aphids out of the root mass in 20-cm diameter bowls and they were classified as adults and nymphs based on the presence of the sub-genital plate as an indicator of maturity. Therefore, all count data were transformed by log (x) before the analysis. Statistical analyses were performed using SAS statistical software (SAS Institute Inc, Version 9.1) and means comparison of treatments were done by Tukey's tests.
Sugar beet variety trials in the laboratory conditions have shown that sugar beet varieties vary significantly in the level of resistance to P. fuscicornis feeding. There was a significant difference among aphid population densities with regard to different host plant varieties (F=10.56, df=11, 43., P=0.0001). Out of 12 genotypes, line 19610 was highly susceptible, OtypeA37.1 and Simin2 were susceptible, 19584, Jit13, Polyrave and OtypeA1 were moderately susceptible, Zarghan, Shirin and OtypeC2 were moderately resistance and Chincko and Branco were resistance to P. fuscicornis at laboratory condition. Also, the effect of root aphid infestation on the sugar content of plant showed that, P. fuscicornis significantly decreased the sugar content (F=42.05, df=3, P=0.0001) in Doreti variety at field conditions. So, more than 15 percent of infestation to root aphid at harvest time significantly decreased the sugar content.
Based of the present results, it is concluded that planting of resistant varieties (Chincko and Branco) or moderately resistant varieties (Zarghan, Shirin and OtypeC2) will have a significant effect on reducing the aphid damage in this area. However, it is recommended that these varieties to be examined under greenhouse or field conditions. In this research, screening for resistance has been carried out under laboratory conditions. Laboratory tests are useful to confirm the resistance observed under field conditions. Procedures for infestation and evaluation of resistance under field, greenhouse or laboratory conditions using artificial infestation need to be standardized to breed for plant resistance to this pest. Insecticides have been unsuccessful for controlling root aphid, P. fuscicornis and for chemical control to be effective, a soil drench or systemic action through the sugarbeet plant may be necessary.

Sunflower rust is one of the most important diseases of the host in main cropping areas of Iran and resistance sources among the plant germplasm are accessible. Sunflower rust disease caused by Puccinia helianthi was reported first time at 1822 on collected samples from Eastern south areas of United States. It is considered as an important disease for sunflower cropping areas of South and North America, Argentina, Africa, India, China, and Australia and has been reported on the host worldwide. Incidence and severity of the disease on commercial hybrids had been increased up to early 1990s in Canada. Between 1988-89, the incidence on crop was reported up to 60 percent; whilst highly infected fields were appeared at the end of crop season. Puccinia helianthi has a worldwide distribution on sunflower and all species of Helianthus. There are also four other species which cause rust on cultivated and wild sunflowers. P. enceliae and P. masalis have been reported on wild sunflower and composites from southwest of United States. P. xanthi with a worldwide distribution on Xanthium Spp from Australia and Coleosporium helianthi from eastern areas of U.S. have been reported. Investigations reported some areas of Mazandaran and Golestan provinces showing infection including Behshahr, Kalaleh, Golidagh, Kalpoosh plain and Gonbad. Sunflower rust in Iran is considered as one of the important diseases which cause economic losses every few years. For instance, it caused 10 percent yield loss and 9.8 percent loss for oil yield. Genetic studies revealed that resistance is controlled by two dominant genes R1 and R2. By these identified genes, four physiological races of the pathogen became determinable. The presence of several resistant sunflower lines to rust with different origins reveals genetic variation for resistance to the disease. In this study, the variation of physiological races of sunflower rust was investigated to identify possible new races of the pathogen, Puccinia helianthi, and reaction of the host genotypes was also evaluated to the identified races.
Rust-infected leaf samples were collected from provinces Golestan and West Azarbayjan in 2010, and 8 isolates were inoculated on susceptible cultivar Record for physiological race identification purpose. Employing single pustule technique, the isolates were purified. The isolates after mass-production in separate chambers were inoculated on 9 standard differential lines. Inoculation and incubation methods were the same as for race identification procedure. The reaction of sunflower genotypes was evaluated by measuring pustule coverage percentage (PCP) according to computer-generated leaf diagrams depicting various percentages of leaf area covered with rust pustules. The interpreting resistance method proposed by Gulya and Masirevic (1995) was used in which three reaction patterns are defined as follows: immune (PCP= 0%), highly resistant (0.5%>PCP>0%) and susceptible (PCP.1%).
All collected isolates from the two main areas (i.e. Khoy and Golidagh) infected the non-resistant Perodovic cultivar indicating the pathogenicity of them. In addition, lines HA-335 and 803-1 were susceptible to all isolates. Lines RHA-265 and QHP1 demonstrated resistance to isolates collected from Golidagh, whereas the isolates of Khoy infected both lines. The results showed physiological differences between the main collection areas and presence of two dominant races. On the basis of pathogenicity similarities on common differential lines, races 302 and 300 were determined as dominant for Golidagh (Golestan) and Khoy (West Azarbayjan), respectively. Resistance evaluation of sunflower germplasm against rust disease was done under controlled greenhouse condition. The genotypes were tested by powdering the plants with mixture of the race's spore and Talc powder. The results demonstrated that 10 and 6 sunflower genotypes including hybrids Ghasem and Barzegar, their restorer lines and cultivar Gabor individuals were resistant against races 302 and 300, respectively.
Occurrence and distribution of physiological races of sunflower rust has importance in plant breeding research; as the process of breeding for resistant genotypes would be broken without considering the variation and distribution of the disease physiological races. In addition, genetic resistance to rust is controlled by dominant genes. Thus, access to new resistant sources in sunflower breeding is more likely. Among 23 lines and individuals of sunflower derived at the breeding processes, 16 resistant ones could help breeders to improve and release new hybrids or varieties containing resistance sources to the rust.

In this research, the reaction of 138 sugar beet half-sib families and their 11 parental populations to powdery mildew (Erysiphe betae Weltzien Vanha) was studied in a randomized complete block design with three replications at Motahari Research Station, Karaj, Iran in 2013. A linear scale of 0-9 was used for disease rating. On the basis of disease scoring conducted in 10th September, 22 genotypes with a score lower than 2.5 were found to be disease resistant. The families HSF-850, HSF-853, and HSF-848 with the disease score of 1, 1.2, and 1.3, respectively, were the most resistant families. Regression analysis showed that white sugar yield and sugar content were decreased by increasing the disease. Cluster analysis classified the initial populations as well as their half-sib families into 7 groups. Among these, most of the tolerant/resistant genotypes were clustered in the group 5 which could be used for resistance transfer. The cluster 2 included the genotypes HSF-584, HSF-582, HSF-557, HSF-551, HSF-866, HSF-844, HSF-670, HSF-556, HSF-628, HSF–610, HSF-564, HSF-685, HSF–619, HSF–664, and HSF-558 which were considered as families with optimum root yield, white sugar yield, white sugar content and sugar content. Therefore, these families could be used as pollinator parents to develop hybrid varieties or they can be exploited in the next cycle of family selection to develop new half-sib or full-sib families.

Sunn pest, Eurygaster integricepsPuton (Hem: Scutelleridae) is one of the most important pests of wheat in Iran, which causes considerable annual quantitative and qualitative damages to the crop.In order to evaluate the resistance of wheat genotypes to the nymphs of Sunn pest, 25 endemic wheat genotypes were studied at the Agricultural Research Station, University of Kurdistan. The experiment was carried out in a random complete block design with three replications. The analysis of variance showed significant differences among the genotypes for the mortality of Sunn pest nymphs, the weight increase of the adults and the percentage of damaged seeds. In addition, the results of correlation analysis showed that there was a positive significant correlation between the percentage of damaged kernel and covering kernel by glume and glomels (P

These days, researchers are trying to develop an efficient production technology based on the innovative techniques to increase seedling vigour and plant establishment through physical seed treatments. Seed germination is an important phenomenon in modern agriculture because it is a thread of life of plants that guarantees its survival. Nanotechnology has emerged as an innovative technology for the elaboration and use of new nanomaterials in the industry and many fields of research. It opens up a wide array of opportunities in various fields like medicine, pharmaceuticals, electronics and agriculture. Nanotechnology has the potential to protect plants, monitor plant growth, detect plant and animal diseases, increase global food production, enhance food quality, and reduce waste for “sustainable intensification”(Chandra Rath et al, 2017). Zinc (Zn) is an essential nutrient required by all living organisms. It has been considered as an essential micronutrient for metabolic activities in plants and animals. Zinc has important functions in the synthesis of auxin or indole acetic acid (IAA) from tryptophan as well as in biochemical reactions required for formation of chlorophyll and carbohydrates. It also regulates the functions of stomata by retaining potassium content of protective cells. The crop yield and quality of produce can be affected by deficiency of Zn (Pandey et al., 2006). Zinc oxide (nano-ZnO) is commonly used metal oxide engineered nanoparticle. It is used in a range of applications such as sunscreens and other personal care products, electrodes and biosensors, photocatalysis and solar cells. Seed is an important stage of plant life history. Most invasive plants primarily rely on seedling recruitment for population establishment and persistence. Rapid spread of many invasive plants is frequently correlated with special seed traits. Seed trait variations exist not only among species but also within species. Seed traits variations within a species are essential for seedling establishment at different habitats (Grundy et al., 1996). Germination of various plants has a different response to nanoparticles. Application of nanoparticles that have a positive effect on germination and growth of crop and a negative effect on weed can be useful in weed control.
In order to study the effect of different concentrations of ZnO on germination characteristics of wild oat and two genotypes of wheat, an experiment was conducted with a factorial arrangement based on completely randomized design with four replications in research laboratory of Ilam University. The experimental treatments were plant genotypes (wild oat and Behrang and Sivand genotypes of wheat) and different concentrations of ZnO (0, 10, 100 and 500 ppm). Germination of seeds was determined by placing 30 seed in a 9-cm-diam Petri dish containing two layers of Whatman No. 1 filter paper, moistened with 5 ml of distilled water or a treatment solution. The treatments of ZnO were applied in Agar complex. After treatment, the dishes were sealed with paraffin tape, and placed in the dark in an incubator at 25 °C. The number of seeds germinated was counted every day. Seedling and radicle length, seedling and radicle dry weight and germination rate were measured. Data were subjected to two-way analysis of variance (ANOVA) and the difference between treatment means was separated using Duncan test. A significance level of 95% was applied by SAS 9.2.
The results showed that the simple and interaction effects of genotype and ZnO had a significant effect (P ≤ 0.01) on all studied traits. The plumule length of both wheat genotypes was increased to 100 ppm ZnO concentration and then was decreased. The plumule length of oat wild was increased by increasing ZnO concentration. Increase in ZnO concentration to 10 ppm caused a significant increment in the radical length of sivand genotype and wild oat, and the trait was reduced after mentioned concentration. The radical length of behrang genotype was declined as ZnO concentration increased. The applied ZnO treatments caused a significant reduction and increase in plumule dry weight of behrang genotype and wild oat, respectively, whereas they had an insignificant effect on plumule dry weight of sivand genotype. Increased ZnO concentration negatively influenced the plumule dry weight of wild oat and behrang genotype and positively affected the plumule dry weight for sivand genotype. Germination rate and percentage of the both wheat genotypes were not affected by nanoparticle, but, increased ZnO concentration caused a significant increment in these traits in wild oat.
Overall, the results illustrated that application of ZnO nanoparticle in wheat agroecosystems can lead to a higher germination rate and growth of wild oat compared to wheat, and is not recommended.

To assess resistance of different genotypes of safflower to safflower shootfly, 10 genotypes of this plant were evaluated in autumn sowing. The experiments were conducted in a complete blocks design with three replications in Agricultural Research Station Gryzeh-Sanandadj and two growing seasons (2011-2012 and 2012-2013). In this trial some parameters such as rates of infestation and damage, yield, weight of 1000 seeds and percent of oil were measured and compared in different plots. Analysis of variance of percent of infested capitula, number of larvae and pupae, number of damaged seeds, weight of 1000 seeds, percent of oil of seeds, and yield revealed significant difference between genotypes at the 1% probability level. Based on the comparison of mean values, the local varieties named Isfahan and Lesaf had highest and Syrian had lowest percent of infested capitula. Accordingly, local variety of Isfahan had maximum and local genotype of Marand had minimum number of larvae and pupae per capitula. The Lesaf genotype was more susceptible and had highest percent of damaged seed and genotypes of local Isfahan, Marand and Syrian had the lowest number of damaged seeds. Evaluated genotypes were divided into two main groups based on the results. The first group including Syrian, local Marand, Sina, 411 and IL111, with lowest percentage of infested capitula, lowest number of larvae and pupae in the capitula and lowest percent and number of damaged seeds, could be considered as relatively tolerant to the safflower fly. Syrian and local genotype of Marand, were more tolerant among the rest. The second group including Isfahan, Lesaf, S-541, Dinser and coarse-grained Almaneh, with the highest percentage of infested capitula, the highest number of larvae and pupae in the capitula and highest percent of damaged seeds, could be considered as susceptible to the safflower fly. Local cultivar of Isfahan and Lesaf were more sensitive than others.

Sulfonylurea (Su) is one of the important groups of herbicides which control weeds through inhibition of the acetolactase synthase enzyme, a key enzyme in the synthesis of amino acids. Their main character by which can be distinguished from other groups are their low cost, effectiveness against wide spectrum of weeds in cereal crops (mostly broad leaved plants), operator safety, and activity at low concentrations. However, many of the crops and vegetables which are grown in rotation with cereals are very sensitive to Su residues. Among crops, legumes are very sensitive at low levels (as low as 0.5 ppm). Therefore much less than 5% of recommended application rates for controlling weeds, will be applied cause not to damage other crops. Root growth is particularly sensitive to Su residues. Since the studies have not been conducted in the country in connection with possible effects of soil residue of foramsulfuron and rimsulfuron herbicides on growth,nodulation and biological fixation in chickpea (Cicer arietinum L.), The objective of this research was to study the effect of soil residue of mentioned herbicides in soil on chickpea, growth, nodulation and nitrogen fixation in control conditions. A greenhouse experiment was conducted at the Research Greenhouse of Ferdowsi University of Mashhad in 2012. Experimental design was completely randomized design in a factorial arrangement with three replications. Treatments included chickpea genotypes (Hashem, Ilc482, Kaka and Kermanshah), herbicides (foramsulfuron and rimsulfuron) and herbicide residues in soil (0, 1, 2.5, 5, 10, 15, 20, and 30% of the recommended dose of application). At the beginning of reproductive stage (48 days after planting), plants shoot, root and nodule biomass, nodule number and plants total nitrogen amount were measured. For statistical analysis, data were changed to percentage of control. Data were subjected to ANOVA using SAS 9.1 software and treatment means were compared using Fisher’s protected LSD at the 0.05 level of significance.Non-linear regression analysis was employed using 3 (equation 1) and 4 (equation 2) logarithmic logistic dose-response model described by (Equation 1) where Y is the response (dry weight), c is the lower limit, d is the upper limit, b is the curve slope, e denotes the dose required to give a response halfway between the upper and lower limits (ED50 (Effective dose required for 50% inhibitation)); and x is the herbicide dose. The analysis of dose-response curves were determined by R, utilizing the drc package. Results Results showed that residues of foramsulfuron and rimsulfuron herbicides in soil affected all traits of chickpea genotypes significantly. All chickpea genotypes trails decreased significantly with increasing of residue concentrations of foramsulfuron in soil. However, shoot biomass of Ilc482 and Kaka genotypes and nodulation of all genotypes except of Kaka were simulated at the lowest level of residues of foramsulfuron in soil. Kermanshahi genotype produced the lowest shoot and root biomass in rimsulfuron soil residue levels. Rimsulfuron decreased nodule number and biomass of Ilc482 and Kaka genotypes. Among the studied genotypes; total nitrogen of Kaka and Kermanshah genotypes negatively affect more than the other genotypes due to foramsulfuron residues in soil. Rimsulfuron soil residues levels also decreased nitrogen in all chickpea genotypes. According to ED50 (Effective dose required for 50% inhibitation) for shoot biomass, Kaka was the lowest and Hashem was the highest tolerant genotype. Kermanshah and Ilc482 were the lowest and the highest tolerant genotypes for root biomass production respectively. Kaka was the lowest and Ilc482 was the highest tolerant genotypes in nodulation, were identified to residues of foramsulfuron in soil. In general, the results of this study showed that herbicide residues of foramsulfuron could be caused to high susceptibility in chickpea. Therefore, limitation of crop rotation is one of the most important problems for using foramsulfuron in crops before the peas. Since the residues of rimsulfuron were investigated in this study, had very low negative effect or even had estimulative effect on growth characteristics of chickpea genotypes, it would be introduced as selective herbicide in chickpea field.

Bean common mosaic virus is widely spread in the world, and also causes functional impairment in the quality of the product. Using tolerant and resistant genotypes is one of the main approaches to the management of this disease. For this purpose, the present study was conducted in two separate sections. 20 cowpea genotypes were studied in two separate experiments, with and without infection in a randomized complete block design, with three replications in greenhouse. The infection was conducted in 2-leaf phase by mechanical inoculation and morphological evaluation was recorded 21 days after infection. ELISA test was used to determine the infection rate of genotypes. Infection of cowpea genotypes were also checked by RT-PCR test using specific BCMV primers. Results suggest amplified fragment with length of 373 bp in the infected plants. The infection rate of different genotypes was 66.6 to 80%. According to the symptoms caused by mechanical inoculation with BCMV to cowpea genotypes was scored between 0-4 which used to obtain disease severity. According the all results, the genotypes divided to hypersensitive, sensitive, semi-resistant and resistant group.

To investigation of pathogenisity and genotype diversity of Xanthomonas oryzae pv. oryzae (Xoo) caused rice bacterial blight, several samples were collected from paddy field of rice in Rasht sangar, Soumeh sara, Rezvan shahr, Daboudasht amol and Rice-Institute-Research guilan during the summer of 2012, from plants that showed blight and yellowing in their leaves. Bacterial isolates were identified according to phenotypic and molecular characteristics. Among isolated bacterial strains 17 isolates were selected for further investigations. Isolates grouped into three pathogenisity groups based on virulence against susceptible international rice cultivar Tetep. The genetic diversity of 17 isolates analyzed by using Repetative extragenomic polymorphism (REPPCR). Cluster analysis based on 33 polymorphic REP markers showed three different genotypic groups among isolates with at least 62% similarity. The results showed limit correlation between different Pathogenisity and genotypic groups of X.oryzae pv. oryzae.

The relationship between densities of leaf trichomes and number of sweetpotato whitefly, Bemisia tabaci (Gennadius) was investigated on six genotypes of upland cotton, Gossypium hirsutum L. (Mehr, Varamin, Sahel, Khordad, Okra and Red okra) genotypes and one genotype of sea island cotton, Gossypium barbadence (Termus 14) at Cotton Research Station Kashmar, east of Iran, during cropping season in 2009. The result indicated that Termus 14 supported the highest numbers of eggs, nymphs and adults, and also had the highest numbers of trichomes compared to other genotypes.While the genotypes Okra and Red okra with the least numbers of trichomes on leaf surface suppprted the least numbers of various stages of whitefly. Therefore, there was asignificant and positive relationship between leaf trichome densities and whitefly population. It is concluded that the genotypes with glabrous leaves cotton may reduce the whitefly population on cotton.