نشریه گیاه پزشکی کاربردی
سال سوم شماره 2 (پیاپی 10، تابستان 1393)

Blight disease of chickpea caused by Ascochyta rabiei (Pass.) Lab.is one of the most important chickpea diseases in the world and Iran, which causes huge damages to chickpea farm in the suitable climatic conditions. Study of genetic diversity and various races exist in the different regions would be necessary for resistant cultivars development. In this research physiological races of 28 isolates of A. rabiei which were collected and purified from five region of Kermanshah province during 2012-2013 were determined using seven differential chickpea cultivars (ILC-202, ILC-1929, ILC-5928, ICC-3996, ILC-194, ILC-1929 and ILC-72). All isolates were classified in six physiological races. Among the all isolates, seven isolates (25%) belonged to race 1, Five isolates (17.8%) belonged to race 2, Seven isolates (25%) belonged to race 3, Four isolates (14.4%) belonged to race 4, two isolates (7.2%) belonged to race 5 and three isolates (10.6%) belonged to race 6. Races 1, 2, 3 and 4 with 23 isolates (82.1%) were occurred in all areas of the province while race 6 with high virulence was detected only in one area (Sararood). Investigation of the morphological traits of isolates on CSA (Chickpea sucrose Agar), showed differences in view of diameter, color and form of colony, pycnidium density and pycnidium size among the isolates, but there was not any difference in term of pycnidiospore size.

Lily (Lilium spp.) from Liliaceae familiy is considered as one of the most important ornamental plants with high economic value. Virus diseases are shown to be as main limiting factor in lily production. During a survey in 2015, a total of 76 symptomatic samples showing mosaic, deformation, chlorosis, reduced growth, necrosis and decline were collected from lily growing greenhouses in Thehran province. Samples were tested for Cucumber mosaic virus (CMV) and Arabis mosaic virus (ArMV) using ELISA, biological and molecular methods. ELISA results showed that 45 and 3 samples were infected with CMV and ArMV, and 5 samples were co-infected with the both viruses. The virus infections were confirmed using biological inoculation tests. CMV and ArMV infection were also tested by RT-PCR method using specific primers which resulted to amplification of 1100 and 690 bp DNA fragments, respectively. CMV lily isolates were confirmed to belong to CMV subgroup I using specific primers in RT-PCR assay. Presence of Lily symptomless virus –LSV and Lily mottle virus-LMoV were tested by RT-PCR assay using specific primers which resulted in amplification of the expected 650 bp DNA product corresponding to CP gene region of LMoV, but there was not any DNA amplifications related to LSV. This is the first report on occurrence of ArMV, CMV and LMoV infections on lily in Iran. Detection of virus infection sources using the optimized methods in this study is a crucial practical approach for virus management in healthy lily bulb production in the country.

Twenty promising wheat lines together with tow susceptible control cultivars Bolani and Morocco were evaluated for slow rusting resistance in Ardebil during 2013-2014 cropping season. Different components of slow rusting including coefficient of infection (CI), final rust severity (FRS), relative area under diseas progress curve (rAUDPC) and apparent infection rate(r) were assessed at both seedling and adult plant stages under filed condition. Pustule size and pustule density were also measured at both grow stages. The results showed that lines  M-91-17 and  M-91-4 were susceptible or moderately susceptible at seedling stage but resistant or immune at adult plant stage which indicates the presence of adult plant resistance in these lines. Lines  M-91-18, M-91-20, M-91-5, M-91-6 and M-91-7 were moderately resistant at seedling stage but showed favorable levels of slow rusting at adult plant stage. Lines  M-91-13, M-91-14,  M-91-12 and M-91-8 which were susceptible at seedling stage and showed higher levels of slow rusting at adult plant steges, seems to pocess some adult plant recsistant genes. Susceptible control cultivars  had the highest r, CI, FRS, rAUDPC, pustule density and pustule size. Based on the values of the measured traits, except M-91-2,  M-91-3, M-91-9, M-91-10, M-91-11,  M-91-15 and M-91-16, the remaining lines had medium to high levels of slow rusting resistance. Correlation cofficients between FRS and CI, rAUDPC and r were 98%, 97% and 97%, respectiveiy.

Tobacco budworm (Helicoverpa armigera) is one of the key pests of tobacco farms. Nucleopolyhedrovirus is one of the most important biological control agents of budworm and a number of other species. In this study the genetic diversity of different isolates of Nucleopolyhedrovirus belonging to 16 natural populations in Mazandaran and Golestan  provinces, were investigated. The tobacco budworm samples were collected from tobacco fields and transferred to biotechnology Laboratory of Tirtash Research and Education Center. Purification of NPV virus and DNA extraction was done using CTAB method. Among ten pair of primers which we used for amplification of NPV, two pair of RAPD primers that showed the highest Polymorphism were selected. Sixteen DNA samples isolated from different geographical regions of Golestan and Mazandaran provinces were checked with these selected RAPD primers and they created countable bands. Totally, 87 Countable bands were generated following the PCR products. Among them,75 bands(86%) were polymorphic. Data analysis was done using the PyElph Software. Population grouping using UPGMA method based on genetic distance of 20, revealed five major clusters. Using the underlying RAPD marker, the isolates of Nucleopolyhedrovirus were in a one gene cluster, showed the greatest genetic affinity.

One of the most destructive soil-borne diseases of carnation is fusarium wilt caused by Fusarium oxysporumf.sp. dianthi. In This study, antagonistic potential of different isolotes of three Trichoderma species on growth of the pathogen in laboratory and control of the disease in greenhouse was investigated. Isolates of the antagonist were Ta1, Ta2 and Ta3 belonging to Trichoderma atroviride, sixteen isolates Th1-Th16 belonging to T. harzianum and one isolate Tl1 belonging to T. longibrachiatum. Dual culture and colonization tests were carried out in a completely randomized design with three replications. Isolates  Ta3, Ta2 and Ta1 which completely covered colonies of the pathogen after five days, were the mosts successful colonizers. Inhibitory effect of volatile metabolites of Ta3 isolate in 72h and 96h cultures of the pathogen and antagonis (60% and 72%, respectively) was higher than those of the other isolates. In greenhouse, soil treatment with isolates of Trichoderma, to study the biocontrol effects the isolates was carried out in an experiment with 21 treatments in three replications. The results showed that different isolates could control the disease in different levels. Isolate Ta3 had the highest effect on disease control and reduction of cuttings death, followed by isolates Ta1, Ta2, Ta3 and Th2. In general, the antagonist isolates had less effects on growth of the plant, but reduced disease severity.

In the present study, first the superior bioformulations for Talaromyces flavus,containging some chemical stabilizers were determined by measuring the presentage  of active spores in bioformulations and then their efficacy in biological control of sugar beet seedling damping-off was investigated in greenhouse. An experiment was performed in split plot based on randomized complete block design with four replications in greenhouse. Three inoculum application methods (soil treatment, seed treatment and combination of both methods) were considered as the main factor and eight different inoculum formulations including six superior bioformulations Dicycloserin-TF-Su-K-1,Dicycloserin-TF-Su-K-2,Dicycloserin-TF-Su-K-3, Carboxymethilcellolose-TF-Su-K-2, Sulfate magnesium-TF-Su-K-3 and Nitratesodium-TF-Su-K-2. together with two control treatments (healthy and infected checks) were considered as the sub-factor.The results indicated that the most effective treatments for biological control of sugar beet damping-off were Dicycloserin stabilizer and isolate TF-Su-K-3, separetely. Results of the interaction effects of inoculum application method and inoculum showed that the treatment of Dicycloserin-TF-Su-K-2 applied as soil treatment or as combination of soil and seed treatment resulted in less disease occurrance.