گسترش پژمردگی و زردی فوزاریومی گوجه فرنگی در ناحیه یک هواشناسی کشاورزی کشور

Temperature, sedimentation, elevation from sea level indices along with the type of crops and scientists experience utilize to determined agro-ecological zones. On this matter, six agro-ecological zones have been identified in Iran. Tomato has a special place among vegetable crops in Iran according to daily consumption, production, and export by covering 148000 ha areas under cultivation. Summer cultivation and production of tomato have been prevalent in Iran Agro-ecological zone one. Samples of infected tomato plants to Fusarium yellows collected during the monitoring of the farms of different cities of Alborz, Tehran, Khorasan Razavi, Zanjan, Kermanshah, Kurdistan, Ardebil, East Azerbaijan, and West Azerbaijan provinces. Samples collected from fully developed plants with an observation of clear disease symptoms including the young leaf vein clearing, branches side yellows, and wilting. Infected samples transferred to the laboratory in a paper envelop to isolate and identify the causal pathogen. Small parts of infected tissue at the border with healthy tissue cut and placed on PDA after two-minute disinfection with one percent sodium hypochlorite and washing with distilled sterile water. After initial incubation fungal isolate purified by a single spore method and then transferred to CLA culture medium for further identification. In total, 152 isolates of the genus Fusarium have been identified. The growth rate of isolate on PDA under two temperatures 18 and 27 degrees Celsius was measured and used along with the test of pathogenicity on cucumber for identification of forma specialis. Isolates belonging to Fusarium oxysporum f.sp lycopersici separated from the F. oxysporum f.sp radices-lycopersici. Isolates of
F. oxysporum f.sp lycopersici from different geographical regions were evaluated on Bunny best susceptible cultivar. This test was performed randomly with four repetitions for each isolate with a concentration of 2 ×106 spores per ml and distilled water used as control. The highest disease incidence was in Khorasan Razavi province and the least was in Ardebil province. The disease severity was evaluated according to Nirmaladevi et al., 2016 and the virulence of isolates were categorized based on the mean disease severity. The most virulent isolate was Ker10 from Kermanshah province. Different levels of virulence observed among the isolates of other province geographical regions. This disease spread increased over the farms of provinces understudy during the recent years and farmers sprayed a lot of agricultural chemicals to control the disease. Therefore, it is important to consider the evaluation of the commercial cultivars for resistance to prevalent isolate of pathogens form the same agro-ecological zone and utilize results for the suggestion to the farmers.