تاثیر نانو کلوییدنقره و نانواکسیدآلومینیوم بر بیماری پوسیدگی ریزوکتونیایی ریشه لوبیا

Rhizoctonia root rot, caused by soil-borne fungus Rhizoctonia solani J.G. Kühn is one of the most important diseases of beans, which has been reported to damage up to 60% of the yield in the world. The disease also has been reported in Iran. The nanotechnology researches have shown that some of these materials also have fungicidal properties. The aim of this research was to investigate the effect of silver nanocolloid, aluminum nanooxide, and the pencycuron fungicide, on the severity of the disease and the growth indicators of two cultivars of bean including Khomein and Kermanshahi. Bean plants with yellowness, wilting, and red-brown cankers on the hypocotyl or roots symptoms, were sampled in the Eghlid region of Fars province. Two isolates of pathogen isolated after surface disinfecting of the diseased tissues and placing them on potato/dextrose/agar (PDA) medium at 28 degrees Celsius after one week, and purified by hyphal tip method. Their hyphae were stained, and the numbers of nuclei in their cells observed, and they were identified as R. solani. They were dual culture with an R. solani Ag4 isolate, with which both formed hyphal anastomosis. The inhibitory effect on the colonies growth of these two isolates of the pathogen with six concentrations of silver nanocolloid, aluminum nanooxide, and pencycuron was investigated by mixing them with PDA culture medium in vitro. All three substances at a concentration of 5 ppm showed the highest percentage of inhibition of the colonies growth of the two isolates. The effect of these materials concentration in the form of seed treatment alone and in the presence of the two pathogen isolates was investigated on the growth indicators of Khomein and Kermanshahi cultivars in the form of a factorial experiment with a completely randomized statistical design with five replications for each treatment under greenhouse conditions. The data were measured after four months, and statistically analyzed with SAS software. Both isolates of the pathogen were identified as R. solani Ag4. Pencycuron, aluminum nanooxide, and silver nanocolloid showed the highest to lowest colony growth inhibitory ability for both pathogen isolates in vitro, respectively. Analysis of variance of the greenhouse test data showed that there is a significant difference between the pathogenicity of pathogen isolates. Pencycuron (52 and 100%), aluminum nano-oxide (50 and 86%) and silver nanocolloid (47 and 80%) significantly reduced the severity of the disease in the presence of hypo-and-hyper-virulent isolates of the pathogen. Aluminum nanooxide improved plant growth indicators more than silver nanocolloid. Therefor aluminum nanooxide and silver nanocolloid have fungicidal properties. The effect of aluminum nanooxide and silver nanocolloid on the severity of this disease and growth indicators of beans are reported for the first time.