تاثیر غلظت‌های مختلف نانو ذرات سیلیکا بر عامل بیماری پوسیدگی فوزاریومی ریشه و طوقه برنج و برخی ویژگی‌های رشدی بذور در شرایط آزمایشگاهی

Fusarium root and crown rot disease of rice caused by Fusarium fujikuroi is one of the most important seed-born diseases of rice. The main challenge in dealing with this disease is the lack of effective management practices after the appearance of disease symptoms in the field. Therefore, the most effective and cost-effective approach to manage this disease is seed disinfection and cultivation of resistant or semi-resistant cultivars. If there is no access to resistant cultivars, inducing resistance through chemical compounds in semi-susceptible and susceptible cultivars is one of the accessible and biocompatible methods in disease management. In this research, the effect of silica nanoparticles in concentrations of 0.125, 0.25, 0.5, 1, 2 and 4 mM in inhibiting mycelial growth, spore germination of pathogen and the rate of sporulation of pathogen was investigated in laboratory conditions in the form of a completely randomized design in 4 Replications. In the wet culture experiment, the rice seeds of Khazar cultivar after priming with concentrations of silica nanoparticles and then contamination with the pathogen, were examined for the percentage of germination and Fusarium contamination. Based on the obtained results, there was statistically significant difference at the five percent probability level between different concentrations of silica nanoparticles in terms of their effect on inhibiting mycelial growth and the rate of spore germination. Silica nanoparticles in concentrations of 0.25 and 0.5 mM showed the highest inhibition percentage of mycelial growth by 23.2 and 18.2%, respectively, and the lowest amount of spore germination by 31.3 and 27.8 %, respectively. In terms of the effect of treatments on the amount of pathogen sporulation, there was no significant difference between the treatments and the number of spores in them were counted in the range of 4.5-7 milion spores per milliliter. In the seeds primed with silica nanoparticles, there was statistically significant difference between the control and different concentrations of nanosilica in terms of the percentage of seed contamination with Fusarium fungus, and the lowest amount of seed contamination was observed in the 0.5 and 1 mM nanosilica treatments. In terms of the effect on the germination of rice seeds, there was no statistically significant difference between the treatments, however, the highest germination percentage belonged to the 0.5 and 1 mM nanosilica treatments. The findings obtained in this research showed that silica nanoparticles with direct inhibitory effect on the pathogen and reducing the contamination of rice seeds with Fusarium fungus, can be used in disease management in susceptible and moderately-susceptible cultivars.