Year 2017, Volume 63 Issue 1 (31.03.2017)

Year : 2017
Volume : 63
Issue : 1 (31.03.2017)
   
Authors : Mohammad Reza Safari MOTLAGH, Saber MOHAMMADIAN
Title : IDENTIFICATION OF NON-PATHOGENIC FUNGI OF RICE AND THE EVALUATION OF THEIR EFFECT ON BIOLOGICAL CONTROL OF BIPOLARIS ORYZAE, THE CAUSAL AGENT OF RICE BROWN SPOT DISEASE IN VITRO
Abstract : Rice brown spot disease is caused by Bipolaris oryzae is an important disease of rice in Iran and other parts of the world. In this research, 137 infected samples of rice were collected from paddy fields of Guilan province in Iran and 68 fungal isolates were isolated. PDA and WA media were used for isolation and identification of fungi. Morphological characteristics such as colony, conidia and conidiophores morphology were used for identification of these fungi. It was found that the isolated fungi belonged to Bipolaris oryzae, Alternaria tenuissima, Preussia sp., Fusarium verticillioides, Alternaria infectoria, Alternaria citri, Trichoderma harzianum and Trichoderma virens. Twenty isolates that didn't cause disease on rice or pathogenicity of them in rice was very low were selected for biocontrol studies and to do so, various methods were used. It was shown that seven isolates, T. harzianum, T. virens, A. tenuissima, Preussia sp., F. verticillioides, A. infectoria and A. citri, had the highest suppression percentage of mycelial growth of B. oryzae, respectively, in dual culture and culture filtrate methods. In volatile metabolites method, T. harzianum, T. virens, A. tenuissima, A. infectoria, A. citri, Preussia sp. and F. verticillioides, had the highest inhibition percentage of mycelial growth of B. oryzae, respectively. In hyperparasitism test, no coiling of Trichoderma spp. was observed around the hyphae of B. oryzae, however, Alternaria spp. penetrated into the mycelium of B. oryzae once they reached them and then, they tore the fungal mycelium and deformed it. Based on obtained results, T. harzianum was the most effective isolate in inhibiting the mycelial growth of B. oryzae. Analysis of variance and means comparison by least significant difference showed significant differences among the fungi used in vitro.
For citation : Motlagh M., Mohammadian S., (2017) Identification of non-pathogenic fungi of rice and the evaluation of their effect on biological control of bipolaris oryzae, the causal agent of rice brown spot disease in vitro, Agriculture and Forestry, 63 (1): 291-308. DOI: 10.17707/AgricultForest.63.1.31
Keywords : antagonist, rice, biological control, Bipolaris spp., non-pathogenic fungi
   
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