Pathogenicity Evaluation of Some Common Soil Borne Fungi on Seeds from Three Local Varieties of Sorghum (Sorghum bicolor L.)

Abstract

Soil borne pathogens appears to be one of the most devastating groups affecting S. bicolor causing wide range of pre-harvest and post-harvest diseases, plant diseases are commonly managed through different strategies, the use of resistant varieties found to be more economical and ecofriendly. This poses the need to screen different varieties of S. bicolor for horizontal resistance of some fungal species commonly found in the soil. Plate technique was used to isolate soil fungi and morphological identification was through macro and microscopy. Koch’s postulate was followed in the assessment of pathogenicity of the identified organisms on the three sorghum germplasms (Yelai, Kaura and Warwarbashi). The isolated fungal species were found to be Aspergillus niger, Aspergillus flavus, Rhizopus stolonifer, Mucor spp and penicillium spp. Pathogens with highest occurrence observed was A. niger , R. stolonifer and Penicillium spp with 30, 25 and 20% occurrence respectively. Thus, all the three cultivars of S. bicolor screened were very susceptible to the tested pathogens, with A. niger and R. stolonifer found to be highly virulent. It was concluded that, all the varieties showed a continuous minute or absence of horizontal resistance against the isolated pathogens which could be responsible for post-harvest diseases in Sorghum germplasm.