Mycoflora associated with seeds of five rice (Oryza sativa) varieties in Ghana

2015

English

An in vitro test was carried out at the Seed Pathology Unit of CSIR-Crops Research Institute to assess the incidence of seed-borne mycoflora associated with seeds of five rice varieties. Two of the varieties namely Jasmine 85 and Toxx 3377 are lowland varieties and the other three, namely Obolo, Nerica 4 and IDSA-85 are upland varieties. The Blotter method was used to identify fungal species. About 31% of the seeds tested were infected by different species of fungi at storage and none of the varieties tested was free from fungal species. Two rice varieties, IDSA 85 and Tox 3377 recorded the highest total fungal infection of 26.7% and 26% respectively while Obolo recorded the least with 9.5%. Sixteen fungal species from 11 genera were identified to be associated with the five rice varieties. The major disease-causing fungi found to be associated with the seeds were: Bipolaris oryzae, Curvularia lunata, Aspergillus flavus, Fusarium moniliforme, F. oxysporum and Rhizopus sp. A. flavus, on Jasmine 85, recorded the highest frequency of occurrence with 21%. It was followed by B. oryzae with frequency of 13.5% on IDSA 85 and C. lunata, 11.5% on Nerica 4. Some of the fungal species showed least frequency of occurrence between 0.5-1%. The most predominant fungus on all the five varieties was C. lunata (25.7%) and was closely followed in order of predominance by A. flavus (23.8%), and B. oryzae (21.2%). Seeds need to be treated before planting to reduce field and postharvest contamination of rice seeds. Development of appropriate and cost-effective technologies to reduce mycoflora infection should be one of the focal points in rice industry in Ghana

Aidoo, A. K.; Appiah-Kubi, Z.; Bam, R. K.