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Identification and quantification of fungi associated with seeds of ryegrass (Lolium multiflorum Lam.)

The study aimed to identify and quantify the fungi associated with ryegrass, to compare the incidence in different culture media, and to determine the number of Claviceps purpurea sclerotia present in samples of ryegrass seeds. We analyzed 37 samples of ryegrass seeds from municipalities at Rio Grande do Sul, Paraná and Santa Catarina. The seeds were plated on three culture media: PDA, Reis' semi-selective medium and Segalin & Reis' semi-selective medium, to analyze the incidence of fungi. For C. purpurea detection, 100g seeds per sample were weighed and by means of visual examination the number of sclerotia was determined. The detected fungi were Alternaria alternata, Bipolaris sorokiniana, Drechslera spp., D. siccans, Fusarium graminearum, Fusarium spp., Aspergillus spp.and Penicillium sp. The incidence of A. alternata ranged from 0.0% to 33.7%, and the frequency was 89.2% for the analyzed samples. For B. sorokiniana, the incidence was 0.0% to 2.2%, and the frequency was 62.2%, Drechslera spp. presented incidence of 0.0% to 40.3% and frequency of 78.4%. D. siccans had incidence of 0.1% to 20.0% and frequency of 100%. For Fusarium spp. and F. graminearum, the incidence was 0.0% to 31.0% and 0.0% to 11.3%, respectively, and the frequency was 81.1% and 64.9%, respectively. Incidence of 0.0% to 43.7% and frequency of 94.6% were detected for Aspergillus spp., while Penicillium sp. had incidence ranging from 0.0% to 51.7% and frequency of 91.9%. The fungus C. purpurea was found in 81.1% of the studied samples.

Drechslera siccans; Claviceps purpurea; culture media; ryegrass


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