Browsing by Author "Mustapha, Oba Toyin"

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    Effects of Different Carbon and Nitrogen Sources on the Biomass of Molecularly Identified Fungi Associated with Fruit Rot of Tomato
    (Journal of the University of Ruhuna, 2022-07-01) Garuba, Taofeeq; Mustapha, Oba Toyin; Oyeyiola, Ganiyu Pacy
    Tomato (Solanum lycopersicum L.) fruit is an important component of the diet but pathogens are a threat to its availability. The purpose of this research work was to identify fungi associated with tomato fruit rot and study their biomass in different carbon and nitrogen sources. Four varieties of tomato were employed in this study: two local varieties (Hausa and Yoruba land races) and two improved varieties (Tropimech and Roma VF). Freshly harvested tomato fruits were collected and stored at room temperature until rot sets in. Fungi were isolated from rotted fruits using Potato Dextrose Agar. The isolated fungi were identified using macromorphological and micromorphological features. Internal Transcribed Spacer (ITS) regions of the ribosomal DNA (rDNA) of fungi were amplified and sequenced. Pathogenicity tests and physiological studies were conducted using fructose, sucrose, and starch as carbon sources and calcium nitrate, sodium nitrate, ammonium chloride, and urea as nitrogen sources. The biomass of the isolates was assessed in response to carbon and nitrogen sources. Aspergillus japonicus, Rhizopus oryzae, Curvularia geniculata, Fusarium proliferatum, and Fusarium oxysporum were isolated from all the varieties. The isolates were differently pathogenic and local tomato varieties were more susceptible to the tested fungi than improved varieties. Comparatively, the fastest mycelial growth was observed in R. oryzae (8.30cm) in the PDA medium at Day 7, followed by A. japonicus (6.60cm). The two Fusarium species grew slower. Biomass of the fungi revealed that fungi showed differential abilities in utilizing different carbon and nitrogen sources.