Browsing by Author "SALANO, NYANGWESO ELSIE"

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    EVALUATION OF PEANUT GERMPLASM FOR Aspergillus spp. RESISTANCE AND VITAMIN E CONTENT FOR AMELIORATION OF AFLATOXICITY IN KENYA
    (Egerton University, 2026-05) SALANO, NYANGWESO ELSIE
    Aspergillus flavus and Aspergillus parasiticus contaminate peanut with aflatoxins, resulting in adverse health effects in humans. Evidence from the literature shows that the ingestion of vitamin E, one of the antioxidants found in peanut, reduces the harmful effects of aflatoxin by acting as an antioxidant against the reactive oxygen species produced during the metabolism of aflatoxins. The current study characterised selected peanut germplasm based on resistance to aflatoxin accumulation and vitamin E production to ameliorate aflatoxicosis. The genetic diversity of the peanut as well as Aspergillus isolates was also determined. A total of 25 peanut accessions were sourced from the Rwanda, Uganda, Kenya Agricultural and Livestock Research Organization (KALRO) Germplasm Collection and farmers from Busia, Kakamega, Baringo, and Migori Counties of Kenya. Phylogenetic relationships of the germplasm were determined using 30 simple sequence repeats (SSR) markers and computation of Shannon information index, Nei’s genetic distance, cluster analysis, and analysis of molecular variance (AMOVA). Genetic diversity of Aspergillus isolates from peanuts was determined by the amplification of the ITS1 and ITS4 regions, subsequent sequencing, and cluster analysis. Resistance to aflatoxin accumulation was determined by inoculating the germplasm with a known toxigenic strain of A. flavus and testing for aflatoxin accumulation using Enzyme-Linked Immunosorbent Assay (ELISA), while expression of vitamin E was assayed High Performance Liquid Chromatography (HPLC). One-way analysis of variance (ANOVA) was used to compare the mean vitamin E and aflatoxin production among the different peanut germplasm. Tukey's hsd test was used for means separation where there were significant differences (p< 0.05). Phylogenetic analysis of Aspergillus isolates showed that A. flavus was the predominant contaminating species in all regions and that these species were genetically similar, suggesting the great capacity of these strains to be dispersed and the persistent risk of contamination. There was low polymorphism between the sampled accessions, which indicated a genetic bottleneck. The phylogenetic analysis of peanut produced three genetic clusters, each showing some correspondence with geographic origin, suggesting patterns of seed exchange and localized selection. The study identified peanut germplasm with high vitamin E production and resistance to aflatoxin accumulation. There was no significant correlation between aflatoxin resistance and vitamin E levels, indicating separate inheritance patterns of the traits. These findings are expected to pave way for future initiatives to improve peanut germplasm through breeding studies to inform future breeding initiatives and contribute towards food safety and nutrition thereby improving food security.