A Theoretical Framework for Understanding the Genetic Architecture of Aflatoxin Resistance in Nigerian Groundnut Germplasm

Aflatoxin contamination of groundnut is a major food safety and market access problem in Nigeria, and developing varieties with genetic resistance to Aspergillus aflatoxin production requires deeper understanding of the genetic architecture of resistance traits, which has been insufficiently studied in Nigerian germplasm. This study developed an original theoretical framework for the genetic architecture of aflatoxin resistance in Nigerian groundnut germplasm, combining quantitative genetic theory with original QTL analysis. A multi-faceted genetic mapping methodology was employed, using a recombinant inbred line (RIL) population of 180 lines derived from a cross between a Nigerian landrace with documented low aflatoxin accumulation and a susceptible variety. The RIL population was phenotyped for aflatoxin accumulation level (ELISA), seed coat integrity, lipid oxidation resistance, and antioxidant enzyme activity under artificial Aspergillus infection conditions at Kano and Ibadan environments over two seasons. Genotyping was performed with a 48k SNP chip. A total of 14 QTL regions for aflatoxin accumulation were identified, explaining 72 percent of total phenotypic variance. Three QTL clusters showed consistent expression across environments and were associated with seed coat polyphenol oxidase activity, linoleic acid concentration, and resistance to A. flavus colonisation. The original Aflatoxin Resistance Genetic Architecture Framework proposes a three-tier resistance model: physical barrier (seed coat integrity), chemical defence (polyphenol and antioxidant composition), and cellular immunity (PR protein induction). Expert review by 18 groundnut breeding and food safety specialists confirmed the framework's original theoretical and practical contribution.

Keywords: aflatoxin resistance, groundnut, QTL mapping, genetic architecture, Nigeria