Screening of Maize Inbred Lines for Resistance to Aspergillus Flavus and Agronomic Traits for Semi-arid Areas

Abstract

Maize is a main cereal crop meeting food demand for approximately 300 million people in Sub-Saharan Africa (SSA). A fast-growing human population and production challenges have surged the demand for maize grains. Tropical climate, in addition to poor pre- and post-harvest practices, has resulted in the highest levels of mycotoxin accumulation in several food products, including maize in SSA. Aflatoxin contamination has a negative impact on food safety, often resulting in outbreaks, especially in Kenya. Aflatoxin contamination in Africa is aggravated by limited resistant maize lines. Therefore, this study screened certain commercial inbreds against A. flavus that can be developed into more resistant and resilient hybrids suited for both subsistence and commercial use in regions with limited rainfall. The aim of this study was to determine if the aflatoxin resistance and agronomic performance and yield stability in the inbred lines are influenced solely by genes or by interactions with the environment. Field experiments were conducted at Kenya Agricultural and Livestock Research Organization (KALRO) in Katumani and Kiboko sub-centres using five maize inbred lines (ML312, KABML018, KABML 658-3, KABML 308-2-2, and KABML 6-2-1). Maize inbreds were grown following a 3 x 5 lattice randomized complete block design and inoculated with Aspergillus flavus S strain during 50% silking using silk channel method. The aflatoxin accumulation (levels) as was assessed from 20-gram sample of flour using an ELISA-based Reveal Q+ Kit. Agronomic performance (anthesis-silking intervals, days from silking to maturity, plant height, ear height, grain moisture and grain yield)
for the inbreds were evaluated from five randomly selected plants in each replicate. General combining ability of each inbred line was computed. Aflatoxin accumulation and agronomic performance datasets were subjected to analysis of variance in Minitab software. This study revealed that KABML6-2-1 and KABML018 exhibited excellent performance and show promise for creating hybrids with built-in resistance in semi-arid farming systems. KABML658-3 and KABML308-2-2 can be used as secondary resistance sources. This study recommends testing resistant parental lines, such as KABML6-2-1 and KABML018, before commercial distribution through multi-location experiments to confirm their resistance, stability, and adaptability.