Assessment of genetic variability for aluminum tolerance in cowpea accessions screened in pots under field conditions

Aluminum toxicity is a major factor limiting crop productivity on acid soils, thus limiting food production. This study assessed the level of genetic diversity for aluminum tolerance in cowpea and the inter-character association of important traits for the effective selection of tolerant genotypes. Ten accessions of the crop were screened in pots filled with topsoil employing a 10 × 4 factorial experiment in a completely randomized design with three replicates. The four aluminum treatments imposed were 0, 50, 100, and 200 µM AlCl3. The study found significant differences among accessions for all traits. Aluminum treatment affected all traits except seeds/plant and seed yield, with significant interaction effects for traits except emergence percentage and plant height. Heritability was high (≥ 60%) for all traits except pods/plant, which had moderate heritability (57.98%). Genetic advance was high (≥ 20%) for all traits except days to flowering (11.08%) and plant height (15.87%), showing moderate values. Based on aluminum tolerance indices, AC03, AC04, AC05, AC06, AC08, and AC09 were classified as highly tolerant, AC02 as moderately tolerant, while AC01, AC07, and AC10 were highly susceptible. Consequently, selection for the traits with high heritability and genetic advance would result in genetic gain and breeding progress for aluminum tolerance in cowpea for acidic soils in Nigeria and other tropical regions. © 2024 The Author(s)