Evaluation of Maize (Zea mays L.) Inbred Lines for Aluminum Tolerance Under a Hydroponic System

Maize ( Zea mays L.) is a staple crop in Ethiopia, but its yield is often reduced by aluminum (Al) toxicity, which commonly occurs in acidic soils. We grew 150 maize inbred lines in hydroponic solutions, one with 222 μM Al 2 (SO 4 ) 3 ·16H 2 O to create aluminum stress and one without aluminum as a control. Root length was used as the main criterion to select Al‐tolerant lines. In every index, analysis of variance showed highly significant genetic variation ( p < 0.001). Root length was measured under both control and Al‐stress conditions, and several tolerance indices were computed to evaluate Al tolerance among lines. ANOVA indicated highly significant genotypic variation across all indices ( p < 0.001), with root length geometric mean productivity (R‐GMP), root length stress tolerance index (R‐STI), root length index (R‐YI), and root length stability index (R‐YSI) demonstrating the strongest discriminatory power. Correlation analysis revealed strong relationships among the significant indices. Principal component analysis (PCA) explained 98% of the variation, with PC1 (60.9%) mainly influenced by productivity indices (R‐MP, R‐GMP, R‐HMP, R‐STI, R‐YI), and PC2 (37.1%) associated with stress susceptibility indices. The genotypes were categorized using cluster analysis into three groups: sensitive, moderately tolerant, and tolerant. Of these, 4.7% of lines had better aluminum tolerance. The top five tolerant genotypes (VL144091, VL153179, VL13682, VL1016452, and VL18322) were identified based on their stable root growth under Al stress across multiple tolerance indices. The most sensitive genotypes were KL154667, VL1110532, KL154705, VL119989, and VL144293, with extreme root inhibition. These tolerant genotypes have the potential to be used as breeding material to improve maize performance in acidic soils. Although hydroponic screening is a successful early selection technique, field testing is usually necessary to validate genotype performance in actual soil conditions.