Response of maize varieties to soil acidity under field conditions in Western Ethiopia

Soil acidity and associated fertility problems is a major challenge to maize production in western Ethiopia, reducing yield and contributing to food insecurity. This is worsened by the fact that breeding programs focused on testing and developing high-yielding varieties under optimum soil conditions, resulting in limited information on the performance of maize varieties across diverse soil pH. This study aimed to evaluate and identify maize varieties tolerant to soil acidity. Nine improved varieties (BH661, BH549, BHQP548, BH547, BH546, BHQPY545, BH5212, BH5211, and Gibe2) were evaluated under two soil pH levels (4.8 and 5.9) at Bako in 2023, using a randomized complete block design with three replications. Results showed that soil acidity and varieties significantly affected maize growth and yield with acidic conditions negatively affecting all varieties. However, BH5211, BH661, and BH547 showed the least yield reductions while BHQPY545 showed the highest yield reduction, indicating variability in adaptability. BH5211, BH661, and BH547 exhibited high grain yield stability across both pH levels, indicating broad adaptability, whereas BHQPY545 showed instability and specific adaptability. Stress tolerance indices supported these findings. Principal component analyses Showed 85.2% of total variability, with PC1 (68%) mainly influenced by biomass and grains per cob, and PC2 (17.2%) majorly affected by grain rows per cob. Varieties were grouped into four clusters; Cluster IV showed superiority in most yield and yield related variables. Overall, findings demonstrate the need for future crop improvement programs to deliberately consider soil acidity tolerance as one of selection criteria in the developing of maize varieties for high yield. Further studies on acid tolerance mechanisms and multi-location field trials are required to validate and refine these results.