Increasing maize production by expanding to marginal areas in the tropics faces substantial challenges, such as drought and acidic soil. Acidic soils may have low availability of plant nutrients because of the soil’s low pH and heavy metals. This study aimed to a) elucidate the response of maize genotypes under optimum and acidic soil, b) determine the correlation between several tolerance indices, and c) predict the response to selection performance based on multiple traits. Thirty-six genotypes, including six checks, laid out in an augmented RCBD, had three replications for the checks under optimum and acidic soil conditions in Bogor, Indonesia. Acidic soil induced late flowering and reduced agronomic performance and yield traits. Genotype, environment, and genotype-by-environment interaction (GEI) had highly significant (P < 0.01) effects on yield and several traits. G05, G15, and G20 were tolerant and high-yielding genotypes evaluated and ranked using tolerance indices. The mean productivity (MP), harmonic mean (HM), geometric mean productivity (GMP), and stress tolerance index (STI) showed significant correlations with yield under both conditions. The multi-trait genotype-ideotype distance index (MGIDI) suggested that genotypes G15 and G20 were better selections in acidic soil, whereas G05’s was better in the tolerance index values. Using tolerance indices can help determine the most tolerant genotypes, whereas the multiple-trait index enables researchers to assess the performance of genotypes and identify the most effective traits. These two parameters require recommendations as tools for describing tolerant genotypes in acidic soils in tropical maize breeding programs.

Keywords: Abiotic stress, maize breeding, MGIDI, tolerance indices

Key findings: The multiple-trait combination index enables researchers to identify desired maize genotypes adapted to optimum and acid soil conditions and elucidate their strengths and weaknesses. Several tolerance indices, i.e., MP, HM, GMP, and STI, revealed correlations with yield in optimum and acid soil conditions.