The study aimed to identify and characterize sources of resistance to aluminium toxicity and progressive soil drying among various genotypes of common bean (Phaseolus vulgaris), runner bean (P. coccineus), and tepary bean (P. acutifolius) accesion G40159. The research employed hydroponic and soil cylinder screening methods. The hydroponic experiment involved using a basal nutrient solution with and without 20 μM Al, while the soil cylinder experiments used two oxisols with high Al (HAl) and low Al (LAl) saturation treatments. These experiments showed an average of 36.9–53.5% inhibition of root growth with HAl compared to LAl treatments.

Eleven bean genotypes were selected for the study, including four runner bean accessions, six common bean genotypes, and one tepary bean accession. The genotypes were evaluated for their phenotypic differences under individual and combined stresses of Al and drought. For the hydroponic experiment, germinated seeds were transferred to small pots containing sterile sand for root development. For the soil cylinder experiments, seeds were surface sterilized with sodium hypochlorite and germinated on filter paper before planting in soil tubes.

Two accessions of P. coccineus (G35346-2Q, G35464-5Q) and one Andean common bean genotype (ICA Quimbaya) demonstrated outstanding root and shoot growth in the HAl treatments. P. coccineus accession (G35346-3Q) was outstanding under combined stress of Al-toxic acid soil and progressive soil drying. These accessions may represent unique sources of Al resistance for the improvement of common bean through interspecific crosses.