Integrating in vitro and hydroponic methods to identify aluminium-tolerant cultivars Medicago sativa L

Aluminium (Al) toxicity is a major limiting factor for plant growth in acidic soils. This study aimed to evaluate the effects of different aluminium concentrations on the growth and viability of alfalfa (Medicago sativa L.) using two complementary approaches: in vitro culture and a hydroponic screening method. In vitro experiments were performed on Murashige and Skoog medium supplemented with 0, 5, 15, 25, and 50.0 µM AlCl3·6H2O (pH 4.5). The viability of micro-plant explants decreased significantly with increasing Al concentrations, with near-complete growth inhibition observed at 50 µM after 60 days of cultivation. In parallel, the hydroponic screening method assessed root and hypocotyl tolerance in six alfalfa cultivars exposed to 0, 5, 15, 25, and 50 µM AlCl3 (pH 4.5) in Blaydes nutrient solution. Among the tested cultivars, Jarka and Europe showed the highest tolerance to Al stress, maintaining superior root development at 50 µM Al. Jarka also demonstrated the greatest hypocotyl length at the highest Al concentration. Overall, the results demonstrate that both methods are effective for identifying genotypic variation in Al tolerance and are suitable for early selection of Al-tolerant alfalfa cultivars intended for cultivation in acidic soils.