Differential responses of alfalfa cultivars to aluminum stress

Abstract

Abstract Toxic levels of aluminum can cause severe yield reduction in alfalfa (Medicago sativa L.), especially in the presence of drought stress. Reactions to Al stress of alfalfa cultivars and germplasms, representing a broad genetic base and the entire range of dormancy types, were evaluated in a Monmouth soil study [26.2% Al saturation (pH 4.8) vs 2.8% Al saturation (pH 5.7)] and in two nutrient solution experiments (0 vs 111 μmol Al; pH 4.5). The soil study, Experiment 1, and Experiment 2 were harvested 28, 40, and 25 d after seeding, respectively. In all studies, entries differed significantly in vigor and yields were reduced significantly by Al stress. In the soil study, only ‘Lahontan’ was not affected significantly by Al stress, although Lahontan, ‘Atlantic’, ‘B13‐A14’ (tolerant check), ‘Ladak 65’, and ‘Mesa‐Slrsa’ had comparable relative weights (dry weight stressed/dry weight unstressed). There were no statistically significant differential responses to Al stress in Experiment 1, however the rel...