Establishment of parameters for water stress tolerance evaluation on bean genotypes

Abstract

Aiming to establish parameters for drought tolerance evaluation, fifteen genotypes of bean (Phaseolus vulgaris L.) were evaluated during a water stress period, applied at the pre-flowering stage through leaf water potential (Y_f) and some other variables. Among the genotypes studied, A 222, A 285, BAT 477, BAT 561 and IPA 7 showed highest Y_f during the water stress, indicating a better stomatal control by these genotypes, while the cultivars Carioca and Ouro Negro showed a more rapid recuperation, after being rehydrated. All the Anthracnose tolerant genotypes evaluated presented an efficient stomatal control. The potential for nitrogen biological fixation, evaluated by the number and weight of nodules, was significantly affected only on few genotypes. Leaf area and shoot dry weight were the morphological variables more sensitive to water stress. The number of pods per plant was only affected on Xodó and CNF 0145 genotypes, while the Carioca, A 285, CNF 0145, BAT 477, cv. 121 genotypes, and the LM 30036 line, showed a decrease on the seed weight per plant, under water stress. Besides having the highest Y_f, the A 222 and IPA 7 genotypes were the only ones that did not show a significant reduction on the leaf area and seed weight per plant, although the first one had a low plant production under stress.