Identification of fava bean genotypes tolerant and susceptible to water deficit.

Of the genus Phaseolus, fava beans are of great socio-economic importance to the Brazilian Northeast due to their nutritional profile and dryland cultivation. Legume cultivation has been threatened by environmental changes and processes of aridity and desertification around the world, especially in the semi-arid region of Brazil, which has high rainfall variability with irregular rainfall throughout the year. This research aimed to identify fava bean genotypes that are tolerant and susceptible to water deficit in seedlings. The trials were carried out at the Plant Biology Laboratory (LABIV) of the State University of Ceará (UECE), in Fortaleza-CE. Sixteen cultivars were selected and parameters related to the physiological quality of the seeds were analyzed under conditions of water stress induced by PEG 6000, with osmotic potentials of 0.0 MPa and -0.3 MPa. A survival curve was used to identify contrasting genotypes. It was observed that the germination test and germination speed index explained approximately 77% of the variability in the data. The genotypes BF 306 and BF 313 presented better performance than the other cultivars, showing tolerance to water deficit, while the genotypes BF 308, BF 302, BF 311, BF 303 and BF 293 obtained the worst values, showing their susceptibility to drought. The Screening Box method showed that genotype BF 301 was susceptible to water deficit and its survival was restricted to 25 days, indicating its greater vulnerability to water deficit in relation to other analyzed cultivars.