Germination and Vigor of Black Bean (Phaseolus vulgaris L.) Cultivars Subjected to Saline Stress Conditions

Natural factors such as salinity act directly on seed germination and vigor and, consequently, affect the establishment and development of seedlings in the field. In view of the above, the objective of this study was to assess the effect of saline stress on the germination and vigor of seeds from black bean cultivars. The study was conducted at the Seed Analysis Laboratory of the State University of Montes Claros, Janaúba-Minas Gerais, Brazil. The experimental design was completely randomized, in a 2 × 5 factorial arrangement (two cultivars × five osmotic potentials), with four repeats of 50 seeds per treatment. Bean seeds from cultivars Campeiro and Esteio were used, with sowing carried out on germitest paper rolls moistened at five osmotic potentials via sodium chloride solutions (NaCl): 0.0 [distilled water]; -0.3; -0.6; -0.9 and -1.2 MPa. Seed rolls were kept in a digital germinator, and the germination and vigor percentages of the seeds were determined by first germination count, germination speed index (GSI), and fresh and dry mass of seedlings. The germination and vigor of seeds from common-bean cultivars, black commercial type, are negatively affected under saline stress caused by NaCl solution with osmotic potential lower than -0.6 MPa. The seeds of the studied cultivars showed a different behavior regarding saline stress conditions, and cultivar Campeiro proved to be more tolerant to saline stress in relation to Esteio during the germination process and seedling formation.