Salt and water stress during germination affect the emergence of seedlings in the field and, consequently, the stand of the plants and crop growth. Two experiments were conducted to evaluate the effects of water and salt stress on germination and vigor of seeds of two sorghum [Sorghum bicolor (L.) Moench] genotypes. The seeding was done inside "Gerbox" boxes, on two sheets of "germitest" paper dampened with distilled water (control) or with solutions of polyethylene glycol 6000 to provide the water potentials of -0.2, -0.4 and -0.8 MPa, or with NaCl at 75, 150 and 300 mM, respectively. The seed germination and vigor were evaluated by the first germination count (FGC), germination test (GT), germination speed index (GSI) and germination average time (GAT). In both studies a randomized complete design in a 2 x 4 factorial arrangement was used, totaling eight treatments, with four replications of 50 seeds each. The CSF 18 genotype germination was affected only at the highest level of salinity (300 mM) with an increase in the GAT and reduction in the FGC, GSI and GT variables. The CSF 20 genotype showed similar performance, except for the GSI and GAT variables, which were affected by NaCl at the 150 mM concentration. The CSF 18 genotype had greater tolerance to water and salt stress during the germination phase than CSF 20.
Sorghum bicolor; physiology quality; osmotic stress; salinity
