The experiment was conducted with the objective of validating the use of the reduced period of seed preconditioning for the tetrazolium test for additional soybean genotypes. The following 14 cultivars were evaluated: BR92-6568, BR92-7303, Embrapa 58, Embrapa 59, Embrapa 60, Embrapa 61, Embrapa 62, BRS 132, BRS 133, BRS 134, BRS 135, BRS 136, BRS 156 and BRS 157. Two preconditioning periods (four and six hours) at 41ºC were tested and compared to the traditionally recommended period of 16 hours at 25ºC. The following parameters were determined: seed moisture content (%), vigor [TZ (1-3)], viability [TZ (1-5)], mechanical damage [TZ (6-8)], weathering [TZ (6-8)] and sting bug damage [TZ (6-8)]. The preconditioning period of six hours at 41ºC resulted in adequate staining of the seeds, allowing excellent interpretation of vigor, viability, mechanical, weathering and stink bug damages for the 14 genotypes. Staining pattern of the seeds after preconditioning for six hours at 41ºC was equivalent to the traditionally recommended period of 16 hours at 25ºC, and superior in precision to the treatment of four hours at 41ºC for all tested genotypes. This last treatment did not result in seed imbibition to 27% seed moisture content or more, which is required for adequate staining of the seeds for the evaluation of all measured parameters, with exception to stink bug damage, which was not affected by this
treatment. It was concluded that the alternative seed-preconditioning period of six hours at 41ºC can
be successfully applied to soybean seeds for the evaluation of seed quality by the tetrazolium test.