Teste de tetrazólio para as sementes de milho: Períodos de hidratação e de coloração das sementes

Abstract

The objective of this research was to determine the conditions to evaluate the viability of corn seeds by tetrazolium test. Using three seed lots, cultivar D657, preconditioning periods and temperatures (4, 6, 12 and 16 hours at 25 and 30°C and 4, 6 and 8 hours at 35 and 40°C) and staining periods and temperatures (seeds moistened during 4h at 25, 30, 35 and 40°C and staining during 1, 2 and 3 hours at 40°C in a solution of 0,075% tetrazolium chloride) were tested. Seed water content (oven method, 105±3°C/24h) and germination (TP, 25°C, count at 4 and 7 days) were determined. The tetrazolium test was performed classifying the seeds in two categories: viable and non- viable. The experimental design was a randomized block with two replications for each seed lot. The multiple mean comparison within treatments was performed using Tukey's test at a 0,05 error level. It was concluded that tetrazolium test constitutes an efficient option for estimate the viability of corn seeds. The most adequate condition would be that resulting from a combination of four hours of preconditioning at 35 or 40°C (seed water contents reached values from 19,5 and 21,3%, respectively) followed by 1, 2 and 3 hours of staining at 40°C.