Adaptation of the tetrazolium test method for estimating the viability of sorghum seeds

The tetrazolium test is part of internal programs of seed quality control because it allows a quick, reliable and accurate assessment of seed viability. The purpose of this study was to determine, among the various methodologies suggested in the literature, a practical and efficient procedure for carrying out the tetrazolium test in sorghum seeds, with a view toward a rapid estimate of their viability. Four seed lots of the simple hybrid Buster were used, testing two forms of seed pre-conditioning (direct immersion in water and between moistened paper towels); two types of preparation (longitudinal cut of the seed through the embryo with immersion of one of the halves in the tetrazolium solution or placement of the two halves on filter paper moistened with tetrazolium solution); two forms of staining (on paper and with direct immersion in the solution) and three concentrations of tetrazolium solution (0.1%, 0.5% and 1.0%). The tetrazolium test may be efficiently conducted for sorghum seeds through pre-conditioning between paper towels for 18 hours at 20 oC, with immersion staining of one half of the seed in tetrazolium solution at 0.1% for three hours at 40 oC.