CRITERIA FOR PEANUT SEED PRECONDITIONING FOR THE TETRAZOLIUM TEST

The staining pattern of peanut (Arachis hypogaea L.) seeds with a tetr azolium solution was evaluated to determine the adequate conditions of seed quality evaluations. Three seed lots with different vigour level s and similar moisture content were pre-conditioned using the combinat ion of five periods of time (4, 8, 12, 16 and 20 hours) and four tempe ratures (20, 25, 30 and 35 degrees C) and then exposed to a 1.0% tetra zolium solution for three hours. The moisture content levels of seeds conditioned for 8 hours at the temperatures of 25, 30 or 35 degrees C, for 12 hours at 20 or 25 degrees C and for 16 hours at 20 degrees C, were above 30%. In this range of moisture level, the staining in tetra zolium was clear and uniform, reflecting an appropriate conditioning o f the seeds. However, under a practical point of view, the period of 1 6 hours at 20 degrees C showed to be the best option, since it allows to start the pre-conditioning an late afternoon of one day and submit the seeds for staining in the following morning.