Teste de envelhecimento acelerado em sementes de Brachiaria brizantha

Abstract

This study aimed to standardize the accelerated aging test for Brachiaria brizantha seeds by determining the optimal exposure time and temperature. The experiment was conducted at the Seed Analysis Teaching Laboratory of the Federal University of Technology – Paraná (UTFPR), Dois Vizinhos Campus, using dehulled seeds from three distinct lots (BM06, BM07, and BM022). A completely randomized design was used in a 3 × 4 × 5 factorial scheme with four replications. Seeds were subjected to four temperatures (30, 35, 40, and 45 °C) for five exposure periods (12, 24, 36, 48, and 60 hours), followed by germination and field emergence evaluations. The results showed that exposure for 12 hours at 30 °C provided the highest percentages of normal seedlings across all three seed lots. There was a tendency for increased seed deterioration with longer exposure times, especially at temperatures above 35 °C. Laboratory germination rates were higher than field emergence, indicating that adverse soil conditions negatively affect seed performance, even for lots with good laboratory results. The accelerated aging test proved effective in distinguishing seed vigor among lots and, when combined with field emergence tests, was suitable for evaluating the physiological quality of forage seeds. It is concluded that the ideal test protocol involves seed exposure for 12 hours at 30 °C.