With the objective of evaluating the delay harvesting effect in the crop on the
physiologic quality of oat (Avena sativa L.) seeds, an experiment was installed in Palma, CAP/
UFPel Agricultural Center, in the crop year of 1999/2000. It was used a factorial combination of
four genotypes (CTC 5, UPF 18, UFRGS 15 and UFRGS 19) and seven harvesting periods. The
experimental design was in a randomized blocks, with three replications. First harvesting has
begin when the panicles had around 30% moisture content (physiological maturity) and the others
to regular intervals of seven days. It was evaluated the moisture content, seed yield, germination
percentage, accelerated aging test, first count in the accelerated aging, germination speed index,
weight of a thousand seeds, protein content and industrial income, for each harvesting period.
Seeds moisture presented a great decrease 14 days after the physiological maturity, in all genotipes.
Harvesting delay caused an yield reduction of 30kg/ha per day of delay, from the physiological
maturity and so on. The harvesting delay effect was not verified on germination percentage,
emergency speed index, weight of a thousand seeds, industrial income and protein content. The
vigour of oats seeds, measured by the tests of accelerated aging and first counting, decresead as
far as harvesting was delaying.