This study was carried out in Capão do Leão, RS, Brazil, with the objective of evaluating the effect of seed vigor on the growth of two cultivars of cultivated black oats (Avena strigosa Schreb), as well as to verify possible interactions with plant population (150, 300 and 450 pl m-2). Seed vigor and plant population affected dry matter production during the vegetative period. The effects were reduced progressively in the growing season, with no more difference after anthesis. The extreme levels of seed vigor and plant population produced differences in dry matter yield of 410 kg ha-1 and 480 kg ha-1, respectively, at the 75th day after emergence, these effects were due to differences in crop growth rates. A compensatory effect of the plant population on dry matter production was verified, so that the effect of low seed vigor could be compensated by an increase in plant population; the lower the seed vigor level, the greater was the plant population required. High vigor seeds also compensated the effects of low plant populations.
Avena strigosa; biological yield; leaf area; growth rate