Abstract the objective of this work was to identify the most adapted and stable genotypes for dry mass and seed yield using the genotype plus environment interaction (gge) biplot technique. The experiment was conducted in the municipality of frederico westphalen, in the state of rio grande do sul, brazil, in 2018, 2019, 2020, and 2021, using five lines and two cultivars of black oat, in a randomized complete block experimental design, with three replicates. The adaptability and stability of the genotypes, as well as their behavior in the environments, were evaluated using the gge biplot. The seed yield of black oat genotypes is highly influenced by the environmental conditions over the four studied cultivation years. The ufsmfw 2-07 genotype stands out, but shows instability. The ufsmfw 2-07 and upfa 21-moreninha genotypes show adaptability in specific years. Mega environments are formed for the dry mass trait in 2018 and 2021 and seed yield in 2018, 2020, and 2021, whereas, 2019 is considered the year for genotype discrimination.