Mass ratio (M_B/M_A) vs. separation for the binaries in our sample, marked with circles for the young moving group members, triangles for the young field objects, and squares for the members of the Scorpius Centaurus region (US, LCC, and UCL in Table 2). The new systems discovered in this paper are marked by filled symbols. The plus signs show the position of the additional objects listed in Table 7. Different colours represent different ranges of primary masses.