Four hypertriploid plants were obtained: two plants were found in the progeny of the primary trisomic for chromosome 4 (Robust) in the F2population of the cross between Robust x KM 200 (a short-awned mutant). The F1hybrid of Robust x zebra Colorado (zbc) and Robust x light green (lg4) contained one plant each. All the four hypertriploids studied were larger than their diploid sibs in various plant organs.