Abstract
Of seven expected allotrisomics with AA genome and an extra chromosome from genome B six were found in the progenies of triploid hybrids Avena barbata Pott. (AABB) crossed with A, strigosa Schreb. (AA) or A. wiestii Steud. (AA). The primary allotrisomics further produced six derived types such as autotrisomic with AA and a chromosome from A, long arm telotriso-mic and long arm isotrisomic. Most of trisomic types were easily distinguished from disomic sibs by dwarf ness, low seed fertility and some morphological characteristics governed by genes located on the trisome from genome B though the former two seem to be mainly due to the genic unbalance caused by aneuploidy. In self ed progenies of the various trisomics, transmission rate of the trisome ranged from 6 to 28 per cent and their fertility varied 30 to 78 per cent. Most of allotrisomic types indicated 7//+1/, but sometimes 6//+1/// at MI. In two allotrisomic types, the extra chromosomes were highly homologous with their homoeologues of genome A. Then, substitution between them, only in a single dose, was sometimes observed in disomic and trisomic progenies.
