Three Argentinian oat lines (P1, P2 and RIL) and three synthetic hybrids among them were analized in the present communication. P1 and RIL differ for one reciprocal translocation. P1 and P2 presented two independent interchanges. For the first time meiotic irregularities during ecuational division in hexaploid oat hybrids are reported. This latter observation throw doubts on the dependence of anaphase onset on metaphase plate completition in oats.