Six crosses between three naked oat (Avena sativa L.) germplasm sources from the USA and Australia and three Brazilian hulled genotypes were studied for the segregation of naked grain and multiflorous spikelet traits in the F2 and F3 generations. One major gene with incomplete dominance and expressivity for both traits was identified in all populations. The occurrence of intermediate types for naked grain varied with the population and did not depend on the germplasm source of naked grain used. The frequency of intermediate types varied among F2 populations indicating that selection for higher expressivity of naked grain could be used to develop Brazilian oat lines with naked grain.
