The objectives of this study were to determine the inheritance of segregation of isozyme loci and some major genes, and to detect the associations between isozyme variation and some major genes with quantitative traits in cultivated oats (Avena sativa L). Four oat crosses involving N327-6, N313-2, Exeter, 78-34Cn5, and Pendragon çultivars were used in this experiment. Parents, F] and F2 material for all crosses were sown in a completely randomized design. The inheritance of spring-habit and husked-naked traits were determined by single dominant genes. The isozyme Diaphorase (DIA) band-present allele behaved as a single dominant gene. The traits, tiller number and kernel content in family 91-232-1 and groat oil content in family 91-228-11 had significant associations with DIA. Winter types had the higher values for biological yield, grain yield, grains per panicle, longer ear emergence, and taller plant height, while spring genotypes possessed higher values for grain weight. The husked genotypes had higher values for biological yield, grain yield, harvest index, groat oil content, and kernel weight, whereas naked genotypes possessed only higher kernel content.