Epistasis in three-way crosses involving early and late inbred lines of maize.

Three single hybrids were crossed with 12 early and late (flint and dent) inbred lines. The three-way and single crosses were compared for the influence of epistasis on grain yield. The inbred lines with the same growing season used as female and male parents were involved in significant epistatic effects. Depiste the fact that both flint and dent types of inbreds were included in the present study, the obtained epistatic deviations were comparable in frequency with other studies with only dent inbred lines. The use of single crosses as parents for three-way crosses was found to cause under estimation of the positive and overestimation of the negative epistatic deviations. The group of three-way hybrids with late parental lines recorded the lowest number of threeway crosses with epistatic deviations from the predicted performances.