Investigation on direct and reciprocal crosses in maize ( Zea mays L.)

Seven traits of twelve hybrids derived from direct and reciprocal crosses of four parental lines were examined during three years in Hungary. No significant differences were found between the direct and reciprocal crosses for stalk diameter or leaf number over the average of three years in any of the hybrids. Significant differences in the number of primary tassel branches were observed between UDH5 and its reciprocal UDH8, and between UDH6 and its reciprocal UDH11. It was evident in both instances that the degree of heterosis in the reciprocal crosses far exceeded that in the direct ones. A high number of tassel branches was dominant over a low number, so this trait was preferentially inherited in the hybrids. A positive correlation was observed between plant height and main ear attachment height (r = 0.67**). A positive correlation (r = 0.89**) was also found between the length of the main tassel axis above the lowest and above the uppermost side-branch. A medium correlation was observed between the number of primary tassel branches and the plant height (r = −0.42**). The number of primary tassel branches exhibited the highest heterosis. These results can be utilized in practical selection and seed production.