HYBRID VIGOR AND GENE ACTION IN A SIX-PARENT DIALLEL CROSS OF SOFT WINTER WHEAT

Abstract

Six soft winter wheat lines were crossed in a diallel fashion and data were obtained from the parents and F1hybrid generation over two years. The mean squares for year by genotype interaction were significant for most measured characters indicating that the genotypes responded somewhat differently each year. The yield response of the F1generation hybrids ranged from −0.7 to 28.1% with 13 of 15 F1hybrids above the higher parent; however, none was significantly higher.Combining ability analyses were performed on the F1hybrids, and mean squares for general combining ability were significant for earliness, plant height, and kernels per spike. No significant mean squares for specific combining ability were detected. Monon was the best general combiner for both number of spikes and yield, and Gaines was a good general combiner for kernels per spike. The Jinks and Hayman (Vr, Wr) graphic analysis indicated that plant height, kernel weight, and number of spikes were controlled by some partial dominance and yield by apparent overdominance.