INHERITANCE OF EXPANSION VOLUME AND YIELD IN 2 POPCORN X DENT CORN CROSSES

Improvement of expansion volume, defined as the volume of popped corn per gram of unpopped corn, generally is considered the most important objective of popcorn (Zea mays L.) breeding programs. Popcorn, however, generally is inferior to dent corn with respect to yield and other agronomic characteristics. Detailed information on the inheritance of expansion volume and grain yield in popcorn X dent corn crosses was not available in the literature. The objective of this study was to determine the inheritance of expansion volume and grain yield, including yield components, in two popcorn X dent corn crosses. Generation means analysis was used to quantify genetic effects in the popcorn X dent crosses Ia53 X B73 and Ia28 X Mo17. Significant additive genetic effects were detected for expansion volume in the cross Ia28 X Mo17, and for grain yield, ear length, ear diameter, and 50-kernel weight in both crosses. Dominance effects resulted in reduced expansion volume, and increased grain yield, ear length, ear diameter, and 50-kernel weight. Significant epistatic effects for grain yield were detected in the crosses Ia53 X B73. Expansion volume was negatively correlated with all yield components except for number of kernel rows. Thus, relative to other yield components studied, selection for high kernel row number would appear to result in the least reduction of expansion volume. Results from this study indicate that breeding methodologies which exploit additive genetic variation associated with expansion volume and dominance variation associated with grain yield are most likely to result in concurrent improvement of these two traits.