Potential Contributions of Five Exotic Maize Populations to Sweet Corn Improvement

Abstract

Sweet corn (Zea mays L.) is deficient in a number of agronomic traits such as stalk and root quality. Table quality (flavor, tenderness, texture, and appearance) is of prime importance in sweet corn improvement. A possible source of both improved agronomic performance and table quality is exotic cultivars of maize that have been developed for direct human consumption. The purpose of this study was to evaluate the potential contributions of five populations: NTZ Mexican Dent, NTZ Cateto, NTZ Caribbean Flint, NTZ Cuzco, and NTZ Coroico to sweet corn improvement. The five populations were crossed to nine sweet corn inbreds adapted to Wisconsin. The 45 resulting topcrosses and appropriate checks were grown at three locations in 1986 and 1987. Fifteen traits were evaluated including yield, stalk breakage, root lodging, and ear appearance factors. All traits varied significantly due to population and inbred effects. The population by inbred interaction effects were significant for growing degree days (GDD) to midsilk, plant height, root lodging, ear moisture, yield, kernel depth and width, ear length and width, and number of kernel rows. Mexican Dent topcrosses were the highest yielding, averaging 7.59 Mg ha−1. The lowest yielding topcrosses were those with Coroico as a parent, averaging 5.43 Mg ha−1. Compared to the sweet corn checks, the exotic populations contributed little to decreased stalk lodging or root lodging. The Mexican Dent population contributed the most positive and least negative effects followed by Caribbean Flint and Cateto. Coroico and Cuzco had little to offer in terms of plant and ear appearance.