Sugary enhancer1 Inbreds to Improve the Quality of Sugary1 Hybrids of Sweet Corn

Abstract

The better emergence and seedling vigor of sweet corn (Zea mays L.) hybrids homozygous for the gene sugary1 (su1) make them more suitable for cultivation under European Atlantic conditions (cold, wet spring) than those homozygous for other traits. Elite sweet corn inbreds homozygous for both su1 and sugary enhancer1 (se1) could improve the table quality of su1 hybrids. The su1se1 inbreds for improving su1su1 hybrid performance can be chosen in several ways. The aim of this paper was to identify donors among su1se1 inbreds that might improve the quality of su1 hybrids. Eight su1se1 inbreds were crossed with eight su1 inbreds that were parents of fifteen su1 hybrids. Hybrids and inbreds were cultivated next to one another in two locations in northwestern Spain in 1999 and 2000. Several possible estimators for identifying su1se1 inbred donors with favorable alleles lacking in the su1 hybrid were determined. These estimators included the relative number of favorable alleles present in the donor but absent in the hybrid (μǴ), predicted three-way cross (PTC), minimum upper bound (UBND), net improvement (NI), probability of the net gain of favorable alleles when there is complete dominance (PNGg), probability of the net gain of favorable alleles when there is partial dominance or epistasis (PNGceg), and general combining ability (GCA). μǴ and NI were chosen for improving hybrid table quality. These estimators indicate that table quality and other traits of su1 hybrids can be improved by using germplasm from the su1se1 inbred lines. The best donor of quality for most of the hybrids was the inbred line IL731a.