Combining three grain mutants for improved-quality sweet corn

Abstract

Our goal was to improve sweet corn (Zea mays L.) by the novel approach of combining three grain mutants in one plant, shrunken-2 (sh2sh2), purple (Pr1Pr1C1C1), and opaque-2 (o2o2), for increased sugar, anthocyanin, and tryptophan content, respectively. We crossed purple opaque-2 waxy maize with sweet corn inbred lines. In the segregating selfed progenies, the opaque-2 gene was detected by the genetic marker phi057, the two other genes by the visual markers purple and shrunken. The purple opaque-2 sweet corn performed well in field tests; it had high total sugar content as required for sweet corn, improved protein quality indicated by 30% higher tryptophan content, and a 10-fold higher anthocyanin content than yellow kernel maize. This new sweet corn germplasm is a first step toward developing specialty maize with increased health benefits.