Breeding colored sweet corn for improved micronutrient content

Sweet corn is mainly grown for human consumption as a fresh, frozen, and canned vegetable and it is valued for its sweetness, flavor, tenderness, and antioxidant properties associated with the carotenoid pigments found in yellow kernels. However, sweet corn lacks diverse kernel color pigmentation often found in field corn as colors often accumulate after the prime eating stage. There is nutritional and market potential, in terms of micronutrients and aesthetic diversity, for creating eating-stage sweet corn with various colored flavonoid compounds. This study sought to generate sugary-1(su1) and shrunken-2(sh2) sweet corn hybrids that accumulated beneficial pigmentation by the prime sweet corn eating stage. Various colored maize varieties of dent corn, and flint corn types were crossed to eight sweet corn inbreds bidirectionally. This was followed by five selfing generations while selecting for color, sweetness, and texture phenotypes at prime-eating stage (20 days after pollination; DAP). Nine colored sweet corn (CS) inbreds were selected and were used to produce 20 CS hybrids. The CS lines were selected for their satisfactory sweetness, flavor, and texture phenotypes. Yellow-orange, purple, blue, and red were the predominant kernel colors observed in the selected inbreds and these color continued to manifest in the hybrids. CS inbreds and hybrids had maintained kernel sweetness and tenderness comparable to parental sweet corns. Analysis of the carotenoids and flavonoids revealed a dynamic increase and decrease of pigment concentrations among the CS inbreds in comparison with the parental sweet corn inbreds. Biochemical assays confirmed that the CS sugar and starch contents did not change substantially from the normal ranges reported in sweet corn parents. This study demonstrates that diverse colors readily accumulate by prime eating stage in sweet corn and thus increase sweet corn carotenoid and flavonoid profiles and the potential to improve its nutritional quality and market potential.