Marker-assisted backcrossing of lcyE for enhancement of proA in sweet corn

Vitamin A deficiency (VAD) compromises the immune system and is the leading cause of preventable blindness in children in many developing countries. Biofortification provides a sustainable way to prevent VAD and other micronutrient malnutrition problems. Sweet corn is one of the most popular vegetables and is an important provitamin A (proA) resource for humans. In this study, one common corn line with favorable lcyE alleles was used as donor parental line, and four elite sweet corn lines were employed as recipient lines. The favorable lcyE allele was introgressed into four sweet corn lines by marker-assisted selection (MAS). The functional marker 3′indel was selected as foreground marker, and 196 simple sequence repeats were utilized as background selection markers. Background selection was performed in each backcrossed population, and individuals with higher recovery ratio were retained. Twelve agronomic traits were investigated in the BC3F3 populations, which did not show any significant difference between the converted BC3F3 families and their recurrent parental lines. Further investigation showed that the favorable lcyE allele significantly improves β-carotene, proA, and total carotenoid contents as well as significantly increases α-carotene levels. The average increase in β-carotene, proA, and total carotenoid content was 1.54, 1.85, and 6.77 μg/g, respectively. The β-carotene/total carotenoid ratio increased among three converted lines, except for the K185-converted lines. The findings of the present study indicate that the introgression of the favorable lcyE allele by MAS efficiently increases proA carotenoid content in sweet corn.