Characterization of carotenoid profiles and presence of functional markers in sub-tropical maize (Zea mays L.) inbred lines

Biofortification provides a sustainable, pragmatic strategy to address the lack of vitamin A and the associated health complications. The objectives of the study encompassed the quantification of the carotenoid content of 147 maize inbred lines, the identification of variable regions within the <i>ZEP1 </i>gene, the correlation of these observed variances in the presence of this gene with carotenoid content, and the identification of lines harbouring the favourable alleles of the <i>crtRB1</i> gene. The observed correlations among the carotenoids synthesised by distinct branches of the biosynthetic process were both significant and positive. Utilising gel-based genotyping, 24 lines with contrasting carotenoid profiles were selected, evaluated and sequenced. Analysis of the variation in the sequence classified these lines based on their similarities to give 8 allele groups. The findings highlight that inbred lines both group 1 and group 8 exhibited significant associations with the carotenoid content of the lines. Specifically, <i>ZEP1_7852</i>, a discernible variation belonging to group 8, was found to be significantly associated with zeaxanthin content and total carotenoid content. Furthermore, 25 lines were found to have provitamin A content above 15 μg/g, harbouring the favourable alleles of the <i>crtRB1</i> gene using KASP SNP zm0016. These lines can serve as parents for source populations and hybrids, leading to the further enhancement of provitamin A in maize.