Unlocking the Nutritional Potential of Sudanese Pearl Millet: Genetic Insights into Carotenoid-Rich Germplasm for Provitamin A Biofortification

Abstract Pearl millet is a vital staple in the arid and semi-arid regions of Sudan and has the potential for biofortification to address provitamin A deficiencies. This study evaluated the genetic variation in carotenoid content and grain color attributes in 116 Sudanese pearl millet accessions under field conditions at the Al Gezira Research Station. Carotenoid profiling (β-carotene, lutein, zeaxanthin, and total carotenoids) was performed using spectrophotometry and high-performance liquid chromatography (HPLC). Grain color traits were assessed using the Chroma Meter and CIE-LAB color space parameters. Highly significant differences were found among the genotypes (P < 0.0001) for all traits. β-carotene ranged from 0.028 to 0.028–0.763 µg/g, lutein from 0.11 to 4.79 µg/g, and zeaxanthin from 0.05 to 1.69 µg/g, with total carotenoids reaching up to 9.15 µg/g. Grain color attributes, such as L*, a*, b*, ΔE, and BI, showed wide variability, with strong correlations among b*, ΔE, and browning index. Broad-sense heritability estimates were high for all traits (> 94%), with β-carotene, lutein, and zeaxanthin exhibiting high genetic advancement as a percentage of the mean (GAM > 140%), indicating strong selection potential. Stepwise regression identified lutein and a* as the major predictors of β-carotene variation (R² >11%). Cluster and principal component analyses revealed distinct groups of carotenoid-dense genotypes, with HSD12345, HSD12415, and HSD12516 ranking among the top for β-carotene content. The identified high carotenoid accessions and color-linked traits offer valuable resources for biofortification and breeding programs aimed at improving the nutritional quality of pearl millet in drought-prone regions.