Sudanese pearl millet (Pennisetum glaucum (L.) R. Br.) germplasm reveals genetic potential for carotenoid improvement and provitamin a biofortification

Abstract

Abstract Pearl millet is a vital staple in Sudan’s arid and semi-arid regions and offers a promising platform for biofortification to alleviate provitamin A deficiency. This study evaluated the genetic variation in carotenoid content and grain color attributes of 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 a Chroma Meter and CIE-LAB color space parameters. Highly significant differences were observed among the genotypes ( P  < 0.0001) across all traits. β-carotene ranged from 0.028 to 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, exhibited substantial variability, with strong correlations among b*, ΔE, and the browning index (BI). 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 a strong selection potential. Stepwise regression identified lutein and a* as the major predictors of 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, respectively. The identified high-carotenoid accessions and color-linked traits provide valuable resources for biofortification and breeding programs to improve the nutritional quality of pearl millet in drought-prone regions.