**Background:** Ethiopia faces significant challenges of malnutrition and vitamin A deficiency, particularly among children under 5 and pregnant women. Orange-fleshed sweet potato (OFSP) is a rich source of provitamin A and other nutrients, but genotype-by-environment interactions (GEIs) affecting its nutritional traits in northern Ethiopia's diverse agro-climatic zones have not been well characterized. This study aimed to evaluate GEIs in five OFSP genotypes across three locations in the Tigray and Afar regions.
**Methods:** Five OFSP genotypes (Amelia, Gloria, Ininda, Kulfo, Melinda) were obtained from the Tigray Agricultural Research Institute and planted in July 2020 at three sites: Aba'ala (arid lowland, 1440 m asl, annual rainfall 394 mm, avg temp 18.6–34.0°C), Mekelle-1 (semi-arid highland, 2220 m asl, rainfall 406 mm, avg temp 13.1–25.3°C), and Mekelle-2 (semi-arid highland, 2220 m asl, rainfall 523 mm, avg temp 12.2–24.4°C). A randomized complete block design with three replicates was used, with 30 plants per plot and 90 plants per genotype per site. Harvesting occurred in November 2020. Measured parameters included total storage root yield, dry matter content (dried at 65°C for 72 h), beta-carotene (HPLC), flavonoids (AlCl₃ colorimetric method), polyphenols (Folin-Denis reagent), soluble sugars (HPLC-RI), starch (Lugol's method), soluble proteins (Bradford assay), and free radical scavenging activity (DPPH assay). Broad sense heritability (H²) was estimated, and correlations among traits were computed.
**Key Results:** Two-way ANOVA showed that genotype, location, and their interaction were statistically significant (p < 0.05) for all nutraceutical traits. Ininda exhibited significantly higher yield across all sites, while Kulfo and Melinda had the lowest. Higher dry matter content was found in Gloria, Amelia, and Ininda, with Aba'ala (arid lowland) producing genotypes with higher dry matter. The highest beta-carotene concentrations were found at Mekelle-1 and Mekelle-2 (semi-arid highlands). Ininda and Kulfo had the highest total flavonoid content. Sucrose concentration was higher than fructose and glucose in all genotypes. High starch content was recorded in Kulfo, Gloria, and Melinda. High protein content was found in Amelia and Melinda. The highest DPPH antiradical activity was observed at Mekelle-1. Very high broad sense heritability was estimated for beta-carotene; high H² values were observed for dry matter and starch; low or very low H² values were observed for all other parameters. Positive correlations (r ≥ 0.50) included fructose-glucose (r=0.87), polyphenols-flavonoids (r=0.76), polyphenols-antiradical activity (r=0.69), sucrose-beta-carotene (r=0.66), and beta-carotene-yield (r=0.53). Negative correlations (r ≥ −0.50) included soluble proteins-starch (r=−0.72), beta-carotene-antiradical activity (r=−0.58), and beta-carotene-polyphenols (r=−0.50). The % RDA/RAI for vitamin A from 250 g (dw) intake was highest for Ininda and lowest for Kulfo; Ininda, Amelia, Gloria, and Melinda had beta-carotene contents sufficient to meet 100% RDA for age groups ≤8 years and >50% RDA for age groups ≥19 years and pregnant women.
**Clinical Implications:** The study demonstrates that OFSP genotypes Ininda, Gloria, and Amelia have the potential to alleviate vitamin A deficiency in northern Ethiopia, where malnutrition rates are high. A daily intake of 250 g (dw) of these genotypes can meet or substantially contribute to vitamin A requirements across all age groups, including pregnant and breastfeeding women. The high antioxidant activity associated with polyphenol and flavonoid content may also help counteract oxidative stress-related diseases. The viability of sweet potato production in arid agro-climatic regions with limited inputs expands the potential for food-based nutritional interventions in marginalized communities. The high heritability of beta-carotene, dry matter, and starch content indicates that genetic improvement through breeding is feasible.