Assessing Suitability of Sorghum to Alleviate Sub-Saharan Nutritional Deficiencies through the Nutritional Water Productivity Index in Semi-Arid Regions

Abstract

Lack of cereal nutritional water productivity (NWP) information disadvantages linkages of nutrition to water–food nexus as staple food crops in Sub-Saharan Africa (SSA). This study determined the suitability of sorghum (Sorghum bicolor L. Moench) genotypes to alleviate protein, Zn and Fe deficiency under water-scarce dryland conditions through evaluation of NWP. Sorghum genotypes (Macia, Ujiba, PAN8816, IsiZulu) NWP was quantified from three planting seasons for various sorghum seed nutrients under dryland semi-arid conditions. Seasons by genotypes interaction highly and significantly affected NWP_{Starch, Ca, Cu, Fe}, and significantly affected NWP_{Mg, K, Na, P, Zn}. Genotypic variations highly and significantly affected sorghum NWP_{Protein, Mn}. Macia exhibited statistically superior NWP_protein (13.2–14.6 kg·m⁻³) and NWP_Zn (2.0–2.6 g·m⁻³) compared to other tested genotypes, while Macia NWP_Fe (2.6–2.7 g·m⁻³) was considerably inferior to that of Ujiba and IsiZulu landraces under increased water scarcity. Excellent overall NWP_{protein, Fe and Zn} under water scarcity make Macia a well-rounded genotype suitable to alleviating food and nutritional insecurity challenges in semi-arid SSA; however, landraces are viable alternatives with limited NWP_{protein and Zn} penalty under water-limited conditions. These results underline genotype selection as a vital tool in improving “nutrition per drop” in semi-arid regions.