Genotype-by-environment interaction analysis of nutritional composition in newly-developed sweetpotato clones

Development of sweetpotato genotypes with enhanced nutritional composition is key to improve food and nutrition security and for industrial applications. The objective of this study was to determine the effect of genotype-by-environment interaction (GEI) on nutritional composition of sweetpotato clones to identify and select promising clones for large-scale production. Root dry matter content (RDMC), protein (Prot), β-carotene (β-car), iron (Fe), Zinc (Zn), starch (Star), sucrose (Suc), fructose (Fruc) and glucose (Gluc) contents were evaluated among 24 newly developed sweetpotato clones and one check variety across six diverse environments in southern Ethiopia using a 5 × 5 simple lattice design. Data was subjected to additive main effects and multiplicative interaction (AMMI) to estimate genotype (G), environment (E) and GEI effects. According to Gollob’s F-test and FR-test, four interactions principal component axis (IPCA) were significant (p ≤ 0.001) in the AMMI model for most traits, except glucose content where three and two IPCA’s were identified as significant by both tests. As a result, AMMI-4 was diagnosed for all traits, except glucose content where AMMI-2 was recommended. AMMI revealed significant (p ≤ 0.001) G, E and GEI effects on the studied nutritional traits. G explained 54 and 93 % of total variation for DRMC and β-car, respectively indicating these traits were less influenced by GEI effects. Larger E effects were observed for Prot (65 %), Fe (55 %) and Zn (64 %) while larger GEI effects were observed for Star (58 %), Fruc (77 %), Suc (50 %) and Gluc (56 %). Some of the newly-developed clones such as G5 (Ukrewe × Ogansagan-5), G6 (Resisto × Ejumula-7), G12 (Resisto × Temesgen-12), G13 (Resisto × Temesgen-14) and G22 (Ejumula × PIPI-19) with high RDMC (> 30 %), Prot (> 7 %), β-car (> 12 mg 100 g⁻¹), Fe (> 2 mg 100 g⁻¹), Zn (> 1 mg 100 g⁻¹), Star (> 60 %), Fruc (> 4 %), Suc (>10 %) and Gluc (> 5 %) contents were selected for further evaluations for large-scale production, industrial use and and use in breeding programmes.