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broad-based and improved varieties were evaluated at 4 locations in 3 years in a randomized complete block design in 4 replicates to determine variability among cultivars for yield components and adaptation to different environments. Results showed fresh root yield was significantly correlated (P < 0.001) with number of roots, harvest index, shoot weight and number of stands harvested. AMMI analysis partitioned main effects into genotypes, environments and G × E with all the components
showing highly significant effects (P < 0.001). Environment had the greatest effect (70.3%), G × E interaction (19.0%) and genotype (10.7%). AMMI1 and unadjusted means selected the same winner in 9
out of 12 environments (75%), but differently in 3 environments. The GGE biplot (E and GxE interaction) delineated environments into mega-environments. Cultivar 4(2)1425 (moderately yielding) was the most
stable and specifically adapted to Zaria. ABBEY-IFE, ATU-IWO and 2ND-AGRIC though moderately yielding were highly tolerant to CMD, suggesting a rich resource within the germplasm that could be
enhanced for further genetic improvement of the crop.