G℅E interaction effects on yield and yield components of cassava (landraces and improved) genotypes in the savanna regions of Nigeria

作者：OO Aina; AGO Dixon; I Paul; EA Akinrinde

来源：African Journal of Biotechnology, 2009.

Genetic enhancement of cassava aimed at increasing production and productivity through the provision of broad-based improved germplasm is a major goal for cassava breeders. At the International Institute of Tropical Agriculture (IITA), Nigeria, 18 varieties comprising 12 landraces and 6 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 %26lt; 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 %26lt; 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 ega-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.