Abstract

Genetic enhancement of cassava aimed at increasing productivity through the provision of broad-based which improved germplasm and is also a major goal for cassava breeders. 10 genotypes (4 landraces and 6 developed lines) were evaluated at Fumesua, Ejura and Pokuase in 2 growing seasons in a randomized complete block design in 3 replicates to determine variability among genotypes for fresh root yield (FRY), root number (RTN), plant stands harvested (PSH), top weight (TW), harvest index (HI) and dry matter content (DMC) and their adaptation to different environments. Genotype main effect was significant (P < 0.001) for all the traits, GEI effect was significant (P < 0.001) for DMC, (P < 0.01) for TW and HI (P <0.05). Environment main effect was significant (P < 0.001) for FRY, RTN and TW. The most stable and high yielding genotype for dry matter content was LA07/012. Genotypes AW07/001 and AW07/015 were adjudged as the most productive genotypes in terms of FRY, DMC, HI and stability. The high genotype and low environmental effects, and the relatively low interaction on DMC imply that evaluation and selection can be effectively done in fewer environments to select clones with high performance while FRY requires multiple environments to identify clones with broad and specific adaptation. The partitioning of GGE through GGE biplot analysis showed that PC1 and PC2 accounted for 84.1 and 9.2% of GGE sum of squares respectively for dry matter content, explaining a total of 93.3% variation. Fum-2, Eju-2 and Pok-2 were the most discriminating and least representative environments while Fum-1 and Ejua-1 environments were the most representative environments.

Key words: Cassava, additive main effects and multiplicative interactions (AMMI), genotype by environment interaction (GGE) biplot, dry matter content.