AMMI- and GGE biplot analysis of taro (Colocasia esculenta (L.) Schott) genotypes in Southern Ethiopia

Abstract

Taro (Colocasia esculenta (L.) Schott) is becoming an important food security crop for millions of smallholder farmers, particularly in some parts of southern Ethiopia as a result of release of a few high yielding varieties. In the process of release of the improved varieties, emphasis has been mainly given on the superiority of corm and cormel yield of the released varieties over the existing cultivars, neglecting the importance of genotype x environment interaction and yield stability analysis. In this study, eleven taro genotypes, designed with RCBD with three replications, were investigated at six locations under rain-fed condition during the 2014/15 cropping season. The objective was to assess the genotype x environment interaction (GEI) and corm and cormel yield stability of the genotypes. Genotype attributed higher proportion of the variation in the data (37.29%), while location contributed 35.78% with their interaction contributing 17.6% of the total variation. The ‘which-wonwhere’ analysis grouped the six test locations into a single mega-environment, which resulted in a non-crossover GEI, with Boloso-1 (G6) being an overall best yielding and specially adapted variety to all test environments. Thus, it could be selected for broad adaptation across the test locations and elsewhere in similar agro-ecologies. G2 (ARC/012/96) was identified as the most stable though low yielder genotype. This study further revealed that E2 (Areka) was an ‘ideal’ environment for evaluating superior taro genotypes.