Interrelationships of Sweet Potato Varieties and their Characters for Yield Determination

Seven sweet potato varieties were evaluated for their relationship (similarity and differences) in southern and eastern zones of Tigray, Ethiopia in 2012. Randomized complete block design with three replications was used for the experiment. Cluster analysis based on ward's method using Squared Euclidian distance was performed for clustering the varieties. Moreover, all characters were standardized before the distance matrix is done due to variables are in different units of characters and to minimize the effect of scale differences. The combined analysis of variance across locations showed significant variation among genotypes, locations and the genotypes by locations interaction..The superior mean total root yield (26.82 t/ha) was obtained at Kukufto testing location while the inferior yield (13.45 t/ha) was at Rarhe. Similarly, genotype LO gave the highest mean total root yield (30.9 t/ha), but bellela gave the lowest (7.78 t/ha). The AMMI analysis also showed highly significant difference for genotypes, locations and the genotypes by locations interaction. The genotype main effect contributed more to the total variability (54.1%) indicating that the variation was largely due to the inheritance of genotype effect. The genotype by location interaction was further partitioned using AMMI model and the first two principal components explained 100% of the total variability. AMMI biplot view of this study identified kukufto as best testing location and LO, Tulla and Kulfo as best genotypes for south and south east zones of Tigray region.