Correlation, Path Coefficient and Multivariate Analysis for Yield and Yield-associated Traits among Potato (Solanum tuberosum L.) Genotypes Grown in Eastern Ethiopia

Genotypic, phenotypic correlation coefficients, and path coefficients analysis as well as cluster and principal component analysis were done for 15 quantitative traits of yield and its related characters among 18 Potato genotypes in Eastern Ethiopia. The experiment was carried out using Randomized Complete Block Design with three replication data were collected for yield and yield-related traits using standard procedure. The results revealed that tuber yield was found to be significantly and positively correlated with marketable tuber yield, large tuber number, large tuber weight, and starch content, while negatively and significantly correlated with small tuber weight both at the genotypic and phenotypic level. Path analysis indicated that total tuber yield was directly associated with marketable tuber yield, average tuber weight, large tuber weight, large tuber number, dry matter content, and total soluble solids and starch content. Based on the complete linkage method of cluster analysis using Euclidian distance, the studied potato genotypes were congregated into different clusters confirming the existence of a high genetic divergence among the studied genotypes. Principal component analysis revealed that the first five principal components accounted for 92.2% of the observed variations among 18 potato genotypes. Of these, the first, the second, the third, the fourth, and the fifth principal components explained 55.33%, 17.18%, and 9.17%, 6.18% & 4.33% of the variation, respectively. In conclusion, the traits that were directly associated with tuber yield should be considered in selection at potato improvement programs that aim to increasing tuber yield. Variety Belete, which was grouped in the first sub-cluster of the first main cluster, was the most superior yielder variety among the tested varieties and local cultivars and therefore could be exploited in potato breeding to improve total tuber yield.

Keywords:Potato; Correlation; Path analysis; Diversity; Cluster; Principal component analysis; Tuber yield