Correlation and path-coefficient analyses of root yield and related traits among selected sweetpotato genotypes

Abstract

The objective of this study was to assess associations between yield and yield-related traits, and to identify the most efficient yield-predicting traits in sweetpotato for effective selection. Twenty-five newly developed sweetpotato genotypes were evaluated across six environments using a 5 × 5 simple lattice design with two replications. Data on root yield and yield-related traits were subjected to analysis of variance, correlation and path-coefficient analyses. Root yield was positively and significantly correlated with most traits studied. Root dry matter content (RDMC) had a significant negative correlation with root flesh colour (r = −0.47) and β-carotene content (r = −0.40). Conversely, β-carotene content and root flesh colour showed a highly positive correlation (r = 0.76). Path-coefficient analysis showed that individual root weight, number of roots per plant, RDMC and above-ground fresh weight had highly positive direct effects of 0.821, 0.776, 0.276 and 0.410, respectively, on fresh root yield. These traits also had significant positive correlations with fresh root yield. Vine length and root length, which had highly significant positive correlations with fresh root yield, showed negative direct effects of −0.086 and −0.033, respectively. Therefore, path-coefficient analysis was more valuable in identifying the most influential traits than simple correlation analysis.