Path analysis under multicollinearity for papaya production of the solo and formosa groups

Abstract

Correlations and path analysis allow the understanding of the interrelations between characteristics of interest to the plant breeding. However, in order for their results to be reliable, the undesirable effect of multicollinearity must be excluded. The objective of this study was to estimate the correlations and their partitioning in direct and indirect effects, by path analysis, on the fruit production per plant (FP) of papaya from the heterotic Solo and Formosa groups, using two different strategies to circumvent multicollinearity. Eleven agronomic variables were evaluated in twelve papaya genotypes from the Solo group and nine from the Formosa group. Path analysis was obtained with the FP as the basic variable and to eliminate multicollinearity were used the discard of variables and the ridge path analysis. For the Solo group, fruit length and pulp thickness had greater direct effects on FP. In the Formosa group, the number of commercial fruits had a direct and indirect effect on FP. The two methodologies used to circumvent multicollinearity had high coefficient of determination, with better values for the ridge path analysis. The results indicated that the interrelation between the study characters was different in the Solo and Formosa groups. Thus, indirect selection strategies should be specific for each heterotic group.