Abstract: Passion fruit is a specialty mountain fruit in Guizhou, but the major varieties currently cultivated in Guizhou are only ‘Tainong 1’ (purple fruit) and ‘Qinguo 9’ (yellow fruit), leading to bottlenecks in industrial development. To address the issue of limited variety, this study was performed on mature fruits from three purple cultivars and seven yellow cultivars, which had been preliminarily evaluated. External and internal fruit quality indicators were measured, and the differences between various strains and the major cultivars were compared. Using analysis of variance, correlation analysis, and principal component analysis (PCA), single fruit mass, superoxide dismutase activity, citric acid content, flavonoid content, and potassium (K) content were identified as the core evaluation indicators. A comprehensive evaluation model for passion fruit quality was established using grey relational analysis, and two excellent strains were selected: one for fresh consumption and one for processing. Transcriptome analysis preliminarily revealed potential differences in molecular regulation among representative strains. The results showed that there were significant differences in the external and internal fruit quality of different passion fruit strains. Citric acid was a key substance affecting the taste of passion fruits, while K was a relatively abundant mineral element in passion fruits. Most quality indicators showed varying degrees of correlation. V2 were identified as the best purple passion fruit strain for processing and V9 as the best purple strain for fresh consumption. As representative purple and yellow fruit strains, they exhibited significant differences in key secondary metabolic pathways of fruits (such as aroma and pigments). These findings provide a reference for establishing a comprehensive evaluation system for passion fruits, as well as for the breeding, extension, and genetic improvement of passion fruit varieties in Guizhou.

Key words: passion fruit; fruit quality; grey relational analysis; comprehensive evaluation; transcriptome