Path analysis reveals simultaneous increase in vitamin C and soluble solids in guava progenies

Abstract A simultaneous increase of the antioxidant vitamin C (VITC) and in the soluble solids/acidity ratio (TSS/ACI) may enhance guava quality and stimulate consumption. The present study aimed to estimate phenotypic correlations and perform path analysis using a causal diagram for VITC and TSS/ACI (dependent variables) and 11 other independent variables in progenies from the crosses [‘Pedro Sato’ × ‘Purple Guava’], [‘Pedro Sato’ × ‘Paluma’], and [‘Paluma’ × ‘Purple Guava’], to guide selection and breeding of new guava cultivars. A total of 295 progenies from the three crosses were evaluated over four production cycles for 13 physicochemical traits. Significant positive correlations between VITC and TSS/ACI were found, ranging from 0.140 to 0.227. Significant positive phenotypic correlations (‘r’) were estimated for VITC × TSS/ACI and significant negative correlations among VITC and TSS/ACI with total fruit yield and mean fruit weight. The direct effects of VITC to TSS/ACI and TSS/ACI to VITC were consistently positive and significant across all analyses, while the ‘r’ were not consistent, highlighting the limitations of the phenotypic correlations in explaining cause-and-effect relationships. The direct effect estimates indicate that a simultaneous increase in VITC and TSS/ACI is possible, though it may have a negative impact in total yield and mean fruit weight. Indirect selection for increased VITC can be achieved through selection for high TSS, or vice versa.