Heritability and Principal Component Analysis of Phytochemical Traits in Guava Under Indian Subtropics

Guava is rich in antioxidant compounds as it contains a high level of ascorbic acid, carotenoids and phenolic compounds. Genotypic variance, heritability and genetic advance study were carried out to assess the magnitude of variation among the different guava genotypes. High phenotypic and genotypic coefficients of variation were recorded for flavonoids (23.56 and 23.55, respectively) followed by antioxidant activity (18.97 and 18.88, respectively). Heritability and genetic advance (1.00 and 39.51, respectively) were recorded to be highest for flavonoids. Phenotypic coefficient of variance was slightly higher than the genotypic coefficient of variance for all the traits under study, indicating the existence of diversity in guava cultivars. Cluster analysis differentiated guava genotypes into distinct clusters based on flesh and skin colour as well as phytochemical properties. Fruit weight was negatively correlated with antioxidant activity, anthocyanins, lycopene and carotenoid content, which clearly indicates that white-fleshed guavas are larger in size but have lower amounts of these compounds. Correlation studies also revealed that antioxidant activity of fruits was strongly and positively regulated by total phenols, carotenoids and flavonoids. Further, it was worth noting that the ascorbic acid content was also negatively correlated with these phytochemical compounds, which might be due to the fact that the presence of anthocyanins has a negative impact on the presence of ascorbic acid. Thus, the results of the study can be further utilized in guava breeding programmes by understanding the inherent association of important phytochemical traits.