Characterization of phytophthora capsici leonian resistance in some pepper genotypes by principal component analysis

Abstract

In the study, resistance analyses were performed on pepper lines and genotypes (60 genotypes) of mainly common local genotypes found in the gene pool by classical testing methods. Classical tests were first applied in seedling stage. Second inoculation (the last) was carried out (in the stage of fruit retention) on resistant genotypes determined in the first inoculation. Varieties resistant to phytophthora capsici (CM 334 and partially resistant P1, P2 and P4) were also included in the study. Peroxidase and catalase enzyme contents of plant materials have been determined. Scale of 0-5 was applied to inoculated plants. Five pepper properties were measured and used as original variables. The first two principal components accounted for 74% of total variance. Score plots of the first two principal components were used to map genotypes according to their morphological properties. Some relationships between genotypes and their morphological traits were obtained. The results revealed that genotypes of P1, 13 (Urfa), 25 (UKST), 38 (UI), 48 (UKDT), 57 (ANKSB) were partial resistant genotypes while CM334 was fully resistant. To conclude, principal component analysis was shown to be a useful tool for mapping the pepper genotypes in terms of phytophthora capsici resistance.