Multivariate analysis of genetic relationships between Italian pepper landraces

Abstract

The heterogeneity of pedoclimatic conditions and the farmer selection for adaptation to local tastes and uses have favored the maintenance in cultivation in Italy of numerous pepper (Capsicum annuum L.) landraces. We have used amplified fragment length polymorphism (AFLP) fingerprinting and morphological variation in fruit type to assess the diversity of 19 pepper ecotypes representative of the autochthonous germplasm. Principal component analysis grouped together triangular and blocky fruited types, while elongate types were subdivided into long and half long, differing mainly with respect to the length/diameter ratio. The half-long types were divided into two further clusters on the basis of overall dimension, weight, and flesh thickness. Genetic similarities between the ecotypes were calculated from AFLP data and this allowed the separation of the accessions into two major and three minor clusters. One major cluster comprised five ecotypes with blocky or triangular fruits, while the other contained nine ecotypes with long or half-long fruits. AFLP markers were successful in both detecting genetic diversity and determining genetic relationships in Italian pepper germplasm. They also made it possible to distinguish most of the provenances within a given landrace, and to identify pairs of genetically similar ecotypes carrying different names. We believe that our analyses will help in the identification of rational strategies for the preservation of Italian pepper genetic resources. © Crop Science Society of America.