Genetic Diversity and Phylogenetic Relationships of Capsicum frutescens in the Asia–Pacific Region: The Pacific Dispersal Route

Abstract

Capsicum peppers are among the oldest domesticated crops in the Americas. Columbus introduced them to Europe, from where they spread to the Far East via Africa, South Asia, and Southeast Asia. However, the details of how Capsicum peppers were introduced into the Asia–Pacific region and their subsequent dispersal remain unknown. Therefore, we investigated the genetic diversity and relationships of Capsicum frutescens in the Asia–Pacific region through restriction site-associated DNA sequencing (RAD-seq) and the sequencing of a variable chloroplast genome locus. The RAD-seq analysis showed that three accessions from Japan are most closely related to those from the Americas and Micronesia, and are distant from most of those from islands and continental Southeast Asia. Although C. frutescens has two chloroplast haplotypes (T and TC), only the T type was found in the Americas and Japan, whereas both types were distributed in other regions. Therefore, we postulate that some C. frutescens accessions were introduced into the Asia–Pacific region from the Americas via the Pacific dispersal route, whereas only the T type was introduced into Japan. Evidence for this Pacific dispersal route of C. frutescens could lead to a reconsideration of the dispersal routes of other crops native to the Americas.