Carob cultivars of the Catalan Countries: Characterization and population structure

Abstract

The carob tree (Ceratonia siliqua L.) is an evergreen, thermophilic and xerophytic species growing in most of the Mediterranean countries. Its geographical distribution in the Iberian Peninsula covers the Mediterranean coastal strip and part of the southern Atlantic coast. Spain is the leading carob pod producer country worldwide. The Mas Bové Center of the Agrofood Research and Technology Institute (IRTA, from the Catalan), located in the town of Constantí (Tarragonès region), hosts the National Carob Germplasm Bank (BNGG, from the Catalan) where 234 accessions from different countries are conserved. This study describes the current carob cultivar situation in Catalonia, the Balearic Islands and the Valencian Country, as well as the characterization of the carob pod and the seed traits of the genetic resources from Catalonia (35), the Balearic Islands (30) and the Valencian Country (41), together with the flower characterization. In addition, the results of the population structure of the BNGG analyzed by microsatellite (SSRs) genotyping with molecular markers of 215 accessions showed the presence of two genetic groups. The cultivars from the Catalan Countries (Catalonia, the Balearic Islands and the Valencian Country) and those from Murcia belong to the same genetic group while the cultivars from other countries and from Andalusia belong to a different genetic group, suggesting the existence of a common past in the origin of these materials.