DIVERSITY ANALYSIS OF MOROCCAN CAROB (CERATONIA SILIQUA L.) ACCESSIONS USING PHENOTYPIC TRAITS AND RAPD MARKERS

Abstract

Diversity analysis of moroccan carob (Ceratonia siliqua L.) accessions using phenotypic traits and RAPD markers. The carob (Ceratonia siliqua L.) is a perennial leguminous (Caesalpinioideae) that grows as an evergreen shrub or tree. It’s an important component of the Mediterranean vegetation and its adaptation in marginal soils of the Mediterranean regions is important environmentally and economically. Phenotypic and genetic diversity among 10 Ceratonia siliqua accessions coming from different areas of Morocco were studied with morphometric and RAPD approaches. The analysis of discriminative fruit characters showed highly significant differences among these accessions, the closely related ones have a similarity level less than 65%. No molecular studies have been carried out so far on Ceratonia siliqua. To provide markers useful for molecular diversity study of the carob tree, genomic DNA extraction and amplification conditions were finalized and 67 arbitrary primers were screened. 52 of them showed clearly reproducible banding patterns. The analysis of RAPD profiles revealed a high degree of genetic diversity within these carob accessions and enabled each of them to be uniquely fingerprinted. Overall, in our study we note that morphological relationship between carob accessions is deeply different to their molecular relationship. Concerning the distribution of the accessions according to their geographical origin, clustering based on RAPD data revealed a rough distribution of theses accessions. Indeed, Sidi Bou Ottman, Demnate and Essaouira accessions coming from the south of Morocco seem to be linked in the PCA plot. However, two geographically distant accessions, Aïn Sfa and Ouazzane coming from the north (about 700 Km) were clustered with Essaouira and Demanate - Sidi Bou Ottman, respectively.