Variability for nuclear ribosomal genes within theobroma cacao

Abstract

Restriction fragment length of the rRNA genes was studied in Theobroma cacao using heterologous rDNA probes. One hundred, ninety-two individuals including both cultivated, wild clones were analysed. Dral, £coRI restriction sites were mapped. Both length heterogeneity, restriction site polymorphism have been found. Fifteen different types of rDNA units have been characterized. As opposed to previous enzymatic studies, the rRNA gene analysis indicates a clear distinction of the three genetic groups Criollo, Forastero, Trinitario within cocoa, points out the hybrid origin of Trinitario. © 1993 The Genetical Society of Great Britain.