DETECTION OF GENETIC DIVERSITY AND SELECTIVE GENE INTROGRESSION IN COFFEE USING RAPD MARKERS

RAPD (randomly amplified polymorphic DNA) markers generated by arbitar y decamers have been successfully employed to detect genetic polymorph isms between coffee species and between Coffea arabica genotypes. The RAPD profiles were used to construct dendrograms and these were consis tent with the known history and evolution of Coffea arabica. Material originating from Ethiopia and the arabica sub-groups - C. arabica var. typica and C. arabica var. bourbon - were clearly distinguished. RAPD analysis therefore reflects morphological differences between the sub -groups and the geographical origin of the coffee material. Species-sp ecific amplification products were also identified, but, more importan tly, amplification products specific to C. canephora were identified i n two C. arabica genotypes, Rume Sudan and Catimor 5175. This diagnost ic product is therefore indicative of interspecific gene flow in coffe e and has biological implications for selective introgressive hybridis ation in coffee. Our study demonstrates the power of the polymerase ch ain reaction technology for the generation of genetic markers for long -lived perennial tree and bush crops.