Molecular markers reveal high variability among populations of Coffea arabica in its native range of the Afromontane forests of Ethiopia

Date: Sunday, January 10, 2016
Time: 5:40 PM
Room: Pacific Salon 3
Kassahun Tesfaye , Addis Ababa University, Addis Ababa, Ethiopia
Ludo Muller , Institut für Biologie/Botanik Freie Universität Berlin, Berlin-Berlin, Germany
Kim Govers , Botanischer Garten und Botanisches Museum Berlin-Dahlem and Institut für Biologie/Botanik, Freie Universität Berlin, Germany, Berlin, Germany
Endashaw Bekele , Addis Ababa University, Addis Ababa, Ethiopia
Thomas Borsch , Botanischer Garten und Botanisches Museum Berlin-Dahlem and Institut für Biologie/Botanik, Freie Universität Berlin, , Germany., Berlin, Germany
Coffea arabica L. is the only tetraploid species (2x = 44) of the genus Coffea, and is the most widely cultivated and traded. The southwestern forests of Ethiopia are its native habitat, where domestication began. Forest (wild), semi-forest (semi-wild), garden, and plantation coffee are the major conventional production systems in Ethiopia, whereby subsequent selection of coffee from wild populations has led to the formation of numerous landraces (farmer’s varieties) and cultivars. Exploring the genetic diversity of Arabica coffee populations in its natural range is an important parameter for conservation and sustainable use.  A total of 10 ISSR and 14 different AFLP primer combinations were used to analyze 9 wild populations and several cultivated genotypes; these markers selectively amplified 84 and 565 fragments, respectively. The NJ and UPGMA clustering analysis of 125 C. arabicaindividuals using 84 polymorphic ISSR markers clearly separated wild genotypes from landrace/cultivars and underscored the existence of wild coffee distinct from the semi-domesticated genotypes. Diversity measure using Shannon’s index showed various levels of variability within wild populations in Ethiopia. Those in Yayu (0.47), Bonga (0.46), and Berhane Kontir (0.41) showed the highest diversity.  Furthermore, AFLP markers detected moderate to high polymorphism (68% - 92%) with overall values of 73.5% (415 loci) among 130 C. arabica accessions. Overall both molecular markers clearly revealed the presence of vast genetic diversity within wild and cultivated coffee landraces and this warrants the need for a multi-site in situ conservation approach.  Development of advanced genomic tools for diversity characterization should accelerate future conservation efforts.