Analysis of genetic variability in Moniliophthora roreri with AP-PCR and RAPD in Antioquia, Colombia

Moniliophthora roreri is the causal agent of moniliasis in cocoa, the most severe disease affecting cocoa plantations in the Antioquia department in Colombia. RAPD (random amplified polymorphism of DNA) and AP-PCR (arbitrarily-primed polymerase chain reaction) molecular markers were used for studying the genetic variability of 170 M. roreri isolates collected from twelve municipalities in Antioquia. Cluster analysis divided the population into six groups: the G1 group was the largest containing 95% of the isolates having high genetic similarity (0.70 to 1.0 similarity coefficients) whilst the other five groups only contained isolates from Apartado and Dabeiba having moderately low genetic similarity (0.45 to 0.55 similarity coefficients). Principal component roanalysis revealed high genetic similarity amongst populations except for isolates from Apartado and Dabeiba which registered the highest levels of genetic variability, having high Shannon’s index values and polymorphic loci percentage whilst low genetic variability was recorded for the other isolates. Genetic diversity and differentiation values in the population showed the recent introduction of M. roreri in cocoa plantations in Antioquia and predominantly clonal reproduction in the population. ANOVA revealed most genetic variation within municipalities (75.68%); only 5.94% variation was present in the sub-regions