Genetic Diversity of Pseudomonas Syringae pv. Syringae Causing Leaf Blight of Mango in Bangladesh

Mango (Mangifera indica L.) belonging to the family Anacardiaceae is the king of fruits. The genetic variations of 25 isolates of Pseudomonas syringae pv. syringae obtained from five regions of Bangladesh were analyzed using RAPD markers by Polymerase Chain Reaction (PCR). The percentage of polymorphic loci was found different from one region to another. Mean diversity across all population for all the loci studied was 0.31. The co-efficient of gene differentiation (Gst) was 1.00 reflecting the existence of high level of genetic variations among the genotypes. Comparatively the highest genetic distance (0.6931) was observed in Isolates of Rangpur vs. Isolates of Dinajpur; the lowest genetic distance (0.2877) was estimated in Isolates of Rangpur vs. Isolates of Bogra. Considering the genetic distance values; the results indicated that the isolates of five regions were genetically different from each other. The dendrogram (UPGMA) constructed from Nei’s (1972) genetic distance produced 2 main clusters of 25 isolates from five regions. UPGMA dendrogram revealed that isolates of Rangpur, Bogra and Mymensingh form same cluster with least genetic distance. Dinajpur and Rajshahi produce another cluster with least genetic distance. Genetic distance among the isolates of Rangpur, Bogra and Mymensingh was found very near and genetic distance among the isolates of Dinajpur and Rajshahi was found very near which means these isolates may be virulent and their genetic variation is minimum. The genetic variation among these isolates of different regions was low indicating geographical variation among the isolates collected from different regions.