Abstract
Genetic variation in 60 isolates of Xanthomonas oryzae pv. oryzae (Xoo), the causal agent of rice bacterial blight disease, investigated using random amplifi ed polymorphic DNA (RAPD) markers. All of 60 strains isolated and characterized through 2006-2008 in Guilan province. Three populations: a) isolates from nursery, b) isolates from fi eld, and c) isolates from panicle studied. Eight decamer primers of RAPD amplifi ed 187 polymorphic bands. The largest and smallest fragments generated by 80.7 and OPA10 primers, respectively. The minimum amount of polymorphic information content was related to OPA12 primer (0.36) and the maximum amount of that was related to OPA10 primer (0.44). Analysis of molecular variance (AMOVA) of data from RAPD analysis showed that the genetic variation within Xoo populations was greater than between populations. The similarity matrix conducted by Simple Matching coeffi cient and cluster analysis made by unweighted pair group method (UPGMA) with NTSYS-pc soft ware. At a similarity index of 0.6 the isolates were grouped into 3 clusters. These results revealed that the RAPD markers used in this study could differentiate nursery and fi eld isolates from each other.