Analysis of population structure of Rosellinia necatrix on Cyperus esculentus by mycelial compatibility and inter-simple sequence repeats (ISSR)

Genetic diversity was studied in a population of 24 isolates of Rosellinia necatrix obtained from Cyperus esculentus and 16 from other hosts by means of mycelial compatibility groups (MCGs) and inter-simple sequence repeat (ISSR) techniques. All isolates obtained from C. esculentus belonged to a unique MCG, irrespective of their geographical origin or year of isolation, and were incompatible with the isolates from other hosts. ISSR analysis gave results which were in agreement with the MCG determination; selected ISSR primers grouped a subset of eight representative isolates from C. esculentus in a unique cluster. The homogeneity found within the population of R. necatrix from C. esculentus in Valencia province could suggest that the pathogen was introduced recently and has spread further via infected tubers inadvertently used as propagating material, as well as by cull tubers swept away by irrigation water.