Genetic and virulence variation of wheat sharp eyespot isolates (Rhizoctonia cerealis AG-D) from Shandong province

Genetic variation of 35 binucleate Rhizoctonia isolates collected from Shandong province was analyzed with RAPD assay after the test of pathogencity.Fifteen oligonucleotide primers were screened from 140 RAPD primers.A total of 171 RAPD bands were amplified,and 161 were polymorphic.The rate of polymorphism of the isolates was 94.15%.The dendrogram derived from RAPD data by UPGMA suggested that 36 isolates could be divided into 4 RAPD groups with a genetic distance of 0.33.Each of three isolates WK-6,WK-37,and WK-13 made a separate group.The other 33 isolates,the members of AG-D,made the 4th group,and could be further divided into 7 RAPD groups with a genetic distance of 0.25.It proved that the isolates of wheat sharp eyespot had an abundant genetic diversity.No significant correlation was found between the RAPD groups and their virulence,but a few sub-RAPD groups had some correlation with their virulence.