RAPD Markers and Microsatellites for Detecting Genetic Polymorphism in Six Isolates of Heterodera zeae from India

RAPD (random amplified polymorphic DNA) markers and microsatellites were evaluated in polymerase chain reactions (PCR) for rapid diagnosis of six populations of com cyst nematode, Heterodera zeae from diverse biogeographical origins in India viz., Delhi, Jammu, Panipat, Pusa, Sonipat and Udaipur. Four selected random decamer primers were chosen to examine the DNA variations in these isolates. The DNA polymorphism that was recorded using primer 3 and 4 differentiated five of the six test populations and proved to be a handy tool for discriminating populations. A total of 42 scorable bands were observed with one to five bands/primer. A maximum of five bands appeared in population from Jammu and a minimum of one in population from Delhi. The size of the amplified fragments distinguishing the populations varied from 200 to 1080 base pairs. Two SSR's (simple sequence repeat primers) (CAG)5 and (AGG)5 produced 16 scorable and reproducible bands which could be successfully utilized in detecting genetic variations in five of the six isolates reflecting their geographic origin, but appeared less sensitive than RAPD primers. This study indicated genetic divergence in H. zeae populations from India and it could be detected by the use of RAPD-PCR or AP-PCR.