Abstract

Thirteen isolates of Biploaris maydis (BM 1- BM13) were collected from different locations of India and their genetic variability was studied using random amplified polymorphic DNA (RAPD), internal transcribed spacer (ITS) and internal transcribed spacer-restriction fragment length polymorphism (ITS-RFLP) techniques. Of the 31 RAPD primers, 21 primers showed polymorphisms in the isolates, but 10 primers failed to exhibit any polymorphic bands. Number of amplified products obtained was specific to each primer ranging from 5 bands (primer 4, A-01) to 21 (primer 7, A-04) and also all primers showed 100%  polymorphism with fragment size varying from 200 bp to 3 Kb. Unweighted pair group method using arithmetic averages (UPGMA) analysis revealed one major cluster excluding the isolates BM1, BM5, and BM12. Jashipur isolate BM12 was outlier and showed minimum similarity of 48% with other isolates. The major cluster was further sub-clustered into two. Maximum closeness (92%) was observed between BM4 and BM11 collected from Ludhiana and Barapani, respectively which were 91% similar with BM7 of Jorhat. PCR-amplified ITS segments exhibited a single band of approximately 596 bp from all the thirteen isolates corresponding to primer pair ITS1/ITS4. PCR-RFLP analysis carried out with HaeIII, RsaI, Hind III, EcoRI, AluI, Basp1431 and TaqI produced two detectable fragments of about 220 and 380 bp uniformly from the test isolates of B. maydis without detecting any genetic variations.

Key words: Bipolaris maydis, Indian isolates, maize, variability, random amplified polymorphic DNA (RAPD), internal transcribed spacer-polymerase chain reaction (ITS-PCR), internal transcribed spacer-restriction fragment length polymorphism (ITS-RFLP).