Molecular Characterization of Phytophthora nicotianae Associated with Diseases of Horticultural Crops by RFLP of PCR Internal Transcribed Spacer Region of Ribosomal DNA and AFLP Fingerprints

Molecular characterization of Phytophthora isolates from tobacco, tomato, carnation, gerbera, crossandra and periwinkle was carried out using internal transcribed spacer(ITS) regions of rDNA gene repeat and amplified fragment length polymorphism (AFLP). All the isolates of Phytophthora were identical in morphology and ITSRFLP patterns, indicating P. nicotianae and P. parasitica are synonymous. However, based on AFLP, four sub groups were evident within population of P. nicotianae (P. parasitica): Group I, includes isolates from tomato, tobacco and periwinkle. Isolates from carnation represents Group II. Isolates from gerbera falls under group III. The crossandra isolates formed a Group IV. Thus, present study showed the existence of four molecular sub groups within population of P. nicotianae (P. parasitica) in India.