National Academy of Agricultural Sciences (NAAS)
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PRINT ISSN : 2319-7692
Online ISSN : 2319-7706 Issues : 12 per year Publisher : Excellent Publishers Email : editorijcmas@gmail.com / submit@ijcmas.com Editor-in-chief: Dr.M.Prakash Index Copernicus ICV 2018: 95.39 NAAS RATING 2020: 5.38 |
The present study was conducted in order to characterize the isolates of the fungus, Ustilaginoidea virens causing false smut disease, collected from different geographical regions of south India and cultured on Potato Sucrose Agar (PSA) medium. Morphological characterization exhibited that, the isolates produced well defined distinct colonies on PSA medium with colony growth ranging from 3.47 cm (TNUv5) to 5.57 cm (TNUv2), colony colour appeared as whitish to yellow except for TNUv5 wherein it showed yellowish to green. Higher mycelia dry weight was observed in TNUv2 (511.00 mg) followed by TNUv1 (503.62 mg) and least weight was recorded by TNUv5 (325.50 mg). Genetic diversity was estimated and dendrogram (UPGMA method) was constructed using 10 polymorphic RAPD markers. It produced two major cluster at 0.62 similarity coefficient, each cluster comprising of two (TNUv1 and TNUv6) and four (TNUv2, TNUv3, TNUv4 and TNUv5) isolates respectively. The divergence among the isolates depended on the geographical location. Beside morphological and molecular identification, the identity of the fungal pathogen was confirmed through ITS sequencing which showed 91 to 99 % identity with U. virens in NCBI-BLAST analysis. Pathogenecity test using TNUv2 isolates revealed that, injection of conidial suspension to the plants at booting stage develops symptoms within 12 days of injection and it will be useful for identification of resistance source and breeding resistant varieties against false smut. This study also emphasize that, different isolates of U. virens exhibit variation in the ITS (internal transcribed spacer) sequence which may be helpful to study the phylogenetic relationships among the isolates/races and seek the specific resistance genes.
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