Pathogenic and molecular variability of Magnaporthe oryzae isolates collected from major rice growing locations of Telangana State, India

• Published in: Indian phytopathology 2022-09, Vol.75 (3), p.661-671
• Main Authors: Aravind, K., Rajeswari, B., Babu, T. Kiran, Pushpavalli, S. N. C. V. L.
• Format: Article
• Language: English
• Subjects: Biomedical and Life Sciences; Life Sciences; Plant Pathology; Research Article
• ISSN: 0367-973X; 2248-9800
• DOI: 10.1007/s42360-022-00496-7

Rice blast is the most important wide spread disease-causing substantial yield losses in different rice varieties grown by the farmers of Telangana state . Host plant resistance is the best means of combating disease, however variability in pathogen population leads to breakdown of resistance in released varieties of rice. To understand the dynamics among pathogen populations, 12 isolates of Magnaporthe oryzae collected from different geographical origin were tested on set of 25 international host differentials during rabi , 2019–2020 in UBN method. Among the isolates , Nizamabad isolate (Pg5) was more virulent (4.2 score on 0–9 scale) and produced compatible reaction on 19 host differentials with PDI of 47.1%. Whereas Karimnagar isolate (Pg1) was least virulent (2.8 score) by showing susceptible reaction on 8 host differentials with PDI of 28.2%. Further, bases on cluster analysis, the isolates were grouped into 6 pathotype groups. A total of 5 races were detected among 12 isolates. The most frequently occurring race was IA followed by IB, IC, ID and II-1. Molecular diversity studies among the isolates of M. oryzae identified a total of 19 alleles by SSR markers. The number of alleles amplified by each primer pair ranged from 2 to 3 with an average of 2.37 alleles per locus. Cluster analysis indicated the presence of four major groups among twelve isolates. This study will help in devising the action for monitoring the virulence change in M. oryzae populations and suitable management practices.