INTERNATIONAL JOURNAL OF AGRICULTURAL TECHNOLOGY

Volume 16, No. 04, Month JULY, Year 2020, Pages 799 - 818

Morphological and biochemical variation of rice blast fungus magnaporthe oryzae in karnataka, india

Jagadeesh, D. and Devaki, N. S.

Abstract Download PDF

Rice blast caused by Magnaporthe oryzae (anamorph: Pyricularia oryzae) is a destructive disease in all rice growing regions of the Karnataka. The morphological and biochemical variations existing among the field isolates collected from different agro-climatic zones was investigated. The influence of culture media on growth, colony character of M. oryzae isolates on two different media viz., potato dextrose agar and oat meal agar was studied. Results revealed that there was a significant variation among the isolates of M. oryzae in different parameters such as growth pattern, colour of media and mycelia, texture and sporulation (P ≤ 0.05). These variations are supported by isozyme analyses which showed significant level of variations among the isolates with 17 polymorphic bands. In UPGMA cluster analysis, the coefficient of similarity ranged from 0.26 to 1. Two distinct clusters were formed among the isolates i.e., from the southern districts (cluster I) and northern district isolates (cluster II). This suggested that there is a correlation among the geographical boundaries with the diverse isozyme profile of the pathogen for its adaptability to the different environmental conditions.

Keywords

Isozyme, Magnaporthe oryzae, Rice blast disease, UPGMA

---