Morphological characterization of five different isolates of Pyricularia oryzae causing rice blast disease

摘要: Rice blast caused by Pyricularia oryzae is one of the most destructive diseases of rice and it’s causing significant grain yield losses. It is not only one of the earliest known plant disease but also one of the most widely distributed, occurring in every region of the world where rice is grown. Keeping in view the importance of disease, studies were conducted on cultural and morphological variability at Indian Institute of Rice Research (IIRR), Hyderabad. Survey was carried out to identify and characterize the fungal pathogen associated with rice blast disease in different crop growing regions of Andhra Pradesh and Telangana states. Blast disease samples were collected from different locations ie., Nalgonda, Mahanandi, Piduguralla, Jagithyala and IIRR. Diversity in cultural characters, such as mycelium colour and texture were noticed among the isolates. The isolates with rough surface produced more spores compared to smooth surface. Variation in size of the conidia and sporulation were observed, but no clear cut groupings were observed. Conidia are produced in clusters on long septate, slender conidiophores. Colony color of all the isolates were grey with good growth and the colony diameter ranged from 78 to 90 mm. The result of the present study demonstrates that there is a certain level of morphological and cultural diversity among isolates of P. oryza.