Assessing the Growth Dynamics and Morphological Traits of Pyricularia grisea (Cooke) Sacc. in Response to Media Variation

Aims: The objectives of this study were to assess the cultural and physiological requirements for growth and development of Pyricularia grisea under in-vitro.

Study Design: Observed data were analyzed by using Completely randomized design with three replications and the critical difference was calculated at 1 % level degree of freedom.

Methodology: Present experiments were conducted at laboratory of Plant Pathology in Shaheed Gundadhoor College of Agriculture and Research Station, Jagdalpur. Pure culture of tested pathogen was isolated from finger millet and maintained in potato dextrose agar (PDA) medium for study. Seven different media were prepared and studied for cultural, physiological and morphological characteristics of Pyricularia grisea.

Results: The significant differences in colony growth and sporulation were observed over 48, 96, and 144 hours of incubation. Potato Dextrose Agar (PDA) supported the highest colony diameters, ranging from 24.20 mm to 73.20 mm, followed by oat meal agar (71.40 mm) and finger millet seed extract agar with 2% sucrose (69.80 mm). Czapek dox agar showed the lowest growth (38.40 mm). In terms of sporulation, oat meal agar exhibited the excellent spore production with index of 4 (37 spores per microscopic field), followed by leaf extract agar (33 spores per microscopic field), while Czapek dox agar failed to support sporulation. Colony morphology varied across media: PDA colonies were grayish with concentric rings and rough surfaces; oat meal agar colonies were white with smooth surfaces; finger millet leaf extract agar produced grayish-white colonies with rough surfaces; seed extract agar + 2% sucrose and corn meal agar colonies were black with white edge with smooth surfaces. Seed extract agar colonies were black with white edge with rough surfaces; Czapek dox agar showed poor growth and colonies were black with white edge.

Conclusion: These findings highlighted that PDA and oat meal agar are the most suitable media for culturing P. grisea for its crucial growth.