In this study, we developed and optimized a growth medium using various nitrogen sources for the cultivation of Ramulariopsis spp. a potential threat to cotton growing areas of Odisha. The composition of basal Richard’s liquid medium was modified and the nitrogen content was replaced by alternative nitrogen sources viz., urea, ammonium chloride, potassium nitrate, ammonium nitrate, sodium nitrate, calcium nitrate, magnesium nitrate and diammonium hydrogen orthophosphate. Results showed that fungal growth was significantly higher when the nitrogen sources incorporated were potassium nitrate, sodium nitrate and diammonium hydrogen orthophosphate. Least growth and sporulation was recorded in medium with urea as nitrogen source. The findings indicated that the isolates exhibited varying degrees of utilization for different nitrogen sources. RGKN1 demonstrated the highest average dry biomass weight, followed by RPGGNPR1. Moreover, the research unveiled the existence of cultural diversity among the Ramulariopsis isolates concerning their nitrogen utilization patterns. The main challenges during the research was the standardisation of isolation procedure for the pathogen. So this research will clearly contribute towards knowing the exact nutritional requirements for the fungus to grow properly.

Variability, Ramulariopsis, nitrogen sources, grey mildew, cotton

Overall, this study highlighted the significance of nitrogen sources in supporting fungal growth and sporulation. Potassium nitrate, sodium nitrate, and diammonium hydrogen orthophosphate were identified as the most favorable nitrogen sources for promoting the growth of Ramulariopsis isolates. These findings have the potential to be valuable in enhancing the culture conditions for the fungus and advancing its subsequent investigation. Future studies should focus on considering other attributes like colony morphology, pH, temperature and photoperiod requirement, differential reactions on cultivars and genetic constitution in order to obtain a clearer picture regarding the basis of variability among the fungal isolates collected from different geographical locations. Further research could also explore the underlying mechanisms by which different nitrogen sources influence the growth and sporulation of Ramulariopsis isolates, providing insights into the fungal physiology and optimizing cultivation conditions for potential applications.

B. Boblina, A.G. Panda and A.K. Senapati (2022). Nitrogen Assimilation Diversity among Ramulariopsis Isolates Collected from Cotton Fields in Odisha: A Comparative Analysis. Biological Forum – An International Journal, 14(4a): 751-754.