Meghaa Sharma, UK Khare, Aparna, Sachin Sharma, Sarita Meena, Shipra .
Rhizoctonia solani Kühn is an important soil-borne fungal pathogen causing severe economic losses in a wide range of agricultural crops. Environmental and nutritional factors play a significant role in the growth, development, and pathogenic behavior of the fungus. Among these factors, hydrogen ion concentration (pH) is one of the most important parameters affecting fungal physiology and metabolism. The present investigation was conducted to study the effect of different pH levels on the growth and sporulation of Rhizoctonia solani under in vitro conditions. Seven pH levels viz., 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, and 8.0 were evaluated using Potato Dextrose Agar medium. The experiment was conducted under laboratory conditions using Completely Randomized Design with three replications. Observations on radial growth and sporulation were recorded at 24-hour intervals up to seven days of incubation. The results indicated that pH significantly influenced fungal growth and sporulation. Maximum radial growth and abundant sporulation were observed at pH 6.5 followed closely by pH 7.0, whereas minimum growth and poor sporulation were recorded at pH 5.0 and pH 8.0. Moderate growth was observed at intermediate pH levels. The study revealed that slightly acidic to neutral pH conditions were most favorable for the growth and sporulation of R. solani. The findings of the present study may be useful for understanding the physiological requirements of the pathogen and developing suitable management strategies under field and laboratory conditions.