Consequences of Ustilaginoidea virens infection, causal agent of false smut disease of rice, on production and grain quality of rice

Nowadays, false smut of rice, caused by Ustilaginoidea virens, is a disease of interest in the world. Presently, its traditional status as 'minor disease' has changed with widespread reports of severity from all the rice growing countries of the world. While many reports are available on the yield loss from the disease, little is known of its effect on grain quality. The present study is planned mainly to evaluate the effect of false smut disease on grain quality of different rice varieties from India. False smut had significant effect on yield (loss of 0.7-8.6%), cooking and nutritional qualities of many popular Indian varieties. Significant changes (p < 0.05) in qualitative characters like hulling, milling, head rice recovery, kernel length after cooking, alkali spreading value, water uptake capacity and gel consistency were observed. Nutritional qualities like total protein content were variable within the 'healthy' varieties as well as within the 'diseased' varieties but the reduction of protein content in diseased grains over healthy was not significant. Amylose content and total phenol were found to be significantly high (p < 0.01) whereas antioxidant activities were significantly low (p < 0.01) in 'diseased' grains. All these changes in different quality parameters are emphasizing the impact of the disease on nutritional properties. This report is first of its kind from India and provides a template for further in-depth study to combat the disease so as to restrict yield loss and maintenance of rice grain quality.