Threatening wheat diseases in the eastern Gangetic plains: the current status of disease resistance

Abstract

Among the different diseases of wheat, spot blotch (causal organism: Bipolaris sorokiniana) is the most dominant disease in the eastern Gangetic plains of Indian subcontinent viz. India, Nepal and Bangladesh. The disease accounts for yield loss of more than 15% even with the adoption of moderately resistant varieties in the farmer’s fields. The severity of the disease has been increased in the last two decades after wide scale adoption of rice–wheat cropping sequence, reduced tillage and occurrence of terminal heat stress. Beside this, wheat blast (Magnaporthe oryzae pathotype Triticum) is also potential threat after its occurrence in Bangladesh in 2016. The present review summarizes current status of knowledge on the importance of the disease, its impact on crop loss, epidemiological conditions for disease development and breeding for disease resistance of both diseases. The future research work on genetics, use of molecular markers, cloning and characterization of genes for spot blotch resistance and monitoring of wheat blast disease, improvement of genetic resistance as well as development of predictive model has been suggested.