Fusarium head blight of wheat in India‐variability in pathogens associated and sources of resistance: an overview

Abstract

During 2019-20 crop season, India harvested record wheat production of 107.19 mt from an area of 30.5 mha thereby registering an all-time high productivity. The most serious fungal diseases which affect wheat production are rusts, spot blotch, Karnal bunt, head scab, powdery mildew, flag smut and loose smut. Recently outbreaks of Fusarium head blight (FHB) or head scab of wheat caused by Fusarium spp., has been reported from Canada, Europe, Asia, Australia and South America. In India, the disease can cause significant yield loss if rain occurs during mid anthesis in the foot hills of Punjab, Himachal Pradesh, Uttarakhand and hilly areas in Tamil Nadu. The Fusarium diseases are likely to increase under the impact of global warming and the fast adoption of reduced tillage practices in the main wheat belt, the north west plains of India. Fusarium graminearum is known to produce mycotoxins which affect human and animal health. Extensive disease surveys undertaken in Himachal Pradesh and Tamil Nadu (Wellington) during 2010–20 revealed the dominance of F. graminearum causing head blight of wheat in India. Pathogenic variation among Fusarium spp./isolates has been studied by inoculating on a set of wheat varieties under artificially inoculated conditions. These studies helped in identifying virulent F. graminearum isolates and their use in evaluating a large number of wheat genotypes for identifying sources of resistance. Genetic variation among F. graminearum isolates have been detected with molecular markers. Since most of the popular cultivars grown in India are susceptible to head scab, there is a need to evaluate a greater number of indigenous and exotic wheat lines for incorporating head scab resistance in popular wheat cultivars. This review provides an overview of the variation in pathogens associated with the disease and resistant sources available for breeding durable FHB resistant wheat varieties.