Impact of Fusarium graminearum on Seed Germination and Seedling Blight in Hard Red Spring Cultivars in South Dakota

Abstract

Fusarium graminearum causes crown rot in wheat affecting seed germination, seedling establishment hence impacting crop productivity. Integrated disease management approaches includes cultural practices, use of good quality seed, resistant varieties, seed treatment. In this study, we surveyed wheat plant samples from South Dakota to determinethe prevalence and distribution of root rot pathogens. F. graminearum and Bipolaris sorokiniana were recovered from 100% and 48% of the root samples (n=39) collected, respectively. Further, we studied the effect of F. graminearum on the seed germination and seedling blight on spring wheat cultivars under greenhouse and field conditions. F. graminearum significantly affected the seed germination and seedling blight in 11 spring wheat cultivars, ranging from 75-96% and 0-9%, respectively in infested seed as compared to uninfested seed (control). The cultivars ‘Forefront’ and ‘Select’ were least impacted by the pathogen; whereas, ‘Russ’ and ‘Oxen’ showed a significant reduction in germination and higher seedling blight. Field experiments were conducted to determine the impact of source of inoculum, fungicide seed treatment and varieties on seed germination and seedling survival at two locations in 2015 and 2016. Cultivars Russ and Oxen showed poor seed germination and high seedling blight; whereas, Forefront, Selectand Briggs had higher germination and seedling survival. Fungicide treatment significantly increased seed germination. The source of inoculum was significant in 2015, however, it was not significant in 2016 due to less disease pressure. Our results showed that F. graminearum lowers seed germination and causes seedling blight in wheat cultivars and genetic variability exists incultivars. Hence the use of fungicide seed treatment can reduce the germination losses caused by the pathogen for fields likely to have high inoculum pressure or likely infested seed and use of tolerant cultivars like Forefront can further reduce the losses due to crown and root rot diseasent.