Nutrient solution nitrogen form and barley yellow dwarf virus disease tolerance in oat and wheat

Abstract

The form of nutrient solution nitrogen (either NH4‐N or NO3‐N or mixtures of the two) provided to plants influences the severity of many crop diseases. This greenhouse study was conducted to determine how growth, grain yield, and yield components of oat (Avena sativa L.) and wheat (Triticum aestivum L.) plants given nutrient solutions containing different ratios of NO3‐N to NH4‐N would react to barley yellow dwarf virus (BYDV) infection. Fifteen‐day‐old seedlings (2nd leaf stage) were either infected with BYDV (PAV strain) or left uninfected. Nutrient solution treatments (started 19 d after germination) provided three ratios of NO3‐N to NH4‐N (100% NO3, 50:50 NH4:NO3, or 100% NH4) for a 30‐d period, after which plant height and tillers plant−1 were measured. Oat and wheat plants given NH4 had fewer tillers than plants given the other nutrient solution treatments. BYDV‐infected oat and wheat plants were shorter than uninfected plants. All pots then received NO3 nutrient solution until plant maturity, after which days to anthesis, primary tiller height, grain yield and yield components were measured. In the NH4 nutrient solution treatments, BYDV infection significantly reduced individual kernel weight in oat and primary tiller height in wheat. These same measures were not significantly affected by BYDV infection in the NO3 or NH4NO3 nutrient solution treatments. There were no other significant nutrient solution by BYDV infection interactions for any other dependent variable measured. Nutrient solution treatments had no significant effect on grain yield, but BYDV infection reduced grain yield by 45% in oat and 46% in wheat. In conclusion, nutrient solution N form interacted with BYDV infection to alter disease tolerance in oat (kernel weight) and wheat (primary tiller height), but these alterations had no effect in ameliorating grain yield loss caused by BYDV disease.