The influence of preinfection cold hardening and disease development period on the interaction between barley yellow dwarf virus and cold stress tolerance in wheat

Abstract

Cold hardness and ice encasement tolerance of 'Fredrick' and 'Norstar' winter wheats as affected by infection with barley yellow dwarf virus (BYDV) were determined during inoculation, disease development periods, and low-temperature growth. Plants were either prehardened to cold, or warm grown before infection; two disease development periods (DDP) were utilized. A long DDP induced greater pathogenesis and greater hardiness reduction than a short DDP. The effect of virus infection on the final level of hardiness of prehardened plants was generally greater than on that of nonprehardened plants. Viral infection reduced hardiness up to 3.5 °C in 'Fredrick' wheat, but reductions of 6–10 °C below hardiness potential were recorded after certain environmental regimes allowing disease development. Ice tolerance was reduced by BYDV infection in early low-temperature growth but was increased by infection after 4 months at low temperature. This increase in survival was associated with higher dry matter content in infected than in noninfected plants.