Modelling influence of virus infection on leaf area and radiation use in oats under controlled climatic conditions

The effects of barley yellow dwarf virus (BYDV) infection on oat plants growing in pots in a greenhouse were incorporated into a plant growth model driven by incident solar radiation and air temperature. Changes in radiation use efficiency (RUE) and leaf area determining parameters were calibrated against observed reductions in leaf area, shoot biomass and grain yield. Plants were infected with BYDV-PAV at the two-leaf stage or left uninfected. Two nitrogen fertilization levels were used. BYDV-infected plants had smaller above-ground biomass and a smaller green plant area than uninfected plants. The decreased biomass could be explained by a decrease in leaf area, causing a decreased radiation interception and growth. Relatively higher RUE in the infected plants during a period of the growing season partially compensated for growth reductions due to the smaller leaf area. Increased RUE of the infected plants was related to higher nitrogen concentration per leaf area. The effects of an infection were similar for the two nitrogen fertilization treatments.