Estimating Yield Losses in Cereals Infected with Barley Yellow Dwarf Virus

摘要

Using a prediction model to estimate yield losses due to barley yellow dwarf virus (BYDV, family Luteoviridae) infection, thus avoiding the need for a healthy control, could facilitate germplasm screening and reduce evaluation costs. In the 1999/2000growing season, 69 barley, 58 spring and winter/facultative bread wheat, and 39 durum wheat lines derived from the ICARDA (barley) and CIMMYT/ICARDA (wheat) improvement programs were evaluated for their resistance/tolerance to BYDV in artificially inoculated plots. Similarly, in the 2000/2001 growing season, 24 barley, 45 spring and winter/facultative bread wheat, and 31 durum wheat lines were evaluated. Many of these lines yielded well in response to infection when compared with control plots (non-inoculated and protected by insecticide treatment). A model developed earlier for spring bread wheat in Canada to predict yield losses due to BYDV infection based on symptom score (0-9) and plant height (cm) [predicted yield index (PYI) = 600 (0.2 - symptomscore/height)] was evaluated. Experiments conducted during 1999/2000 indicated that correlation between PYI and percent yield loss was r= -0.665, -0.080 and -0.304 for barley, bread wheat, and durum wheat, respectively. In the 2000/2001 trials, correlation between PYI and percent yield loss was -0.88, -0.31 and -0.41, for the three crops respectively. It can be concluded that this prediction model is reliable for BYDV screening in barley but less so in bread or durum wheat, under growing conditions in northern Syria.