The aim of this study was to assess the damage caused by the Barley yellow dwarf virus (BYDV-PAV) in five wheat cultivars (BRS 177, BRS 179, BRS 194, BRS Camboatá and BRS Angico) grown in a greenhouse at Embrapa (Empresa Brasileira de Pesquisa Agropecuária), Passo Fundo, state of Rio Grande do Sul, Brazil, in 2005. The damage caused by the BYDV-PAV was determined by the analysis of agronomic traits (plant height and dry matter) and yield (number of tillers, ears, and grains per plant; thousand-grain weight). The data were submitted to the analysis of variance and the means were determined by Tukey's test at 5%. The virus significantly affected all of the tested variables. Among the agronomic traits, dry matter was the most affected one, with rates between 26.1% (BRS 177) and 51.4% (BRS 179). Reductions in plant height ranged between 12.5% (BRS 177) and 15.5% (BRS Camboatá). Total grain yield was greatly affected by the viral infection, with significant damage in all cultivars, with a reduction between 34.2% (BRS Camboatá) and 60.8% (BRS 179). There was a reduction in the mean number of tillers per plant only in BRS Angico and BRS 179 cultivars, which amounted to 20 % and 26.6% respectively. The reduction in the mean number of grains varied between 26.1% (BRS Camboatá) and 54.3% (BRS 179). Finally, the reduction in thousand-grain weight corresponded to 16.9% and 38.4% in BRS Camboatá and BRS 194 cultivars, respectively.
Luteovirus; aphids; Triticum aestivum
