Anatomia circulativa
Palavras-chave adicionais: Luteovírus, afídeos, Triticum aestivum.
--------------------------------------------------------------------------------ABSTRACT
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 ofagronomic 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 % and26.6% 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.
Additional keywords: Luteovirus, aphids, Triticum aestivum.
--------------------------------------------------------------------------------O trigo (Triticum aestivum L.) está sujeito a diversas doenças, entre as quais se destacam, por sua importância econômica, a ferrugem da folha, a ferrugem do colmo, manchas foliares e a virose do nanismo amarelo da cevada, causada pelo Barley yellow dwarf virus (BYDV) (Burnett et al., 1995).
O BYDV causa a enfermidade viral mais disseminada em cereais de inverno em todo o mundo.Ocorre em toda a América do Norte, na Europa, na Ásia, na América do Sul, na Austrália e na Nova Zelândia (Lister & Ranieri, 1995). O vírus é transmitido de maneira persistente circulativa por 23 espécies de pulgões e infecta aproximadamente 100 espécies de gramíneas anuais e perenes, incluindo cevada, milho, aveia, arroz e trigo, ficando restrito aos tecidos do floema das plantas infectadas (Gray,...
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