Efeito de desfolha nas características agronômicas e na qualidade fisiológica de sementes de trigo

• Ano de defesa: 2006
• Autor(a) principal: Gondim, Tânia Cristina de Oliveira
• Orientador(a): Rocha, Valterley Soares
• Banca de defesa: Sediyama, Tocio , Araújo, Roberto Fontes , Sediyama, Maria Aparecida Nogueira , Souza, Moacil Alves de
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Doutorado em Fitotecnia
• Departamento: Plantas daninhas, Alelopatia, Herbicidas e Resíduos; Fisiologia de culturas; Manejo pós-colheita de
• País: BR
• Palavras-chave em Português: Triticum; Desfolha; Remobilização
• Palavras-chave em Inglês: Triticum; Defoliation; Remobilization
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA
• Link de acesso: http://locus.ufv.br/handle/123456789/1163

The objective of this work was to evaluate the defoliation effects on agronomic characteristics and physiological quality of wheat seeds of varieties Anahuac, BRS 207 and BR 24. The experiment was set up in the Experimental Field of the Federal University of Viçosa, May 2004. The experiment was organized following a split plot randomized block design. The treatments consisted of three varieties (as main plots), three defoliation levels and a control without defoliation, for each variety (as subplots), with four repetitions. Defoliation was carried out during the reproductive stage, removing the blade of the flag leaf, second and third top leaves. Plants were harvested by hand, close to the ground, and the following traits were evaluated: grain yield, hectoliter weight, thousand grain weight, number of spikes per plot, number of grains per spike, stem dry matter, husk dry matter, total dry matter, grain yield per spike, dry matter of individual stem, husk dry matter of individual spike and total dry matter per individual plant, tests of germination, first count vigor, accelerated aging and field emergence. The evaluation of the agronomic characteristics under defoliation showed difference among varieties, with defoliation affecting negatively most of the traits. Among the studied varieties, Anahuac showed the largest capacity to maintain yield with lower photoassimilate remobilization under the stress condition caused by defoliation, while the variety BR 24 showed the largest assimilate remobilization to grain filling. The path analysis showed that thousand grain weight and number of grains per spike were the main yield components for the varieties under defoliation. Grain yield under stress was associated with the reduction in stem dry matter, therefore, the direct selection for thousand grain weight and number of grains per spike is an efficient strategy to increase yield in stress condition. The study also showed that the levels of defoliation did not affect the physiological quality of the seeds.