Avaliação do comportamento de cultivares de milho na presença da helmintosporiose causada por Exserohilum turcicum (Pass.) Leonard & Suggs

• Autor(es): Guiomar, Pedro Manuel Carvalho Nunes
• Data: 2011
• Identificador Persistente: http://hdl.handle.net/10400.5/4102
• Origem: Repositório da UTL
• Assunto(s): maize cultivars; NLB; fungicide; severity; grain yield; Exserohilum turcicum
• Tipo de Documento: Dissertação de mestrado
• Idioma: Português
• Orientador(es): Lima, Arlindo; Grifo, Luís Manuel Cordeiro
• Contribuidor(es): Repositório da Universidade de Lisboa

Descrição

Mestrado em Engenharia Agronómica - Instituto Superior de Agronomia

The Northern leaf blight (NLB) caused by Exserohilum turcicum is one of the maize key diseases in all regions of production. In this dissertation, the susceptibility of four maize cultivars to reference isolates of E. turcicum was established under controlled conditions and the grain yield of the same cultivars evaluated and submitted to six treatments. Four treatments were engaged with fungicides (carbendazim+flusilazol or tebuconazol), one with NPK fertilizer and the sixth as a control. Field trials were conducted in Odemira and Coimbra, both places with known endemic presence of NLB in recent years. The susceptibility of cultivars to E. turcicum was evaluated with the Pioneer scale “Scoring Northern Leaf Blight” and the grain yield determined as 1000 grains weight and as specific weight. In the inoculation trials all cultivars showed the same level of susceptibility. The Coimbra trial didn‟t show any incidents of NLB. In the Odemira tests significant differences in disease severity were registered amongst cultivars and between treatments. The lower disease severity was recorded in the PR34P88 cultivar and in the treatment with two applications of tebuconazol. The treatments also led to significant differences in specific weight and 1000 grains weight. The grain yield varied significantly depending on the location and the cultivar