Levantamento de raças do agente causador do míldio da alface no estado de São Paulo em 2012 e 2013

• Ano de defesa: 2014
• Autor(a) principal: Nunes, Renata de Castro [UNESP]
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Estadual Paulista (Unesp)
• Palavras-chave em Português: Alface; Alface - Doenças e pragas; Alface - Resistencia a doenças e pragas; Genes; Hortaliças - Melhoramento genetico; Agricultural pests
• Link de acesso: http://hdl.handle.net/11449/110321

Lettuce is among the leafy vegetables, economically, the most important to Brazil. In winter, with low temperatures and with leaf wetness, downy mildew of lettuce, a disease caused by the agent Bremia lactucae, occurs in almost all regions of the world where the lettuce is grown, and is considered one of the most severe foliar diseases for the culture. To obtain information to assist breeding programs for resistance to downy mildew, this study aims to report the emergence of races of B. lactucae in 2012 and 2013 that occurred in the main producing regions of São Paulo, such as Ribeirão Preto, Jaboticabal, Pirangi, Catanduva, São José do Rio Preto, Atibaia, Salesópolis, Biritiba Mirim, Mogi das Cruzes, Campinas, Itapira , Mogi Mirim, Cândido Mota, Presidente Prudente, Echaporã, Assis, Marilia, Botucatu and Bauru. During the month of July / August 2012 and 2013,we collected samples of lettuce leaves with symptoms of downy mildew, and in each sample collected, the pathogen structures, referred to a secluded. The sporangia collected were multiplied on susceptible cultivar Solaris, with subsequent inoculation in differential cultivars, performing evaluations on the same day of the 12º appearance of sporulation in the susceptible cultivar 'Green Tower' (Dm-0), according to the code “Sextet”. In 2012, the results showed the two new codes, identifying two new races, SPBl: 10 (63/31/02/00) and SPBl: 11 (63/63/18/00). In 2013, a new code was determined (63/31/18/00), which proposed the name SPBl: 12.Genes Dm-14 and Dm-15 and resistance factors R-17, R-18, R-36, R-37 and R-38 confer resistance to these new races identified. It is recommended, therefore, in breeding programs lettuce the use of factors R-17, R-18 and R-38 as sources of resistance in cultivars developed for the State of São Paulo, because they confer resistance to all 12 races already identified