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(Reference retrieved automatically from SciELO through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Survey of races of the causal agent of downy mildew of lettuce in the state of São Paulo in 2012 and 2013

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Author(s):
Renata de Castro Nunes [1] ; Renata Castoldi [2] ; Rafaelle Fazzi Gomes [3] ; Dora Enith Tobar-Tosse [4] ; Leila Trevisan Braz [5]
Total Authors: 5
Affiliation:
[1] UNESP. FCAV. Departamento de Produção Vegetal - Brasil
[2] UNESP. FCAV. Departamento de Produção Vegetal - Brasil
[3] UNESP. FCAV. Departamento de Produção Vegetal - Brasil
[4] UNESP. FCAV. Departamento de Produção Vegetal - Brasil
[5] UNESP. FCAV. Departamento de Produção Vegetal - Brasil
Total Affiliations: 5
Document type: Journal article
Source: Summa Phytopathologica; v. 42, n. 1, p. 53-58, 2016-03-00.
Abstract

ABSTRACT Lettuce is, among leafy vegetables, the most economically important one to Brazil. In the winter, at low temperatures and under leaf wetness, downy mildew of lettuce, a disease caused by the etiologic agent Bremia lactucae, occurs in almost all regions where this vegetable is grown and is considered one of the most severe foliar diseases for the culture. The aim of this study was to identify the races of B. lactucae in 2012 and 2013 that occurred in the main producing regions of São Paulo State, 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 months of July / August 2012 and 2013, we collected samples of lettuce leaves showing symptoms of downy mildew, and in each collected sample the pathogen structures referred to an isolate. The sporangia were multiplied on the susceptible cultivar Solaris, with subsequent inoculation in differential cultivars, performing evaluations on the 12th day from the appearance of the first sporulation in the susceptible cultivar ‘Green Tower’ (Dm-0), according to the code “Sextet”. In 2012, two new codes were determined, identifying two new races, SPBl:10 (63/31/02/00) and SPBl:11 (63/63/18/00). In 2013, a new codification was determined (63/31/18/00), to which the name SPBl:12 was proposed. The genes Dm-14 and Dm-15 and the resistance factors FR-17, FR-18, FR-36, FR-37 and FR-38 confer resistance to these new races that were identified. It is recommended, therefore, in breeding programs of lettuce, the use of factors FR-17, FR-18 and FR-38 as sources of resistance for new cultivars developed in the state of São Paulo, because they confer resistance to all 12 already identified races. (AU)

FAPESP's process: 12/09705-4 - Monitoring races of Bremia lactucae on lettuce, advancing lettuce resistant progenies and genotype x environment interaction
Grantee:Leila Trevisan Braz
Support Opportunities: Regular Research Grants
FAPESP's process: 12/15703-4 - MONITORING RACES OF Bremia lactucae ON LETTUCE IN 2012 AND 2013 AT SÃO PAULO STATE
Grantee:Renata de Castro Nunes
Support Opportunities: Scholarships in Brazil - Master