Data/hora: 25/06/2024 19:20:01

Biblioteca(s): 	Embrapa Soja.	
Data corrente: 	06/04/2004	
Data da última atualização: 	29/10/2010	
Autoria: 	ARIAS, C. A. A.; RIBEIRO, A. A.; YORINORI, J. T.; BROGIN, R. L.; OLIVEIRA, M. F. de; TOLEDO, J. F. F. de.	
Título: 	Inheritance of resistance of soybean to rust (Phakopsora pachyrhizi Sydow).	
Ano de publicação: 	2004	
Fonte/Imprenta: 	In: WORLD SOYBEAN RESEARCH CONFERENCE, 7.; INTERNATIONAL SOYBEAN PROCESSING AND UTILIZATION CONFERENCE, 4.; CONGRESSO BRASILEIRO DE SOJA, 3., 2004, Foz do Iguassu. Abstracts of contributed papers and posters. Londrina: Embrapa Soybean, 2004.	
Páginas: 	p. 100.	
Série: 	(Embrapa Soja. Documentos, 228).	
Idioma: 	Inglês	
Notas: 	Editado por Flávio Moscardi, Clara Beatriz Hoffmann-Campo, Odilon Ferreira Saraiva, Paulo Roberto Galerani, Francisco Carlos Krzyzanowski, Mercedes Concordia Carrão-Panizzi.	
Conteúdo: 	Soybean rust was recently detected in Brazil and represent a high hazard to the sustainability of Brazilian crops. Under favorable environmental conditions, the disease can attack the leaves causing premature defoliation and severe yield losses. All the soybean resistance sources, including plant introductions (PI) with the four previously described resistance genes (Rpp1 to Rpp4), a series of other PIs and a group of varieties carrying a single gene derived from soybean variety FT-2, were resistant to the first isolate observed in Brazil. The fungus P. packyrhizi is capable of developing new races and infecting resistant cultivars. In the crop season 2002/03, a new isolate broke the resistance conferred by the genes Rpp1 and Rpp3, gene derived from FT-2, and also genes from other PIs. Nowadays, there is no commercial variety resistant to this new isolate of the fungus and chemical control will be extensively used to prevent losses in the following plantings. Studies on the remaining resistance sources will help breeding programs to define their strategies with this disease. Crosses between the resistant genotypes PI200487, PI471904 and GC-001138-29 with susceptible varieties FT-2 or BRS 134 were used to study the inheritance of resistance to the new isolate. Five plants of each parental and 100 F2 plants from each cross were planted in the greenhouse at Embrapa Soybean, Londrina, PR, arranged in a Completely Randomized Design. Plants were submitted to rust spores since their emergency by placing highly infected plants next to the pots. Humidity on leaves was ensured by spraying water six times along the night. Three assessments were made on the single leaf and on the first and second trifolium, respectively, classifying plants according the reaction: RB = "reddish brown" resistance reaction; RT = predominant RB reaction with presence of some TAN lesions; TR = predominant TAN reaction and presence of RB lesions; and TAN = only susceptible TAN lesions. The relative proportions of resistant and susceptible plants in the F2 generation agree with a segregation pattern of a single dominant gene determining the resistance reaction for the three genotypes. Complementary studies are being performed to know if these genes are the same of those described as Rpp2 and Rpp4, which persist resistant to the new isolate.	
Palavras-Chave: 	Ferrugem asiática da soja.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Soja (CNPSO)	
Exemplares: 	CNPSO - (23704-1) - UMT - PL - -- - RF 633.34072 - W927a -  - DIS