Data/hora: 18/06/2024 04:04:58

Biblioteca(s): 	Embrapa Cerrados; Embrapa Trigo.	
Data corrente: 	18/12/1995	
Data da última atualização: 	14/01/2000	
Autoria: 	NASSER, L. C. B.	
Título: 	Studies on microorganisms carried by cereal seeds produced in Brazil and Washington: their influence on seedling vigor, chemical and biological control, and histology of Septoria nodorum (Berk.) Berk. on wheat seed.	
Ano de publicação: 	1983	
Fonte/Imprenta: 	[Pullman]: Washington State University, 1983.	
Páginas: 	195p.	
Idioma: 	Inglês	
Notas: 	Ph.D. Dissertation.	
Conteúdo: 	Four hundred kernels of each of 82 imported seed lots were plated on each of three cultural media for the purpose of establishing the sanitary status of cereal seed produced in Brazil. The media were somewhat differential in revealing microorganisms. Of 32,800 seeds plated on potato-dextrose agar, 17,783 yieded a fungus colony. Alternaria spp. and Drechslera spp. were among the most frequently isolated fungi. The blotter method tended to favor the emergence of Cladosporium spp. and Drechslera ssp., while oxgall agar medium permitted the development of Septora nodorum, Fusarium spp. and Pseudomonas syringae. In general, Brazil-grown seed was heavily laden with pathogens. Barley, with an infection level of 50.5 percent, was more infested than triticale (43.3 percent) or wheat (26.6 percent). Of undoubted significance was the fact that 88 percent of the seed lots were infected with Drechslera; 59percent with Fusarium and 52 with S. nodorum. Seeds produced in Brazil had lower germination, lower emergence rate indices, and a higher rate of pathogen transmission to emerging seedlings than counterpart seeds produced in Pullman. Cereal seed produced in Pullman was virtually free of pathogens, indicating an inability of most organisms to persist from one host generation to the next in the dry climate attending crop maturation at Pullman. However, it was revealed for the first time that wheat seed produced under moist conditions of western Washington was sometimes infected with S. nodorum and Pseudomonas syringae. The seedborne phase of S. nodorum was controlled by benomyl when used alone or in combination with thiram or captan. Several isolates of P. syringae were antagonistic to S. nodorum. Septoria nodorum was found to penetrate wheat seed coats only as deeply as the testa layer. There is a strong probability that cereal yields in Brazil would be increased by reducing the amount of seeborne pathogens.	
Palavras-Chave: 	Brasil; Estados Unidos; Fungal diseases; Seed; Seed longevity; Washington; Wheats.	
Thesagro: 	Controle Biológico; Controle Químico; Doença; Doença Fúngica; Fungo; Fusariose; Fusarium; Histologia; Microrganismo; Semente; Septoria Nodorum; Trigo; Triticum Aestivum.	
Thesaurus Nal: 	biological control; Brazil; chemical control; Drechslera; fungi; plant tissues; United States; vigor.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Cerrados (CPAC)	
Exemplares: 	CPAC - (20167-1) - UPC - TS - -- - T040/83 - NAS - T040/83 - DIS
CNPT - (30086-1) - ADD - TS - -- - TS-0506 -  - 0506 - DIS