Efeito da solarização do solo sobre a população de Pseudomonas spp. fluorescente antagonista a Rhizoctonia solani Kuhn GA 4 HGI
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Data
2001-01
Autores
Bueno, César Júnior [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O trabalho foi realizado nas instalações do Departamento de Produção Vegetal/Defesa Fitossanitária da Faculdade de Ciências Agronômicas-UNESP (22º51’S e 48º26’W)- Botucatu/SP e consistiu da instalação de dois experimentos idênticos em épocas distintas com duas etapas cada. A primeira destas objetivou verificar o efeito da solarização sobre a comunidade nativa de Pseudomonas spp. fluorescentes no campo e em túnel plástico. Nesta fase, monitorou-se a população das bactérias aos 0, 7, 14, 21, 28 e 35 dias durante a solarização. Na segunda etapa, verificou-se a indução de supressividade do solo, no controle da doença, em feijoeiro na cultivar ‘IAC Carioca’, causada por Rhizoctonia solani GA 4 HGI, agente causal do ‘damping-off’ do feijoeiro, através do emprego do solo previamente solarizado ou não, transportado para vasos, sob condições de casa-de-vegetação. Monitorou-se a população das bactérias em meio B de King e o índice de severidade de R. solani aos 7, 14 e 21 dias após a semeadura através de escala de notas. Para a inoculação o fungo foi cultivado em substrato areno-orgânico e incorporado ao solo na proporção de 0,5% p/v. A detecção endofítica ou epífita de Pseudomonas spp. fluorescentes em sementes de feijão, o teste de antagonismo a Rhizoctonia solani e a caracterização genérica através de testes morfológicos e bioquímicos, foram feitos em condições de laboratório. O tempo de solarização foi de 35 dias nos períodos de 19/11/99 a 24/12/99 e de 17/02/00 a 23/03/00. Observou-se maiores temperaturas em túnel plástico nos dois períodos. As maiores médias máximas no campo e túnel plástico foram maiores no primeiro período do que no segundo. A solarização e ausência de cobertura vegetal diminuíram a população das bactérias a níveis indetectáveis no campo e túnel... .
The study was carried out at the Departament of Plant Production - UNESP– Botucatu/SP, Brazil (22º51’S and 48º26’W). The study consisted of two identical experiments installed in different periods with two stages each. The objective of the first experiment was to verify the effect of solarization on the native community of fluorescent Pseudomonas spp. under field and plastic tunnel conditions. The bacterium population was monitored at 0, 7, 14, 21, 28 and 35 days of solarization. In the second experiment, it was verified a possible induction of soil suppressiveness to control disease, caused by Rhyzoctonia solani GA 4 HGI on bean ‘IAC Carioca’, through solarized or not solarized soil transferred to vases, under greenhouse conditions. The bacterium population was monitored in King’s B medium and the severity rate of R. solani was determined at the 7, 14 and 21 days after sowing using a scale of notes. R. solani was cultivated for inoculation in sand-organic substratum and incorporated at the soil in the 0.5 w/v proportion. The detection of the endophytic or epiphytic forms of the fluorescent Pseudomonas spp. in bean seeds, the antagonism test against Rhizoctonia solani and the generic characterization by the morphological and biochemistry tests were made under laboratory conditions. The extension of the solarization was 35 days, from 11/19/00 to 12/24/00 and from 02/17/00 to 03/23/00. The greatest temperatures were observed in plastic tunnel in both periods. The greatest maximum media temperatures were bigger in the first period than in the second one. The soil solarization and the absence of vegetable mulching decreased the bacteria population at undetected levels in the field and tunnel. The soil solarization in the field and tunnel did not induce soil suppressiveness to R. solani. It was not observed endophytic and epiphytic forms of... (Complete abstract, click electronic address below).
The study was carried out at the Departament of Plant Production - UNESP– Botucatu/SP, Brazil (22º51’S and 48º26’W). The study consisted of two identical experiments installed in different periods with two stages each. The objective of the first experiment was to verify the effect of solarization on the native community of fluorescent Pseudomonas spp. under field and plastic tunnel conditions. The bacterium population was monitored at 0, 7, 14, 21, 28 and 35 days of solarization. In the second experiment, it was verified a possible induction of soil suppressiveness to control disease, caused by Rhyzoctonia solani GA 4 HGI on bean ‘IAC Carioca’, through solarized or not solarized soil transferred to vases, under greenhouse conditions. The bacterium population was monitored in King’s B medium and the severity rate of R. solani was determined at the 7, 14 and 21 days after sowing using a scale of notes. R. solani was cultivated for inoculation in sand-organic substratum and incorporated at the soil in the 0.5 w/v proportion. The detection of the endophytic or epiphytic forms of the fluorescent Pseudomonas spp. in bean seeds, the antagonism test against Rhizoctonia solani and the generic characterization by the morphological and biochemistry tests were made under laboratory conditions. The extension of the solarization was 35 days, from 11/19/00 to 12/24/00 and from 02/17/00 to 03/23/00. The greatest temperatures were observed in plastic tunnel in both periods. The greatest maximum media temperatures were bigger in the first period than in the second one. The soil solarization and the absence of vegetable mulching decreased the bacteria population at undetected levels in the field and tunnel. The soil solarization in the field and tunnel did not induce soil suppressiveness to R. solani. It was not observed endophytic and epiphytic forms of... (Complete abstract, click electronic address below).
Descrição
Palavras-chave
Pseudomonas, Rhizoctonia solani
Como citar
BUENO, César Júnior. Efeito da solarização do solo sobre a população de Pseudomonas spp. fluorescente antagonista a Rhizoctonia solani Kuhn GA 4 HGI. 2001. ix, 71 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Ciências Agronômicas, 2001.