Podridão vermelha da raiz em variedades de soja associada a níveis de irrigação e de compactação do solo
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Data
2012-01-09
Autores
De Luca, Helena Baroni Junqueira Franco [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Objetivou-se verificar se a época de semeadura, o grau de compactação do solo e o conteúdo de água no solo influenciam o comportamento de duas cultivares de soja (CAC-1, classificada como resistente e FT-Cristalina, como suscetível), em relação a severidade da podridão vermelha da raiz (PVR). Os experimentos foram desenvolvidos na FCAV/UNESP/Jaboticabal, envolvendo etapas de casa de vegetação e de campo. No campo, as cultivares FT-Cristalina e CAC-1 apresentaram níveis de doença variáveis conforme a época de semeadura, sendo que no outono/inverno 2009, na cultivar CAC-1 foi observado maior número de plantas com sintomas da PVR na parte aérea. Na primavera/verão 2009/10, a cultivar FT-Cristalina apresentou maior número de plantas com sintomas. Graus mais elevados de compactação e de umidade do solo (-0,001 MPa) favoreceram a ocorrência da PVR, e reduziram o desenvolvimento e produtividade da soja. Houve maior desenvolvimento radicular na camada superficial (0,0-0,10 m) onde a compactação foi menor comparada a camada de 0,10-0,20 m. Tanto na cultivar resistente quanto na suscetível à PVR, observaram-se maiores áreas, comprimentos, densidades e massas seca de raízes nas plantas inoculadas. Em casa de vegetação, na primavera/verão de 2009/10, o maior grau de compactação (resistência a penetração = 0,602 MPa) foi o qual proporcionou menor desenvolvimento radicular. No outono/inverno de 2010, a PVR foi influenciada pela irrigação, sendo que nas menores tensões de água observaram-se maiores severidades dos sintomas na parte aérea em ambas cultivares. Os tratamentos infestados, nesta época, tiveram a altura de plantas reduzida em relação aos não infestados. A infestação do solo com F. tucumaniae promoveu redução significativa do desenvolvimento do sistema radicular
The objective of this experiment was to assess the influence of sowing time, soil compaction level, and soil water content on the severity level of sudden death syndrome (SDS) in two soybean cultivars – one (CAC-1), classified as resistant and another (FT-Cristalina) as susceptible. Experiments were carried out in Jaboticabal, a campus of the Paulista State University, in Jaboticabal, state of São Paulo, Brazil. The experiments were conducted both in the field and under green house conditions. In the field both cultivars showed variable levels of SDS, depending on sowing time. When sowing was made during the 2009 Fall/Winter period, CAC-1 cultivar showed the highest number of plants with the sudden death syndrome. When sowing took place during the 2009/10 Spring/Summer period, FT-Cristalina was the cultivar with the highest number of plants exhibiting the symptoms. High soil compaction and moisture (-0.001 MPa) degrees favored the occurrence of SDS and this resulted in plant growth and yield reductions. Plant root system, due to soil compaction, was more developed at the depth of 0.0 – 0.10 m than at 0.10 – 0.20. Plants of both cultivars showed root larger areas, lengths, densities, and dry matter when they had been previously inoculated. Under green house conditions, during the 2009/10 Spring/Summer period, the highest degree of soil compaction (penetration resistance of 0.602 MPa) was the factor causing the lowest root development. During the 2010 Fall/Winter period, SDS was influenced by irrigation – the lower soil water´s tensions (high irrigation level), the more severe the symptoms in both cultivars. Infected plants were shorter than the non infected ones. Soil infection with F. tucumaniae caused significant reductions in root system development
The objective of this experiment was to assess the influence of sowing time, soil compaction level, and soil water content on the severity level of sudden death syndrome (SDS) in two soybean cultivars – one (CAC-1), classified as resistant and another (FT-Cristalina) as susceptible. Experiments were carried out in Jaboticabal, a campus of the Paulista State University, in Jaboticabal, state of São Paulo, Brazil. The experiments were conducted both in the field and under green house conditions. In the field both cultivars showed variable levels of SDS, depending on sowing time. When sowing was made during the 2009 Fall/Winter period, CAC-1 cultivar showed the highest number of plants with the sudden death syndrome. When sowing took place during the 2009/10 Spring/Summer period, FT-Cristalina was the cultivar with the highest number of plants exhibiting the symptoms. High soil compaction and moisture (-0.001 MPa) degrees favored the occurrence of SDS and this resulted in plant growth and yield reductions. Plant root system, due to soil compaction, was more developed at the depth of 0.0 – 0.10 m than at 0.10 – 0.20. Plants of both cultivars showed root larger areas, lengths, densities, and dry matter when they had been previously inoculated. Under green house conditions, during the 2009/10 Spring/Summer period, the highest degree of soil compaction (penetration resistance of 0.602 MPa) was the factor causing the lowest root development. During the 2010 Fall/Winter period, SDS was influenced by irrigation – the lower soil water´s tensions (high irrigation level), the more severe the symptoms in both cultivars. Infected plants were shorter than the non infected ones. Soil infection with F. tucumaniae caused significant reductions in root system development
Descrição
Palavras-chave
Solos - Manejo, Agua na agricultura, Fungos fitopatogenicos, Soil and water management
Como citar
DE LUCA, Helena Baroni Junqueira Franco. Podridão vermelha da raiz em variedades de soja associada a níveis de irrigação e de compactação do solo. 2012. viii, 87 f. Tese (doutorado) - Universidade Estadual Paulista, Faculdade de Ciências Agrárias e Veterinárias, 2012.