Distribuição espacial de Phytophthora nicotianae e reação de cultivares de cebola ao fungo
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Data
2011-03-01
Autores
Almeida, F.A.
Barreto, M. [UNESP]
Barbosa, J.C. [UNESP]
Costa, F.M. [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Grupo Paulista de Fitopatologia
Resumo
A cultura da cebola vem se mostrando altamente suscetível ao ataque de Phytophthora nicotianae, com danos econômicos e alto custo de produção pelo uso excessivo de produtos químicos. O presente trabalho teve como objetivo avaliar a dependência espacial do patógeno por meio da Geoestatística e em seguida, testar a resistência de cultivares de cebola sob sistema convencional de cultivo ao fungo. Os experimentos foram conduzidos no campus da FCAV-UNESP. Para detectar a presença do fungo nas amostras de solo, foram coletadas e processadas em laboratório onde, discos de folhas de limão Siciliano (Citrus limonum) foram utilizados como iscas na suspensão do solo para contagem desses discos infectados. Logo após, na mesma unidade experimental, avaliou-se treze cultivares (Dom Victor, BZ 21; Princesa, Taiko, Óptima, BZ 50, Mercedes, Sunset, Duquesa, Gobi, Sirius, Colina e Superex) de cebola, num experimento com delineamento em blocos casualizados com quatro repetições. Foram feitas avaliações semanais, do transplantio até a colheita. Pelo modelo de semivariograma isotrópico esférico ajustado aos dados, os resultados demonstraram não haver dependência espacial, revelando que a área apresentava uma distribuição agregada do patógeno. Com o mapeamento pelo método de Krigagem ordinário em blocos, verificou-se maior incidência do fungo, entre os três primeiros canteiros localizados na baixadas, com uma redução gradual para o restante que apresentou menor declividade na área. Dentre as cultivares avaliadas quanto à resistência ao fungo - Mercedes, Princesa e Duquesa são altamente suscetíveis, e as demais, demonstraram baixa suscetibilidade ao patógeno nessa primeira avaliação de campo.
Onion culture has demonstrated to be highly susceptible to Phytophthora nicotianae with economic damages and high crop costs due to the excessive use of chemical products. The present work has as objective to evaluate the spatial dependence of pathogen by Geostatistic and after that, to test the resistance of onion cultivars to this disease under conventional crop. The experiments were conducted at FCAV/UNESP. Soil samples were collected and processed at the laboratory in relation to pathogen, presence through the count of disks of Sicilian lemon infected of the solution of the soil. Immediately after that, at the same experimental unit, thirteen onion cultivars (Dom Victor, BZ 21; Princesa, Taiko, Óptima, BZ 50, Mercedes, Sunset, Duquesa, Gobi, Sirius, Colina e Superex) were analysed in a randomized blocks design with four repetitions. Weekly evaluations were effectuated, from transplanting to harvest. By spherical isotropic semivariogram model, results demonstrated no spatial dependence, revealing that the area presented uniform distribution of the pathogen. With the mapping incidence by Krigage method in blocks, it was verified higher incidence of fungi between the first three patches of lower place, being sequenced reduced with area declivity. No cultivar evaluated presented resistance to the pathogen. It's detached that - Mercedes, Princesa and Duquesa cultivars are highly susceptible, and the others demonstrated low susceptibility to the pathogen in that first field evaluation.
Onion culture has demonstrated to be highly susceptible to Phytophthora nicotianae with economic damages and high crop costs due to the excessive use of chemical products. The present work has as objective to evaluate the spatial dependence of pathogen by Geostatistic and after that, to test the resistance of onion cultivars to this disease under conventional crop. The experiments were conducted at FCAV/UNESP. Soil samples were collected and processed at the laboratory in relation to pathogen, presence through the count of disks of Sicilian lemon infected of the solution of the soil. Immediately after that, at the same experimental unit, thirteen onion cultivars (Dom Victor, BZ 21; Princesa, Taiko, Óptima, BZ 50, Mercedes, Sunset, Duquesa, Gobi, Sirius, Colina e Superex) were analysed in a randomized blocks design with four repetitions. Weekly evaluations were effectuated, from transplanting to harvest. By spherical isotropic semivariogram model, results demonstrated no spatial dependence, revealing that the area presented uniform distribution of the pathogen. With the mapping incidence by Krigage method in blocks, it was verified higher incidence of fungi between the first three patches of lower place, being sequenced reduced with area declivity. No cultivar evaluated presented resistance to the pathogen. It's detached that - Mercedes, Princesa and Duquesa cultivars are highly susceptible, and the others demonstrated low susceptibility to the pathogen in that first field evaluation.
Descrição
Palavras-chave
Allium cepa, Geostatistics, pathogen, Allium cepa, Geoestatística, Patógeno
Como citar
Summa Phytopathologica. Grupo Paulista de Fitopatologia, v. 37, n. 1, p. 13-17, 2011.