Reação de cultivares de algodoeiro a Ramularia areola
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Data
2010-03-01
Autores
Lima, Lonjoré Leocádio de [UNESP]
Barreto, Modesto
Scaloppi, Érika Auxiliadora Giacheto
Título da Revista
ISSN da Revista
Título de Volume
Editor
Grupo Paulista de Fitopatologia
Resumo
Dentre as doenças causadoras de manchas foliares em algodoeiro, a mancha de ramulária (Ramularia areola Atk) tem se tornado importante em virtude das condições climáticas favoráveis para o desenvolvimento do patógeno, aliadas ao uso de cultivares suscetíveis, plantio consecutivo e extenso. Neste trabalho avaliaram-se os cultivares Delta Opal, Acala 90, Makina, Delta Penta e Sure Grow 821 quanto à resistência a R. areola, em condições de campo na FCAV-UNESP, no ano de 2006. A severidade da doença, que ocorreu por infecção natural das plantas pelo fungo, foi avaliada semanalmente em trinta plantas devidamente marcadas, utilizando-se uma escala descritiva de notas: 1 = 0%, 2 = até 5%, 3 = de 5,1 a 25%, 4 = de 25,1 a 50% e 5 = acima de 50% de área foliar com sintomas. Foram elaboradas curvas de progresso da doença para os cinco cultivares e o modelo monomolecular foi o que melhor se ajustou aos dados, em comparação com o logístico, o exponencial e o modelo de Gompertz. A análise dos dados indicou que houve diferença significativa entre os genótipos, sendo que Delta Opal, Makina e Sure Grow 821 mostraram-se mais suscetíveis e Delta Penta e Acala 90 mais resistentes ao fungo.
Among the disease causing leaf spot in cotton, the gray mildew (Ramularia areola Atk.) has become important due to environmental conditions favorable for development of the disease susceptible cultivars, consecutive and intensive and extensive cultivation. This work evaluated the resistance of the cultivars Delta Opal, Acala 90, Makina, Delta Penta and Sure Grow 821 to resistance the R. areola, in field conditions in FCAV-UNESP. The disease occurred under natural infection and, its severity was evoluated weekly, in thirty previously marked plants using the following rating scale: 1 = 0%, 2 = up to 5%, 3 = 5,1 to 25%, 4 = 25,1 to 50% and 5 = over of 50% of foliar area with symptoms. The monomolecular model was better adjusted to the data in comparison with the logistic, exponential and Gompertz models, for elaboration of the curves of progress of the disease. The analysis of the data indicated significant differences between the genotypes.The cultivars Delta Opal, Makina and Sure Grow 821 were more susceptible and Delta Penta and Deltapine Acala 90 more resistant to gray mildew.
Among the disease causing leaf spot in cotton, the gray mildew (Ramularia areola Atk.) has become important due to environmental conditions favorable for development of the disease susceptible cultivars, consecutive and intensive and extensive cultivation. This work evaluated the resistance of the cultivars Delta Opal, Acala 90, Makina, Delta Penta and Sure Grow 821 to resistance the R. areola, in field conditions in FCAV-UNESP. The disease occurred under natural infection and, its severity was evoluated weekly, in thirty previously marked plants using the following rating scale: 1 = 0%, 2 = up to 5%, 3 = 5,1 to 25%, 4 = 25,1 to 50% and 5 = over of 50% of foliar area with symptoms. The monomolecular model was better adjusted to the data in comparison with the logistic, exponential and Gompertz models, for elaboration of the curves of progress of the disease. The analysis of the data indicated significant differences between the genotypes.The cultivars Delta Opal, Makina and Sure Grow 821 were more susceptible and Delta Penta and Deltapine Acala 90 more resistant to gray mildew.
Descrição
Palavras-chave
Gossypium hirsutum, Cultivars reaction, Curves of progress of diseases, Chaves Adicionais, Gossypium hirsutum, Resistência de Cultivares, Curvas de progresso de doenças
Como citar
Summa Phytopathologica. Grupo Paulista de Fitopatologia, v. 36, n. 1, p. 57-60, 2010.