Assessing susceptibility of Hevea clones to Microcyclus ulei

Chee, K. H.

doi:10.1111/j.1744-7348.1976.tb01743.x

Cited by 38 publications

(28 citation statements)

References 2 publications

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“…The four variables used characterise different stages of the infection cycle of the fungus; they enable classification of clones during the immature period of the trees, which is the first 3 years after planting (Chee 1976;Junqueira et al 1990;Rivano 1992Rivano , 1997bLe Guen et al 2002). The four variables are attack severity on young leaves, attack severity on mature leaves, conidial sporulation intensity on young leaves, and stroma density on mature leaves.…”

Section: Introductionmentioning

confidence: 99%

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Assessing resistance of rubber tree clones to Microcyclus ulei in large-scale clone trials in Ecuador: a less time-consuming field method

et al. 2009

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Resistance of rubber tree clones to South American Leaf Blight (SALB) caused by the fungus Microcyclus ulei is normally assessed in specific large-scale clone trials, which in general entail a considerable amount of work. Four variables are observed monthly on each tree over many years: disease severity and conidial sporulation intensity on young leaves, and severity and stroma density on mature leaves. In order to simplify this field assessment method, we tested the resistance of eight rubber tree clones to M. ulei in Ecuador in a Fisher block design with four replicates per treatment. Three months after planting, monthly observations were made for a period of 12 months on the foliage focusing on the four variables, in order to quantify disease development. Given the correlations between the four variables, assessment of conidial sporulation intensity on young leaves and stroma density on mature leaves should be sufficient. The most suitable period to start the assessment was 6 months after planting, for a duration of six to nine months. As repeated observations on the same trees were autocorrelated, it was possible to reduce the assessment frequency to once every 2 months. To conclude, assessing the resistance of rubber tree clones to SALB in large-scale clone trials can be optimized to reduce the number of observation times by 50%.

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Section: Introductionmentioning

confidence: 99%

“…SALB research programmes have largely focused on identifying resistance mechanisms in Hevea spp. (Garcia et al 1995(Garcia et al , 1999, and selecting resistant rubber tree clones, with a view to combining them with latex productivity (Chee 1976;Rivano 1997b). Two types of resistance have been found.…”

Section: Introductionmentioning

confidence: 99%

Assessing resistance of rubber tree clones to Microcyclus ulei in large-scale clone trials in Ecuador: a less time-consuming field method

et al. 2009

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“…O mal-das-folhas foi quantificado diretamente nas brotações -em dois estádios de desenvolvimento dos folíolos -, denominadas brotações novas e maduras e apresentando as fases conidiais e ascógenas do patógeno, respectivamente, conforme escala diagramática proposta por Chee (1976), em duas épocas de avaliação (janeiro e abril). Avaliou-se o desfolhamento natural das plantas, no ano de 1996, visando verificar o hábito decíduo e também o desfolhamento secundário, provocado pelo M. ulei, conforme escala proposta por Gomes et al (1983), modificada por Furtado (1990).…”

Section: Methodsunclassified

Clones promissores de seringueira para a região do Vale do Ribeira, São Paulo

Gonçalves

Saes

Furtado

et al. 2000

Pesq. agropec. bras.

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“…Bastante ilustrativo, porém, é o trabalho de Chee (1976) Langford (1945), a respeito da inconsistência da esporulação em relação à suscetibilidade".…”

Section: O Patossistema Tropicalunclassified

Epidemiologia comparativa entre os patossistemas temperado e tropical: conseqüências para a resistência a fungicidas

Filho

Amorim

2001

Fitopatol. bras.

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RESUMOO patossistema tropical difere do patossistema temperado tanto em estrutura quanto em comportamento. Nesta revisão, ambos os patossistemas são caracterizados e, com base nessa caracterização, o risco de origem e de seleção de resistência a fungicidas é discutido para ambas as situações. As características diferenciais relevantes para análise foram: sobrevivência I (entre estações de cultivo); sobrevivência II (entre ciclos do patógeno); taxa aparente de infecção; via antihorária de infecção; ingresso e/ou manutenção de mutantes resistentes; via horária de infecção; persistência de mutantes resistentes; adaptabilidade dos mutantes resistentes. Concluise que o patossistema tropical não apresenta risco maior para a seleção de mutantes resistentes, mas pode, em alguns casos, apresentar risco maior de origem de mutantes resistentes.Palavras-chave: sobrevivência de patógenos, taxa de infecção, mutante resistente. ABSTRACT Comparative epidemiology between temperate and tropical pathosystems: its consequences for fungicide resistanceTropical and temperate pathosystems differ in structure and behavior. In this article, both pathosystems are characterized and the risk of origin and selection of fungicide resistance is discussed for both situations. The differential characteristics found relevant were: survival I (between crop seasons); survival II (between cycles of the pathogen); apparent infection rate; ingress and/or survival of resistant mutants; clockwise manner of infection; persistence of resistant mutants; fitness of resistant mutants. It is concluded that the tropical pathosystem does not have a higher risk of selecting resistant mutants. However, in some cases, a higher number of resistant mutants can be originated in tropical pathosystems. O PATOSSISTEMA TEMPERADO"Uma doença infecciosa pode se manter unicamente por meio de contínuas reinfecções baseadas na cadeia de infecção. Por cadeia de infecção entende-se a transmissão contínua, seriada, de material infetivo de uma planta para outra" (Gäumann, 1950). Essa frase, síntese do principal princípio da epidemiologia temperada, contém informação reveladora: epidemias só ocorrem na natureza caso propágulos do patógeno (produzidos em determinada planta) sejam liberados, transportados e depositados em outra planta suscetível.Os autores, cada um a sua maneira, chamam a atenção para esse princípio. Vanderplank (1963)

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Assessing susceptibility of Hevea clones to Microcyclus ulei

Cited by 38 publications

References 2 publications

Assessing resistance of rubber tree clones to Microcyclus ulei in large-scale clone trials in Ecuador: a less time-consuming field method

Assessing resistance of rubber tree clones to Microcyclus ulei in large-scale clone trials in Ecuador: a less time-consuming field method

Clones promissores de seringueira para a região do Vale do Ribeira, São Paulo

Epidemiologia comparativa entre os patossistemas temperado e tropical: conseqüências para a resistência a fungicidas

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