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Previous issue date: 2009-09-21 / CNPq / Defining methods of quantification of tomato late blight, caused by Phytophthora infestans, is important to many researches about strategies of management of the disease. The aim of this present study was to assess and to validate the diagrammatic grading keys - Simplified, James-modified and Broad - and to determinate the possible correlations between the measures of severity and plants? physiological and nutritional state and biomass accumulation. Two simultaneous experiments were carried out: one in greenhouse and the other in field conditions. Two cultivars were studied in greenhouses, Super Sweet and ?Perinha ?gua Branca?, a resistant and a susceptible to late blight genotypes, respectively. The plants were inoculated or not with a sporangia suspension, and submitted to ten evaluations: 1, 2, 3, 4, 6, 7, 9, 10, 17 and 24 days after inoculation. The avaliations were performed in the fifth oldest leaf, and eighth and eleventh leaves, by visual estimation of severity, using three diagrammatic grading keys, Simplified, Broad and James-modified, but also measuring photosynthetic potential (Fv/Fm), by chlorophyll ?a? fluorescence emission. In field conditions, four cultivars were evaluated ? ?Perinha ?gua Branca?, Super Sweet, Santa Clara and Carmen F1. Periodically, late blight severity was quantified using the same three grading keys in leaves of different plant parts, at 51, 62, 74, 94 and 102 days after transplant (DAT). At the day following each severity disease evaluation, one plant was harvested per plot to measure the accumulation of biomass and macronutrients of different plant organs. Fruit yield was determined by summing fruits harvested between 68 and 114 DAT. In greenhouse conditions, the estimative of late blight severity with the three diagrammatic grading keys proved to be adequate to the disease?s quantification, enabling the discrimination between inoculation effects and differences between the cultivars in four and in nine days after inoculation, respectively, which were confirmed by measures of the photosynthetic potential of the leaves. In field conditions, the diagrammatic grading keys Simplified and Broad were more adequate to tomato late blight quantification. Quantifications in the youngest leaves, in the medium and superior third part of the plant, were the most representative of the disease progress and also discriminated the cultivars regarding disease resistance. Negative correlations were observed between severity, estimated with the three grading keys considering the whole plant and its medium third part, and leaf dry mass and leaf concentrations of K and P. The cultivar ?Perinha ?gua Branca? showed the lowest stem and leaf dry mass at the beginning of plant evaluations, and also late fruit yield, but had the higher stem and leaf mass and at the end of the experiment. The cultivar Perinha ?gua Branca and the hybrid Carmen F1 had higher commercial fruit yield. Based in the results, it is recommended the use of Simplified diagrammatic grading key and evaluations in the medium or superior tomato third to quantify the late blight disease. / A defini??o de m?todos de quantifica??o da requeima no tomateiro, causada por Phytophthora infestans, ? importante para v?rias pesquisas sobre estrat?gias de manejo da doen?a. Esse trabalho teve como objetivo aferir e validar as escalas diagram?ticas, Simplificada, James-modificada e Detalhada e determinar as poss?veis correla??es entre as medidas de severidade e o estado fisiol?gico e nutricional da planta e o ac?mulo de biomassa. Realizaram-se dois experimentos simult?neos, um sob condi??es de ambiente protegido e o outro sob condi??es de campo. Em casa de vegeta??o, utilizaram-se duas cultivares de tomate cereja, ?Perinha ?gua Branca? e Super Sweet, suscet?vel e resistente ? requeima, respectivamente. As plantas foram inoculadas ou n?o com suspens?o de espor?ngios de P. infestans e em seguida, avaliadas aos 1, 2, 3, 4, 6, 7, 9, 10, 17 e 24 dias ap?s a inocula??o. As avalia??es foram feitas na quinta, oitava e d?cima primeira folha, contadas do ?pice para a base, usando as tr?s escalas acima citadas e medi??es do potencial fotossint?tico (Fv/Fm) pela emiss?o da clorofila ?a?. No campo, utilizaram-se quatro cultivares, ?Perinha ?gua Branca?, Super Sweet, Santa Clara e Carmen F1. Periodicamente, quantificou-se a severidade da requeima utilizando-se as mesmas escalas acima citadas em folhas de diferentes partes da planta, aos 51, 62, 74, 94 e 102 dias ap?s o transplante (DAT). No dia seguinte a cada avalia??o de severidade, foi coletada uma planta por parcela para mensurar o ac?mulo de biomassa e de macronutrientes nos diferentes ?rg?os da planta. A produ??o de frutos foi determinada pelo somat?rio das colheitas realizadas entre 68 e 114 DAT. Em condi??es de casa de vegeta??o, a estimativa da severidade da requeima com as tr?s escalas se mostrou adequada para quantifica??o da doen?a tendo permitido discriminar efeito de inocula??o e diferen?as entre as cultivares aos quatro e nove dias ap?s a inocula??o, respectivamente, que foram confirmadas pelas medidas do potencial fotossint?tico das folhas. Em condi??es de campo, as escalas Simplificada e Detalhada, foram mais adequadas para a quantifica??o da requeima do tomateiro. Quantifica??es feitas nas folhas mais jovens, no ter?o m?dio e superior da planta, foram as que melhor representaram o progresso da doen?a e discriminaram as cultivares quanto a resist?ncia ? doen?a. Observaram-se correla??es negativas entre a severidade, estimada com as tr?s escalas, considerando a planta inteira e o ter?o m?dio, e a massa seca de folhas e os teores foliares de K e P nas quatro cultivares. A cultivar ?Perinha ?gua Branca? apresentou menor massa seca de caule e de folha no in?cio das avalia??es e produ??o de frutos mais tardia, por?m ao final do ciclo destacou-se pela maior massa seca de caule e de folha. A cultivar ?Perinha ?gua Branca? e o h?brido Carmen F1 apresentaram maior produ??o de frutos comerciais. Com base nos resultados pode-se recomendar o uso da escala simplificada e avalia??es no te?o m?dio ou superior do tomateiro para quantifica??o da requeima.
| Identifer | oai:union.ndltd.org:IBICT/oai:localhost:jspui/1415 |
| Date | 21 September 2009 |
| Creators | COSTA, Evandro Silva Pereira |
| Contributors | Carmo, Margarida Gor?te Ferreira do, Ara?jo, Adelson Paulo de, Pimentel, Carlos, Carmo, Margarida Gor?te Ferreira do, M?dici, Leonardo Oliveira, Maffia, Luiz Ant?nio |
| Publisher | Universidade Federal Rural do Rio de Janeiro, Programa de P?s-Gradua??o em Fitotecnia, UFRRJ, Brasil, Instituto de Agronomia |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da UFRRJ, instname:Universidade Federal Rural do Rio de Janeiro, instacron:UFRRJ |
| Rights | info:eu-repo/semantics/openAccess |
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