Respostas fisiológicas e de susceptibilidade de acessos de Jatropha curcas L. ao ácaro branco

• Autor(a) principal: Evaristo, Anderson Barbosa
• Data de Publicação: 2011
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/4548
• topic: Pinhão manso; Polyphagotarsonemus latus; Trocas gasosas; Jatropha; Polyphagotarsonemus latus; Gas exchange; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA

Jatropha (Jatropha curcas L.) is a plant species of great economic potential, especially for their seeds constitute the raw material for the production of oil for biodiesel. This feature has contributed to the increase in its commercial exploitation. Several pests have caused considerable damage in the culture of J. curcas, especially the broad mite (Polyphagotarsonemus latus). This mite attacks mainly the early stage of crop causing morphological and physiological damage. The objective of this work was to identify and characterize physiologically accessions of J. curcas less susceptible to broad mite, to support the breeding program of the species. The study was set up at the Federal University of Viçosa (UFV), Viçosa, MG, Brazil, in a greenhouse. We used 15 accessions of J. curcas with high oil content (> 30 %) in the seed, belonging to different clusters of genetic diversity of the genebank of UFV. Sowing was on four liters pots using seeds from mother plant with one plant per pot. We evaluated the following traits: population growth of P. latus (ri), symptoms of injury caused by P. latus, relative water content in the leaf (RWC), specific leaf area (SLA), net assimilation rate of carbon (A), gas exchange, photosynthetic pigments, nitrogen, biomass of area part (BAP), increase of stem diameter (ISD), of final number of leaves (FNL) and of plant height (IPH). We used a randomized block design with three replications and plots of one plant per pot. Analyses of variance were processed in a factorial 15 x 2, being 15 accessions of J. curcas, with and without broad mite infestation. Differences between the means of access were analyzed by the Tukey test at 5% probability. There were significant differences (P < 0.05) for ri and for the symptoms of injuries caused by P.latus. The accessions did not differ to agronomic and physiological characterization. There was a 23.8 % reduction in IPH in infested plants. The rate of net carbon assimilation (A) was on average 50.5 % lower in infested plants, whereas stomatal conductance (gs) and transpiration (E) decreased by 46.2 % and 51.6 %, respectively. With respect to photosynthetic pigments, SLA, BAP, FNL and ISD no significant differences among accessions infested and not infested with white mites were verified. P.latus causes significant changes in gas exchange, providing a significant reduction in net photosynthesis.