Caracterização anatômica foliar de clones de seringueira (Hevea spp.) visando resistência ao Microcyclus ulei
Carregando...
Data
2003-02
Autores
Sambugaro, Rosana [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
O mal das folhas é um dos mais sérios problemas patogênicos da seringueira no Brasil, sendo uma constante ameaça para as plantações do Oriente, principalmente Tailândia, Indonésia e Malásia, países responsáveis por 90 % da produção mundial de borracha natural. Esta doença causa desfolhamentos sucessivos às plantas em materiais suscetíveis, reduzindo a produção de látex e acarretando na mortalidade das plantas adultas. O objetivo do presente trabalho foi: caracterizar a anatomia foliar em três estágios fenológicos nos clones de seringueira PB 314, PB 235, MDF 180 e Fx 2784; aspectos anatômicos envolvidos com a patogênese do Microcyclus ulei em três clones (PB 314, PB 235 e Fx 2784) avaliados aos 5, 10, 45 e 90 dias após inoculação. Foi possível classificar três estágios (B, C e D) de acordo com os aspectos anatômicos. Verificou-se que PB 314 possibilitou o completo desenvolvimento do fungo nas fases assexual e sexual; MDF 180 apresentou alta concentração de compostos fenólicos no mesofilo, ausência da ascogênese e maior tempo da esporulação conidial que em PB 314; Fx 2784 apresentou maior espessura da epiderme da face abaxial, no estágio foliar B, que os outros clones, podendo ser considerada um fator de resistência anatômica à infecção e colonização pelo fungo.
The South American leaf blight is the most serious disease of rubber tree: is currently a serious threat to many regions of rubber plantation of the world, particularly in Indonesia, Tayland and Malaysia, responsible for 90% of natural rubber; and was the most important single factor in the complete failure of attempts to cultive rubber in the North region of Brazil. This disease caused successive defoliation in susceptible materials reducing the latex production and the plants death after third defoliation. The aim of this work was: a)To characterize the leaflets anatomy in three phenoligic stage in four rubber tree clones: PB 314, PB 235, MDF 180 and Fx 2784; b)Anatomical aspects involved with pathogenesis of Microcyclus ulei in three clones (PB 314, MDF 180 and Fx 2784) evaluated on 5, 10, 45 and 90 days after inoculation. It was possible classified 3 leaves stages (B, C and D) according to anatomical aspects. In PB 314 it was possible the complete fungus development in asexual and sexual stage, MDF 180 showed phenolic compounds concentration in the mesophil and the fungus ascogenese it was not possible, but the conidial sporulation was longer than PB 314; Fx 2784 has more larger thickness epidermic of abaxial surface in the B stage than the other clones, contributed with important anatomic factor of resistance to infection and colonization by fungus.
The South American leaf blight is the most serious disease of rubber tree: is currently a serious threat to many regions of rubber plantation of the world, particularly in Indonesia, Tayland and Malaysia, responsible for 90% of natural rubber; and was the most important single factor in the complete failure of attempts to cultive rubber in the North region of Brazil. This disease caused successive defoliation in susceptible materials reducing the latex production and the plants death after third defoliation. The aim of this work was: a)To characterize the leaflets anatomy in three phenoligic stage in four rubber tree clones: PB 314, PB 235, MDF 180 and Fx 2784; b)Anatomical aspects involved with pathogenesis of Microcyclus ulei in three clones (PB 314, MDF 180 and Fx 2784) evaluated on 5, 10, 45 and 90 days after inoculation. It was possible classified 3 leaves stages (B, C and D) according to anatomical aspects. In PB 314 it was possible the complete fungus development in asexual and sexual stage, MDF 180 showed phenolic compounds concentration in the mesophil and the fungus ascogenese it was not possible, but the conidial sporulation was longer than PB 314; Fx 2784 has more larger thickness epidermic of abaxial surface in the B stage than the other clones, contributed with important anatomic factor of resistance to infection and colonization by fungus.
Descrição
Palavras-chave
Seringueira, Resistência a doenças e pragas, Mal das folhas da seringueira
Como citar
SAMBUGARO, Rosana. Caracterização anatômica foliar de clones de seringueira (Hevea spp.) visando resistência ao Microcyclus ulei. 2003. ix, 61 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Ciências Agronômicas, 2003.