Eucalyptus pellita as a source of resistance to rust, ceratocystis wilt and leaf blight

L.M.S Guimarães,M Titon,C.C.G Rosado,A.C Alfenas,G.G.O Christo,L.N Rosse,L.S.S Oliveira,D Lau

doi:10.12702/1984-7033.v10n02a04

Abstract

Rust (Puccinia psidii), ceratocystis wilt (Ceratocystis fimbriata) and cylindrocladium leaf blight (Cylindrocladium pteridis) are important diseases of eucalyptus. Planting of resistant genotypes is the most suitable control strategy of forest diseases under field condition. Resistance level of 23 Eucalyptus pellita clones was evaluated by artificial inoculations. Among the inoculated clones, 12 were resistant to rust, 16 to ceratocystis wilt and 12 to cylindrocladium leaf blight, and three of them were resistant to all three diseases. The high intra-specific variability found in this study demonstrates the importance of E. pellita as a disease resistance source to be employed for introgression of novel resistance genes in eucalyptus genetic breeding programs.

Highlights

The main objectives of forest genetic breeding are to reduce damage caused by disease and pests and produce trees adapted to grow in adverse environments (Sobrosa and Martins-Coder 2001)
A wide spectrum of rust reaction was found among resistant genotypes, as some of them showed immunity (Figure 1A), hypersensitivity reaction (HR)
(Figure 1B), or hypersensitive reaction (HR) followed by puntiform pustules with sporulation (Figure 1C)

Summary

Introduction

The main objectives of forest genetic breeding are to reduce damage caused by disease and pests and produce trees adapted to grow in adverse environments (Sobrosa and Martins-Coder 2001). With the expansion of plantations, the use of high-yielding genotypes with no previous knowledge of its resistance level to many diseases, the implementation of clonal forestry and the introduction of new management techniques have favored the emergence of epidemics, caused by endemic or accidentally introduced pathogens (Alfenas et al 2004). Rust (Puccinia psidii Winter), ceratocystis wilt (Ceratocystis fimbriata Ellis and Halsted) and cylindrocladium leaf blight (Cylindrocladium pteridis Wolf) are currently among the most damaging diseases in eucalyptus plantations (Alfenas and Zauza 2007). P. psidii infects juvenile organs of the plant either in nursery or in the field (Coutinho et al 1998).

Objectives

Methods

Results