Resistance of Eucalyptus Clones to Ceratocystis fimbriata

Abstract

Ceratocystis fimbriata, the inciting agent of wilt, canker, and dieback in eucalyptus plantations, was first reported in Brazil in 1998. There is no information regarding the resistance of Eucalyptus spp. to this pathogen. We determined the reaction of 18 Brazilian, commercial clones of the hybrid Eucalyptus grandis × E. urophylla to inoculation by two isolates of the pathogen in two experiments. Container-grown, 8-month-old rooted cuttings of each clone were wound-inoculated with a conidial suspension (2.5 × 106/ml). Plants similarly injected with sterile distilled water served as controls. The plants were evaluated after 30 days for length of xylem discoloration. There was a significant isolate by clone interaction, but most clones reacted similarly to the two isolates. Six clones, including one observed to be highly susceptible under field conditions, were highly susceptible (>20 cm discoloration) to one or both isolates of the pathogen. Four clones showed no more discoloration with either isolate than with the control inoculations, and the other eight clones were intermediate in susceptibility. Thus, highly resistant clones are available to manage this disease.

Resistance to Ceratocystis Wilt (Ceratocystis fimbriata) in Parents and Progenies of Eucalyptus grandis x E. urophylla

“…For the spore collection (conidia + ascospores), sterilized distilled water was added to the dishes and, after scraping off the colony surface with Drigalski spatula, the spore suspension was filtered through double gaze and calibrated at 2.5 x 10 6 spores mL -1 (ZAUZA et al, 2004). A cut lengthwise approximately 2 cm length was made on the stem (about 3 cm above soil surface) and 0.5 mL of the spore suspension was deposited and the inoculation area was covered with plastic film.…”

“…Although genetic resistance is the best control strategy (ZAUZA et al, 2004), the inheritance pattern and mechanisms involved in resistance have not yet been determined. However this information is essential to guide the use of resistance sources in genetic breeding programs of eucalyptus.…”

Characterization of Ceratocystis fimbriata from passion fruits

“…Wilt or drought symptoms were not observed in inoculated plants, but this may be due to the short evaluation period to which plants were subjected. There are stories of susceptibility to this fungus in eucalyptus plants which, even after 30 days of inoculation, did not show external symptoms of the disease, but had significant lesions internally in the xylem (Zauza et al, 2004).…”

“…This Ceratocystis isolate from passionflower plants (one month of age) was subjected to pathogenic characterization by adopting two methods: inoculation with mycelial disks of this fungus, as described by Silveira et al (2006), and deposit of a suspension of 10 8 cylindrical spores on the stem of the plant (Zauza et al, 2004). Evaluation occurred at 30 days post-inoculation.…”

Brief history of Eucalyptus breeding in Brazil under perspective of biometric advances

“…Rust, canker and wilt of Eucalyptus are examples that can be cited among the common incidence of diseases in its plantations that are widely disseminated throughout Brazil. Breeders attempted to select resistant individuals to these and other pathogens, and implement new breeding techniques to ensure plantations health, as it causes serious damage in nurseries, plantations, and wood quality (ZAUZA et al, 2004;ZAMPROGNO et al, 2008;TEIXEIRA et al, 2009;GUIMARÃES et al, 2010).…”