Research Focus




Wattle Tree Improvement

Dr Julian Moreno Chan

Dr Julian Moreno Chan

Principle Scientist: Wattle Tree Improvement

The ICFR is the sole supplier of research breeding services and improved germplasm to the South African wattle companies, wattle growers and nurseries. The overall aim of the Wattle Tree Improvement programme at the ICFR is to develop genetic material of better growth than current planting stock, and resistant to existing and new pest and diseases, frost, and other environmental risks.

Black wattle (Acacia mearnsii de Wild) is widely planted in South Africa for bark tannin and woodchip exports. The species is susceptible to the rust fungus Uromycladium acaciae and prone to frost damage, two major limitations to its cultivation. The wattle rust disease emerged in 2013/2014 and is a major threat to the South African black wattle industry. Identification and deployment of genetically rust tolerant sources is currently the only alternative to manage this pathogen in black wattle plantations. The breeding strategy seeks to develop both seed orchards and clones resistant to the rust and of superior growth in the shortest possible time.

In areas prone to frost damage, there is ongoing work to develop genetic stock tolerant to frost and resistant to rust which is a major challenge as such material is very limited in the current breeding population. Genetic improvement for other traits of economic importance including growth, stem form, gummosis resistance and tannin quality is part of the long-term breeding strategies for both the rust-resistant and frost-tolerant breeding populations.

The development of wattle hybrids between black wattle and green wattle (Acacia decurrens Willd) is a recent focus area in the breeding programme. Unlike A. mearnsii, A. decurrens is not affected by rust, however, its tannin is of inferior quality and is not favoured by the bark processing factories. Thus, the view is to develop wattle hybrid varieties with increased rust resistance and acceptable tannin quality.