Acacia mearnsii De Wild (black wattle) is an important forestry plantation species for tannin production and woodchip exports in South Africa, and breeding of this species is the key focus of the Acacia Tree Improvement project at the ICFR. Research to date has made significant improvements in bark yield, tannin content, tree volume, stem form and disease incidence (gummosis) during the first decades of the breeding programme.
During the last decade, one of the main challenges for further improvement has been the high levels of relatedness that has built up in the breeding population. Different approaches to managing this problem have included sublines and multiple populations. A breeding strategy and operational breeding plan was developed in 2013 with the aim of ensuring short and long term genetic gains, while maintaining relatedness within acceptable levels. The main objectives are to increase timber and bark yield, and to continue improving stem form. Improvement in frost tolerance is also a priority for the frost-prone areas.
In 2014, a new disease in black wattle, caused by a rust fungus (Uromycladium acaciae), emerged in KwaZulu-Natal, and research is now prioritised on the development of wattle-rust tolerant genetic material. In addition, the establishment of new seed orchards to supplement the four remaining Production Seed Orchards is another activity of high priority for the wattle industry.