The length and frequency of stomata on leaf surfaces were examined as rapid techniques for future identification of ploidy level of Acacia mearnsii (de Wild). Diploid (2n = 2x = 26) and tetraploid (2n = 4x = 52) plants were germinated from chipped seed at 25°C and grown under nursery conditions. After one month, measurements showed that the mean stomatal length was 27.17 ± 0.474 µm for diploids and 40.24 ± 0.521 µm for tetraploids and these differed significantly from each other (P < 0.001). The frequency of stomata per leaf surface was shown to decrease significantly (P < 0.001) as the ploidy level increased, with a mean of 22.11 ± 0.495 for diploids and 10.26 ± 0.495 for tetraploids. It was concluded that stomatal length and stomatal frequency are rapid indirect methods to identify ploidy level in black wattle. © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society, 2003, 141, 177–181.

No abstract

No abstract

The genus Acacia comprises many species which are important for firewood, fodder, tannin, pulpwood, shelterbelts, and soil improvement. Species of Acacia are dispersed widely in tropical and subtropical regions of Australia, South America, Asia, and Africa. In the past, the majority of forest trees have been propagated through the traditional family forestry method, where trees are grown from seeds and propagated sexually. Clonal propagation through tissue culture offers an alternative to vegetative practices and has the potential to provide high multiplication rates of uniform genotypes, resulting in short-term gains. Extensive in vitro research and success have been achieved for a number of forest trees, including the Pinus, Eucalyptus, and Acacia species. Acacia mearnsii is fast becoming one of the most important trees in South African forestry. For this reason it is important to employ biotechnology to enable the industry to compete in the international market. However, for these procedures to be commercially viable, the post-culture performance in the field must be improved because the initial financial outlay is high. This review provides an overview on in vitro work done on the Acacia species.

Recent research has shown, Acacia mearnsii (black wattle) to be a source of high quality pulp. This led to a change in the emphasis in the breeding programme at the Institute for Commercial Forestry Research, from improving bark yield and quality, to improving timber yield and quality while maintaining an acceptable bark quality. A Multiple Population Breeding Strategy was implemented to cater for these changes. Five sub-populations were established across different sites in KwaZulu- Natal and were determined by origin of seed. Each sub-population was established as a progeny trial with a seedling seed orchard adjacent to it. The management of the seed orchards will be determined according to the performance of the families within the progeny trials. This paper reports on the first year height measurements taken from the five sub-populations. The intention of this paper is not to base any selections from this data but rather to establish a set of analyses using REML/BLUP which will be used for future data analysis. This will also allow for future assessment of age-age correlations for the various traits being assessed and provide an appropriate decision-making tool, for selecting individuals for future generations.