Harvesting genetics for productive plantations : creating new germplasm

Abstract

Tree breeding has had significant impacts on the success of the South Africa forest industry. Examples are cited for tree growth rate, where for instance, a mean genetic improvement of 39% has been measured in F2 E.grandis over unimproved controls over various sites. The mean improvement of F1 over P0 was recorded as 15% in the genetic gains trials, which compares with the realised reduction of rotation length by 10-15% in sawtimber crops. In E.grandis sawtimber, the impact of wood splitting has been reduced by approximately 29%. Similarly, substantial progress has been made in stem form, and species selection against pest and diseases. Selection of species with suitable properties for pulp yield is currently gaining momentum, with the increasing use of E.smithii, and the initiation of Project Pulp. Tree breeding will have to harness increasingly sophisticated technologies to make advances in the traits which have already undergone some improvement, such as tree growth. This is due to the gradual fixing of the genes which are easily captured, leaving the more challenging inheritance for advanced breeding techniques. There is a constant change in the market needs from trees (and tree breeders), as technologies change, markets change, and the environment changes. Tree breeding will continue to be a critical tool in maintaining a healthy forestry industry.


Southern African Forestry Journal No.195 2002: 83-88