OUT OF PRINT Manipulation of the genetic composition of a plant via crossing and selection offers the opportunity for improvements in both yield and quality. In Malaysia it was observed that some natural hybrids of Acacia mangium and A. auriculiformis are very vigorous and had desirable stem form characteristics for timber production. To capitalise on the hybrid vigour and other benefits of breeding, it was essential to develop simple, practical techniques to transfer pollen from the male parent to the stigma of the female parent. In response to this problem ACIAR commissioned a project which included the development of procedures for controlling crossing of acacias. The results of the work on methods are reported in this technical report. It is intended that they will provide a guide to enable tree breeders to take advantage of the benefits of hybrids or other germplasm derived from the controlled crossing of acacias.