Genetic and environmental factors affecting rooting in Eucalyptus grandis X Eucalyptus longirostrata hybrid cuttings.

Many factors affect the success of a clone in forestry, particularly its rooting ability.An investigation was undertaken to determine the genetic control of rooting in E. grandis x E. longirostrata hybrid cuttings.The plant material was sourced from five families in hedges at two nurseries in KwaZulu-Natal, South Africa.The rooting ability was assessed by determining the percentage of cuttings that developed roots, using two different rooting methods, i.e., either in air or media.The mean rooting ability between the five families were significantly different (p<0.05) and ranged from 23% to 34%.The mean rooting ability between the 25 clones tested were significantly different (p<0.0001) and ranged from 12% to 52%.The broad-sense heritability was estimated to be 0.197 (S.E.0.070).The results of this study suggest that the independent culling of poor rooting clones prior to their field testing may be a fair compromise between the cost of the programme and genetic gains.2.2 Chapter Three: A comparison of the effects of two different rooting methods on ramet productivity and cutting rootstrike in Eucalyptus grandis x Eucalyptus longirostrata hybrids 3.1