Assessing the nursery performance of clonal eucalyptus cuttings that have undergone different time duration treatments before insertion.

Abstract

Hybrid clonal technology can radically change the way in which Eucalyptus plants are selected and grown. It offers a means of producing planting materials with highly desirable growth characteristics. Propagation by cuttings is the main tool in Eucalyptus breeding programs by which it is possible to multiply the Eucalyptus trees quickly as well as retaining the parental plant characteristics. This doesn’t occur under natural conditions, it is therefore affected by different factors such as rooting media, nature and management of cuttings, which should be manipulated appropriately to get increased nursery output. This study was conducted at NTSC, to determine the best time duration within which cutting insertion should be done. Three eucalyptus hybrids were considered i.e. GC796, GC796/2 and GU7. 150 cuttings were used for each clonal type, with 50 cuttings for each of a 60-minute difference time treatment. 50-cutting batches for each of the three clones were inserted at 60, 120, and 180 minutes respectively after harvesting. GC796 and GC796/2 clones attained the highest survival percentage for cuttings inserted at 120 minutes, whereas GU7 had the highest survival percentage with cuttings inserted at 60 minutes. GU7 exhibited a consistent reduction in survival percentage with increasing time of insertion while GC796 had the lowest survival percentage for cuttings inserted at 60 minutes as GC796/2 attained the lowest survival percentage with cuttings inserted at 180 minutes, which was the same case with GU7. GC796/2 registered the highest survival percentages whereas GU7 exhibited the lowest survival percentage under all treatments. Only GC796 cuttings registered a significant difference, in the number of roots between 60 and 180 minutes, and in the length of the longest root between 60 and 120 minutes. Given that GU7 cuttings were more sensitive to the effect of time lapse between coppice harvesting and cutting insertion, it is recommended that its cuttings be inserted immediately after cutting preparation. The study further recommends that more studies should be done under strict control of all other influencing factors as well as using a larger sample size since this study was associated with a smaller sample size due to cutting mortality, i.e. cutting survival was generally poor.