A review on the effects of donor maturation on rooting and field performance of conifer cuttings

Abstract

SYNOPSISThe maturation and ageing effects of parent or donor plants have been reported to have both positive and negative influences on the performance of rooted cuttings. A general decline in rooting ability, root quality and speed of rooting in the nursery, and a reduction in tree survival, growth and form in the field, have been associated with donor plants that have reached a state of reproductive or ontogenetic maturity. Increased maturation has also been shown to affect wood quality negatively. Provided that donor plants are still relatively young, positive effects from increased donor age have been observed through an improvement in tree form and branching habit, as well as a reduction in bark thickness and stem taper. These improvements have resulted in increased timber yields over seedlings of the same genetic origin. This report summarises current understanding of the effects of donor maturation.

Effects of cutting size and exogenous hormone treatment on rooting of shoot cuttings in Norway spruce [Picea abies (L.) Karst.]

“…The physiological conditions of the stock plants (Mitchell et al 2004), time and place of cutting collection (Hannerz et al 1999;Jurásek and Martincová 2004), and environmental conditions (Ragonezi et al 2010;Repáč et al 2011) significantly affect the efficiency of Norway spruce cutting propagation. Initial cutting size is a very important factor involved in rooting ability and growth performance (Burgess et al 1990;Foster et al 2000;Vigl and Rewald 2014).…”

Tissue Culture of Corymbia and Eucalyptus

“…The proliferation capacity of shoot tips, nodes, or axillary buds and the subsequent growth of their plantlets may also be influenced strongly by the position of the tree from which the explant was harvested. Maturation effects such as reduced rooting capacity, shorter internode length, and decreased stem growth [54,55,[59][60][61][62] can become evident from very early stages (i.e., from relatively low explant positions) during the development of eucalypt trees [44,[63][64][65][66][67].…”

“…In vitro storage can also delay the maturation of valuable clones, especially if their shoots or callus are stored under minimal-growth or nil-growth conditions [39,40,42,[180][181][182]. Plantation trees generally display higher adventitious rooting capacity, stem growth, internode length, and developmental commitment to vegetative growth when they are propagated from juvenile, rather than mature, explants or cuttings [54,55,61,62,183,184]. However, many eucalypt species progress through some of these juvenile-to-mature phase transitions at a very young age and low canopy height [11,39,40,44,63,64,67,185].…”

A comparative evaluation of the application of somatic embryogenesis, rooting of cuttings, and organogenesis of conifers

“…Because of the often poor correlation between juvenile and mature traits, proper testing generally requires at least about one-third to one-half the rotation age (Zobel 1981;Hodgetts et al 2001;Weng et al 2008). Juvenility can be prolonged a few years by repetitive pruning (hedging) or repeated cutting cycles (Bentzer 1993;Mason et al 2002;Mitchell et al 2004) but often not long enough to allow long-term field testing of the ortets to determine their suitability for clonal planting. Only for a few conifers has longer term clonal testing been possible.…”

“…When older ortets are used, differences in volume, form, and shape can occur (Mitchell et al 2004). For P. radiata, the ortet age that delivers the best ramets is 3-4 years (Menzies et al 2000).…”