Effect of species, cutting position and exogenous rooting substances on rooting of honeybush (Cyclopiaspp.) cuttings

Abstract

Effect of the cutting position, terminal and subterminal, and rooting substance on the rooting of cuttings of two Cyclopia species (Cyclopia genistoides and C. intermedia) taken in winter, spring or summer was studied under controlled glasshouse conditions. Cuttings taken in summer, irrespective of the species, rooted better than cuttings taken either in winter or spring. This poor rooting performance of cuttings in winter and spring resulted in no significant treatment effects and for this reason only results of cuttings taken in summer are discussed. Cyclopia genistoides rooted significantly better than C. intermedia as measured by rooting percentage, number of roots per cutting, length of longest root and mean root length. Terminal cuttings from C. genistoides also increased rooting percentage and number of roots compared to subterminal cuttings, but not so in C. intermedia. Longest roots were produced by terminal cuttings irrespective of species. Treatment with different exogenous rooting substances as a main factor did not have any significant effect on rooting in this study.

Propagation and cultivation practices of honeybush (Cyclopia spp.) for the sustainable production of an export quality indigenous South African tea

“…However, the nature of these semi-hardwood cuttings was not well defined. Mbangcolo (2008) and Mbangcolo et al (2013) compared the rooting success of C. genistoides and C. intermedia cuttings made from either terminal or subterminal stock plant stem material in summer (December), winter (May), and spring (September). Terminal cuttings harvested from C. genistoides in summer achieved a relatively high rooting percentage of 75%, whilst cuttings collected from subterminal material only rooted on average at 41%.…”

“…In contrast, when Mbangcolo (2008) used smoke primer disks to improve germination of C. intermedia and C. genistoides seed, neither species reacted positively to this treatment, leading to the conclusion that these two resprouters may be unresponsive to smoke. However, such lack of response could also be ascribed to the use of a suboptimum dilution of the smoke extract used by Mbangcolo (2008) and the lack of quantification of the concentration of the active ingredients. Further investigation is therefore required to establish whether any of the other commercially important honeybush species seeds may be responsive to smoke water treatment and, if so, whether this technology could be used to improve seed germination for commercially important Cyclopia species.…”

“…However, for C . genistoides , starch concentrations were reported to be highest from late spring to autumn, with the highest rooting percentage of 57.8% being obtained for cuttings made during summer (Mbangcolo, 2008; Mbangcolo et al., 2013). For both species, starch concentrations were lowest in winter and early spring, possibly due to reserve allocation to flowering in spring, along with partitioning to root development in winter (Wooldridge et al., 2012a, 2012b, 2012c).…”

“…In these studies, 7‐yr‐old seedlings from the resprouters C. intermedia and C. genistoides had rooting successes of 29 and 58%, respectively, in the summer months, when terminal cuttings were made. However, no rooting was achieved when cuttings were rooted later during the season, either in autumn or winter, regardless of the species (Mbangcolo, 2008; Mbangcolo et al., 2013).…”

“…In a study on C. genistoides by Mbangcolo (2008), rooting percentages were found to be comparable, regardless of the cutting type, or the concentration or formulation of rooting hormones used. Rooting percentages of 86% were achieved when cuttings were treated with IBA at 2 g L −1 , or 82% with IBA at 4 g L −1 , whereas a lower rooting percentage of 70% was achieved using 4‐indole‐3‐butyric acid at 3 g L −1 (as the commercial formulation Seradix B2).…”