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Thesis (MTech (Horticulture))--Cape Technikon, Cape Town, 1999 / Vegetative propagation techniques for rooting of cuttings of indigenous tree species, i.e. Olea europaea subsp. African, Podocarpus falcatus, Syzigium cordatum and introduced species, i.e. Acacia mearnsii, A. melanoxylon, Eucalyptus grandis and Melia azedarach were studied and improved at the Cape Technikon nursery from May 1994 to June 1998. These tree species are considered problematic since the indigenous species produce unwanted fruits in urban areas which attract frugivores, while the introduced species are a threat to indigenous vegetation and natural habitats, though they are of great commercial value. The progress in mutation breeding of sexual sterility in most of the problematic species created a need to propagate them vegetatively. Without cloning of seedless species, their beauty and economic value to South Africa will be lost, as the indigenous species will be neglected, while invasive species will continue to threaten the natural habitat of indigenous species. Experiments were conducted to test age, type and length of cuttings, environmental factors, growth season, hormone application, various treatments and rooting media for each of these species. This study showed that relatively few publications relevant to the vegetative propagation of indigenous tree species are available. However, some introduced species, e.g. Eucalyptus grandis, are propagated successfully for commercial forestry purposes. Ficus sur and Syzicium cordatum showed the highest rooting success, i.e. 85-90%, followed by Olea europaea subsp. africana (75-80%), and Podocarpus falcatus (60%). The introduced species showed no rooting success, however, callusing in Eucalyptus grandis (35-61%), and Melia azedarach (50%), and survival rates in Acacia mearnsii (10%) and A. melanoxylon (20%) were achieved. Treatments, i.e. etiolation, placing plants under stress, sealing basal stems of cuttings, and fungicide treatments all showed positive results in promoting callusing success. The study showed that rooting success in individual species are directly related to the growth stage of parent plants as well as the season during which the cuttings were taken. With progress towards successful vegetative propagation of sterile problem plant species, propagators and horticulturists can in future apply these improved techniques. These plants will then continue to supply timber, fire wood and improve aesthetics in the South African urban environment.

Eucalyptus spp. and hybrids dominate the global plantation forestry industry, and vegetative propagation through cuttings is the preferred method for their commercial use. However, the cuttings of some species and hybrids show recalcitrance to rooting. The first aim of this study was to improve percentage rooting of three clones of E. grandis x E. nitens (Clones 1, 2 and 3) identified by a commercial nursery as having variable rooting abilities. The second was to relate their rooting responses as cuttings to their rooting responses in vitro. Minicuttings (3.5 – 4 cm in length) (hereafter referred to as cuttings) were subjected to commercial nursery propagation practices. Initial results revealed that in the absence of exogenous plant growth regulators (PGRs), soft (juvenile, thin diameter) cuttings survived (87 – 95%) and rooted (29 – 32%) significantly better than hard (mature, thick diameter) ones (62 – 71% survival and 2 – 8% rooting). This validated the use of soft cuttings by the nursery and all subsequent studies were conducted with soft cuttings. The other nursery practice of applying the commercial rooting powder Seradix 2 (3 g kgˉ¹ indole-3-butyric acid [IBA]) adversely affected the survival and subsequent rooting of cuttings of Clones 1 and 2. Ensuing studies investigated: 1) the effect of mode of IBA application (powder vs. liquid); 2) concentrations of Seradix (0, 0.5, 1, 2 and 3 g kgˉ¹ IBA), applied at initial placement of cuttings and two weeks later; and 3) the influence of season on the survival and subsequent rooting of cuttings. Results showed that regardless of the mode of application, IBA significantly reduced percentage survival and rooting in cuttings of Clones 1 and 2. The delayed application of Seradix, two weeks after cuttings were initially set, resulted in a higher percentage survival and rooting than when cuttings were supplied with Seradix at initial placement. Nevertheless, the best survival for Clones 1, 2 and 3 (95%, 99% and 71%, respectively) and rooting (83%, 64% and 47%, respectively) occurred in the absence of Seradix. In addition, the survival and rooting of cuttings were seasonally variable, with particularly low rooting during winter (e.g. for Clone 1, 32%) when compared with summer (e.g. for Clone 1, 83%). Shoots from all the clones were multiplied in vitro, followed by elongation on either of two media (E1= kinetin, α-naphthalene acetic acid [NAA] and IBA; E2 = kinetin and indole-3-acetic acid [IAA]), and then rooting on 0, 0.1 or 1.0 mg 1ˉ¹ IBA. The latter were selected to typify the range of Seradix concentrations used for the cuttings (i.e. no IBA, low and high IBA concentrations). For all three clones, shoots elongated on E1 or E2 displayed high survival (> 80%) but failed to root without IBA in the rooting medium. For Clones 1, 2 and 3 the best in vitro survival (80%, 100% and 100%, respectively) and rooting (40%, 75% and 40%, respectively) occurred when shoots were elongated on E2 and rooted on 0.1 mg 1ˉ¹ IBA. However, 1.0 mg 1ˉ¹ IBA in the rooting medium severely inhibited survival (0 – 50%), irrespective of the clone or the elongation treatment used. Overall, cuttings demonstrated the best survival and rooting in the absence of exogenous IBA, which suggested that sufficient endogenous auxin was present within the shoots for successful root induction. The application of exogenous IBA may have disrupted the cuttings’ endogenous PGR balance resulting in an inhibition of survival and rooting. In vitro shoots required a low concentration of IBA (0.1 mg 1ˉ¹) in order to counteract the antagonistic effect of cytokinins that were supplied during the multiplication and elongation culture stages, and promote rhizogenesis. Essentially, both cuttings and in vitro shoots demonstrated adverse survival and rooting responses when subjected to excessively high IBA concentrations. / Thesis (M.Sc.)-University of KwaZulu-Natal, Durban 2013.

Copies no. 3007841664 and 3007841665 are photocopies of the original. / Thesis (MScAgric)-- University of Stellenbosch, 2003. / ENGLISH ABSTRACT: Buchu (Agathosma betulina and A. crenulata) are grown commercially as an aromatic crop and are endemic to the Western Cape of South Africa. Poor rooting of cuttings have limited the development of superior clones. Under standard mist bed conditions terminal, sub-terminal or basal stem cuttings were taken from March to August. When not treated with an auxin, rooting percentages of between 20 and 25 were obtained. Rooting percentages increased to between 40 and 45 after treatment with 500-1000 ppm indolebutyric acid (lBA). Substituting lBA with naphthaleneacetic acid (NAA) did not improve rooting. There was a tendency for cuttings with fewer than four leaf pairs to give lower rooting percentages. Plants of Agathosma betulina x A. crenulata, grown in Paarl, and A. betulina, grown in Piketberg, were used as source plants for making cuttings. Paarl plants were shaded with 80 percent shade and Piketberg plants with 60 or 80 percent shade respectively from February to October 2002. Plants in full sun served as a control. Plants were pruned back initially in February and then two months before samples were taken in March, June, August and October at both locations. New shoots were used as cuttings. Terminal cuttings for rooting and for carbohydrate analyses were collected on four different dates (March, June, August and October). Cuttings were treated with 500 ppm indolebuteric acid (lBA) and placed in misting beds with bottom heating (18-25°C) for a period of three months. Shading reduced rooting of cuttings from the Paarl plants. However, it did not significantly increase rooting of cuttings taken from Piketberg plants. Rooting percentage was the highest in August (43%) for cuttings from sun grown plants in Paarl. No consistent relationship between, respectively, dry mass or carbohydrate content of cuttings and rooting could be established. Terminal current years' growth, taken from Agathosma crenulata x A. betulina (hybrid) softwood cuttings, collected in January 2002, were extracted with methanol and fractioned by thin layer chromatography (Silica gel) in isopropanol: acetic acid: water (4: 1:1 v/v). The chromatographs were divided in ten fractions and were bio-assayed for a rooting co-factor with the mung bean rooting test. Extracts from buchu cuttings showed significant activity at the Rf values of co-factor 3. Co-factors 1,2 and 4 do not seem to be present in significant quantities. However, co-factors with Rf values different from previous reported values were present in significant quantities. No inhibition was found in buchu. In fact, all Rf values stimulated rooting. / AFRIKAANSE OPSOMMING: Boegoe (Agathosma betulina x A. crenulata) word kommersieël verbon as 'n aromatiese gewas en is endemies tot die Wes-Kaap. Die ontwikelling van superieure klonale materiaal word beperk deur swakbeworteling. Terminale, sub-terminale en basale steggies is gesnyonder standaard misbed toestande van Maart tot Augustus. Beworteling was tussen 20 en 25 persent as geen ouksien gebruik word nie. As indolebottersuur (IBS) gebruik word tussen 500-1000 dpm, verhoog die bewortelingspersentasie tot tussen 40 en 45 persent. Die gebruik van naftaleen asynsuur (NAS) in plaas van IBS het nie beworteling verbeter nie. Daar was a tendens dat steggies wat minder as vier blaarpare gehad het 'n verlaging in bewortelingspersentasies gehad het. Plante van Paarl, A. betulina x A. crenulata, en Piketberg, A. betulina, is gebruik as plantmateriaal vir steggies. Plante in die Paarl was onder 80 persent skadu geplaas en plante in Piketberg onder 60 en 80 persent skadu van Februarie tot Oktober 2002. Plante in vol son was as 'n kontrole gebruik. Plante was eers in Februarie teruggesny en dan weer twee mande voor monsters geneem is. Die monsters is in Maart, Junie, Augustus en Oktober geneem in beide liggings. Terminale steggies is vier keer ingesamel (Maart, Junie, Augustus en Oktober) vir beworteling en koolhidraat analises. Die steggies is met 500 dpm IBS behandel. Daarna is die steggies vir drie maande in die misbed geplaas met bodem-verhitting (18- 25°C). Dit is gevind dat die gebruik van skadu die beworteling in Paarl verminder het alhoewel die beworteling in Piketberg nie beduidend beinvloed is nie. Die hoogste bewortelingspresentasies is waargeneem in Augustus (43%) in Paarl van plante wat in vol son was. Geen verband tussen onderskeidelik die droe massa of koolhidraat inhoud en beworteling kon gevind word nie. Terminale steggies van dieselfte jaar se groei van Agathosma betulina x A. crenulata (hibried) is in Januarie 2002 ingesamel. Die materiaal is geëkstraheer en gefraksioneer deur dunlaag kromatografie in isopropanol: asynsuur: water (4: 1:1 v/v). Die kromograaf is in 10 fraksies verdeel. Die fraksies was bioassaieer VIr beworteling ko-faktore met die mungboontjie bewortelingstoets. Die ekstrakte van boegoe het beduidende aktiwiteit by die Rf waardes van ko-faktor 3 getoon. Ko-faktore 1, 2 en 4 is nie in groot genoeg hoeveelhede waargeneem nie. Ko-faktore, wat nie voorheen gevind is nie, is waargeneem in beduidende hoeveelhede. Geen inhibitors is in boegoe gevind nie en al die getoetste ko-faktore het beworteling gestimuleer.

In clonal deployment programmes of plantation species, there is frequently the need to deploy Eucalyptus species and interspecific hybrids as rooted cuttings. However, the rooting ability of a particular species or hybrid is a major, and usually limiting, factor affecting the economics of commercial deployment. There is also significant between-species and between-family variation for this trait. Recently, Eucalyptus longirostrata was crossed with E. grandis in an effort to combine its desirable wood properties, drought tolerance and disease resistance with the latter's vigorous growth. Should progeny with these suitable characteristics be identified, there is the possibility of extending plantations to more marginal areas and increasing the quality and volume from existing plantations. An investigation was undertaken to study the rooting ability of E. grandis x E. longirostrata hybrid cuttings. The plant material was sourced from five families in seedling derived hedges at two nurseries, as well as five families coppiced from an unreplicated progeny trial planted in the midlands of KwaZulu-Natal. Their rooting ability was assessed by determining the percentage of cuttings that developed roots using two different rooting methods. The variation between and within families and clones is presented. The study shows that root strike is under moderate genetic control, with an estimate of broad-sense rooting heritability of 0.197 (S.E. = 0.070). The two nurseries used in this study used different rooting technologies, with cuttings rooted either in media (traditional method) or in air (aeroponically). The aeroponics technology was highly significantly (p<0.0001) superior, in terms of rooting success. Rooting was also highly significantly affected (p<0.0001) by the temperature at the time of cutting. Rooting success of cuttings from seedling-derived parental hedges was similar to cuttings from coppiced stumps. The consequences of the low repeatability of measurements of rooting ability, 0.187 (S.E. 0.067) by clone and 0.340 (S.E. 0.072) by ramet, which was influenced by the response to age of material and nursery conditions, is discussed. This study demonstrated that large improvements in rooting success can be made by the optimization of rooting protocols and selecting for superior genotypes, as long as the performances of genotypes are accurately assessed. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.

Thesis (M. Tech. (Agriculture)) -- Central University of Technology, Free State, 2013 / ntroduction: Good quality Eucalyptus is of importance to South Africa’s pulp and paper industry. Limited land is available for forestry, therefore Eucalyptus with genotypes for good pulp and paper qualities, particularly hybrids, are bred and cloned via cuttings. Although these Eucalyptus clones keep the favourable genotypes in the population, many have difficulty with rooting. Research has shown that rhizobacteria can improve rooting. Thus, one strategy to enhance the rooting of cuttings is to use rhizobacterial preparations. The aim of this study was to characterise rhizobacterial communities of Eucalyptus hybrid and species and identify possible plant-growth promoting rhizobacteria (PGPR). Materials and methods: Rhizospheric samples were collected from Eucalyptus hybrids and species. The rhizobacterial communities were characterised using fatty acid methyl esters (FAME) analysis and denaturing gradient gel electrophoresis (DGGE). DGGE fragments were further sequenced to identify rhizobacteria. Results and discussion: FAME analysis successfully achieved a broad characterisation of the Eucalyptus hybrid and species rhizobacterial communities based on their fatty acid composition. Myristic acid (C14:0) was the most abundant fatty acid. DGGE profiles gave a molecular profile of the Eucalyptus hybrid and species rhizobacterial communities based on their DNA composition. Nitrosomona eutropha was present in all samples which illustrates a nitrogen-rich environment. Adhaenbacter aquaticus was unique to the better rooting Eucalyptus hybrid GU111. Conclusion: This study provided some insight into the diversity of rhizobacterial communities of Eucalyptus hybrids and species. Possible PGPR were identified and the observation made that the nature of the soil environment changes with the aging of the associated host. These findings allow further investigation into the formulation of potential rhizobacterial preparations for rooting enhancement of Eucalyptus cuttings.

Clones of the Eucalyptus grandis x Eucayptus nitens (GN) hybrids were produced and selected through the CSIR‟s breeding programmes for colder plantation sites in South Africa. Some GN clones consistently exhibit high and superior pulp properties, which makes them valuable for commercial plantations in South Africa. In nurseries, stockplants are usually seven cm in length and maintained at high (100 x1.5 m-2) planting density. However, rooting frequency varies with season and little is known about the impact of position of cuttings on overall rooting frequency of a clone. The aim of this study was to investigate the effect of size and planting density of stockplants in mini-hedges, on the yield and subsequent rooting of cuttings from various positions of GN clones of known rooting potential (i.e. GN 018B: difficult-to-root and PP 2107: easy-to-root clones). Stockplants (10 cm vs. 20 cm) were established at high (100 x 1.5 m-2) and at low (25 x 1.5 m-2) densities for GN 018B and PP 2107 under commercial nursery conditions in a polyethylene tunnel. Cuttings were harvested every two to three weeks in September-October 2010 (spring), December 2010-January 2011 (summer), April-May 2011 (autumn) and June-July 2011 (winter). The harvested material was 5 – 7 cm in length and the light intensity received by individual stockplants at the two planting density levels was recorded. Harvested cuttings from the three positions (apical, middle and basal shoots) were used for: (i) rooting experiments under nursery conditions, (ii) bio-stimulant analysis using the mung bean bioassay, and (iii) analysis of soluble sugars. Between spring and summer 2010, the two GN clones established at low density yielded a similar number of cuttings, but differences in the rooting frequencies were significant in favour of PP 2107 clone. Similar observations were made at high density in terms of production of cuttings, but the significant differences in the rooting observations were reversed between the clones. The GN 018B clone had low rooting rates in summer under nursery conditions but its tissue extracts promoted higher rooting in the bioassay during that time, when compared to spring. Spring and summer had similar effects on rooting responses of PP 2107 cuttings in nursery and bioassay experiments. For both clones, short stockplants produced fewer cuttings but had a higher rooting frequency than cuttings from tall stockplants, with a high rooting frequency recorded from basal cuttings. Similar results were observed in the bioassay experiments which showed high rooting potential of mung bean hypocotyls cuttings using tissue extracts of PP 2107 cuttings maintained at high planting density. Although apical cutting tissues had high concentration of sugars (i.e. sucrose, glucose and fructose), their rooting rates were usually lower at high and low planting density compared to middle and basal cuttings. Sucrose concentration was the highest sugar present in stockplants grown under low planting density. A higher and lower rooting frequency was also observed in autumn although the two clones responded differently to Quambalaria eucalypti (Sporothrix eucalypti) disease infestations. Position, size and genotype had a significant impact on type and concentration of sugar (i.e. sucrose, glucose and fructose), particularly in PP 2107 clone, although rooting rates in the bioassay did not correlate with sugar contents of Eucalyptus cuttings. High carbohydrate (i.e. soluble sugar) content and auxin concentration increased production and subsequent rooting of cuttings across both clones, particularly in spring. Furthermore, rooting was enhanced by relatively higher light intensity intercepted by individual stockplants and in particular the GN 018B clone. Light intensity in the high and low planting densities caused variation in the rooting frequencies thereby increasing or decreasing soluble sugar and auxin concentrations of the two clones. Light intensity and fertiliser concentration received by tall and short stockplants impacted on endogenous hormone levels thereby increasing or decreasing rooting. High sugar concentration levels of PP 2107 clone increased its susceptibility to fungal infection thereby decreasing its rooting frequency in autumn, as its rooting rates increased in winter. Overall results of the investigation revealed that PP 2107 clone has higher rooting potential than GN 018B clone, in particular at high planting density and if stockplants are not infected by fungal diseases. Higher sugar levels were recorded in spring for PP 2107, although rooting rates of mung bean hypocotyl cuttings were higher in summer for GN 018B, suggesting that sugars have nothing to do with rooting of GN cuttings. Season, planting density and size of stockplants affect the rooting frequency of GN clone. Thus, short stockplants maintained at low and high planting densities are recommended for GN 018B and PP 2107 respectively, although the impacts of fertilisers and pathogen resistance on rooting rates still need to be investigated under similar conditions. / Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.