Early and late root formation in epicotyl cuttings of Pinus sylvestris after auxin treatment

Auxin stimulated rooting of epicotyl cuttings of Pinus sylvestris irrespective of the physiological stage of the plant from which the cuttings were taken. The epicotyl cuttings were divided into two groups, those that differentiated roots early (within 6 weeks after cutting) and those that differentiated roots late (more than 6 weeks after cutting). Auxin treatment significantly stimulated the frequency of early rooting of epicotyl cuttings, whereas it had no effect on the frequency of late rooting of epicotyl cuttings. The number of roots per rooted cutting was significantly higher after auxin treatment both on early and late rooted cuttings. Anatomical studies showed that most of the roots on both early and late rooted cuttings developed from wound tissue. However some types of rooting were found only after auxin treatment of early rooted cuttings, e.g., roots that developed from resin duct wound tissue or from vascular tissue or in the pith.     

Vegetative propagation of African Mahogany: effects of auxin, node position, leaf area and cutting length

Applied auxin, node position, leaf area and cutting length were examined to investigate the requirements for rooting stem cuttings of Khaya ivorensis. All these variables were shown to be important factors affecting rooting, confirming the hypothesis that successful rooting can be achieved if these primary variables are optimised.The best concentration of the auxin IBA was found to be 200 g per cutting, which hastened rooting, increased the percentage of cuttings rooted and increased the number of roots per cutting. One clone (8013) was unresponsive to auxins in terms of the percentage of cuttings rooted, but was the most responsive in terms of the numbers of roots per cutting. A greater percentage of cuttings from basal nodes were rooted than from apical nodes. Cuttings cut squarely at the base produced a radially-arranged root system, whereas an oblique cut resulted in a one-sided root system.Trimming the leaf area of cuttings to 10 cm² gave greater rooting percentages than trimming to 100 cm². In general, long cuttings (39 mm) rooted better than short cuttings (19 mm), however, there was an interaction between leaf area and cutting length, in which cuttings with short stems and large leaves had the lowest rooting percentage.     

Mist, substrate water potential and cutting water potential influence rooting of stem cuttings of loblolly pine

We investigated the influence of cutting water potential (Psicut) on rooting of juvenile hardwood (dormant) and softwood (succulent) stem cuttings of loblolly pine (Pinus taeda L.) propagated under varying substrate water potentials (Psisub) and volumes of mist application. Mist treatment and Psisub contributed to the Psicut of unrooted stem cuttings. When Psisub was held constant across mist treatments, mist treatment contributed strongly to Psicut. Substrate water potential affected rooting percentage when mist treatment was sub-optimal or excessive, otherwise mist treatment had a stronger effect than Psisub on rooting percentage. Cuttings rooted best when subjected to moderate cutting water potentials (-0.5 to -1.2 MPa) during the initial 4 or 5 weeks of the rooting period. Cuttings experiencing either severe water deficit or no water deficit rooted poorly. We conclude that the rooting environment should impose a moderate water stress on loblolly pine stem cuttings to achieve optimum rooting.     

The effects of propagation environment on the rooting of leafy cuttings of ash (Fraxinus excelsior L.), sycamore (Acer pseudoplatanus L.), and sweet chestnut (Castanea sativa Mill.)

The effect of propagation environment on the rooting of field collected leafy cuttings of ash (Fraxinus excelsior, sycamore (Acer pseudoplatanus) and sweet chestnut (Castanea sativa) was investigated in two experiments. In the first experiment, rooting of all three species in mist enclosed inside a polythene tent was greater than 50%, while rooting of ash cuttings was reduced from 63% in enclosed mist to only 16% in open mist. Rooting in open mist, enclosed mist, and contact polythene was studied in a second experiment. Sycamore cuttings rooted equally well in the two mist systems with an average rooting of 78%. In contrast cuttings of both ash and sweet chestnut rooted most under the enclosed mist system, at 64 and 46% respectively. Rooting of ash cuttings was again depressed in the open mist system where less than 30% of cuttings rooted. This reduction was related to an increase in the percentage of cuttings which remained alive without rooting, while showing proliferation of callus at the cutting base. The percentage of sweet chestnut cuttings which callused without rooting was also much greater in the open mist system than in enclosed mist or contact polythene.     

Clonal propagation of Pterocarpus santalinoides L'Hér. ex DC.: the effect of substrate,cutting type,genotype and auxin

Pterocarpus santalinoides is a multipurpose tree species, native to Africa and South America. However, excessive pruning for fodder is jeopardising its seed production leading to poor regeneration in the Sahel region. Efficient vegetative propagation techniques may overcome this concern. To address this issue, four experiments were conducted to determine the effects of substrate (Experiment 1), cutting type (Experiments 2 and 3), genotype (Experiment 4) and auxins (Experiments 1, 2, and 4) on rooting ability in a non-mist propagating unit in Mali. Among the four tested substrates, no significant differences were found in rooting parameters, including the percentage of rooted cuttings, the number of roots and secondary roots per rooted cutting, and the length of the longest root per rooted cutting. Semi-hardwood cuttings rooted significantly better than softwood cuttings with a higher percentage of rooted cuttings (31.7?±?6.5% vs. 9.2?±?2.7%), greater number of roots (8.2?±?4.8 vs 1.5?±?0.7), greater number of secondary roots (16.7?±?4.2 vs 4.6?±?1.8) and longer root length (17.8?±?12.0?cm vs 2.3?±?1.0?cm) per rooted cutting. In addition, one-node cuttings cut below the second and third nodes, respectively, had the highest rooting success (88% and 90%, respectively) followed by cuttings cut below the fourth node (68%) and the first node (62%). Significant differences in the percentage of rooted cuttings were found among 12 randomly selected genotypes with rooting varying from 2% to 75%.The results also showed that auxin application, especially IBA, had a significant effect on rooting success, the number of roots and secondary roots per rooted cutting. Single-node cuttings, and cuttings of 10?cm length with multiple softwood and semi-hardwood nodes, can be used with or without auxin treatment for successful clonal propagation of P. santalinoides. The results of the present study indicated that P. santalinoides is amenable to clonal propagation using low-cost propagators and sand-based rooting media.     

Physiological studies for tropical tree improvement and conservation. Factors affecting root initiation in cuttings of Triplochiton scleroxylon K. Schum.

Applying auxins to freshly cut basal ends of leafy single-node cuttings of Triplochiton scleroxylon, an important timber tree of West Africa, considerably enhanced rooting percentages. The optimal concentrations in 10 μl MeOH droplets of a 50 : 50 mixture of α-naphthalene acetic acid (NAA) and indole-3-butyric acid (IBA) ranged from 8–40 μg according to clone. Larger amounts, which tended to increase numbers of roots per rooted cutting, inhibited root production in some clones. When applied singly, IBA was more effective than NAA in most clones.Leafless cuttings rarely rooted even when treated with auxins. Rooting occurred following the retention of 5 cm² of leaf lamina, and was maximal, as judged by rooting percentages, with 50 cm². The inability of leafless cuttings to root was associated with the rapid depletion of all carbohydrates in stem tissues, while those in unshaded leafy cuttings tended to increase.Percentages of cuttings rooting increased when temperatures of propagating-beds were raised above 20°C, and 28°C was optimal for most clones, especially if treated with auxins. Cutting survival declined above 28°C, although up to 38°C surviving cuttings rooted equally well.     

Loblolly pine cutting morphological traits: Effects on rooting and field performance

Shoot cuttings were harvested fromfour-year-old, loblolly pine hedges in March andSeptember of 1987, and placed into a series offactorial combinations of cutting length, diameterclass, and the presence/absence of a terminal bud toassess effects on rooting and field performance.Average rooting in the March trial was 50 percent andonly 20 percent for the September trial; however, thebest treatment in March yielded 100 percent rooting.Terminal bud status did not appear to influencepercent rooting. Shorter cuttings (5.1 or 7.6 cm)with an average diameter of 2 or 3 mm tended to rootbetter and develop more roots. Field performance ofthe rooted cuttings through age five suggests that theoriginal cutting does not require a terminal bud, butthe best set of morphological traits differ dependingon bud status. Considering both rooting ability andfield growth with an original tip bud present, thebest cutting dimensions were 5.1 or 7.6 cm long and 2or 3 mm in diameter. Without a tip bud present,cutting dimensions were restricted to 7.6 or 10.2 cmlong and 3 mm in diameter. Number of main roots wasa weak predictor of tree height or dbh at age five.     

Vegetative propagation of Prunus africana: effects of rooting medium, auxin concentrations and leaf area

The region of West and Central Africa is endowed with high-value fruit trees and medicinal plants, which are currently traded locally as well as on regional and international markets. Unfortunately, they are all exploited from the wild and there has been little or no focussed effort to domesticate and cultivate them. Prunus africana is one of these important medicinal plant under domestication. A series of nursery experiments were conducted to assess the effects of rooting medium (sawdust, sand and a 50:50 mixture of sand and sawdust), auxin concentration (0, 50, 100, 150, and 200 μg IBA), and leaf area (0, 5, 10, 20, and 25 cm²) on rooting success of juvenile cuttings of P. africana. The percentage of cuttings rooted was significantly greater (P < 0.05) in sawdust (80%), than in sand alone (72%) or in mixture with sawdust (71%). Leaf area also significantly affected the percentage of rooting. Leafless cuttings did not root and were all dead by week 6, but in leafy cuttings rooting ability increased proportionally with leaf area up to 20 cm² (79%). Larger leaf cuttings (25 cm²) rooted at the same level as those of 20 cm². The cuttings with the largest leaves also had the greatest mean number of roots per cutting (14 roots cutting⁻¹), while those with the smallest (5 cm²) leaf area produced the fewest roots (5 roots cutting⁻¹). The application of auxin (IBA) promoted rooting (P < 0.05) up to an optimum application of 100–200 μg IBA per cutting, but 300 μg was supraoptimal. It can be concluded that P. africana is amenable to vegetative propagation. This revised version was published online in June 2006 with corrections to the Cover Date.     

Influence of irradiance on water relations and carbon flux during rooting of Shorea leprosula leafy stem cuttings

Single-node leafy stem cuttings of Shorea leprosula Miq. were subjected to a high, intermediate or low irradiance treatment for 16 weeks in an enclosed mist propagation system. Before rooting, maximum photosynthesis of the cuttings occurred at an irradiance of 400 micro mol m(-2) s(-1). Although none of the irradiance treatments affected the number of roots produced per cutting, the numbers of cuttings that formed roots were 50 and 30% in the high irradiance (diurnal range of 0-658 micro mol m(-2) s(-1)) and low irradiance (diurnal range of 0-98 micro mol m(-2) s(-1)) treatments, respectively, compared with 62% in the intermediate irradiance treatment (diurnal range of 0-360 micro mol m(-2) s(-1)). Low rooting frequency of cuttings in the high irradiance treatment was associated with water deficits (maximum leaf-to-air vapor pressure deficit (VPD) = 3.6 kPa), whereas cuttings in the low irradiance treatment had a low rooting frequency because they were below the light compensation point most of the time. In the intermediate irradiance treatment, cuttings withstood a daily maximum VPD of 1-2 kPa and recovered overnight from the previous day's deficit, as indicated by higher relative water content (RWC) and stomatal conductance (g(s)) in the morning than in the previous afternoon and evening. Higher RWC and g(s) of cuttings in all treatments on Days 14 and 21 compared with Day 8 probably indicated recovery from water deficit following severance and insertion of the cuttings in rooting medium. There were negative relationships between stem volume of cuttings and both number of cuttings that rooted and number of roots per cutting.     

Root initiation of Shorea macrophylla cuttings: Effects of node position,growth regulators and misting regime

Single-node leafy cuttings from 8- and 15-month-old seedlings of the large Bornean Dipterocarp Shorea macrophylla (Illipe nut) rooted easily under continuous mist, both with and without the application of auxins. Callus production was greatest in the untreated cuttings. Rate of rooting was enhaced by 1200 ppm and 3600 ppm IBA, but the overall level of rooting after 61 days was unaffected by auxin treatment. In a second experiment, 3600 ppm IBA was found to be more effective than 3600 ppm NAA and mixtures of 1800 ppm NAA + 1800 ppm IBA. Mortality of cuttings was greatest with IBA especially at 10800 ppm. Cuttings from the second node below the apex rooted best, with rooting ability of those from nodes 3, 4 and 5 being progressively worse, and mortalities rising with distance from the apex. Cuttings from the uppermost node, which included the developing apex, had the lowest rooting ability. When continuous misting was replaced with misting for alternate hours, rooting was still good, but the absence of misting overnight resulted in much increased cutting mortality and, subsequently, in decreased rooting. It is suggested that Shorea macrophylla could be domesticated for fruit or timber production by the propagation of superior clones.     

Effect of position,size of cuttings and environmental factors on adventitious rooting in neem (Azadirachta indica A. Juss)

The effect of adventitious rooting of proximal and distal position of cuttings of neem of different length and diameter (with 1000 ppm IBA treatment) was studied. Cuttings from the distal end rooted better than the proximal end, probably due to higher endogenous auxin level. Cuttings of 25 cm length and 0.5 cm diameter from the distal end gave 100% rooting. The percentage of rooting decreased significantly when the length of the cutting was reduced, and no rooting was observed in 5 cm long cuttings irrespective of the position, suggesting a sub-optimal level of endogenous auxin and other root-inducing factors in small cuttings. Low radiation may have had a significant role in the induction of rooting.     

Distinct effects of auxin and light on adventitious root development in Eucalyptus saligna and Eucalyptus globulus

Adventitious rooting is essential for vegetative propagation of woody species. We studied the effects of auxin and light on the development of adventitious roots in cuttings obtained from seedlings of Eucalyptus saligna Smith and E. globulus Labill in an attempt to characterize the adventitious rooting process and identify factors controlling rhizogenesis. Root development was scored as rooting percentage, root density (roots per rooted cutting), mean rooting time and root length. In both species, rooting time was reduced in the presence of auxin. Cuttings from 2-month-old E. saligna seedlings were responsive to lower auxin concentrations than comparable cuttings from E. globulus seedlings. Cuttings from 3-month-old E. saligna seedlings rooted promptly and rooting was not significantly affected by light conditions. In contrast, rooting of cuttings from 3-month-old E. globulus seedlings exhibited recalcitrant behavior and no roots were formed if illuminated during the root formation phase. Effective root regeneration of E. globulus cuttings was obtained by a 4-day exposure to 10 mg l(-1) IBA and culture in darkness during the root formation step. Loss of rooting capacity with seedling age was more pronounced in E. globulus than in E. saligna. The possibility of switching adventitious rooting off and on by manipulating light regime and exogenous auxin supply in E. globulus, and the constitutive nature of rooting in E. saligna may provide useful models for examining the rooting process at the biochemical and molecular levels in Eucalyptus.     

Effects of IBA and NAA treatments on rooting Douglas-fir stem cuttings

The effectiveness of six IBA and fourNAA concentrations, four combinations of IBA and NAAconcentrations, and control were tested for theirability to enhance rooting frequency (%) ofDouglas-fir cuttings. Two IBA and one NAA treatmentswere also compared to the control for quality of rootsystem. Between 1984 and 1998, six independentstudies were conducted in mist or fog environmentswith the same 11 or 14 clones. Auxin concentrationstested ranged from 0 to 123 mM IBA and 0 to 10 mM NAA. Auxin, clone, and auxin by clone effects weresignificant in every study, although individual cloneanalyses showed only two clones to differsignificantly for auxin. All auxin treatments but the10 uM NAA treatment induced significantly greaterrooting percentage than the control, but no singleauxin, auxin concentration or combination of auxinswas clearly superior in every study. The 10 mM NAAconcentration was the only concentration tested thatreduced rooting percentage to less than the control. Both NAA and IBA appeared to have broad ranges ofroot-enhancing activity. However, within theeffective range of IBA evaluated, 24.6 mM produced thegreatest rooting percentage in four of five studiestesting IBA. NAA solutions with concentrationsbetween 2.5 and 7.4 mM NAA generally resulted insimilar rooting success. Rooting responses toincreased IBA and NAA were both nonlinear; rootingdecreased with both too little and too much auxin. Combinations of IBA and NAA in the same solution didnot increase rooting percentage above what wasachieved with one auxin. For root system quality,auxin treated cuttings in one study, had significantlybetter root systems than control, but there was nodifference in the other study in which root qualitywas estimated.     

Vegetative propagation studies of gum arabic trees. 1. Propagation of Acacia senegal (L.) Willd. using lignified cuttings of small diameter with eight nodes

In order to study and monitor rates of rooting, callusing and survival, small diameter stem cuttings (less than 0.4 cm) with eight nodes (12–14 cm long) were taken from trees in the field at different times of the year in tests with small batches of cuttings. Among the four tested substrates, well drained crushed basalt powder placed on a bed of gravel was the best rooting medium. Rooting was generally poor or even non-existent with this type of cutting, but the presence of leaves both promoted rooting and significantly (using Chi square test) improved survival of the cutting. Four leaves were sufficient to assure the necessary metabolic functions. Only stem cuttings collected during the rainy season gave roots and then, only when hormonal treatments were applied to the cuttings. 8%-IBA resulted in significantly better rooting than did 2%-IBA, 0.2%-NAA and 1%-IAA. With 8%-IBA, the rate of rooting varied between 50 and 70% for leafy cuttings collected in the rainy season. Hormonal treatments had a significant effect on the survival rate of the stem cuttings during the two months observation period. Further investigations are being conducted with different types of cuttings.     

Variation in Shoot Anatomy and Rooting Behaviour of Stem Cuttings in Relation to Age of Donor Plants in Teak (Tectona grandis Linn. f.)

Shoot anatomical features viz., number of vessel elements, width and length of vessel and fibre elements were studied in relation to juvenility/maturity of teak (Tectona grandis Linn. f.). The findings show significant differences in these features, which indicates that variation in shoot anatomy can be used as a reliable indicator of juvenility/maturity in teak. The effect of age of donor plants and application of auxins on adventitious root formation in single noded leafy stem cuttings of teak was also investigated. Aging of donor trees suppressed rooting and sprouting of cuttings, but increased callus formation at the base of cuttings. Per cent rooting and per cent sprouting in cuttings decreased as age of donor plants increased from 2-months to 15-years and up to 30-years. IBA treatment promoted per cent rooting as well as per cent sprouting, NAA promoted only rooting and it suppressed sprouting. The effect of auxin treatment on rooting and sprouting of teak stem cuttings varied with the age of donor plants. Auxin and its concentration, which suppressed rooting and sprouting in cuttings of younger donor plants, actually promoted rooting when cuttings were taken from more mature donor plants. It appears that the auxin requirement for causing and promoting rooting in teak cuttings increased with increasing age of donor plants. The higher auxin requirement for causing and promoting rooting in cuttings of older trees may be due to a decrease in the content on endogenous auxins or decreased sensitivity of aging tissues to rooting promoters and /or accumulation of inhibitory substances which inhibit rooting.     

Effect of branch position and auxin treatment on clonal propagation of <Emphasis Type="Italic">Tectona grandis</Emphasis> Linn. f.

The main objective of our clonal propagation program is the production of high quality timber and faster tree growth. Teak (Tectona grandis Linn. f.) is an important plantation species in the tropics but the demand of teak timber is increasing globally. Teak planting stock is still produced from seeds of unselected elite genotypes which may lead to poor stand establishment. The number of seeds per fruit and their germination ability are also variable and limited by several factors. Therefore an alternative method i.e., clonal propagation is required for mass multiplication of elite trees. It is an established fact that the clonal propagation or adventitious root formation in cuttings is markedly affected by several external and internal factors. Considering these, an experiment was conducted on leafy soft wood shoot cuttings of 3-year-old hedged teak stock plants grown in a hedge garden to study the effects of branch position and auxin treatment on adventitious root formation. A factorial completely randomized design was used for experimentation. Coppice shoots were collected from basal, middle and upper positions of the hedge garden; and mono-nodal leafy cuttings were prepared. These cuttings were treated with different concentrations of IBA and NAA; and were cultured in a mist chamber for rooting where the relative humidity was maintained at 85 ± 2% with maximum and minimum day-night temperature at 32 ± 1°C and 26 ± 1°C respectively. After 45 days the cuttings were removed from the rooting medium and observations were made. It was observed that the rooting parameters viz., percent rooting and percent sprouting, mean number of leaves, mean number of shoots and length, and mean number of roots and length per cutting were significantly influenced by the branch position and auxin treatment. Treatment with 4000 ppm IBA increased percent rooting and percent sprouting whereas NAA suppressed it. Treatment with 4000 ppm IBA also increased the mean number of leaves and shoots, and the length, and the mean number of roots per cutting. The highest mean number of roots and length were observed in cuttings taken from the branch emerging at the upper position followed by branches of middle and lower position. Cuttings of branches at a middle position showed the highest values of percent rooting, percent sprouting, mean number of leaves and shoots and mean shoot length per cutting. Furthermore, the interactive effect of branch position and auxin treatment on rooting and sprouting response was also found to be significant. Overall, the findings of this investigation suggest that middle branch position in hedge plants and 4000 ppm IBA can be made to induce maximum rooting and to produce high quality planting stock material for clonal forestry program of teak.     

Improving regeneration of mahogany: techniques for vegetative propagation of four African mahogany species using leafy stem cuttings

Regeneration to ensure sustainable production and conservation of mahogany species globally is considered very important to foresters, investors in plantation, conservationists and timber industries worldwide. Natural regeneration of the mahoganies has been found to be far less than the rate of exploitation hence strong efforts are being made to develop other methods to regenerate mahogany seedlings to augment the low natural replacement and to ensure sustainability. This study was commissioned to investigate the effect of rooting media (river-sand, top soil and a mix of the two (50:50 v/v) on the rooting ability of four mahogany species (Khaya grandifoliola, K. ivorensis, Entandrophragma angolense and E. utile) using non-mist propagators. We investigated the effects of the source of stem cutting within a shoot (top, middle and basal position) on the rooting ability of stem cuttings from the four species in river-sand. Roots per cutting, longest root length and rooting percentage differed significantly among species in all three rooting media. Rooting ability was greatest in K. grandifoliola, which exhibited the highest average rooting percentage (73 %), longest average single root (9.9 mm) and the most roots per cutting (4.9). Rooting percentage was higher in the Khaya species than in the Entandrophragma species in all three rooting media. The mixed medium had the highest rooting percentage and the highest number of roots per rooted cutting in the two Khaya species, while the topsoil media had the best rooting percentage in the Entandrophragma species. Rooting of the two Khaya species can be maximized using a mixture of river-sand and topsoil. Cutting position within a shoot had significant impact on rooting in all four species with rooting percentage being best from middle positions in all four species. However, length of longest root and the number of roots per rooted cutting varied between the middle and basal portions. The study provides useful information for vegetative propagation of leafy stem cutting of the four African mahogany species, which could contribute to regeneration and conservation of these important timber species in the tropics.     

Influence of nitrogen,photoperiod, cutting type,and clone on root and shoot development of rooted stem cuttings of sweetgum

This study was designed to test the effects of nitrogen fertilization, photoperiod, cutting type, and clone on root and shoot development of stem cuttings of sweetgum (Liquidambar styraciflua). Differences in the growth of roots and shoots were observed as a result of weekly applications of varying levels of nitrogen (N) fertilization (0, 25, 50, 100, or 200 mg N/liter). As the concentration of N increased, new-shoot dry weight increased, but root dry weight decreased at rates greater than 50 mg N/liter. The percentage of rooted cuttings surviving also decreased as N concentrations increased past 50 mg N/liter. A night-interruption light treatment did not significantly affect survival percentages or the amount of root and shoot growth. Across all treatments, only 46% of all cuttings produced new-shoot growth within a 15-week period following rooting. Cutting type (terminal or sub-terminal) affected rooted cutting development. A higher percentage of terminal cuttings survived and were deemed plantable. In contrast, sub-terminal cuttings produced more shoot and root growth. Differences among clones were observed for all traits measured.Manipulating N fertilization, in conjunction with using clones that propagate well, has the potential of producing rooted cuttings of a size adequate for plantation establishment. However, higher percentages of cuttings that produce new shoot growth shortly after rooting must be achieved.     

Rooting of juvenile succulent cuttings from haif‐sib families of Picea abies

Leader shoots from juvenile succulent Norway spruce seedlings were used as cuttings 11 weeks after sowing. The seedlings were grown for 6 additional weeks and then apically dominant and lateral shoots were also used as cuttings. These three cutting categories, leaders, dominants and laterals, rooted 99.4, 99.0 and 97.5 % respectively and performed differently with respect to rooting development, number of roots per cutting and response to IBA and PIBA treatments (synthetic auxins). A large individual variation in number of roots per cutting, which auxin treatments did not reduce, was present within each cutting categoty. Laterals from the three different families included in the study showed a different variation than did leaders and dominants. Generally, the juvenile succulent cuttings were easy to root. Seedlings grown at a rather high light intensity (62 W/m²) had the potential to give good rooting even without hormonal treatments.     

Key roles of leaves, stockplant age, and auxin concentration in vegetative propagation of two African mahoganies: Khaya anthotheca Welw. and Khaya ivorensis A. Chev

Leaf area, IBA concentration and age of stockplants were all found to be important factors for successful rooting for vegetative propagation using single-node cuttings of the two main African mahogany species: Khaya anthotheca and K. ivorensis. Cuttings with leaf area of 30–50 cm² had the best rooting percentage and cuttings with about 30 cm² had the most number of roots per cutting in K. anthotheca. Khaya ivorensis, cuttings with 10–30 cm² leaf area had the highest rooting percentage. Cuttings collected from 1-year-old stockplants recorded the highest rooting percentage and largest number of roots per cutting. Cuttings from 3-year-old stockplant of the same seeds sources had the lowest rooting suggesting aging negatively impacted rooting ability. The effect of auxin concentration, on rootability was examined with cuttings of K. anthotheca. An IBA concentration of 0.8% was the best exogenous auxin concentration for percentage rooting, number of roots per cutting and the length of the longest root per cutting.