and subterminal cuttings for propagating ‘Coy’ alder-leaf mountain mahogany. The purpose of this study was to develop an efficient protocol to propagate ‘Coy’ alder-leaf mountain mahogany successfully via stem cuttings. We evaluated wounding methods
Propagation of Corylus avellana stem cuttings may be limited by either root initiation or bud abscission. We divided juvenile shoots of 3 varieties growing in layering beds in mid-July into 4 or 5 3-node cuttings with leaves at the upper two nodes, except that terminal cuttings had one expanded leaf. Cuttings were treated with 5 mM IBA in 50% EtOH, a mixture of A. rhizogenes strains A7 + 22 or left untreated. IBA and bacteria stimulated rooting of cuttings from all shoot positions. Rooting of the terminal cuttings (<50%) was less than that of the sub-terminal cuttings (>80%). Bud retention was <50% on terminal cuttings, nearly 100% on sub-terminal cuttings. Using juvenile stock plants of various varieties, sub-terminal cuttings treated with Agrobacterium or 5 mM IBA may yield 70-90% cuttings with both roots and buds, Agravitropic roots, characteristic of genetic transformation, were observed on Agrobacterium-treated cuttings. Dot blots probed for TL-DNA were negative, however.
Propagation of Corylus avellana stem cuttings may be limited by either root initiation or bud abscission. We divided juvenile shoots of 3 varieties growing in layering beds in mid-July into 4 or 5 3-node cuttings with leaves at the upper two nodes, except that terminal cuttings had one expanded leaf. Cuttings were treated with 5 mM IBA in 50% EtOH, a mixture of A. rhizogenes strains A7 + 22 or left untreated. IBA and bacteria stimulated rooting of cuttings from all shoot positions. Rooting of the terminal cuttings (<50%) was less than that of the sub-terminal cuttings (>80%). Bud retention was <50% on terminal cuttings, nearly 100% on sub-terminal cuttings. Using juvenile stock plants of various varieties, sub-terminal cuttings treated with Agrobacterium or 5 mM IBA may yield 70-90% cuttings with both roots and buds, Agravitropic roots, characteristic of genetic transformation, were observed on Agrobacterium-treated cuttings. Dot blots probed for TL-DNA were negative, however.
Rooting experiments have been conducted with a pink flowered redbud (Cercis canadensis) in anticipation of its release to the nursery trade. Cuttings taken in May, June and August were treated with NAA or IBA at 0, 1,000, 10,000 and 20,000 ppm and rooted under mist. Rooting percentages as high as 94% have been obtained by using IBA at 20,000 ppm on cuttings taken 3 weeks after growth began. Fifty percent of cuttings taken in June rooted when treated with the highest IBA rates. Cuttings taken later than June did not root. In a separate test, terminal (semi-hardwood) cuttings making active growth were compared to sub-terminal (hardwood) cuttings. IBA and NAA application at 20,000 ppm resulted in 57% rooting for terminal cuttings while producing only 14% rooting for sub-terminal cuttings. Data will be presented on the comparison of the rooting ability of this clone as compared to seedling trees.
Endodormant `Hawthorne' peach shoots were collected in early autumn and sectioned into long (30-40 cm), short terminal (10-15 cm), or short sub-terminal (IO-15 cm) cuttings. Dormancy-breaking treatments included application of hydrogen cyanamide H2C N2), thiourea (TU), sodium azide (NaN3) or gibberellic acid (GA3) solutions; atmospheric methyl jasmonate (MJ); hot water (50C for 1-2 h); or chilling (3.5C for 1-4 weeks). During forcing at 24C, & budbreak of all bud types on long cuttings was very low. On short cuttings, % apical budbreak was greater than % lateral vegetative budbreak, with almost no floral budbreak. Relative to H2CN2-induced lateral vegetative budbreak, budbreak induced by MJ, TIJ, GA,, and NaN3 was 17, 34, 50, and 92%, respectively. Relative apical budbreak was 0, 95, 53, and 63%, respectively. Addition of aminooxyacetic acid (AOA) to the beaker solution (in which cuttings were forced) induced apical, but not lateral, budbreak by itself; AOA synergistically improved H2CN2-induced budbreak by 23%. Latetal budbreak on short sub-terminal cuttings treated with hot water (1 h) was similar to that of H2CN2 treatment. Chilling increased apical budbreak to 100% as duration increased to 3 weeks, lateral vegetative budbreak only reached 43% after 4 weeks of treatment. The use of different bud and cutting types as model systems to study the differential regulation of dormancy by various treatments will be discussed.
Factors affecting the greenhouse propagation of firebush (Hamelia patens) by leafy stem cuttings during winter were studied. Without bottom heat (BH), mid-day rooting medium temperature was 22 ± 3 C. About half of the auxin-treated cuttings without BH rooted. Maintaining the rooting medium at 29-39 C increased rooting for auxin-treated cuttings to 96-100% and increased root length and visual rating scores several-fold. Rooting percentage, root length, and visual ratings were consistently high in perlite and low in peat. Stem-tip cuttings and sub-terminal stem segment cuttings with basal stem diameters of 3-5 mm rooted slightly better than stem segment cuttings with basal diameters of 6-8 mm. Stem-tip cuttings not treated with auxin but with BH had rooting percentages of 81-86%. Treatment of stem-tip cuttings with auxin generally yielded 90% rooting or above. Despite this, plants grown from auxin-treated cuttings were indistinguishable from plants grown from non-treated cuttings 2 months after the rooting period. Of the variables studied, BH had the most dramatic effect on rooting of firebush cuttings during winter months.
Abstract
Dormant hardwood stem cuttings of Fraser Fir [Abies fraseri (Pursh) Poir.] were severed from upper and lower tree crowns and artificially chilled at 4°C for 0, 4, or 8 weeks to achieve a partial break in rest. Following chilling, the resulting semi-dormant cuttings were treated with 0, 1500, 3000, or 4500 ppm IBA, and rooted for 135 days using a heated medium in a cool greenhouse. Rooted cuttings were evaluated, potted, and rechilled for 11, 7, or 3 weeks so that all cuttings were chilled a total of 11 weeks. Vegetative growth then was evaluated after a 12-week growing period. Cuttings initially chilled 4 weeks rooted in highest percentages, regardless of crown position, and exhibited little or no bud activity. Subsequent expansion of terminal and subterminal buds was greatest for cuttings initially chilled 0 or 4 weeks. Superior overall responses were achieved with upper-crown cuttings chilled 4 weeks and then treated with 4500 ppm IBA, or lower-crown cuttings dipped in 3000 ppm IBA after 4 weeks of chilling. The separation of rooting and budbreak apparently produced rooted cuttings comparable in size to 2-year-old plants grown from traditional hardwood cuttings. Chemical name used: 1H-indole-3-butanoic acid (IBA).
Bougainvillea glabra is a tropical species with reportedly difficulty to propagate. Previous research has shown the importance of talc-based rooting hormones when propagating Bougainvillea, yet little has been published on the efficacy of liquid-based formulations. Therefore, our objective was to determine the optimum concentration of indolebutyric acid potassium salt (KIBA) needed to effectively root semi-hardwood stem cuttings of Bougainvillea `California Gold' and `Helen Johnson'. Sub-terminal cuttings measuring 6.5 cm were harvested from stock plants of Bougainvillea on 3-week intervals from 6 June to 8 Aug. and repeated 6 Sept. to 8 Nov. 2005. Cuttings were dipped 0.5 cm in a solution of 0, 1500, 3000, or 6000 mg·L-1 KIBA or in a 1500-mg·L-1 solution containing indolebutyric acid (IBA) 1%: napthaleneacetic acid (NAA) 0.5% and propagated under mist. Cuttings were evaluated for percent survival, rooting quality (1 = poor; 5 = best), and number of primary and lateral roots 5 weeks after planting (WAP). Differences in `California Gold' for percent survival, average rank, and number of roots were determined not significant at P ≤ 0.05. However, application of rooting hormone to `Helen Johnson' increased rooting quality, number of primary roots, and number of lateral roots by up to 24%, 53%, and 50%, respectively. Results indicated rooting performance was generally improved with application of KIBA; therefore, cuttings of Bougainvillea may benefit from a 1500-mg·L-1 solution. KIBA was also found to be as effective as the industry standard liquid formulation. Growers will have to consider the availability and cost of KIBA when propagating Bougainvillea.
serving as a block) of confederate rose under evaluation in a breeding program and growing in field rows at the USDA-ARS Thad Cochran Southern Horticultural Laboratory (lat. 30°50′26″N, long. 89°32′46″W; USDA hardiness zone 8b). Subterminal cuttings were
unaltered ( Fig. 1A ). After that, they were pruned in Winter (Feb) 2021 and allowed to grow for another full season ( Fig. 1B ). Pruning involved heading back the primary growth axis (trunk) to a height of 1 m and cutting back axillary shoots to a 10- to 15