applications. Deciduous shrubs, like the four native species identified, are generally propagated using softwood stem cuttings taken sometime during spring to summer. However, research has shown that for some species, softwood cutting success is improved when
Julia A. Cartabiano and Jessica D. Lubell
James A. Schrader and William R. Graves
Alnus maritima (Marsh.) Nutt. (seaside alder) is a rare, woody-plant species with potential for use in managed landscapes. Information on the propagation and production of this species is not available. Our objective was to evaluate the use of softwood cuttings to propagate A. maritima, with emphasis on how indole-3-butyric acid (IBA), plant provenance, and time of collection affect cutting survival, rooting percentage, the number of roots produced, and their length. Propagation trials were conducted with cuttings from seven trees on the Delmarva Peninsula (Eastern Shore of Maryland and southern Delaware) and seven trees in Oklahoma. Cuttings from mature plants in both provenances were collected on 14 June and 23 Aug. 1998; wounded; treated with IBA at 0, 1, or 8 g·kg-1; and placed under intermittent mist in a greenhouse for 9 weeks. Use of IBA at 8 g·kg-1 caused a greater rooting percentage (68%), root count (7.2), and root length (39.2 mm) than did the other IBA rates when applied to cuttings from Oklahoma in June, but IBA had little effect on cuttings from the Delmarva Peninsula. Across IBA treatments, rooting of cuttings from Oklahoma (55% in June and 12% in August) was greater than the rooting of cuttings from Delmarva (27% in June and 3% in August). Cuttings from Oklahoma had greater survival, callus development, root length, and root count than did cuttings from the Delmarva Peninsula during June and August trials. Averaged over IBA treatments and provenances, cuttings collected on 14 June rooted more frequently (41%) than did cuttings collected 23 Aug. (8%). We conclude that softwood cuttings from mature plants are an effective way to multiply clones of A. maritima, particularly when cuttings are collected early in the season and treated with IBA at 8 g·kg-1.
Silvia R. Marino, Jeffrey G. Williamson, James W. Olmstead, and Philip F. Harmon
Blueberries have traditionally been propagated by softwood, semihardwood, or hardwood cuttings. Although plants can be produced at low cost, cuttings from some cultivars have low or very low rooting percentages, particularly when propagated from
Muhammad Hatta, Caula A. Beyl, and Stephen Garton
Trees of jujube (Ziziphus jujuba), particularly older ones, root with great difficulty. A greenhouse experiment was conducted to assess the effects of two strains of Agrobacterium rhizogenes (A4 and TR105) on softwood cuttings from two trees—a tree 10 years old not currently bearing flowers, which we called “juvenile” because it still exhibited many juvenile characteristics; and a tree ≈70 years old containing many flower buds, which we called “mature”. The cuttings were collected on 11 May 1994 and trimmed to 7.5 cm. Both strain and source of cutting influenced inoculation success—TR105 was more responsive to A. rhizogenes than was A4 and the “juvenile” cuttings more responsive than “mature” cuttings. Strain TR105 was very effective in increasing rooting percentages and root number. “Juvenile” cuttings had better rooting percentages, greater root number, and greater root length than did “mature” cuttings. Agrobacterium rhizogenes exhibits great potential for rooting other difficult woody ornamental or fruit tree species as well.
James A. Schrader and William R. Graves
Alnus maritima [Marsh.] Nutt. (seaside alder) is a rare, North American species with strong potential for use in managed landscapes. Information on the propagation and production of this species is not available. Our objective was to evaluate the potential for using softwood cuttings to propagate A. maritima, with emphasis on how IBA and plant provenance affect rooting success. Propagation trials were conducted with cuttings from seven trees native to the Delmarva Peninsula and seven trees from Oklahoma. Cuttings from both provenances were collected on 14 June and 23 Aug. Cuttings were wounded; treated with 0, 1, or 8 g/kg IBA; and placed under intermittent mist in a greenhouse for 9 weeks. The highest percentage of rooting (67.9) was achieved for the Oklahoma provenance by using 8 g/kg IBA in June. Across IBA treatments, rooting of cuttings from Oklahoma, 54.8% (June) and 12.4% (August), was higher than rooting of cuttings from Delmarva, 27.1% (June) and 3.1% (August). IBA at 8 g/kg caused a higher rooting percentage than the other IBA rates at both times of the season. More cuttings collected 14 June rooted (41%) than those collected 23 Aug. (7.7%) over IBA treatments. Another experiment involved cuttings from one juvenile, greenhouse-grown seedling from Oklahoma that showed 100% rooting with both 1 and 8 g/kg IBA. Shoot growth appeared more vigorous on rooted cuttings from these juvenile stems than on plants derived by rooting mature tissue collected in nature. We conclude that using softwood cuttings can be an effective way to multiply clones of A. maritima, particularly when stock plants are juvenile and cuttings are treated with IBA.
Guochen Yang and Paul E. Read
A forcing solution containing 200 mg 8-hydroxyquinoline citrate per liter and 2% sucrose has been demonstrated to extend the season for obtaining softwood growth suitable for use as explants in micropropagation (Yang & Read 1989). Forcing dormant woody stems in the off-season in this fashion also enhances the macropropagation of woody plant species by providing softwood outgrowth that can be rooted as softwood cuttings. GA3, IBA, IAA and NAA were incorporated into softwood growth which was later used as cuttings for rooting by adding plant growth regulators at various concentrations to the forcing solution. GA3 incorporated into the forcing solution hastened bud break, increased shoot elongation, but inhibited rooting of softwood cuttings taken from stems forced in this manner. IBA, IAA and NAA in the forcing solution exhibited typical auxin effects on rooting of cuttings by increasing root number per cutting and root elongation. In order to expedite macropropagation of woody plants, GA3 and IBA were added SEQUENTIALLY to the forcing solution. Addition of IBA to fresh forcing solution following initial use of GA3 in the forcing solution counteracted the negative effects of GA3 and stimulated rooting. This protocol is proposed as a method to assist propagation in rooting difficult species by softwood cuttings in the off-season.
Paula M. Pijut and Melanie J. Moore
Juglans cinerea L. (butternut) is a hardwood species valued for its wood and edible nuts. Information on the vegetative propagation of this species is currently unavailable. Our objective was to determine the conditions necessary for successful stem-cutting propagation of butternut. In 1999 and 2000, 10 trees (each year) were randomly selected from a 5- and 6-year-old butternut plantation located in Rosemount, Minn. Hardwood stem cuttings were collected in March, April, and May. Softwood cuttings were collected in June and July. K-IBA at 0, 29, or 62 mm in water and IBA at 0, 34, or 74 mm in 70% ethanol were tested for root induction on cuttings. The basal end of cuttings were dipped in a treatment solution for 10 to 15 seconds, potted in a peat: perlite mixture, and placed in a mist bed for 5 to 8 weeks. Rooted cuttings were gradually hardened off from the mist bed, allowed to initiate new growth, over-wintered in a controlled cold-storage environment, and then outplanted to the field. For hardwood cuttings, rooting was greatest for those taken in mid-May (branches flushed out), 22% with 62 mm K-IBA and 28% with 74 mm IBA. Softwood cuttings rooted best when taken in June (current season's first flush of new growth or softwood growth 40 cm or greater) and treated with 62 mm K-IBA (77%) or 74 mm IBA (88%). For 1999, 31 out of 51 rooted softwood cuttings (60.8%) survived overwintering in cold storage and acclimatization to the field. For 2000, 173 out of 186 rooted softwood cuttings (93%) survived overwintering and acclimatization to the field. Chemical names used: indole-3-butyric acid-potassium salt (K-IBA); indole-3-butyric acid (IBA).
Sharon Morrison, John M. Smagula, and Walter Litten
For accelerating the filling in of bare areas in native lowbush blueberry fields or converting new areas to production, micropropagated plantlets rooted after three subcultures outperformed seedlings and rooted softwood cuttings. After 2 years of field growth, they averaged 20.3 rhizomes each of average dry weight 3.5 g, as compared with 5.7 rhizomes of average dry weight 1.1 g for rooted softwood cuttings. After 1 year of field growth, seedlings produced on average 3.3 vs. 0.4 rhizomes from micropropagated plants that had not been subcultured and 0.3 rhizomes from stem cuttings. Apparently, subculturing on cytokinin-rich media induces the juvenile branching characteristic that provides micropropagated plants with the desirable morphologies and growth habits of seedlings. These characteristics favor rhizome production while the benefits of asexual reproduction are retained. The advantage in rhizome production of micropropagation over stem cuttings varied among clones.
Hatice Gulen, Yasar Erbil, and Atilla Eris
A stock plant etiolation treatment was tested to improve rooting of the important cherry rootstock Gisela-5. To create the etiolation effect, at the beginning of the growing season, banding (blanching) was initiated on stock plants by placing black plastic tape at the base of new shoots for 6 or 10 weeks. Cuttings were excised so that the banded area was at the cutting base. IBA was applied at two concentrations (5 and 10 mm) to the cutting base following wounding and cuttings were placed in perlite (100%) rooting medium under mist. The rooting percentage, number of roots per cutting and root length were measured 4 weeks after planting. Banding and duration significantly stimulated rooting of leafy softwood cuttings. The highest rooting percentage (80.0%) was obtained on cuttings banded for 6 weeks and treated with 5 mm IBA.
Brian K. Maynard and Nina L. Bassuk
Effects of stockplant etiolation, stem banding, exogenous auxin, and catechol on the rooting response of softwood cuttings of paperbark maple (Acer griseum Pax.) were studied. Etiolated cuttings rooted better than light-grown cuttings, while stem banding did not affect rooting percentage (light-grown, 10%; light-grown + banding, 18%; etiolated, 41%; etiolated + banding, 37%). IBA did not promote, but catechol inhibited rooting (control, 31%; IBA, 37%; catechol, 17%; IBA + catechol, 21%). Root number was increased by IBA and unaffected by catechol. The distance from the cutting base to the first emerged root was measured as an indication of auxin toxicity. IBA interacted with etiolation and stem banding to increase this distance, which was greater in catechol-treated cuttings. Chemical names used: 1,2-benzenedio1 (catechol); 1H-indole-3-butanoic acid (IBA).