To improve the success of vegetative propagation of Sciadopitys verticillata, stem cuttings were subjected to three treatments designed to minimize the accumulation of a latex-like sap at the cut ends of stems. A 24-hour soak in water before a hormone dip significantly enhanced rooting success and root mass. The water soak pretreatment was more beneficial to hardwood cuttings compared with softwood cuttings. Cuttings from shade-grown source trees showed the highest rooting success, but source tree age, height, and place of origin were not important factors. The water-insoluble latex-like sap had strong antibacterial activity against 3 of 11 bacterial species tested, but activity was not related to bacterial Gram reaction or the bacterial natural environment. In contrast, pine resins and latexes from selected angiosperms showed no antibacterial activity. The antibacterial component of the Sciadopitys latex-like sap was heat stable and therefore probably not protein based.
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David I. Yates, Brandi L. Earp, Foster Levy, and Elaine S. Walker
Anjana R. Sharma, Robert N. Trigiano, Willard T. Witte, and Otto J. Schwarz
Cultivars of flowering dogwood (Cornus florida L.) are commercially propagated by vegetative methods such as rooting cuttings or grafting. The results of these methods can be unpredictable. A reliable method of producing dogwoods through tissue culture would be very useful to rapidly produce many copies of important genotypes with horticulturally important characters such as resistance to diseases. One of the primary difficulties of propagating dogwoods (seedlings only) by axillary bud multiplication has been the low rooting efficiency of the microshoots. Various treatments were tried in order to enhance rooting. Eighty-three percent of microshoots harvested between 5 and 7 weeks and treated continuously with 4.9 micromolar IBA rooted after 4 weeks, whereas <20% of microshoots harvested before 5 weeks and after 7 weeks rooted after 4 weeks of continuous exposure to IBA. Differences were also observed in rooting potentials of microshoots that had reddish brown stems rooting at a higher frequency compared to those that had green stems. We hope to translate this method to the propagation of cultivars and potential new releases.
Allison H. Justice, James E. Faust, and Julia L. Kerrigan
Shoot tip cuttings are a common means of asexual propagation of ornamental plants. After a cutting is removed from the stock plant, it must form adventitious roots to become a new plant. Adventitious root formation is a complex process regulated by
Andrew R. King, Michael A. Arnold, Douglas F. Welsh, and W. Todd Watson
heritable genetic improvement in this species ( Pezeshki and DeLaune, 1994 ). Relatively high percentages of successful rooting have been reported for Taxodium supporting the practice of commercially propagating baldcypress by cuttings. Rooting percentages
Ana Fita, Belén Picó, Antonio J. Monforte, and Fernando Nuez
The root system plays a very important role in plant development. A root system that is strong, healthy, and has an adequate architecture for the environment in which it develops provides numerous benefits to the plant, such as a greater capacity
Jen Colcol Marzu, Elizabeth Straley, and Michael J. Havey
Pink root [PR, caused by Phoma terrestris (Pt), synonym Pyrenochaeta terrestris ] is a major soil-borne disease of onion ( Entwistle, 1990 ). The disease was first reported in Texas ( Tabenhaus, 1917 ) and has since been identified in onion
Shengrui Yao, Ian A. Merwin, and Michael G. Brown
have shown that GMSs influence aboveground tree growth and yield ( Merwin and Stiles, 1994 ; Neilsen et al., 2003b ; Pedersen, 1997 ), whereas only a few studies have investigated how GMSs affect root growth. Atkinson and White (1976) reported that
Bandara Gajanayake, K. Raja Reddy, Mark W. Shankle, and Ramon A. Arancibia
Sweetpotato is an important root crop grown in tropical and subtropical regions and ranks as the seventh major food crop produced annually worldwide ( Bovell-Benjamin, 2007 ; Ku et al., 2008 ). Production of sweetpotato is an important agricultural
Kendra Baumgartner, Phillip Fujiyoshi, Greg T. Browne, Chuck Leslie, and Daniel A. Kluepfel
Armillaria root disease affects orchards in all Juglans regia (Persian walnut)-growing regions of California ( Gardner and Raabe, 1963 ). The causal agent is Armillaria mellea (Basidiomycota, Physalacriaceae), which attacks walnut and other
L. Eric Hinesley, Frank A. Blazich, and Layne K. Snelling
Hardwood and softwood stem cuttings of 5-year-old Atlantic white cedar [Chamaecyparis thyoides (L.) B.S.P.] were cut to 12-cm (short) or 24-cm (long) lengths, treated with 0 to 15 g IBA/liter in 50% isopropyl alcohol, and rooted in a raised greenhouse bench under intermittent mist. When hardwood cuttings were collected in February, short cuttings survived and rooted better than long cuttings. Survival and percent rooting for softwood cuttings collected in late August was virtually 10070 regardless of cutting length. Long cuttings produced more roots and longer roots with hardwood and softwood material. IBA was unnecessary for rooting, but it markedly increased the number of roots. Chemical name used: 1H-indole-3-butyric acid (IBA).