Christmas trees provide a significant source of revenue in southern Appalachia, resulting in millions of dollars in sales during the holiday buying season. The most popular species in the region is fraser fir, appreciated for its fragrance and consumer-friendly traits such as soft needles, strong branches, exceptional needle retention, and natural Christmas tree shape.
Frasers, indigenous to isolated high-elevation mountains in southwestern Virginia, western North Carolina, and eastern Tennessee, are under attack by a pathogen called Phytophthora cinnamom, an insidious adversary that causes root rot, kills seedlings, and threatens serious economic losses for the region's Christmas tree industry. "Once a growing site is infested, the pathogen is nearly impossible to eradicate. Fir seedlings often die within 2 or 3 weeks from infection", noted John Frampton, a professor in the Department of Forestry and Environmental Resources at North Carolina State University.
To develop planting stock that is resistant to or tolerant of Phytophthora cinnamomi, some growers in the southern Appalachian Mountains are turning to grafting practices, predominantly grafting fraser fir scions onto rootstocks of resistant momi or turkish fir. To aid growers in the region seeking effective grafting techniques, Frampton and his team designed a study, implemented by graduate student Haley Hibbert-Frey, to compare success rates of the traditional April grafting time with eight summer/early fall grafting dates. The study, published in HortScience, contains important recommendations for tree growers.
Fraser fir is usually grafted in April when the rootstock and scion are dormant. But spring is a busy time for growers, who would welcome the flexibility of performing grafting at other times of the year (e.g., late summer or early fall). The NCSU study compared success and growth of grafting fresh fraser fir scions onto turkish fir rootstocks during the traditional April grafting window with eight biweekly grafting dates from mid-July through mid-October. The scientists also assessed the effect of shade and irrigation treatments on graft success and growth and evaluated grafting during the mid-July through mid-October season using dormant fraser fir scions collected during April and stored at °C.
The team concluded that the effect of grafting date was significant for graft success. Grafting during April when scions were dormant and rootstocks were just becoming active yielded a noteworthy 95% success rate; graft success was significantly lower for the first three summer grafting dates and was unsuccessful from August 24–October 20. "April graft success was 95% but when grafting fresh scions in summer/fall, graft success decreased from 52% in July to 0% in October. To ensure optimal grafting success, grafting should be performed in the late winter or early spring when scions are dormant and the rootstocks are becoming active", recommended Frampton.
The experiment results showed that shade improved summer graft success (52% with shade, 38% without), while irrigation did not significantly affect graft success or subsequent growth. In a supplemental storage study, grafting of stored scion material in summer/early fall was not successful (less than 1%). "Until more successful techniques can be developed, it is prudent to graft fraser fir in early spring with freshly collected dormant scion material", the researchers concluded.
The complete study and abstract are available on the ASHS HortScience electronic journal web site: http://hortsci.ashspublications.org/cgi/content/abstract/45/4/617
Founded in 1903, the American Society for Horticultural Science (ASHS) is the largest organization dedicated to advancing all facets of horticultural research, education, and application. More information at ashs.org
Michael W. Neff | EurekAlert!
Ammonium nitrogen input increases the synthesis of anticarcinogenic compounds in broccoli
26.04.2017 | University of the Basque Country
New data unearths pesticide peril in beehives
21.04.2017 | Cornell University
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
28.04.2017 | Event News
20.04.2017 | Event News
18.04.2017 | Event News
28.04.2017 | Medical Engineering
28.04.2017 | Earth Sciences
28.04.2017 | Life Sciences