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!
Fighting a destructive crop disease with mathematics
21.06.2017 | University of Cambridge
Unusual soybean coloration sheds a light on gene silencing
20.06.2017 | University of Illinois College of Agricultural, Consumer and Environmental Sciences
An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.
Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...
19.06.2017 | Event News
13.06.2017 | Event News
13.06.2017 | Event News
23.06.2017 | Physics and Astronomy
23.06.2017 | Physics and Astronomy
23.06.2017 | Information Technology