Southern Research Station Headquarters - Asheville, NC
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Issue 10
Pine Clones...
In the plant world, cloning is part of the age-old process humans have used to produce the best plants for food and other products. When you root a cutting, you are essentially creating an identical copy, or clone, of the plant you took the cutting from. The clonal propagation of loblolly pines for largescale production, however, is not so simple.
For pine cuttings to root, you have to take them from young seedlings, usually about a year old. You can “trick” a pine into staying young by pruning it, but over time it loses the ability to produce cuttings. This method also produces a limited number of seedlings for a limited period of time for any given pine variety.
Another method of producing pine clones involves culturing embryonic pine tissue in the laboratory, allowing embryos to multiply and mature in a process called somatic embryogenesis. Somatic embryos can be produced in much greater quantities than cuttings and stored indefinitely at very low temperatures, so are available in large quantities when needed.
Genome Guided Selection
Tree selection is based on traits that manifest in the mature tree— crown size, growth pattern, or leaf density. Because trees may take decades to mature, selecting for a tree that combines specific traits could conceivably take a lifetime.
Researchers, including Dana Nelson and his team at the SRS Southern Institute for Forest Genetics (SIFG), hope to improve the ability of managers to select which varieties of a tree—loblolly pine, for example—they will plant based on genetic information. This could prove critical in adapting forests to the rapid alterations that climate change may bring. The first step is to produce maps of pine genomes, then associate genes with specific traits and produce DNA markers which can be used to identify and track individual genes. SIFG researchers have developed over 200 genetic markers for loblolly and related pines—improving genetic maps, allowing comparisons among pine species, and providing the tools for the next generation of tree improvement.
