The future may also bring higher temperatures and drought if the global climate changes as predicted. So, it seems practical to raise fast-growing trees that not only provide fuel by capturing carbon from the atmosphere but also flourish under dry conditions.
A recent finding by the Department of Energy's (DOE) Oak Ridge National Laboratory (ORNL) may help to attain this goal. Hybrid willow trees have been cloned because they grow fast and serve as good fuel sources. However, there are important gender differences. Male willow clones are generally more tolerant of drought than female willows. Also, male willows cause no weed problems because they do not disperse seeds.
It is not easy to tell a male willow from a female willow because the trees do not express their gender identity until they are 6 to 20 years old. However, Jerry Tuskan and Greg Roberts, researchers in ORNL's Environmental Sciences Division, in collaboration with Swedish scientists through the International Energy Agency, have found a potentially useful method for early gender identification in willows.
Tuskan and Roberts have identified a DNA marker for gender determination in hybrid willow trees. The marker is present in all female hybrid willow and absent in all males.
The marker will ultimately be used to isolate and characterize the DNA sequence responsible for gender expression, which should greatly increase researchers' ability to identify highly-productive drought-resistant trees for biofuels.
This work was funded partly by DOE's Biofuels Feedstock Development Program and partly by the International Energy Agency.
ORNL, one of the Department of Energy's multiprogram research laboratories, is managed by Lockheed Martin Energy Research Corp.