Much attention has been given to the seeds of a poisonous weedy shrub, jatropha, as a potential feedstock, particularly in India and Africa. Because it's not edible, jatropha used for fuel doesn't compete with its use as a food crop -- a frequently cited concern with many biofuel sources. The jatropha plant is hardy and drought-resistant, and it grows quickly. And it's of particular interest to scientists looking for inexpensive feedstock because the seeds can contain up to 40 percent oil. These qualities all sound promising, but so far jatropha crops don't seem to be providing high enough yields, most likely because it has been planted in "marginal" soil that isn't of high enough quality [source: Johnson]. Jatropha also requires a lot of water during the growing process. So, while the plant is inexpensive, it may not be ideal for large-scale production.
