Commercialization of New Industrial Crop Germplasm and Cropping Systems
Location: Plant Physiology and Genetics Research
Title: Guayule: Culture, breeding and rubber production
Submitted to: Industrial Crops and Uses
Publication Type: Book / Chapter
Publication Acceptance Date: August 1, 2009
Publication Date: May 4, 2010
Citation: Ray, D.T., Foster, M.A., Coffelt, T.A., Mcmahan, C.M. Guayule: Culture, Breeding and Rubber Production, Industrial Crops and Uses (2010), pp. 384-410.
Interpretive Summary: Pressure on worldwide Hevea rubber supplies and other factors are renewing interest in guayule rubber. A review of past and recent research on the production, breeding, and product development of guayule was conducted to determine the current stage of guayule research in these areas. Lack of consistent funding and support has hampered progress in guayule research, especially with respect to breeding and development of new germplasm. This book chapter should help scientists and others identify those problems where further work is needed in the areas of guayule production, breeding, and product development research in order to move guayule commercialization forward.
Pressure on worldwide Hevea rubber supplies and other factors are renewing interest in guayule rubber. The objective of this chapter is to review recent and past research dealing with guayule production, breeding, and product development. Production research continues to show that although guayule is a semi-arid, drought-tolerant shrub, it must be irrigated with 1300 mm or more of water for maximum production. Although, transplanting remains the major method of stand establishment, research shows direct-seeding stands may be feasible. Multiple harvests from a stand can translate into lower stand establishment costs. Guayule does not require high nutrient levels except with high irrigation applications. Herbicides are an integral part of guayule production, but only special local needs permits are currently available. Breeding guayule is difficult because of its perennial growth; long immature stage before the initial harvest; facultative apomictic reproduction system; and necessity for evaluating multiple harvests. Breeders must be innovative and able to change approaches and methodology rapidly to meet opportunities and constraints as they are encountered. In spite of these difficulties, there have been guayule breeding successes resulting in 300% increases in rubber and resin yields. These increases have been accomplished mainly by selection of high yielding individual plants. Other breeding methods such as mass selection, pedigreed natural selection, interspecific and intraspecific hybridization, and family selection can also be used. Genetically modifying guayule is another tool that might be used; however, initial experiments using this method have not proved successful. Much work remains to be done to make future progress in guayule breeding. While rubber remains the primary driver in development, the next priority is co-product development as increasing quantities of guayule bagasse are produced. Uses of the resin are also receiving increased interest due to its insecticidal properties, potential as an adhesive, and potential as a bio-oil and bio-fuel.