Postharvest Degradation of Guayule Rubber

Abstract

Abstract Most guayule genotypes lose considerable amounts of rubber after harvest. The time that the harvested shrub stays in storage is an important factor controlling the amount of degradation. This study identifies genotypes which are more stable with respect to postharvest degradation of rubber quality and quantity. Genotypes carrying such an economically valuable trait provide for the development of high-rubber-yielding cultivars that prevent substantial losses between harvest and processing. Further studies are expected to throw light on the mechanisms of postharvest rubber degradation, in general, and on the genetic nature of this variation in particular. More genotypes must be exposed to more storage conditions in order to identify genotypes that may withstand the adverse effects of long storage. The observation that some genotypes continue to synthesize rubber after harvest, at least for a short period of time, is also encouraging. Such genotypes make it possible to handle the shrub between field and processing, within 1 to 2 weeks, with no rubber loss.