Taraxacum kok-saghyz

Taraxacum kok-saghyz. It is a species of dandelion native to the Tian Shan mountains of Kazakhstan and Uzbekistan, notable for its production of high-quality natural rubber within its root system. First described scientifically by the Russian botanist Eduard August von Regel in the early 20th century, it gained prominence as a strategic emergency crop during periods of natural rubber shortage. Its common name derives from local Turkic languages, translating roughly to "rubber root".

Description and taxonomy

This perennial herbaceous plant is morphologically similar to the common dandelion but is typically smaller in stature. It features a basal rosette of lanceolate leaves and produces bright yellow composite flower heads on hollow scapes. The taxonomy of the genus Taraxacum is complex due to apomixis, but this species is distinguished by its significant latex content. It belongs to the large Asteraceae family, which also includes sunflowers and lettuce. The plant was formally identified during botanical explorations of Central Asia sponsored by institutions like the Saint Petersburg Botanical Garden.

Natural rubber content

The primary economic interest lies in its roots, which contain latex vessels producing polyisoprene virtually identical to that harvested from the *Hevea brasiliensis*. The rubber, known as cis-1,4-polyisoprene, is of high molecular weight and quality, suitable for demanding applications like aircraft tires. The latex concentration varies but can reach up to 20-30% of the dry root weight under optimal conditions. This biochemical pathway is an example of secondary metabolism in plants, analogous to rubber production in other species such as *Parthenium argentatum*.

Historical and economic significance

Its strategic value was first recognized by the Soviet Union in the 1930s following Japanese expansion in Southeast Asia, which threatened Allied access to rubber plantations. Large-scale cultivation was initiated under Joseph Stalin's Five-Year Plans, particularly in the Kazakh Soviet Socialist Republic. During World War II, the United States, through the Emergency Rubber Project, also investigated it as an alternative source after the Japanese conquest of British Malaya. The Manhattan Project even considered its rubber for specialized seals and gaskets.

Cultivation and agronomy

Cultivation presents challenges, as the plant yields far less latex per hectare than the Para rubber tree and requires a temperate climate with a distinct vernalization period. Optimal growth occurs in well-drained soils, and it is typically grown as an annual crop to maximize root harvest. Key agronomic research has been conducted by institutions like the United States Department of Agriculture and the Vavilov Institute of Plant Industry. Breeding programs aim to improve agronomic traits such as root mass and rubber concentration, while managing pests like Taraxacum mosaic virus.

Research and development

Modern research is driven by desires for biosecurity and a sustainable, domesticated rubber crop. Significant genetic and genomic studies are underway, including efforts to sequence its genome by consortia involving the University of Guelph and the Fraunhofer Society. Genetic engineering techniques are being explored to transfer its rubber biosynthesis genes into other plants, such as tobacco relatives. The European Union has funded projects like EU-PEARLS to develop it as a commercial crop, while companies like Continental AG and Bridgestone have invested in related biomaterial research.

Category:Asteraceae Category:Rubber