Planting Density and Growth Cycle Affect Actual and Potential Latex and Rubber Yields in Taraxacum kok-saghyz

Abstract

<jats:p>Rubber dandelion (<jats:italic>Taraxacum kok-saghyz</jats:italic>, Rodin) is being developed as a temperate-zone source of rubber, but best agronomic practices must be determined before it can become a viable supplement to imported rubber produced from para rubber tree (<jats:italic>Hevea brasiliensis</jats:italic>, hevea) plantations located mostly in Southeast Asia. In our study, the effect of planting density and harvest time on yield was determined by transplanting 1.5-month-old greenhouse-produced plants at planting densities of 1.24, 2.47, 4.94, and 9.88 million plants/ha, randomized across four planting boxes with two densities per box (i.e., two planting areas at each density). Half of each planting area was selected randomly and hand-harvested after 6 months, and the remaining plants were hand-harvested after 1 year. Rubber yields per plant were greater after 1 year than after 6 months, but yields per unit area were similar as a result of the loss of half the plants during the severe 2013–14 Ohio winter. A maximum rubber yield of 960 kg dry rubber/ha was obtained from the 9.88 million-plants/ha planting density after 1 year, but root size was significantly decreased compared with lower densities, and appeared too small for mechanical harvest. A planting density between 2.47 and 4.94 million plants/ha may produce the optimal combination of root size and total rubber yield. Greater rubber concentrations, faster-growing plants, short-season germplasm, and in-field weed control are required before yields obtained in outdoor planting boxes can be matched or exceeded on farms, especially in a direct-seeded rubber dandelion crop.</jats:p>

Inflorescence Development and Floral Organogenesis in Taraxacum kok-saghyz

“…Taraxacum kok-saghyz has been studied as an important alternative source of natural rubber, cis-1, 4-polyisopropene [ 10 , 11 , 12 , 13 , 14 ], a raw material that can be used for producing both industrial and medical products. TK rubber is especially valuable because it is renewable and of superior quality, presenting a uniformly high molecular weight polymer when compared with synthetic rubber [ 15 ].…”

“…It has ideal agronomical properties for efficient production as an annual crop including fast development and high biomass production [ 17 ]. Capitalizing on research studies in TK domestication and rubber content extraction and analyses [ 11 , 12 , 13 , 14 , 16 , 17 , 20 ], a few companies have invested in the use of TK as an alternative rubber-producing crop [ 19 ]. Some studies also indicate that TK has the potential to be a source of additional important products, including inulin and proteins [ 14 , 21 ].…”

Extraction process and characterization of Taraxacum kok-saghyz (TKS) latex

“…In terms of rubber yield, due to differences in varieties, growth cycles and planting densities, there are large differences among countries. In the United States, Bates [ 27 ] measured the yield of TKS under different planting densities (1.24～9.88 million plants/ha) and growth cycle (6 months and 1 year). The results showed that the rubber yield was 400～1000 kg/ha, and Cornish [ 8 ] cultivated a high yield plant phenotype with a yield of 2160 kg/ha under the condition that the plant density is 1 million plants per acre (1ac = 0.4047ha) and the growth cycle is 1.5 year.…”

Natural rubber – Increasing diversity of an irreplaceable renewable resource

“…Overall, 16.2 wt % THF-soluble rubber was recovered from the dried root. In comparison, rubber content in most rubber dandelions is ∼4–8 % although 22.8 wt % has been reported [ 29 , 30 ]. Also, the large size of S. tau-saghyz roots may lead to a more robust rubber production system than the smaller rubber dandelion.…”