Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Saving rubber for future generations

09.03.2006


Natural rubber is currently technically unavoidable for some purposes, despite the competition from synthetic rubber. Most notably, it accounts for 75% of the rubber used in the tyre industry. However, although Hevea brasiliensis originated in the Amazon Basin, rubber growing has only really developed in Asia and Africa. In Latin America, “South American leaf disease”, caused by the fungus Microcyclus ulei, has until now totally prevented the development of rubber growing, or at least almost totally: rubber trees have become resistant to the fungus in some areas of Amazonia. However, to date, there have never been any varieties that combine parasite resistance and productivity. This could be disastrous for rubber growing worldwide were the fungus to be introduced accidentally into Asia or Africa.



Resistant and high-yielding rubber plants in quarantine at CIRAD

The threat is on the verge of being overcome. In late December 2005, plants of thirteen high-yielding rubber varieties resistant to Microcyclus were shipped to CIRAD from Michelin’s Itubera estate in Brazil. They are now in quarantine in a confinement zone, where they will remain for two years and undergo a range of tests to ensure that they do not carry any spores of the parasite.


These varieties are the first major step forward in over twenty years’ research at CIRAD, working since 1992 with Michelin, in Montpellier, French Guiana and Brazil. They are controlled crosses produced by hand pollination, and have been assessed for twelve years at Michelin’s Itubera estate. The process is continuing, crossing very high-yielding varieties that are susceptible to the disease, such as those currently grown in Asia and Africa, with resistant or highly tolerant trees from the Amazon Basin that are not so high-yielding*. Every year, during the short flowering period, researchers remove the stamens from the flowers of one variety so as to inseminate the flower by hand with the pistils of another. The resulting seeds are then germinated to produce thousands of seedlings that will grow in the presence of the disease. Those that resist strong parasite pressure in the field are selected based on their productivity after five to seven years. New plants are produced each year.

The plants that have been in the CIRAD glasshouses for the past few weeks are the first varieties produced under this research programme to reach the pre-development stage.

A new phase of tests in metropolitan France and several African and Asian countries

The latest phase of tests should provide answers to several questions. While the varieties are both resistant and high-yielding at Michelin’s estate in Bahia, will they remain so under other environmental conditions, particularly in Asia and Asia, and even in other parts of South America? CIRAD’s Microcyclus ulei fungus collection in Kourou, French Guiana, which includes several strains from different countries, could help to answer that question. There is also another question: what are the risks of the plants being susceptible to other parasites?

The first step is to ensure that the parasite was not introduced into France during transport, despite all the precautions taken. The planting material was transferred in the form of budded stumps of the thirteen genotypes involved. Before they left Brazil, they were given pesticide and fungicide treatments against Microcyclus ulei but also other parasites, as laid down in French law. On arrival, they were potted in the CIRAD glasshouses in Montpellier. They are now growing, and testing will begin in the next few months, once they have leaves. The parasite may not immediately be visible, which is why non-resistant control plants have been placed next to the test plants. If the plants pass this first test, a second round of budding should rule out any risk of “dormant” spores. If this stage is successful, the plants will be sent to partner research organizations in Africa and Asia, where they will again be placed in quarantine and undergo further tests. Trees of varieties created subsequently in Brazil will be tested in the same way each year.

Improving the breeding technique

Alongside this, researchers are working to improve the breeding technique, and have plans to use genetic markers. We now know which parts of the rubber genome are involved in resistance. However, things are not as simple as they look. Natural resistance to Microcyclus in rubber uses mechanisms that involve a large number of genes. Moreover, the fungus has already proved capable of overcoming resistance. What are the mechanisms involved? The answers that researchers manage to come up with in the coming years should shed light on how resistance develops and make it easier to breed resistant individuals.

* The rubber varieties currently grown in Asia and Africa in fact originated from a very small part of Amazonia. In the late 19th century, a British planter took tens of thousands of rubber seeds back to Kew Gardens. The resulting trees were shipped to Ceylon and Singapore, triggering the Asian commodity chain. Asia now produces 93% of the world’s natural rubber. It is Thailand that leads the market, with three million tonnes or 35% of global output. Africa accounts for 4% and South America the remaining 3%.

Jérôme Sainte-Beuve | alfa
Further information:
http://www.cirad.fr/en/actualite/communique.php?id=402

More articles from Ecology, The Environment and Conservation:

nachricht Upcycling of PET Bottles: New Ideas for Resource Cycles in Germany
25.06.2018 | Fraunhofer-Institut für Betriebsfestigkeit und Systemzuverlässigkeit LBF

nachricht Dry landscapes can increase disease transmission
20.06.2018 | Forschungsverbund Berlin e.V.

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

NYSCF researchers develop novel bioengineering technique for personalized bone grafts

18.07.2018 | Life Sciences

Machine-learning predicted a superhard and high-energy-density tungsten nitride

18.07.2018 | Materials Sciences

Why might reading make myopic?

18.07.2018 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>