MONTPELLIER, France (March 10) -– Michelin and CIRAD, the French agriculture research body, have bred 13 natural rubber varieties that are both resistant to the Microcyclus ulei fungus and high-yielding.
The varieties were developed at Michelin´s Itubera estate in Brazil and are in quarantine at CIRAD in Montpellier.
Microcyclus ulei is the fungus that causes South American leaf blight in non-resistant varieties. Up to now all the high-yield clones used for NR production in Asia have minimal resistance to the blight. The NR industry in Asia implements strict quarantines on vegetable matter coming from South America in the hope of avoiding outbreaks of the blight. If an outbreak took hold, it could severely damage all NR production throughout Asia.
Furthermore, commercial production of NR is impossible in the Americas, with the exception of a small microclimate in Guatemala, due to the presence of Microcyclus ulei in the environment. It was this leaf blight that destroyed the Fordlandia and other "rubber boom" plantations of the early 20th century.
According to CIRAD, "These varieties are the first major step forward in over 20 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 12 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."