Wonder Wheat Breaks the Yield Barrier

NEW DELHI, INDIA--A new wheat variety that yields a whopping 18 tons per hectare was unveiled here yesterday at a conference sponsored by the International Wheat and Maize Improvement Center (CIMMYT) in Mexico. The advance could dramatically boost farm productivity, but some experts worry that the runoff from fields of the fertilizer-hungry plant might worsen river pollution.

During the next 50 years, the world will have to grow more food to support its booming population than all the food produced in the last 10,000 years, according to CIMMYT Director-General Timothy Reeves, an Australian agronomist. Although the best wheat varieties yield up to 12 tons per hectare, breeders have for several years been unable to boost that yield substantially. To drastically alter the structure of the wheat plant--such as create a bigger ear--CIMMYT researchers spent almost 20 years using standard breeding techniques to enhance traits such as fertility, branching, and robustness in varieties ranging from Polonicum wheat to wild goat grass. Researchers also knew, says Reeves, that "the whole plumbing system of the plant has to be overhauled so that it can partition more resources into grain."

In early trials this year in Chile, the plant beat the world record for yield by 50%--a stunning feat, considering new strains had only managed a 1% annual increase in recent years. "The yield barrier has been broken," says Reeves. "But we still need to incorporate the necessary disease resistance genes--the know-how of which already exists--and if all goes well, in the next 5 years the new plant type should be available to the farmers."

Not all experts are ready to embrace the new variety. "How are you going to feed the plant? Does it mean massive inputs of chemical fertilizers?" asks geneticist Monkombu Sambasivan Swaminathan, director of an eponymous research foundation in Chennai, India. "There should [also] be active research on developing a methodology of feeding the plant which is environmentally benign, if the real potential of this genetic breakthrough is to be realized," he says. Reeves says CIMMYT is already preparing a new planting technique called "bed planting" that requires 30% less fertilizer for the same yields.