National Geographic : 2014 Oct
44 national geographic • october 2014 growth rate, now 1.14 percent a year, is projected to slow to 0.5 percent by 2050. For many decades IRRI focused on improving traditional varieties of rice, grown in fields that are flooded at planting time. Lately it has shift- ed its attention to climate change. It now offers drought-tolerant varieties, including one that can be planted in dry fields and subsist on rain- fall, as corn and wheat do. There’s a salt-tolerant rice for countries like Bangladesh, where rising seas are poisoning rice fields. “Farmers don’t re- alize the salt water is coming into their fields,” says Gregorio. “By the time the water is salty enough to taste, the plants are already dying.” Only a few of the rice varieties at IRRI are GM crops, in the sense that they contain a gene transferred from a different species, and none of those are publicly available yet. One is Golden Rice, which contains genes from corn that al- low it to produce beta-carotene; its purpose is to combat the global scourge of vitamin A defi- ciency. Last summer an IRRI test plot of Golden Rice was trampled by anti-GM activists. IRRI creates GM varieties only as a last resort, says director Robert Zeigler, when it can’t find the desired trait in rice itself. Yet the institute’s entire breeding operation has been accelerated by modern genetics. For decades IRRI breeders patiently followed the an- cient recipe: Select plants with the desired trait, cross-pollinate, wait for the offspring to reach maturity, select the best performers, repeat. Glenn Gregorio, a plant geneticist at the Interna- tional Rice Research Institute, shows me the rice that started the green revolution in Asia. We’re in Los Baños, a town about 40 miles southeast of Manila, walking along the edge of some very special rice fields, of which there are many on the institute’s 500 acres. “ This is the miracle rice—IR8,” says Gregorio, as we stop beside an emerald patch of crowded, thigh-high rice plants. Roosters crow in the distance; egrets gleam white against so much green; silvery light glints off the flooded fields. IRRI, a nonprofit, was founded by the Ford and Rockefeller Foundations in 1960. Two years later a plant pathologist named Peter Jennings began a series of crossbreeding experiments. He had 10,000 varieties of rice seeds to work with. His eighth cross—between a dwarf strain from Tai- wan and a taller variety from Indonesia—created the fast-growing, high-yielding strain later known as India Rice 8 for its role in prevent- ing famine in that country. “It revolutionized rice production in Asia,” says Gregorio. “Some parents in India named their sons IR8.” Walking along the paddies, we pass other landmark breeds, each designated with a neatly painted wooden sign. The institute releases doz- ens of new varieties every year; about a thousand have been planted around the world since the 1960s. Yields have typically improved by just un- der one percent a year. “We want to raise that to 2 percent,” Gregorio says. The world’s population Traditional breeding Desired traits are identified in separate individuals of the same species, which are then bred to combine those traits in a new hybrid variety. Interspecies crosses Breeders can also cross different yet similar species. Modern wheat comes from such hybrid- izations, some of which hap- pened naturally. Breeding Better Crops Genetic modification gets the public attention—and the con- troversy—but plant breeders today have numerous tools for creating crops with new traits. The goal: continually increasing yields in an increasingly chal- lenging climate.