Seeds of Progress
Susan McCouch and colleagues around the globe breed better rice.
By Sharon Tregaskis
Rice is a staple of diets from China to West Africa, South America to India, feeding nearly half the world's population. Although apple orchards and cornfields outnumber rice paddies in New York state, one of the world's leading experts on the crop is a professor in the College of Agriculture and Life Sciences who lives with her family on a 200-acre farm outside Ithaca. And for Susan McCouch, it's a good fit. "I wanted to work on a crop that was internationally important, but I wanted to live in an environment where agriculture was locally important," says McCouch. "I also wanted to work in a community where the intellectual pursuit of science was part of the game plan. Plant breeding is the perfect marriage between the new biology-genetics and genomics-and the opportunity to have an impact on global food supplies."
McCouch's goal is to create maps of the genetic material of rice as a resource not only for other rice researchers, but also as a guide to the genomes of related grasses, such as corn and wheat. "We want to understand how we can select the genes and gene combinations that will be productive in a given agricultural environment," she says. "How can we maximize the selection for genes that underlie traits important in a sustainable agricultural system so that we're able to produce good quality food with fewer wasted resources? If you can breed pest resistance into your crops, then you don't have to apply so many pesticides. If you can breed water use efficiency into your crops, you obtain the same yields with less water. We've got to look at how we can manage the combination of environment and genetics."
While some plant breeders use transgenics-the splicing of genetic material across species, from a bacteria into a tomato, for example-to improve crops, McCouch focuses on incorporating traits from wild rice into its domesticated cousins. Her studies rely on the same principles of genetic variability that Austrian monk Gregor Mendel discovered in his observation of pea plants two centuries ago but use molecular markers to pinpoint the locations of desirable genes along particular chromosomes to speed the selection process. "We've opened the door to the idea that there are genes in wild species that you can use to drive your breeding program, so you don't have to go to a bacteria or an unrelated species to move in the direction that you want genetically," she explains. "The objective is to increase the genetic base of crop plants, not to cut and paste genes from other organisms."
Colleague and Department of Plant Breeding Chair Ronnie Coffman calls McCouch's research approach "revolutionary." "Susan's approach increases productivity and adaptability in areas that lack water or where the soil is poor, areas that are inhabited by poor people, and so it offers a comparative advantage to poor farmers. It also reduces the price to impoverished urban dwellers."
Internationally, public debate over genetic modification of food crops has focused primarily on transgenics. And although there's been little controversy over her work, McCouch says the public needs more information about where food comes from and how it's bred. "There's nothing natural about those plants we've come to rely on for food over the past 10,000 years," she points out. "They're completely dependent on human beings for their growth and survival. But it's also important to realize that, in exchange, we are completely dependent on them. It's a very mutualistic kind of development. What's considered natural is a moving target."
As a girl, McCouch didn't plan on becoming a scientist, and even after she earned her PhD from Cornell in 1990, she had no intention of pursuing the professorial career track. But since her start in higher education, she has had a passion for international development. As an undergraduate in the 1970s, she studied Hispanic literature at the University of Barcelona-until it was shut down in the political turmoil surrounding Franco's death. Returning to the United States, she finished her degree and struck out on an 18-month journey from eastern Massachusetts to the southern tip of Argentina, before settling in Uruguay for the remainder of the decade. "I was interested in lots of things that just hit me as I traveled," she recalls. "Because I was hitchhiking, I was exposed to environments that I wouldn't have seen if I had been in a hurry to reach my destination."
In addition to broadening her view of the world, the trip furnished McCouch with a value that has guided her subsequent studies: "One of the really important opportunities for people who have access to education and an interest in the developing world," she says, "is to somehow take scientific knowledge and try to develop appropriate responses to the immediate human needs- clean water, basic health care, and access to a more diverse food system." And while she considered studying medicine, she found that most medical curricula didn't address the most fundamental challenges facing the developing world. "Most of the kinds of problems that I had confronted and that moved me to go back into a technical field involved access to information and access to some of the most basic technologies," she says.
Aesthetically intrigued by plants, and with a passion for the outdoors, McCouch turned to plant pathology, and then plant breeding. "The element of surprise, the potential for creativity, the opportunity to find something that you didn't expect," she says, "that's the coolest thing about plant breeding. You generate a cross, you observe what comes out. Sometimes it's what you expect, and you breed on that basis. Sometimes it's the very fact that you see something you didn't expect, and you build on that. I like to be in a field where expectation of the unexpected is ever present and the challenge is to use your creativity to take the unexpected and turn it into something of value."
With her passion for international development, she's also been a critical force in the globalization of genetic studies, linking researchers around the world through the Internet. "Over the years she has developed a tremendous network of rice researchers interested in molecular genetics," says Coffman, who led McCouch's first research foray, a Cornell trip to Costa Rica in the late 1980s. "She has close contacts in practically all of the major rice-growing countries-Thailand, India, China, Korea, Japan, Philippines, Ivory Coast-who count her as a friend, colleague, and collaborator."
Rice may be among the simplest of the grasses, but its wide range of habitats provides ample fodder for genetic analysis and collaboration. "Korea has a temperate climate and they prefer the japonica subspecies of rice; Indonesia represents the irrigated tropics and they grow tropical japonica or indica rice," says McCouch. "In China we're working with some of the highest-yielding hybrids in the world. In the Ivory Coast in West Africa, we're looking at crosses between native African rices and Asian rices, in a very different environment in terms of soils and diseases and the socioeconomic situation. In Colombia and Brazil we're working with upland rices that are grown in dry lands, in the savanna- very low-input agriculture. And then we're working with laser-level fields and industrial combines and a very high input system in the United States."
While McCouch's work makes for long days on campus and significant travel, she's struck a balance that accommodates her family and their pastoral life in Locke, New York, a 45-minute drive from Cornell. As a new mother with a three-month-old daughter when she started her grad studies at Cornell, McCouch defended her dissertation just ten days before the birth of her son, now 11. "It was a lot riskier, and in many ways harder, to hitchhike from Massachusetts to Argentina than it was to navigate the professional white water at Cornell," she says. "The big challenge for me was to do the science, balance my family, and travel and maintain contacts in the developing world. I guess I've always been asking a lot."