Volume 28 · Number 4 · Summer 2011
Nurturing a rare breed
UC Davis plant breeding education expands to meet global need.
For his doctoral studies, Iago Lowe researched genetic resistance to stripe rust, a fungal disease that has plagued wheat growers for centuries. (Karin Higgins/UC Davis)
While working in Tanzania on community development projects several years ago, Iago Lowe came to two life-changing conclusions:
Food security is central to projects that make a lasting difference in people's well-being. It ensures that communities have the seeds, soil, water and environment to produce enough to eat.
His bachelor's degree in physics and religion from Dartmouth College did not adequately prepare him to spearhead those kinds of projects.
To address that gap in his ability to "make some small difference in the world," Lowe started doctoral studies at UC Davis in 2007 in plant breeding and genetics.
"There are so many needs in developing nations — for schools, roads, water, other infrastructure — but when the money and people leave, so often the projects die," Lowe said. "The few projects I saw that continued to thrive, that really made a tangible difference in people's lives, almost always dealt with local food security, seed systems, soil and water conservation and ecological restoration — projects that demanded a set of skills I didn't have. I'm now nearing the end of my time studying plant breeding at UC Davis and that's no longer the case."
Lowe exemplifies a new breed of plant breeders at UC Davis. Long a global leader in plant breeding, UC Davis has been retooling its programs — offering new training, creating new curriculum, hiring new faculty (as the budget allows) and conducting world-class research to meet a growing demand for new crops and for breeders.
The new generation of scientists that those programs will produce — and their research breakthroughs — can't come soon enough for industry, government and philanthropic foundation leaders who say that a shortage of plant breeders is hampering efforts to alleviate hunger around the world. Hundreds of high-paying industry jobs for plant breeders are going unfilled.
"Plant breeding is such a vital tool for helping us deal with significant challenges in the 21st century such as food security, population increase, urbanization, and water and energy shortages," said Xingping Zhang, a watermelon breeder with the Davis-based seed company Syngenta. "Who is going to educate the plant breeders? UC Davis is in a perfect position to do so because it's a great center of science and technological inventions, located right in the heart of agricultural abundance. No place in the world offers the diversity of crops [like those] grown in California."
In another major nod to UC Davis expertise, the U.S. Department of Agriculture awarded $40 million in grants earlier this year to develop climate-change-tolerant plants and new bioenergy sources. UC Davis scientists will lead two research teams from more than 50 universities in more than 20 states.
"Each of these projects features transdisciplinary, regional, integrated teams, including scientists from institutions that represent underserved populations," said Roger Beachy, director of the USDA's National Institute of Food and Agriculture, in announcing the grants at UC Davis. "This approach represents a new paradigm in how USDA science can best solve critical issues facing agriculture today."
A century of breeding
Since opening its doors in 1908, UC Davis has helped develop and manage many of the more than 250 crops now grown in California.
Best of Breed
To see plant breeding in action, watch strawberries grow at the 200-acre UC South Coast Research and Extension Center in Irvine, where the winters are mild, the summers are warm and the coastal breezes are lovely.
The impact of UC Davis crop science is found on farms and nurseries throughout the state. Take walnuts, for instance. Virtually all the walnut varieties sold in California nurseries are UC Davis varieties. One variety — Chandler, with its mid-season leafing and light, golden kernels — accounts for 90 percent of all nursery sales of walnuts. Year-round strawberry production is another example [see "Best of Breed," page 29].
Beyond this, UC Davis research and its graduates helped nurture a fruit boom in Chile and other parts of the world. Most of those crops were developed by traditional selective breeding methods.
However, classical plant breeding programs have withered at UC Davis and other universities in recent decades, as the life sciences underwent a revolution and faculty and student researchers turned their focus from developing new plant varieties to understanding the molecular, cellular and genetic underpinnings of plant life.
UC Davis continues to support breeding programs for grapes, peaches, almonds, walnuts, prunes, strawberries, peppers, beans, lettuce, tomatoes, rice and wheat — but in different ways than before.
With some of those crops, like lettuce, researchers no longer develop and release new varieties into the public domain. Rather, they focus on the molecular side of the breeding spectrum, identifying genes likely to control important traits and releasing the corresponding germplasm, or living tissue, which can by used by industry and others to develop new varieties.
With highly competitive crops like corn, vegetables and flowers, where new varieties can reap big dividends — the business of releasing new ones has moved to the private sector. Industry looks to UC researchers to help solve problems but not compete with them in the marketplace.
"Our plant breeding programs are science driven," said Neal Van Alfen, dean of the College of Agricultural and Environmental Sciences. "That's what distinguishes our program and puts us at the forefront of helping solve critical agricultural, biological and environmental issues worldwide."
Van Alfen said UC researchers allow both public and private breeders to keep up with advances in plant science.
Adapting plants for climate change
The two USDA-funded research projects, in particular, showcase how advances in molecular breeding techniques have revolutionized plant breeding.
Wheat geneticist Jorge Dubcovsky
(Karin Higgins/UC Davis)
One team, headed by wheat geneticist Jorge Dubcovsky, received $25 million to identify variations in wheat and barley genes that can enhance the ability of the plants to resist disease, make efficient use of water and nitrogen, and optimize crop yield. These discoveries will help plant breeders develop varieties of wheat and barley that will thrive and be productive despite anticipated climate variability.
Forest tree geneticist David Neale received $14.6 million to head a team — which includes Charles Langley, professor of genetics in the College of Biological Sciences — to sequence the genomes of loblolly pine, sugar pine and Douglas fir. This is a particularly ambitious project because the genomes of pine tree species are huge — as much as 10 times the size of the human genome. The researchers hope to accelerate breeding efforts for fast-growing varieties of these trees — enhancing their use as feedstocks for biofuels and contributing to carbon sequestration, capturing and storing carbon from the atmosphere, thus mitigating the effects of climate change.
Need for field training
The grants also illustrate another important point in today's plant science education: Funding is ample for plant biology, genetics and biotechnology, but not for field training. As a result, colleges and universities have invested in faculty on the basic-science side, and less on the applied side. Therefore, fewer students are being trained to set up a field experiment and develop new varieties, and fewer fully trained breeders are entering the job market.
Allen Van Deynze, a professional researcher with the UC Davis Seed Biotechnology Center, said UC Davis and other universities made a mistake in not replacing breeders as they retired. "All the biotechnological advances don't mean much if you don't have people who know how to develop varieties."
Chris van Kessel — a professor, agronomist and chair of the Department of Plant Sciences, explained it like this: "Plant breeding refers to a wide set of skills, from basic to applied science, and we're not as strong as we once were on the applied side. Why does that matter? Let's say you're looking for a wheat variety with stripe-rust resistance. Using advanced molecular tools, you find a gene of interest . . . But until you make your crosses — grow the plants in the field — you don't really know what you have. Did you make the plant especially susceptible to another disease? Or did you affect yield? . . . And knowing how to set up those test plots requires a very specialized set of skills."
Scientists have begun spelling out the need for field-trained plant breeders in their grant applications. Dubcovsky's team, for example, will spend one-third of its $25 million USDA grant to develop a Plant Breeding Education Network to train 30 new doctoral students in plant breeding and provide educational opportunities for 100 undergraduate students interested in plant improvement.
The Seed Biotechnology Center is also helping to fill the gap by training professionals in its Plant Breeding Academy, which has grown into a thriving resource for trained plant breeders worldwide. Now offered in Europe as well, the academy is modeled on professional M.B.A. programs that allow participants to continue in their current jobs. Students meet for three six-day weeks each year for two years in small hands-on classes.
"Most of our students are working in the field, doing plant breeding, but they don't yet have the training to set up their own programs and trials," Van Deynze said. "In the academy, they develop a deeper knowledge of genetics, statistics and breeding theory so they can direct their own breeding programs."
Academy graduates earn a UC Certificate of Completion, not a degree. The program doesn't replace the need for plant breeding faculty, researchers and curriculum, Van Deynze said. "It's complementary," he explained. "The [Plant Breeding Academy] is more geared toward advancing within industry, not for academic research."
Four classes — a total of 66 people — have either graduated from or are current students in the academy. The Center also offers short courses on seed biology, production, quality and breeding with molecular markers.
A new breed
Plant breeding education at UC Davis involves many disciplines — plant biology, computer science, entomology, plant pathology and nutrition, quantitative genetics, to name a few. Graduates can focus on ecology, genetics, horticulture and agronomy and plant biology — and even then their course loads incorporate the full array of disciplines.
Lowe, the graduate student, is working to identify and characterize genetic sources of resistance to stripe rust, a fungal disease that has plagued wheat growers for centuries, and destroyed billions of bushels of wheat. In some parts of the world, wheat is the major source of protein — people can go hungry when a rust epidemic strikes.
Working with Dubscovky, Lowe has identified stripe rust resistance genes that are now being introduced into elite California wheat varieties. They may eventually contribute to the long-term development of more stripe-rust resistant wheat.
"What is especially appealing about working in a public research and breeding program is that our results are made available to breeders everywhere, to expand on and use as they see fit," Lowe said.
Wisconsin native Shelby Repinski came to UC Davis in 2006 to pursue a doctorate in plant breeding and genetics. "Plant breeding gives me a way to apply my love of genetics, statistics and plants. Science can be so abstract. In the lab, it's just a hypothesis — this gene controls this trait. When you take that hypothesis into the field, you can test it; see how the components interact with weather conditions, the pH of the soil, etc. You're dealing with the whole plant, and I just love that link between the basic and applied side of science."
Students also learn the importance of genetic diversity to plant breeding, a lesson that can take them all over the world searching for wild and domesticated ancestors of our modern crops. In order to develop high-quality crops that can resist constantly evolving pests, diseases and environmental stresses, plant breeders need genetic diversity in germplasm, the living tissue from which new plants can be grown.
Sexually compatible wild species and landraces — ancestral varieties of crop species — are the keys to genetic diversity, but the amount of land where plants grow wild continues to shrink and many plant species and varieties are disappearing. That's why the plant science community has developed conservation programs to gather, preserve, catalogue and distribute germplasm to researchers and breeders around the world.
Repinski traveled to Mexico with plant sciences professor Paul Gepts to collect wild bean plants. She also took advantage of one of the many plant breeding internships available to UC Davis students at area industries. She worked on drought-tolerance in corn for Monsanto in Woodland.
"I learned pollination techniques, phenotyping and many other things — [and discovered] that I can work in a field all day and be happy," she said.
Repinski applauded UC Davis' renewed plant breeding efforts. "Plant breeding is becoming a more popular field of study," she said. "More and more students are gravitating to it because it has so many uses. It can help all of humanity."
Seed Biotechnology Center videos on plant breeding