Developing drought-tolerant crops: International problem tackled locally
This article first appeared in the St. Louis Beacon, April 28, 2009 - When the world faces so many problems - from economic meltdowns to public health menaces - can we face up to yet another? We talk about this particular problem, however, with a ray of hope brought to you by people in our region.
Here's the challenge: How can we feed an ever-growing world population in the face of limited arable land and increasingly erratic weather?
We can't control the weather. Thanks to global warming or possibly just the fickleness of Mother Nature, drought will be a recurrent obstacle to growing the crops needed to feed the world. But local plant biologists are working hard on both the basic research and commercial levels to develop new crop strains that will produce abundant food even when water is scarce.
Corn Clears Hurdle
In January, Monsanto announced that its first biotech drought-tolerant corn is ready for final examination by regulatory agencies and may be on the market within three years. This product is aimed at farmers in the so-called dryland areas of eastern Kansas and Nebraska.
This part of the United States doesn't require constant irrigation, but is very likely to experience some drought during the summer. Conditions vary year to year, but the average annual rainfall is only 20-25 inches. (By contrast, the main corn-growing states -- Indiana, Illinois and Iowa -- get 40-45 inches.) Drought-tolerant corn is designed to give farmers yield stability during periods of inadequate water supply. In field trials, the product demonstrated a 6-10 percent yield benefit over non-transgenic corn.
This corn is the first biotechnology drought-tolerant crop to have reached the final regulatory hurdle before market. Monsanto and other agricultural companies have drought-tolerant soybeans, cotton and other crops in the pipeline. Universities are also engaged in intensive research aimed at growing more food with less water.
Using less water is crucial not only because of the weather, but because our stores of below-ground water (aquifers) are drying up. At present, agriculture accounts for about 80 percent of water consumption in the United States according to the USDA. As water supplies shrink, the present level of irrigation can't be maintained.
Time to Develop
Some drought-tolerant soybean strains have been developed by conventional genetics, cross-breeding Asian soybean varieties with American. Thomas Carter of USDA's Agricultural Research Service has been looking at slow-to-wilt soybean varieties since the early 1980s. They will be on the market soon.
Monsanto is using a combination of the latest breeding and biotechnology techniques to achieve the goal of doubling crop yields by 2030 over a base year of 2000, while using less water and fertilizer. However, even the high-tech approach is far from instantaneous in product development. The product development cycle for each new product is 6-15 years, and costs $50 million-$100 million. Getting new genes into plants is relatively easy. Selecting, testing and re-testing the product plants is a long process. Complying with regulatory requirements is also time intensive.
Scientists and researchers are looking at how plants respond to the stress of inadequate water. Since about 2,000 genes seem to change their activities during drought stress, the possibilities for manipulation are enormous. There is no clear path to solving the problem. But the goal remains the same: develop a plant that will not only continue to grow under dry conditions, but will produce increased amounts of seed and produce the seed in time for harvest.
Partners in Research
Cultivation of biotech crops has spread across the globe. Still, genetic modification of foods is controversial, especially in some of the areas where it has the potential to do the most good. In sub-Saharan Africa, about 300 million people depend upon corn as their primary food, but the crops are often decimated by drought.
Monsanto has entered into an African-led partnership to develop drought-tolerant corn for small-scale farmers. The project, called Water Efficient Maize for Africa includes as partners the Bill and Melinda Gates Foundation, the nonprofit International Maize and Wheat Improvement Center and the national agricultural research systems in Kenya, Mozambique, South Africa, Tanzania and Uganda.
Monsanto has pledged to contribute its expertise in conventional breeding and testing, and also some of the drought-tolerant genes that it has developed with its collaborators. The partnership expects to have some drought-tolerant corn available royalty free to small African farms by 2018.
A mutation changes the chemical composition of a gene. Some sequence may be added or deleted, or a single point in the DNA sequence can be changed (a point mutation). The organism that contains the mutated gene is called a mutant. Every cell in that organism will contain the mutated gene. Mutations that cause changes are the ones studied. Some mutants will be easy to detect because they are altered in appearance. Others may look normal, but will respond differently to changes in environment.
Biologists today can actually copy a gene and add it to the DNA of the experimental organism. The organisms with the inserted new gene are called transgenic.
Jo Seltzer is a freelance writer with more than 30 years on the research faculty at the Washington University School of Medicine and seven years teaching tech writing at WU's engineering school.