June 4, 2012
Maize Genome Research Could Help Meet Nutrition Needs Of Growing Population
Brett Smith for redOrbit.com
With the world's population expected to jump from 7 billion people this year to an estimated 9 billion by 2050, the Food and Agriculture Organization (FAO) of the United Nations predicts that worldwide food production will need to increase by 70 percent over the next four decades to meet the growing demand.
Two new reports published in Nature Genetics provide a window into how the production of corn, or maize, could be modified to ramp up production of the food staple over the coming decades.
The reports both derive from an international study by 18 different institutions that involved comprehensive sequencing of the maize genome.
"This project is a stellar example of how collaborations of scientists, here and abroad, leverage resources across multiple agencies to enable transformational research with the potential to address urgent societal needs for a bio-based economy," said John Wingfield, assistant director for National Science Foundation, which help to fund the study along with the USDA.
While one report examined the genetic structure and the relationships among individual genes in more than 100 varieties of wild and domesticated corn, the other looked into how corn evolved around 10,000 years ago from a wild grass in the lowland areas of southwestern Mexico. Researchers found evidence of a new genetic diversity that has arisen since domestication, possibly due to the incorporation of wild strains. They also identified a number of genes that played important roles in the transition from wild to domesticated maize.
Interestingly, the results pointed to selection techniques applied by ancient farmers that seemed to play a stronger impact on maize evolution than those used by modern breeders. The study also said that while a substantial amount of diversity was lost during the domestication process, new varieties of maize have arisen since domestication in the form of novel mutations.
The scientists found a substantial continuity of genetic content between maize relatives, suggesting that environmental adaptations such as perennialism, and frost and drought tolerance could be transferred from wild relatives into domesticated maize. These findings also propose that modern breeders should devote more efforts to improve production by introducing more diversity in certain regions of the maize genetic code.
Because the maize plant cannot withstand cold winters, it must be planted during the spring in temperate zones. Also, because its root system is generally shallow, the plant is highly dependent on soil moisture. Production in the United States has generally been robust and affected more by agricultural incentives and ethanol subsidies than weather patterns. Traditionally, a good American harvest was predicted if the corn fields were "knee-high by the Fourth of July"; although modern strains generally exceed this growth rate.
Last year, the U.S. corn crop was valued at $76 billion, with producers generating an estimated 12 billion bushels, more than a third of the world's supply. It is the biggest production crop worldwide and other top producing countries include China, Brazil, Mexico, Indonesia, India, France and Argentina.