...“These two studies provide a new and more comprehensive understanding of genomic variation in maize, which will be critically important to plant breeders as they work to increase corn yield in the face of global population growth and climate change,” said plant geneticist Jeffrey Ross-Ibarra, the lead researcher on the UC Davis-directed study.
...The world’s population is expected to climb from 7 billion people this year to an estimated 9 billion by 2050. The Food and Agriculture Organization of the United Nations predicts that food production will need to increase by 70 percent over the next four decades to meet anticipated demand. Globally, 90 percent of these production increases will need to come from increasing crop yield on existing farmland rather than by bringing new land into agricultural production.
The new UC Davis-led study analyzed the evolution of maize during the period when it was domesticated 10,000 years ago, as well as during subsequent breeding. The study was based on the resequencing of 75 genomes of maize and its relatives, including wild strains, traditional cultivated varieties and improved modern inbred lines. (The first sequencing of the reference maize genome was announced by a U.S.-based consortium of researchers in 2009.) The new maize genome study showed that:
- Though a substantial amount of diversity was lost during domestication, new diversity has arisen since domestication in the form of novel mutations;
- Hundreds of identified genes appear to have played a role in domestication of maize from the wild, and many of these genes also appear to have been important for modern breeding;
- Selection applied during initial domestication appears to have been much stronger than selection applied more recently during maize breeding; and
- Modern strategies of breeding for hybrid vigor have been accompanied by marked changes in gene expression in maize.