TRADITIONAL BREEDING, together with biotechnology, has allowed researchers for the past couple of decades to develop corn hybrids that not only yield well, but also offer defensive traits and better nutritive qualities. Scientists can insert genes into corn plants, screen the resulting offspring and choose plants where the modification provides sought-after traits. The pro- cess reduces the amount of time it takes to develop desired characteristics compared to traditional breeding. More recent innovations are cutting development time even further. Gene editing allows breeders to make changes within a plant rather than insert extra genes into a plant. Zinc-finger nucleases (ZFNs) provide targeted genome modification, binding novel DNA sequences with high sequence-specificity. Transcription activator-like effector nucleases (TALEN) cut specific DNA sequences to modify genomes. CRISPR technology is another option. “CRISPR shows even more promise, especially since it’s been run up the regulatory tree. Federal officials have confirmed scientists were able to knock out the gene causing yield drag in waxy corn using a natural analog,” says Nathan Fields, director of biotech and crop inputs for the National Corn Growers Association (NCGA). “If we get gene editing tools to market with less regulation and manage public perception from the start, we can take advan- tage of these natural variations and implement them in high-yielding corn hybrids more quickly.” CRISPR works with a segment of RNA called the guide RNA, or gRNA. The gRNA is able to identify homologous segments in the genome, and the gene editing is done during the subsequent DNA repair process. Benson Hill Biosystems, which uses cloud biology to unlock genetic potential of plants, recently launched CRISPR 3.0, a novel family of Cms1 nucleases. “CRISPR 3.0 expands the portfolio of genome editing capabilities… to lever- age natural genetic diversity of plants and develop more nutrient-dense crops, improve crop productivity and use natural resources more efficiently,” says Matt Crisp, CEO and co-founder of the company. No matter the path taken to get there, one goal for corn breeders remains the same: developing hybrids that can lower costs and increase yields for farmers. As the number of paths to reach that goal grows, industry experts say so also may opportunities for greater success. Barb Baylor Anderson anderagcom@sbcglobal.net INNOVATION BROADENS SCOPE OF CORN BREEDING CAPABILITIES 58 / SEEDWORLD.COM DECEMBER 2017 Martin Medina, North America hybrid breeding lead for Monsanto, visits a winter nursery in Rancagua, Chile.