Corn Research

Fusarium resistant corn inbreds
Dr. Laima Kott, University of Guelph

The production of Fusarium resistant corn inbreds is based on the ability to generate young corn plants from corn pollen in culture plates. This method works well in other crops, but has not been achieved in corn. Briefly, corn pollen is cultured in a liquid medium where the pollen grains develop into corn embryos that eventually grow into normal corn plants. This pollen-to-plant protocol has now been largely defined in our lab and some lines and hybrids respond predicatively. Globally, no other lab has been able to deliver these results to date, making this research unique and extremely important to corn breeding.

Progress was made by defining the carbon source and growth enhancers in media, culture temperatures, and tissue manipulation, among others. Not only can this method deliver 100 percent homozygosity through a one culture sequence, but more importantly can be used in in vitro selection to identify new traits, such as Fusarium resistance, in new corn inbreds.

While in culture the pollen is exposed to a short pulse of ultra violet (UV) radiation that induces minor genetic changes. The UV exposure is long enough to kill half of the pollen grains, but survivors likely carry small point mutations. As these surviving pollen grains grow into embryos we can identify those of interest by adding specific chemicals to the media, thereby killing all pollen grains that do not carry the trait that we are looking for. The biochemicals used are specific selection agents that preserve those embryos with mutations that may now carry Fusarium resistance.



To date, positive results indicate that a UV pulse of 10 to 20 seconds generates point mutations in cultured pollen that can be screened in vitro with bio-chemicals such as oxalic acid that can identify those embryos with Fusarium resistance. Some selected green plants have already been produced using this selection protocol.

This project is supported through ORD.