Breeding patterns and biotechnological approach in sugarcane and sugarbeet

The biology of sugarcane and sugarbeet differs considerably. Sugarbeet is used as an annual dicotyl crop and has a small and well-defined genome. It has been adapted for high yield performance by hybrid breeding involving a minimum of 3 different lines with specific biological traits. The application of genomics is concentrated on various methods of marker assisted selection to biological traits and resistance to pests and diseases. Genetically modified (GM) sugarbeet is transformed for the purpose of achieving improved agronomic (input) traits in terms of herbicide tolerance and resistance to rhizomania, while the resistance to nematodes and fungi is under research. Creating a GM variety is a very complex process which takes more than 10 years. Sugarbeet hybrid seed is always propagated by breeding companies alone, and due to the specific hybrid breeding patterns involved, varieties are in effect be kept under lock and key.

Sugarcane is a perennial grass and has a large and variable genome. Different directly related species were crossed to commercial varieties, which are clones. These are easily propagated by stecklings. Genomics are used primarily to define precisely the genetics of varieties and their relation to wild species. GM sugarcane is transformed to achieve herbicide tolerance and resistance to various pests and diseases. Compared to sugarbeet, creation of a GM variety is very easy and takes only a few years. Stecklings can be propagated by breeders, research institutes and even by farmers.

The improvement of biochemical output traits in both crops by transgenics was yet described. Realization of this in the short term is not likely because of the complex biochemical relations requiring elucidation. In contrast to the situation with sugarbeet, a biotechnological approach with the closely related crops of maize, sorghum and even rice can be used intensively in sugarcane research.

In Germany, the first GM sugarbeet varieties tolerant to herbicides are now being officially tested. Highest care is taken to ensure that all parts of trial beets are properly disposed of, as all usages as a foodstuff are as yet prohibited both in Germany and throughout Europe. Market release is not expected within the short term owing to low yield performance of varieties and delayed authorization of marketing by the EU. Furthermore, the point in time of sufficient consumer acceptance to allow effective marketing of sugar derived from GM sugarbeet remains unforeseeable.