Measuring the sugar content of beet roots is surprisingly tedious and time-consuming. You have to pull out a root, cut off a piece, and dip it into a molasses solution calibrated to a precise concentration. If the piece of root floats, the cells contain little sugar; if it sinks, they contain a lot.
However, breeders working to improve sugar beets go out into the fields with a small flat box strapped to their waist. A long, flexible wire with a needle at the end extends from the box. When they spot a promising root, the breeder inserts the needle into it, and an indicator on the box moves. The less sugar the root contains, the more the indicator needle deflects.
This needle lets breeders quickly estimate the sugar content of beet varieties growing in experimental plots.
