Vriezen is highly involved in food crop breeding, with the goal of adding or improving current crops' qualities. That is not easy. Assume biologists discover a wild cucumber variety that can use the limited available water more efficiently. "You cannot just pass on such a genetic feature to the cultivated plants that farmers use today. Cultivated crops must meet strict requirements. Cucumbers have a distinct shape, colour, weight, and flavour. If a farmer deviates from this, it could affect cucumber sales."

When crossing crops, it is critical to maintain all present qualities. When you cross a cultivated cucumber with a heat-resistant wild species, you either acquire unwanted qualities or lose beneficial ones. “It can take up to ten years for a new, complicated characteristic to be incorporated into an otherwise unmodified cultivated cucumber plant. That pace is far slower than the rate at which the climate has altered in recent years."

So far, the professor has discussed classical plant crossing, in which offspring are naturally produced and then selected in the laboratory for the presence of novel genes and/or proteins. There is a faster technique to change the genetic traits of plants, which is targeted genetic modification. Genetically modified crops are strictly regulated in Europe. Though, in February, the European Parliament passed legislation allowing for the commercial use of genetically modified crops using innovative techniques such as CRISPR-Cas, as long as the new plants remain patent-free. 

CRISPR-Cas can make tiny changes to plant DNA with high precision. According to Vriezen, this approach is not without its difficulties. "You modify one plant cell, which then must grow into a complete plant. Sometimes this is simple, such as plants that regenerate when one leaf is inserted into the soil. However, not all plants are capable of performing this trick. That is why we are developing techniques to enable CRISPR-Cas in plants that cannot or only rarely grow from a single cell. With this new strategy, we hope to perform fundamental scientific research while also looking for practical applications.