This type of seed is not at all common in today’s industrial states. For instance, a very large share of the plants commercially grown in Germany are hybrids, where the seeds, are either infertile or, if the second generation can be grown, yields are far lower. UN Food and Agriculture Organisation (FAO) statistics show that in the past 100 years around three quarters of the seed biodiversity which had existed in 1900 have disappeared. Many vegetables are commercially available practically only as hybrids. This includes kohlrabi, cauliflower, broccoli and radishes. Hybrids are created through self-pollination with parent lines which are as different as possible, but because plant breeders select over many years for specific characteristics, such as size, shape, colour or disease resistance, hybridisation results in high-performance, high-yield plants. The positive characteristics, however, often apply only to the first generation of plants, often yield shrinks even as early as the second generation. This means that the seed from hybrid plants can’t be collected, saved and sown from year to year, in other words they are a genetic cul de sac. Farmers become dependent on big agricultural companies from whom they must buy seed year after year.