Sunflower seed: current production and uses Globally, sunflowers are the fourth most important oil crop. Most of the sunflower seed crop is crushed for
oil, and most of the oil is consumed by humans. A major byproduct of crushing is protein-rich cake, an excellent feed for livestock. A tiny proportion of the global sunflower crop is directly eaten as “nuts” or kernels.
Wild perennial relatives of sunflower There are 82 species of sunflowers (genus
Helianthus), all native to North America. Of these, 38 are perennials. Sunflower breeders have crossed many of these species with the crop sunflower because they are a source of useful genes. Perennial sunflowers survive the winter by storing food in underground freezing-tolerant stems called rhizomes. Rhizomes enable a plant to spread into new territory. Tubers are storage organs and are modified rhizomes.
Jerusalem Artichoke: the other perennial sunflower Native Americans domesticated the wild perennial sunflower
Helianthus tuberosus by selecting individuals with larger tubers. This crop plant (now called by the misleading name
Jerusalem artichoke) was grown for its tubers and not for its seed. The perennial sunflowers being developed as an oilseed crop by modern plant breeders may have tubers, but they will probably not be harvested. Digging tubers is probably ecologically sustainable on a small scale. On a large scale, annually disturbing the soil makes it vulnerable to soil erosion. Avoiding annual tillage is one of the main motivations for developing
perennial grain crops. == Breeding perennial sunflower ==