Here’s proof that cultural diversity sustains plant diversity. Using DNA collected by immigrant farmers in Southern California, scientists at UC Riverside have determined that the genetic diversity of the corn they have planted in their home gardens far exceeds that of the commercially available varieties available at local supermarket.
Though the study was only preliminary, and utilized only a small initial sample, it has already urged scientists to broaden their inquiry into the nature and diversity of the corn and how it expresses characteristics relevant to drought tolerance, cob size, and flowering time.
Today, crop diversity is threatened around the globe as policies and programs encourage the use of a relatively few modern cultivars. This loss is compounded when the small farmers who are the stewards of that heritage of diversity abandon their farms and gardens to migrate to urban centers.
In 2008, when researchers first collected corn samples from home and community gardens in Southern California, the genetically compared the varieties they found there to five commercially available strains of corn, including two horticultural varieties, two industrial varieties, and one bulk-bin variety purchased from a supermarket. The results showed that corn in the immigrants gardens contained higher levels of genetic diversity than what was found in the commercially available varieties.
Southern California turns out to be an ideal location in which to study the combined effect of human and plant migration as Mexican and Central American immigrants often seed their gardens with crops imported from their home countries.