The State of the crops that have a narrow genetic base, which could lead to the growing threat of attack by pests and pathogens. Genetically vulnerable crops have a limited number of varieties with a narrow range of genetic resistance to pests and diseases. Modern farming has reduced the genetic base of crops, in comparison with what farmers plant in traditional systems. These systems are often characterized by many different varieties, often expressing different levels of susceptibility to a particular pest or disease. This heterogeneity, as opposed to the uniformity in the modern varieties, reduces the risk of attack by pests and pathogens.