Once in the field, it may also be backcrossed a number of times to restore the desired genetic background. Regardless of how the trait was initially introduced, the subsequent development follows a well esta blished and formal process. The information gathered in these steps is extensive. A great number of characteristics are considered in detail during the process of developing a new variety because the developer is keenly interested in being certain that the new variety behaves just like other successful varieties of the crop in as many agronomically significant ways as possible. So aside from the desired phenotypic change, engineered plants are usually similar to their non-engineered parents, and that allows the agency to assess them based on previous experience with the biology of the crop and its environment and what is known about the introduced trait.
Familiarity varies from case to case.
Consider one example. This is part of what forms our basis for familiarity with pest resistance in melon. Generally, many traits for pest resistance available from traditional breeding can be used as a base for our familiarity with genetically engineered traits. Resistance genes found in traditional breeding sources are not the same as those introduced by genetic engineering, but they confer similar phenotypes. In other deregulated pest resistant crops the resistance traits are found in the gene pool, but are not necessarily found in commercial lines.