What does genetic modification in crops involve?

Genetic modification in crops specifically involves altering the DNA of a plant to achieve desired traits. This process allows scientists to directly modify the genetic material of the plant, enabling the introduction of new characteristics such as resistance to pests, tolerance to herbicides, or improved nutritional content. This technique can lead to advancements that traditional breeding methods may not be able to achieve as quickly or efficiently.

The other options reflect practices that do not encompass genetic modification. For instance, cross-breeding different plant species is a traditional breeding method that relies on the natural reproductive processes of plants rather than direct manipulation of their genetic material. Applying chemical fertilizers involves enhancing soil nutrient content to promote plant growth but does not change the plant's genetic makeup. Similarly, using traditional farming methods refers to established agricultural practices without the inclusion of modern genetic engineering techniques. Thus, the correct answer highlights the specific and innovative aspect of modifying genetic material in crops to introduce desirable traits.