What happens to genes in traditional plant breeding?

Plant breeding is the art and science of changing the genetics of plants in order to produce desired characteristics.

"Conventional" breeding relies on cross-pollination between two sexually compatible crop varieties.

Generally, these are from the same species (e.g. wheat), but breeding can also take place between related species (e.g. rye and wheat to produce triticale, or blackberry and raspberry to give tayberries).

However, the term also covers techniques such as radiation- or chemical-induced mutation.