A group of similar individuals that have the potential to interbreed in nature are called:
species
A species is often defined as a group of organisms in which two individuals are capable of reproducing and producing a fertile offspring. A population is a group of individuals of the same species that are found in a given area. Therefore individuals of a given population can interbreed. However, 'population' is also a spatial concept, and sometimes individuals of different populations, but belonging to the same species can interbreed. And therefore the answer here is only 'species'. Community, on the other hand, is a group of interacting populations.