Intraspecific breeding is the act of breeding two varieties within the same species.
The breeding of intraspecific organisms produce hybrids that often show "hybrid vigour" (heterosis), growing more vigorously and yielding more than in-bred lines. Intraspecific offspring are usually fertile, but will not breed "true", although they share the same gene pool. Intraspecific interactions do not generally lead to the extinction of a species although their offspring will be highly variable, some resembling one parent, some the other, and others showing a whole range of characteristics and combinations between the two.
Intraspecific offspring, should not be confused with interspecific hybrids such as the mule which are generally not fertile.
In natural environments, intraspecific organisms are much more likely to show pronounced territorial and aggressive behaviour in competition for resources, compared with interspecific organisms.