variety

In biology, a stable group of organisms within a single species, clearly different from the rest of the species. Such a group would generally be called a variety for plants and a breed for animals. The differences lie in their genetic make-up and could have arisen naturally – through natural selection or as a result of selective breeding by humans. Most varieties have been produced by selective breeding, for example ‘Cox's’, ‘Golden Delicious’, and ‘Bramley’ apple varieties.

In most species there are often genetic differences between individuals that cause them to be distinct. These are not varieties – a variety is a group of individuals. However, not every genetically distinct group can be a variety. There must be a greater degree of variation between varieties than within the varieties for the term to be appropriate. This can be shown by collecting data on the mass, length, and diameter of varieties of tomato, potato, or runner bean, for example.

Selective breeding results in the production of new varieties if enough useful characteristics are brought together in one group. The ‘Bramley’ apple variety had the characteristics of vigorous growth, disease resistance, large apples, good storage, and soft texture on cooking. This has made it a popular cooking apple in some countries.