Breeding of strawberries variety "Old Black", which is of uncertain origin. This variety was created by pollination, not direct manipulation of the plant's genes. Molecular breeding is the application of molecular biology tools in a breeding program. Genetic engineering is typically defined as the introduction of non-native genes into an organism. An excellent example of transgenic modification is in the case of cold resistant strawberries. In one particular variety genes from the arctic flounder, a fish that lives in very cold water, were used to give plants resistance to cold. This modification works because of the genetics of the arctic flounder. It lives
Plant breeding similar to the favored parent as possible. Returning to the example of the mildew resistant pea being crossed with a high-yielding but susceptible pea, to make the mildew resistant progeny of the cross most like the high-yielding parent, the progeny will be crossed back to that parent for several generations (See backcrossing ). This process removes most of the genetic contribution of the mildew resistant parent. Classical breeding is therefore a cyclical process. With classical breeding techniques, the breeder does not know exactly what genes have been introduced to the new cultivars. Some scientists therefore argue that plants produced by