Open pollination

Detasseling corn (maize) plants from one variety in a field where two varieties are planted. The male flowers are removed so that all seeds are hybrids sired from the second variety.

Open pollination is pollination by insects, birds, wind, or other natural mechanisms, and contrasts with cleistogamy, closed pollination, which is one of the many types of self pollination.[1] Open pollination also contrasts with controlled pollination, a procedure used to ensure that all seeds of a crop are descended from parents with known traits, and are therefore more likely to have the desired traits.

The seeds of open-pollinated plants will produce new generations of those plants; however, because breeding is uncontrolled and the pollen (male parent) source is unknown, open pollination may result in plants that vary widely in genetic traits. Open pollination may increase biodiversity.

Some plants (such as many crops) are primarily self pollenizing and also breed true, so that even under open pollination conditions the next generation will be (almost) the same. Even among true breeding organisms, some variation due to genetic recombination or to mutation can produce a few "off types".

One of the bigger challenges in maintaining a strain by open pollination is avoiding introduction of pollen from other strains. Based on how broadly the pollen for the plant tends to disperse, it can be controlled to varying degrees by greenhouses, tall wall enclosures, or field isolation.

Popular examples of plants produced under open pollination conditions include heirloom tomatoes.

Relationship to hybrid inbred lines

Hybrid pollination, a type of controlled pollination in which the pollen comes from a different strain (or species), can be used to increase crop suitability, especially through heterosis. The resulting hybrid strain can sometimes be inbred and selected for desired traits until a strain that breeds true by open pollination is achieved. The result is referred to as a inbred hybrid strain. To add some confusion, the term hybrid inbred applies to hybrids that are made from selected inbred lines that have certain desired characteristics (see inbreeding). The latter type of hybrid is sometimes designated F1 hybrid, i.e. the first hybrid (filial) generation whose parents were (different) inbred lines.

References

  1. ↑ Kearns, C.A.; Inouye, D.W. 1993. Techniques for pollination biologists. University Press of Colorado, Niwot, CO.

Further reading