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"Open pollination" and "open pollinated" refer to a variety of concepts in the context of the sexual reproduction of plants. Generally speaking, the term refers to plants pollinated naturally by birds, insects, wind, or human hands. [1]
"Open pollinated" generally refers to seeds that will "breed true". When the plants of an open-pollinated variety self-pollinate, or are pollinated by another representative of the same variety, the resulting seeds will produce plants roughly identical to their parents. This is in contrast to the seeds produced by plants that are the result of a recent cross (such as, but not confined to, an F1 hybrid), which are likely to show a wide variety of differing characteristics. Open-pollinated varieties are also often referred to as standard varieties or, when the seeds have been saved across generations or across several decades, heirloom varieties. [2] While heirlooms are usually open-pollinated, open-pollinated seeds are not necessarily heirlooms; open-pollinated varieties are still being developed.
One of the challenges in maintaining an open-pollinated variety 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, field isolation, or other techniques.
Because they breed true, the seeds of open-pollinated plants are often saved by home gardeners and farmers. [2] Popular examples of open-pollinated plants include heirloom tomatoes, beans, peas, and many other garden vegetables.
A second use of the term "open pollination" refers to pollination by insects, birds, wind, or other natural mechanisms. This can be contrasted with cleistogamy, closed pollination, which is one of the many types of self pollination. [3] When used in this sense, open pollination may contrast 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".
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.
In biology, a hybrid is the offspring resulting from combining the qualities of two organisms of different breeds, varieties, species or genera through sexual reproduction. Generally, it means that each cell has genetic material from two different organisms, whereas an individual where some cells are derived from a different organism is called a chimera. Hybrids are not always intermediates between their parents, but can show hybrid vigor, sometimes growing larger or taller than either parent. The concept of a hybrid is interpreted differently in animal and plant breeding, where there is interest in the individual parentage. In genetics, attention is focused on the numbers of chromosomes. In taxonomy, a key question is how closely related the parent species are.
A true-breeding organism, sometimes also called a purebred(biology slang: pure line or true-breeding line), is an organism that always passes down certain phenotypic traits to its offspring of many generations. An organism is referred to as true breeding for each trait to which this applies, and the term "true-breeding" is also used to describe individual genetic traits.
Heterosis, hybrid vigor, or outbreeding enhancement is the improved or increased function of any biological quality in a hybrid offspring. An offspring is heterotic if its traits are enhanced as a result of mixing the genetic contributions of its parents. The heterotic offspring often has traits that are more than the simple addition of the parents' traits, and can be explained by Mendelian or non-Mendelian inheritance. Typical heterotic/hybrid traits of interest in agriculture are higher yield, quicker maturity, stability, drought tolerance etc.
Backcrossing is a crossing of a hybrid with one of its parents or an individual genetically similar to its parent, to achieve offspring with a genetic identity closer to that of the parent. It is used in horticulture, animal breeding, and production of gene knockout organisms.
An F1 hybrid (also known as filial 1 hybrid) is the first filial generation of offspring of distinctly different parental types. F1 hybrids are used in genetics, and in selective breeding, where the term F1 crossbreed may be used. The term is sometimes written with a subscript, as F1 hybrid. Subsequent generations are called F2, F3, etc.
In agriculture and gardening, hybrid seed is produced by cross-pollinated plants. Hybrid seed production is predominant in modern agriculture and home gardening. It is one of the main contributors to the dramatic rise in agricultural output during the last half of the 20th century. The alternatives to hybridization are open pollination and clonal propagation.
A monohybrid cross is a cross between two organisms with different variations at one genetic locus of interest. The character(s) being studied in a monohybrid cross are governed by two or multiple variations for a single location of a gene. Then carry out such a cross, each parent is chosen to be homozygous or true breeding for a given trait (locus). When a cross satisfies the conditions for a monohybrid cross, it is usually detected by a characteristic distribution of second-generation (F2) offspring that is sometimes called the monohybrid ratio.
Detasseling corn is removing the pollen-producing flowers, the tassel, from the tops of corn (maize) plants and placing them on the ground. It is a form of pollination control, employed to cross-breed, or hybridize, two varieties of corn.
An heirloom plant, heirloom variety, heritage fruit, or heirloom vegetable is an old cultivar of a plant used for food that is grown and maintained by gardeners and farmers, particularly in isolated or ethnic minority communities of the Western world. These were commonly grown during earlier periods in human history, but are not used in modern large-scale agriculture.
An heirloom tomato is an open-pollinated, non-hybrid heirloom cultivar of tomato. They are classified as family heirlooms, commercial heirlooms, mystery heirlooms, or created heirlooms. They usually have a shorter shelf life and are less disease resistant than hybrids. They are grown for various reasons: for food, historical interest, access to wider varieties, and by people who wish to save seeds from year to year, as well as for their taste.
Plant breeders use different methods depending on the mode of reproduction of crops, which include:
Hand pollination, also known as mechanical pollination is a technique that can be used to pollinate plants when natural or open pollination is either undesirable or insufficient.
Hybrid rice is a type of Asian rice that has been crossbred from two very different parent varieties. As with other types of hybrids, hybrid rice typically displays heterosis or "hybrid vigor", so when grown under the same conditions as comparable purebred rice varieties, it can produce up to 30% more yield. To produce hybrid seeds in large quantity, a purebred sterile rice variety is fertilized with fertile pollen from a different variety. High-yield crops, including hybrid rice, are one of the most important tools for combatting worldwide food crises.
A doubled haploid (DH) is a genotype formed when haploid cells undergo chromosome doubling. Artificial production of doubled haploids is important in plant breeding.
Cannabis strains are either pure or hybrid varieties of the plant genus Cannabis, which encompasses the species C. sativa, C. indica, and C. ruderalis.
Plant breeding is the science of changing the traits of plants in order to produce desired characteristics. It has been used to improve the quality of nutrition in products for humans and animals. The goals of plant breeding are to produce crop varieties that boast unique and superior traits for a variety of applications. The most frequently addressed agricultural traits are those related to biotic and abiotic stress tolerance, grain or biomass yield, end-use quality characteristics such as taste or the concentrations of specific biological molecules and ease of processing.
Plant breeding started with sedentary agriculture, particularly the domestication of the first agricultural plants, a practice which is estimated to date back 9,000 to 11,000 years. Initially, early human farmers selected food plants with particular desirable characteristics and used these as a seed source for subsequent generations, resulting in an accumulation of characteristics over time. In time however, experiments began with deliberate hybridization, the science and understanding of which was greatly enhanced by the work of Gregor Mendel. Mendel's work ultimately led to the new science of genetics. Modern plant breeding is applied genetics, but its scientific basis is broader, covering molecular biology, cytology, systematics, physiology, pathology, entomology, chemistry, and statistics (biometrics). It has also developed its own technology. Plant breeding efforts are divided into a number of different historical landmarks.
Starmaya is an F1 hybrid coffee tree that can be propagated by seed rather than through somatic embryogenesis (SE). It was propagated from a parent plant that is male-sterile. This facilitates controlled pollination because breeders do not have to manually castrate each individual flower of the autogamous coffee tree.
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