Everything About Wood: 03/24/16

Thursday, 24 March 2016

HORTICULTURE

Horticulture is the branch of agriculture that deals with the art, science, technology, and business of growing plants. It includes the cultivation of medicinal plants, fruits, vegetables, nuts, seeds, herbs, sprouts, mushrooms, algae, flowers, seaweeds and non-food crops such as grass and ornamental trees and plants. It also includes plant conservation, landscape restoration, landscape and garden design, construction, and maintenance, and arboriculture. Inside agriculture, horticulture contrasts with extensive field farming as well as animal husbandry.

A fruit and vegetable market in Milan

Horticulturists apply their knowledge, skills, and technologies used to grow intensively produced plants for human food and non-food uses and for personal or social needs. Their work involves plant propagation and cultivation with the aim of improving plant growth, yields, quality, nutritional value, and resistance to insects, diseases, and environmental stresses. They work as gardeners, growers, therapists, designers, and technical advisors in the food and non-food sectors of horticulture. Horticulture even refers to the growing of plants in a field or garden.

A vertical garden

Etymology

The word horticulture is modeled after agriculture, and comes from the Greek χόρτος, which in Latin became hortus "garden" and cultūra "cultivation", from cultus, the perfect passive participle of the verb colō "I cultivate". Hortus is cognate with the native English word yard (in the meaning of land associated with a building) and also the borrowed word garden.

Horticultural and health-related produce

Scope

Horticulture involves nine areas of study, which can be grouped into two broad sections: ornamentals and edibles:

Arboriculture is the study of, and the selection, plant, care, and removal of, individual trees, shrubs, vines, and other perennial woody plants.
Turf management includes all aspects of the production and maintenance of turf grass for sports, leisure use or amenity use.
Floriculture includes the production and marketing of floral crops.
Landscape horticulture includes the production, marketing and maintenance of landscape plants.
Olericulture includes the production and marketing of vegetables.
Pomology includes the production and marketing of pome fruits.
Viticulture includes the production and marketing of grapes.
Oenology Includes all aspects of wine and winemaking.
Postharvest physiology involves maintaining the quality of and preventing the spoilage of plants and animals.

Anthropology

Horticulture has a very long history. The study and science of horticulture dates all the way back to the times of Cyrus the Great of ancient Persia, and has been going on ever since, with present-day horticulturists such as Freeman S. Howlett and Luther Burbank. The practice of horticulture can be retraced for many thousands of years. The cultivation of taro and yam in Papua New Guinea dates back to at least 6950–6440 cal BP. The origins of horticulture lie in the transition of human communities from nomadic hunter-gatherers to sedentary or semi-sedentary horticultural communities, cultivating a variety of crops on a small scale around their dwellings or in specialized plots visited occasionally during migrations from one area to the next (such as the "milpa" or maize field of Mesoamerican cultures). In the Pre-Columbian Amazon Rainforest, natives are believed to have used biochar to enhance soil productivity by smoldering plant waste. European settlers called it Terra Preta de Indio. In forest areas such horticulture is often carried out in swiddens ("slash and burn" areas). A characteristic of horticultural communities is that useful trees are often to be found planted around communities or specially retained from the natural ecosystem.

Horticulture primarily differs from agriculture in two ways. First, it generally encompasses a smaller scale of cultivation, using small plots of mixed crops rather than large fields of single crops. Secondly, horticultural cultivations generally include a wide variety of crops, even including fruit trees with ground crops. Agricultural cultivations however as a rule focus on one primary crop. In pre-contact North America the semi-sedentary horticultural communities of the Eastern Woodlands (growing maize, squash and sunflower) contrasted markedly with the mobile hunter-gatherer, communities of the Plains people. In Central America, Maya horticulture involved augmentation of the forest with useful trees such as papaya, avocado, cacao, ceiba and sapodilla. In the cornfields, multiple crops were grown such as beans (using cornstalks as supports), squash, pumpkins and chilli peppers, in some cultures tended mainly or exclusively by women.

Horticulture organizations

Desh Bhagat School of Horticulture Sciences at Desh Bhagat University, Punjab is a prestigious institution in India to encourage the research and promote horticulture techniques throughout the country. The Royal Horticultural Society is a UK charity which overseas several major shows and gardens.

The professional body representing horticulturists in Great Britain and Ireland is the Institute of Horticulture (IOH). Also, the IOH has an international branch for members outside of these islands.

The International Society for Horticultural Science promotes and encourages research and education in all branches of horticultural science.

The American Society of Horticultural Science, promotes and encourages research and education in all branches of horticultural science in the Americas.

The Australian Society of Horticultural Science was established in 1990 as a professional society for the promotion and enhancement of Australian horticultural science and industry.

The National Junior Horticultural Association (NJHA) was established in 1934 and was the first organization in the world dedicated solely to youth and horticulture. NJHA programs are designed to help young people obtain a basic understanding of, and develop skills in, the ever expanding art and science of horticulture

The New Zealand Horticulture Institute

The Global Horticulture Initiative (GlobalHort) fosters more efficient and effective partnerships and collective action among different stakeholders in horticulture. The organization has a special focus on horticulture for development (H4D), i.e. using horticulture to reduce poverty and improve nutrition worldwide. To be efficient, GlobalHort is organized in a consortium of national and international organizations to collaborate in research, training, and technology-generating activities designed to meet mutually-agreed-upon objectives. GlobalHort is a not-for-profit organization registered in Belgium.

References

^ "Xόρτος". Wiktionary. Retrieved 2016-01-20.
^ hortus. Charlton T. Lewis and Charles Short. A Latin Dictionary on Perseus Project.
^ Harper, Douglas. "horticulture. Online Etymology Dictionary.
^ Entry for yard Dictionary.com (presenting information supposedly from Random House Dictionary)
^ Fullagar, Richard, Judith Field, Tim Denham, and Carol Lentfer (2006) Early and mid Holocene tool-use and processing of taro (Colocasia esculenta), yam (Dioscorea sp.) and other plants at Kuk Swamp in the highlands of Papua New Guinea Journal of Archaeological Science 33: 595–614
^ von Hagen, V.W. (1957) The Ancient Sun Kingdoms Of The Americas. Ohio: The World Publishing Company
^ Solomon, Dawit, Johannes Lehmann, Janice Thies, Thorsten Schafer, Biqing Liang, James Kinyangi, Eduardo Neves, James Petersen, Flavio Luizao, and Jan Skjemstad, Molecular signature and sources of biochemical recalcitrance of organic carbone in Amazonian Dark Earths, 71 Geochemica et cosmochemica ACTA 2285, 2286 (2007) ("Amazonian Dark Earths (ADE) are a unique type of soils apparently developed between 500 and 9000 years B.P. through intense anthropogenic activities such as biomass-burning and high-intensity nutrient depositions on pre-Columbian Amerindian settlements that transformed the original soils into Fimic Anthrosols throughout the Brazilian Amazon Basin.") (internal citations omitted)
^ Glaser, Bruno, Johannes Lehmann, and Wolfgang Zech, Ameliorating physical and chemical properties of highly weathered soils in the tropics with charcoal – a review, 35 Biology and Fertility of Soils 219, 220 (2002) ("These so called Terra Preta do Indio (Terra Preta) characterize the settlements of pre-Columbian Indios. In Terra Preta soils large amounts of black C indicate a high and prolonged input of carbonized organic matter probably due to the production of charcoal in hearths, whereas only low amounts of charcoal are added to soils as a result of forest fires and slash-and-burn techniques.") (internal citations omitted)
^ McGee, J.R. and Kruse, M. (1986) Swidden horticulture among the Lacandon Maya [videorecording (29 mins.)]. University of California, Berkeley: Extension Media Center
^ Thompson, S.I. (1977) Women, Horticulture, and Society in Tropical America. American Anthropologist, N.S., 79: 908–10

CULTIGEN

A cultigen (from the Latin cultus - cultivated, and gens - kind) is a plant that has been deliberately altered or selected by humans; it is the result of artificial selection. These "man-made" or anthropogenic plants are, for the most part, plants of commerce that are used in horticulture, agriculture and forestry. Because cultigens are defined by their mode of origin and not by where they are growing, plants meeting this definition remain cultigens whether they are naturalised in the wild, deliberately planted in the wild, or growing in cultivation. Cultigens arise in the following ways: selections of variants from the wild or cultivation including vegetative sports (aberrant growth that can be reproduced reliably in cultivation); plants that are the result of plant breeding and selection programs; genetically modified plants (plants modified by the deliberate implantation of genetic material); and graft-chimaeras plants grafted to produce mixed tissue, the graft material possibly from wild plants, special selections, or hybrids).

Cultigens may be named in any of a number of ways. The traditional method of scientific naming is under the International Code of Nomenclature for algae, fungi, and plants and many of the most important cultigens, like maize (Zea mays) and banana (Musa acuminata), are so named. Although it is perfectly in order to give a cultigen a botanical name, in any rank desired, now or at any other time, these days it is more common for cultigens to be given names in accordance with the principles, rules and recommendations laid down in the International Code of Nomenclature for Cultivated Plants (ICNCP) which provides for the names of cultigens in three classification categories, the cultivar, the Group (formerly cultivar-group), and the grex. From that viewpoint it may be said that there is a separate discipline of cultivated plant taxonomy, which forms one of the ways to look at cultigens. The ICNCP does not recognize the use of trade designations and other marketing devices as scientifically acceptable names, but does provide advice on how they should be presented.

Not all cultigens have been given names according to the Cultivated Plant Code. Apart from ancient cultigens like those mentioned above there may be occasional anthropogenic plants such as those that are the result of breeding, selection, and tissue grafting that are of no commercial value and have therefore not been given names according to the ICNCP.

Formal definition

A cultigen is a plant whose origin or selection is primarily due to intentional human activity.

The distinction "wild" and "cultivated"

Interest in the distinction between wild and cultivated plants dates back to antiquity. Botanical historian Alan Morton notes that wild and cultivated plants (cultigens) were of intense interest to the ancient Greek botanists (partly for religious reasons) and that the distinction was discussed in some detail by Theophrastus (370–285 BCE) the "Father of Botany". Theophrastus was a pupil of both Plato and Aristotle and succeeded the latter as head of the Peripatetic School of Philosophy at the Lyceum in Athens. Theophrastus accepted the view that it was human action, not divine intervention, that produced cultivated plants (cultigens) from wild plants and he also "had an inkling of the limits of culturally induced (phenotypic), changes and of the importance of genetic constitution" (Historia Plantarum III, 2,2 and Causa Plantarum I, 9,3). He also noted that cultivated varieties of fruit trees would degenerate if cultivated from seed.

Origin of term

The word cultigen was coined in 1918 by Liberty Hyde Bailey (1858–1954) an American horticulturist, botanist and cofounder of the American Society for Horticultural Science. He was aware of the need for special categories for those cultivated plants that had arisen by intentional human activity and which would not fit neatly into the Linnaean hierarchical classification of ranks used by the International Rules of Botanical Nomenclature (which later became the International Code of Nomenclature for algae, fungi, and plants).

Liberty Hyde Bailey 1858-1954, who coined the word cultigen in 1918

In his 1918 paper Bailey noted that for anyone preparing a descriptive account of the cultivated plants of a country (he was at that time preparing such an account for North America) it would be clear that there are two gentes or kinds (Latin singular, gens; plural, gentes) of plants. Firstly, those that are of known origin or nativity "of known habitat". These he referred to as indigens. The other kind was:

" ... a domesticated group of which the origin may be unknown or indefinite, which has such characters as to separate it from known indigens, and which is probably not represented by any type specimen or exact description, having therefore no clear taxonomic beginning."

He called this second kind of plant a cultigen, the word derived from the conflation of the Latin cultus - cultivated, and gens - kind.

In 1923, Bailey extended his original discussion emphasising that he was dealing with plants at the rank of species and he referred to indigens as:

"those that are discovered in the wild"

and cultigens as plants that:

"arise in some way under the hand of man"

He then defined a cultigen as:

"a species, or its equivalent, that has appeared under domestication"

Bailey's definitions

Bailey soon altered his 1923 definition of cultigen when, in 1924, he gave a new definition in the Glossary of his Manual of Cultivated Plants as:

" Plant or group known only in cultivation; presumably originating under domestication; contrast with indigen "

This, in essence, is the definition given at the head of this piece. This definition of the cultigen permits the recognition of cultivars, unlike the 1923 definition which restricts the idea of the cultigen to plants at the rank of species.

In later publications of the Liberty Hyde Bailey Hortorium, Cornell, the idea of the cultigen having the rank of species returned (e.g. Hortus Second in 1941 and Hortus Third in 1976): both of these publications indicate that the terms cultigen and cultivar are not synonymous and that cultigens exist at the rank of species only.

"A cultigen is a plant or group of apparent specific rank, known only in cultivation, with no determined nativity, presumably having originated, in the form in which we know it, under domestication. Compare indigen. Examples are Cucurbita maxima, Phaseolus vulgaris, Zea mays'".

Recent usage in horticulture has, however, maintained a distinction between cultigen and cultivar while nevertheless allowing the inclusion of cultivars within the definition (see "Usage in horticulture" below).

Cultigens and cultivars

Cultigen and cultivar may be confused with one another. Cultigen is a general-purpose term encompassing not only plants with cultivar names but others as well (see introductory text above), while cultivar is a formal classification category (in the ICNCP).

Although in his 1923 paper Bailey used only the rank of species for the cultigen, it was clear to him that many domesticated plants were more like botanical varieties than species and so he established a new classification category for these, the cultivar, generally assumed to be a contraction of the words “cultivated” and “variety”. Bailey was never explicit about the etymology of the word cultivar and it has been suggested that it is a contraction of the words “cultigen” and “variety”. He defined cultivar in his 1923 paper as:

... " a race subordinate to species, that has originated and persisted under cultivation; it is not necessarily, however, referable to a recognised botanical species. It is essentially the equivalent of the botanical variety except in respect to its origin ".

This definition and understanding of cultivar has changed over time (see current definition in cultivar).

Usage

Usage in Botany

In botanical literature the word cultigen is generally used to denote a plant which, like the wheat (Triticum aestivum) is of unknown origin, but presumed to be an ancient human selection. Plants like these have been given binomials according to the Botanical Code and therefore have names that have the same form as those of plants that occur naturally in the wild. As these cultigens are the result of deliberate human selection there is no difference, in principle, between them and modern plants with additional names under the Cultivated Plant Code. The use of binomials for cultigens occurs for the most part because they were following the accepted nomenclatural conventions that pre-dated the Cultivated Plant Code. In theory cultigens can be named under either Code or both, although in practice almost all have cultivar names governed by the Cultivated Plant Code.

Usage in Horticulture

The year 1953 was an important one for cultivated plant taxonomy because this was the date of publication of the first International Code of Nomenclature for Cultivated Plants in which Bailey’s term cultivar was introduced. It was also the year that the eponymous journal commemorating the work of Bailey (who died in 1954), Baileya, was published. In the first volume of Baileya taxonomist and colleague of Bailey, George Lawrence, wrote a short article clarifying the distinction between the new term cultivar and the variety. In the same article he also tried to clarify the critical term taxon which had been introduced by German biologist Meyer in the 1920s but had only just been introduced and accepted in botanical circles. This brief article by Lawrence is useful for its insight into the understanding of the meaning of the word cultigen at this time. He opens the article:

In 1918, L.H. Bailey distinguished those plants originating in cultivation from the native plants by designating the former as cultigens and the latter as indigens (indigenous or native to the region). At the same time he proposed the term cultivar to distinguish varieties originating in cultivation from botanical varieties known first in the wild.

In horticulture the definition and use of the term cultigen has varied but generally, unlike usage in botany, it encompasses cultivars. One example is the definition given in the Botanical Glossary of The New Royal Horticultural Society Dictionary of Gardening which defines cultigen as:

" A plant found only in cultivation or in the wild having escaped from cultivation; included here are many hybrids and cultivars, "...

The use of cultigen in this sense is essentially the same as the definition of the cultigen published by Bailey in 1924.

Others Usage

The term cultigen is occasionally applied in a very general sense to any organisms that do not have a wild or uncultivated counterpart, see for example. Animal breeds raised in captivity would be included here. It might seem that the word "domesticate" could serve the same purpose as cultigen. However, the widely held view that domesticated plants and animals are simply wild plants and animals used in domestic situations (often as tamed wild animals, or plants introduced directly from the wild, rather than being specially selected for particular desirable characteristics) would not support this view. However, there is debate about what constitutes domestication and some authors maintain that to be termed domesticated or a "domesticate" a plant or animal must have been genetically "changed" in some way from its wild counterparts, either by conscious or unconscious selection. Regardless of this debate, it is clear that the term cultigen originated within horticulture and botany and that these areas are where it has mostly been applied.

Recommended usage

Wider use of the term cultigen as defined here has been proposed or the following reasons:

supports current usage in horticulture
assists clarity in non-technical discussions about “wild” and “cultivated” plants (for example, cultivated plants as commonly understood (plants in cultivation) are not the same as the "cultivated plants" of the Cultivated Plant Code, and the distinction between "wild" and "cultivated" habitats is becoming progressively blurred)
has the potential to simplify the language and definitions used in the Articles and Recommendations of the Cultivated Plant Code
gives greater precision and clarity to the definition of the respective scope, terminology and concepts of the Botanical Code and the Cultivated Plant Code
avoids the potential for confusion within the Cultivated Plant Code over its scope, that is, whether it is concerned with:

where plants are growing (in the wild or in cultivation)
how they originated (whether they are the result of intentional human activity or not)
whether it simply provides a mechanism for regulating the names of those cultigens requiring special classification categories that are not part of the Linnaean hierarchy of the Botanical Code i.e. cultivar and Group names

Critique of definition

Potential misunderstandings and questions arising from the definition of cultigen given here have been discussed in the literature and are summarised below.

Natural and artificial selection

The selection process is termed "artificial" when human preferences or influences have a significant effect on the evolution of a particular population or species (see artificial selection). Note: artificial selection is a part of the overall selection process – it does not imply that humans are not part of nature, it is simply useful sometimes to distinguish when there has been human influence on selection (as with cultigens).

What exactly does altered mean?

There are cases that do not seem to comply with the definition. For example, we can presume that the entire global flora is changing as a result of human-induced climate change. Does this mean that all plants are cultigens?

In cases like this the definition refers to "deliberate" selection and this would be of particular plant characteristics that are not exhibited by a plant's wild counterparts (but see Selections from the wild).

What exactly does deliberately selected mean?

From the moment a plant is taken from the wild it is subject to human selection pressure – from the selection of the original propagation material to the purchase of the plant in a nursery. Surely this form of selection is not deliberate? Again, the early human selection of crops 7,000-10,000 years ago is thought to have occurred quite unintentionally. Variants useful to horticulture often arise spontaneously, they are not deliberate products. Are these cases of unintentional, accidental, or unconscious selection?

There certainly appear to be cases where origin or selection of a plant is not "deliberate". However, the long term propagation of plants that have some utility, usually economic or ornamental, can hardly be regarded as unintentional and these plants will, almost without exception, have characteristic(s) that distinguish them from their wild counterparts.

What about plants selected from the wild?

Plants like Quercus robur, Pedunculate or English Oak, Liquidambar styraciflua, Sweetgum and Eucalyptus globulus, Blue Gum grown in parks and gardens are essentially the same as their wild counterparts and are therefore not cultigens. However, occasionally within natural plant variation there occur characters that are of value to horticulture but of little interest to botany. For example a plant might have flowers of several different colours but these may not have been given formal botanical names. It is customary in horticulture to introduce such variants to commerce and to give them cultivar names. Technically these plants have not been deliberately altered in any way from plants growing (or once growing) in the wild but as they are deliberately selected and named it seems permissible to refer to them as cultigens. These occurrences are very few. The definition could be (clumsily) extended by mentioning that selection can be for "desirable variation that is not recognised in botanical nomenclature".

What about gene flow between populations?

Occasionally cultigens escape from cultivation into the wild where they breed with indigenous plants. Selections may be made from the progeny in the wild and brought back into cultivation where they are used for breeding and the results of the breeding again escape into the wild to breed with indigenous plants. Lantana has behaved much like this. The genetic material of a cultigen may become part of the gene pool of a population where, over time, it may be largely or completely swamped. In cases like this what plants are to be called cultigens?

Whether a plant is a cultigen or not does not depend on where it is growing. If it complies with the definition then it is a cultigen. Cases like this have always been difficult for botanical nomenclature. Unnamed progeny in the wild might be given a name like Lantanaaff. camara (aff. = having affinities with) or may remain unnamed. Its cultigenic origin may or may not be recognised by the allocation of a cultivar name.

Plants of unknown origin

Occasionally plants will occur whose origin is unknown. Plants growing in cultivation that are unknown in the wild may be determined as cultigenic as a result of scientific investigation, but may remain a mystery.

Difficult cases

It may happen that a hybrid cross that has occurred in nature is also performed deliberately in cultivation and that the progeny appear identical. How do we know which plants are cultigens?

If the cross in cultivation is followed by deliberate selection and naming then this will indicate a cultigen. However in a case like this it may not be possible to tell.

References

^ McNeill, J.; Barrie, F.R.; Buck, W.R.; Demoulin, V.; Greuter, W.; Hawksworth, D.L.; Herendeen, P.S.; Knapp, S.; Marhold, K.; Prado, J.; Prud'homme Van Reine, W.F.; Smith, G.F.; Wiersema, J.H.; Turland, N.J. (2012). International Code of Nomenclature for algae, fungi, and plants (Melbourne Code) adopted by the Eighteenth International Botanical Congress Melbourne, Australia, July 2011, Regnum Vegetabile 154. A.R.G. Gantner Verlag KG. ISBN 978-3-87429-425-6. Art. 28 "Note 3. Nothing precludes the use, for cultivated plants, of names published in accordance with the requirements of this Code."
^ Brickell, C.D.; Alexander, C.; David, J.C.; Hetterscheid, W.L.A.; Leslie, A.C.; Malecot, V.; Jin, X.; Editorial committee; Cubey, J.J. (2009). International Code of Nomenclature for Cultivated Plants (ICNCP or Cultivated Plant Code) incorporating the Rules and Recommendations for naming plants in cultivation, Eighth Edition, Adopted by the International Union of Biological Sciences International Commission for the Nomenclature of Cultivated Plants (PDF). International Association for Plant Taxonomy and International Society for Horticultural Science. Article 10 and Appendix 10.
^ ^a ^b ^c Spencer, R.D. and Cross, R.G. 2007. The cultigen. Taxon 56(3):938-940
^ Morton, A.G. 1981. History of Botanical Science. London: Academic Press. ISBN 0-12-508382-
^ Bailey, L.H. 1918. The indigen and cultigen. Science ser. 2, 47:306-308
^ Bailey, L.H. 1923. Various cultigens, and transfers in nomenclature. Gentes Herb. 1:113--136
^ Bailey, L.H. 1924. Manual of cultivated plants. Macmillan, New York
^ Bailey, L.H. 1941. Hortus second : a concise dictionary of gardening, general horticulture and cultivated plants in North America. The Macmillan Company, New York.
^ Bailey, L.H. 1976. Hortus third : a concise dictionary of plants cultivated in the United States and Canada. Macmillan Collier Macmillan, New York.
^ Trehane, P. 2004. 50 years of the International Code of Nomenclature for Cultivated Plants. Acta Horticulturae 634: 17-27.
^ Lawrence, George H. M. 1953. "Cultivar, Distinguished from Variety." Baileya 1: 19–20.
^ Huxley, A., Griffiths, M., and Levy, M. (eds.) 1992. The New Royal Horticultural Society Dictionary of Gardening. Macmillan, London
^ "Definition of cultigen from Online Medical Dictionary" Retrieved 2008-06-25.
^ see, for example, Goudie, A. 2006. The human impact on the natural environment. Blackwell, Oxford.
^ ^a ^b Spencer, R.D. 1999. Cultivated plants and the codes of nomenclature – towards the resolution of a demarcation dispute. pp.171—181 in: S. Andrews, A.C. Leslie and C. Alexander (eds). Taxonomy of Cultivated Plants: Third Symposium. Royal Botanic Gardens, Kew. ISBN 1-900347-89-X Cite error: Invalid <ref> tag; name "spencer2" defined multiple times with different content (see the help page).

FootnotesEdit

^ The category grex was added in the 2009 Cultivated Plant Code and applies only to orchids (Article 4).

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Thursday, 24 March 2016

HORTICULTURE

CULTIGEN

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