The agricultural weed syndrome is the set of common traits which make a plant a successful agricultural

weed A weed is a plant considered undesirable in a particular situation, growing where it conflicts with human preferences, needs, or goals.Harlan, J. R., & deWet, J. M. (1965). Some thoughts about weeds. ''Economic botany'', ''19''(1), 16-24. Pla ...

. Most of these traits are not, themselves,

phenotype In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology (physical form and structure), its developmental processes, its biochemical and physiological propert ...

s but are instead methods of rapid

adaptation In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the p ...

. So equipped, plants of various origins - invasives, natives, mildly successful marginal weeds of agriculture, weeds of other settings - accumulate other characteristics which allow them to compete in an environment with a high degree of human management. Nonetheless, some of the syndrome traits are themselves phenotypic.

Syndrome traits

* Rapid

growth Growth may refer to: Biology *Auxology, the study of all aspects of human physical growth *Bacterial growth *Cell growth *Growth hormone, a peptide hormone that stimulates growth *Human development (biology) *Plant growth *Secondary growth, growt ...

* Efficient use of

nutrient A nutrient is a substance used by an organism to survive, grow and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi and protists. Nutrients can be incorporated into cells for metabolic purposes or excret ...

s *

Seed dormancy Seed dormancy is an evolutionary adaptation that prevents seeds from germinating during unsuitable ecological conditions that would typically lead to a low probability of seedling survival. Dormant seeds do not germinate in a specified period of ...

* Effective

seed dispersal In spermatophyte plants, seed dispersal is the movement, spread or transport of seeds away from the parent plant. Plants have limited mobility and rely upon a variety of dispersal vectors to transport their seeds, including both abiotic vectors, ...

, often more aggressive shattering *

Vavilovian mimicry In plant biology and agriculture, Vavilovian mimicry (also crop mimicry or weed mimicry) is a form of mimicry in plants where a weed evolves to share characteristics with a crop plant through generations of involuntary artificial selection. It ...

including introgression of crop alleles if there are nearby crop relatives *

Herbicide resistance Herbicides (, ), also commonly known as weed killers, are substances used to control undesired plants, also known as weeds.EPA. February 201Pesticides Industry. Sales and Usage 2006 and 2007: Market Estimates. Summary in press releasMain page f ...

* Short

life cycle Life cycle, life-cycle, or lifecycle may refer to: Science and academia *Biological life cycle, the sequence of life stages that an organism undergoes from conception to reproduction *Life-cycle hypothesis, in economics *Erikson's stages of psy ...

* High

fertility Fertility in colloquial terms refers the ability to have offspring. In demographic contexts, fertility refers to the actual production of offspring, rather than the physical capability to reproduce, which is termed fecundity. The fertility rate ...

Some of these are the opposite of

domestication traits Domestication syndrome refers to two sets of phenotypic traits that are common to either domesticated plants or domesticated animals. Domesticated animals tend to be smaller and less aggressive than their wild counterparts; they may also have ...

Evolution

Insufficient information is available as to the exact contribution of

mutation In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, ...

s, particular mutation types, pre-existing

genetic diversity Genetic diversity is the total number of genetic characteristics in the genetic makeup of a species. It ranges widely, from the number of species to differences within species, and can be correlated to the span of survival for a species. It is d ...

, specific genes, and

introgression Introgression, also known as introgressive hybridization, in genetics is the transfer of genetic material from one species into the gene pool of another by the repeated backcrossing of an interspecific hybrid with one of its parent species. Introg ...

to syndrome acquisition. It is also unknown whether we can discern the genetic signatures of adaptation to different weed management regimes from different times. In some cases domestication alleles may produce weeds that are weedier than the wild parent they were derived from. For example, California wild radish is weedier and more aggressive than ''

Raphanus raphanistrum ''Raphanus raphanistrum'', also known as wild radish, white charlock or jointed charlock, is a flowering plant in the family Brassicaceae. The species is native to western Asia, Europe and parts of Northern Africa. It has been introduced into mo ...

'', despite being merely a combination of ''R. raphanistrum'' and ''R. raphanistrums own subspecies ''R. r. sativus''. Pre-existing allelic variety which suddenly became more adaptive when the cultivated environment appeared likely has contributed to the success of ''

Amaranthus tuberculatus ''Amaranthus tuberculatus'', commonly known as roughfruit amaranth, rough-fruited water-hemp, tall waterhemp, or common waterhemp, is a species of flowering plant. It is a summer annual broadleaf with a germination period that lasts several mont ...

'', '' A. palmeri'', ''

Lolium rigidum ''Lolium rigidum'' is a species of annual grass. Common names by which it is known include annual ryegrass, a name also given to Italian ryegrass (''Lolium multiflorum''), rigid ryegrass, stiff darnel, Swiss ryegrass and Wimmera ryegrass. It is ...

'' and ''

Ipomoea purpurea ''Ipomoea purpurea'', the common morning-glory, tall morning-glory, or purple morning glory, is a species in the genus ''Ipomoea'', native to Mexico and Central America. Description Like all morning glories, the plant entwines itself around stru ...

'' especially their quick development of herbicide resistance. On the other hand, novel mutations may be the source herbicide resistance in ''

Echinochloa crus-galli ''Echinochloa crus-galli'' is a type of wild grass originating from tropical Asia that was formerly classified as a type of panicum grass. It is commonly known as cockspur (or cockspur grass), barnyard millet, Japanese millet, water grass, commo ...

'' and '' E. oryzicola'', whose worldwide combined populations have developed resistance to nine

modes of action In pharmacology and biochemistry, mode of action (MoA) describes a functional or anatomical change, resulting from the exposure of a living organism to a substance. In comparison, a mechanism of action (MOA) describes such changes at the molecular ...

. Some weeds are themselves the descendants of

crop A crop is a plant that can be grown and harvested extensively for profit or subsistence. In other words, a crop is a plant or plant product that is grown for a specific purpose such as food, Fiber, fibre, or fuel. When plants of the same spe ...

s, while some are unrelated to any cultivated species. The origins of those arising from cultivars are variously better and worse understood: Weedy ''

Helianthus annuus The common sunflower (''Helianthus annuus'') is a species of large annual forb of the daisy family Asteraceae. The common sunflower is harvested for its edible oily seeds, which are often eaten as a snack food. They are also used in the pro ...

'' is well understood as wild/cultivar hybrids, weedy ''

Secale cereale Rye (''Secale cereale'') is a grass grown extensively as a grain, a cover crop and a forage crop. It is grown principally in an area from Eastern and Northern Europe into Russia. It is much more tolerant of cold weather and poor soil than o ...

'' and ''O. sativa'' as purely feral crops, ''

Beta vulgaris ''Beta vulgaris'' (beet) is a species of flowering plant in the subfamily Betoideae of the family Amaranthaceae. Economically, it is the most important crop of the large order Caryophyllales. It has several cultivar groups: the sugar beet, of gre ...

'' weeds are highly studied although some further analysis is called for, and at the other end of the spectrum lie ''

Sorghum halepense Johnson grass or Johnsongrass, ''Sorghum halepense'', is a plant in the grass family, Poaceae, native to Asia and northern Africa. The plant has been introduced to all continents except Antarctica, and most larger islands and archipelagos. It re ...

'' and weedy races of '' S. bicolor'', weedy congeners of cultivated ''S. bicolor'' with complicated interbreeding histories that have yet to be untangled. Recently ()

teosinte ''Zea'' is a genus of flowering plants in the Poaceae, grass family. The best-known species is ''Z. mays'' (variously called maize, corn, or Indian corn), one of the most important crops for human societies throughout much of the world. The four ...

s have begun invading

Spain Spain, or the Kingdom of Spain, is a country in Southern Europe, Southern and Western Europe with territories in North Africa. Featuring the Punta de Tarifa, southernmost point of continental Europe, it is the largest country in Southern Eur ...

and

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

. DNA testing of Spanish teosinte shows it to be intermediate between ''Zea mays'' subsp. ''mays'' and ''Zea mays'' subsp. ''mexicana''.

Genes

* Antioxidant pigmentation: ** ' in ''

Oryza rufipogon ''Oryza rufipogon'' is a species of flowering plant in the family ''Poaceae''. It is known as brownbeard rice, wild rice, and red rice. In 1965, ''Oryza nivara'' was separated off from ''O. rufipogon''. The separation has been questioned, a ...

'' and its weedy rice descendants. * Shattering: ** ' in ''O. rufipogon'' and its weedy rice descendants, including some new alleles of similar function but entirely new origin. * Germination temperature: ** Unknown in weedy rice. * Vavilovian mimicry: ** ' alleles conveying shorter stature, slower growth, and earlier flowering, introgressed from ''O. sativa'' cultivars into weedy rice. (May or may not be adaptive, not actually confirmed.) * Herbicide resistance: ** Various genes identical to genetically engineered domesticated ''O. sativa'' introgressed into weedy rice. ** Codon deletion in ' in ''A. tuberculatus''. ** Various alleles of ''ALS'' - the

acetolactate synthase The acetolactate synthase (ALS) enzyme (also known as acetohydroxy acid or acetohydroxyacid synthase, abbr. AHAS) is a protein found in plants and micro-organisms. ALS catalyzes the first step in the synthesis of the branched-chain amino acids ...

gene - in a variety of species. ** The same

amino acid substitution Amino acid replacement is a change from one amino acid to a different amino acid in a protein due to point mutation in the corresponding DNA sequence. It is caused by nonsynonymous missense mutation which changes the codon sequence to code other ...

in all 43

genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

which have triazine resistance. Some of these are the same genes as domestication traits, but with alleles of opposite effect.

Example species

Polygonum aviculare ''Polygonum aviculare'' or common knotgrass is a plant related to buckwheat and dock. It is also called prostrate knotweed, birdweed, pigweed and lowgrass. It is an annual found in fields and wasteland, with white flowers from June to October. I ...

'', ''

Plantago lanceolata ''Plantago lanceolata'' is a species of flowering plant in the plantain family Plantaginaceae. It is known by the common names ribwort plantain, narrowleaf plantain, English plantain, ribleaf, lamb's tongue, and buckhorn. It is a common weed on ...

'', ''

Spergularia rubra ''Spergularia rubra'', the red sandspurry or red sand-spurrey, is a plant species in the family Caryophyllaceae. It is native to Europe, Asia and North Africa, and it is present on other continents, including North and South America and Australia ...

'', ''

Senecio vulgaris ''Senecio vulgaris'', often known by the common names groundsel and old-man-in-the-spring, is a flowering plant in the family Asteraceae. It is an annual plant, annual herbaceous plant, herb, native to the Palaearctic and widely naturalised as a ...

'', ''

Poa annua ''Poa annua'', or annual meadow grass (known in America more commonly as annual bluegrass or simply poa), is a widespread low-growing turfgrass in temperate climates. Notwithstanding the reference to annual plant in its name, perennial bio-types ...

'', weedy rice, ''

Sorghum ''Sorghum bicolor'', commonly called sorghum () and also known as great millet, broomcorn, guinea corn, durra, imphee, jowar, or milo, is a species in the Poaceae, grass genus ''Sorghum (genus), Sorghum'' cultivated for its grain. The grain i ...

'' weeds including ''S. halepense'' and weedy races of ''S. bicolor'', weedy ''Helianthus annuus''.

References

{{reflist Domestication Agriculture Weeds Genetics

Syndrome traits

Evolution

Genes

Example species

See also

References