Triticeae is a
tribeIn biology, a tribe — or infrafamily — is a taxonomic rank between family and genus. It is sometimes subdivided into subtribes.-See also:* Rank * Rank *International Code of Botanical Nomenclature...
within the
Pooideae subfamily of grasses that includes genera with many domesticated species. Major crop genera are found in this tribe including wheat (See
Wheat taxonomyDuring 10,000 years of cultivation, numerous forms of wheat have evolved under human selection. This diversity has led to much confusion in the naming of wheats. This article explains how genetic and morphological characteristics of wheat influence its classification, and gives the most common...
),
barleyBarley is a cereal grain derived from the annual grass Hordeum vulgare. It serves as a major animal feed crop, with smaller amounts used for malting and in health food. It is used in soups, stews and barley bread in various countries, such as Scotland and in Africa...
, and
ryeRye is a grass grown extensively as a grain and as a forage crop. It is a member of the wheat tribe and is closely related to barley and wheat. Rye grain is used for flour, rye bread, rye beer, some whiskies, some vodkas, and animal fodder...
; crops in other genera include some for human consumption and others used for animal feed or rangeland protection. Among the world's cultivated species this tribe has some of the most complex genetic histories.
Triticeae is a
tribeIn biology, a tribe — or infrafamily — is a taxonomic rank between family and genus. It is sometimes subdivided into subtribes.-See also:* Rank * Rank *International Code of Botanical Nomenclature...
within the
Pooideae subfamily of grasses that includes genera with many domesticated species. Major crop genera are found in this tribe including wheat (See
Wheat taxonomyDuring 10,000 years of cultivation, numerous forms of wheat have evolved under human selection. This diversity has led to much confusion in the naming of wheats. This article explains how genetic and morphological characteristics of wheat influence its classification, and gives the most common...
),
barleyBarley is a cereal grain derived from the annual grass Hordeum vulgare. It serves as a major animal feed crop, with smaller amounts used for malting and in health food. It is used in soups, stews and barley bread in various countries, such as Scotland and in Africa...
, and
ryeRye is a grass grown extensively as a grain and as a forage crop. It is a member of the wheat tribe and is closely related to barley and wheat. Rye grain is used for flour, rye bread, rye beer, some whiskies, some vodkas, and animal fodder...
; crops in other genera include some for human consumption and others used for animal feed or rangeland protection. Among the world's cultivated species this tribe has some of the most complex genetic histories. An example is bread wheat, which contains the genomes of three species, only one of them originally a wheat
Triticum species.
Seed storage proteins in TriticeaeTriticeae glutens are seed storage proteins found in mature seeds of grass tribe Triticeae. Seed glutens of non-Triticeae plants have varieties of similar properties, but none singly can perform on a par with those of the Triticeae taxa, particularly the triticum species...
are implicated in various
food allergiesA food allergy is an adverse immune response to a food protein. Food allergy is distinct from other adverse responses to food, such as food intolerance, pharmacologic reactions, and toxin-mediated reactions....
and intolerances.
Genera of Triticeae
This list of tribes broadly follows that in
Grass Genera of World. Although there are taxonomic disagreements about the precise circumscription of some genera, this scheme is typical of those used in taxonomic literature.
AegilopsAegilops is a genus of plants generally known as goatgrasses and belonging to the grass family, Poaceae. There are about 23 species and numerous sub species in the genus. Various members of the genus are classed as agricultural weeds. Growing through the winter, they resemble winter wheat...
(
goat grasses -
jointed goatgrass,
Tausch goatgrass, etc)
AgropyronAgropyron is a genus of grasses , native to Europe and Asia. Species in the genus are commonly referred to as crested-wheat grasses...
(
crested wheatgrasses -
http://herbarium.usu.edu/triticeae/agropyron.htmDesert wheatgrass,
quackgrass, etc)
Amblyopyrum (
Slim wheat grass -
amblyopyrum)
Australopyrum (
http://herbarium.usu.edu/triticeae/australopyrum.htm Australian wheatgrasses -
velvet wheatgrass,
pectinated wheatgrass, etc)
Cockaynea {See
Stenostachys; Cockaynea is a younger, and hence invalid, name for
Stenostachys
Crithopsis (
delileana grass)
Dasypyrum (
http://herbarium.usu.edu/triticeae/dasypyrum.htm Mosquito grass)
Elymus (
http://herbarium.usu.edu/triticeae/elymus.htm Elymus (wild ryes - blue wildrye,Texas ryegrass, etc)
Elytrigia
(This genus is often included in Elymus
)
Eremium
(This genus is sometimes included in Leymus
; Argentine desert ryegrass)
Eremopyrum
(http://herbarium.usu.edu/triticeae/eremopyrum.htm false wheatgrasses - tapertip false wheatgrass,annual wheatgrass, etc)
Festucopsis
Haynaldia
Henrardia
Heteranthelium
Hordelymus
HordeumHordeum is a genus of about 30 species of annual and perennial grasses, native throughout the temperate Northern Hemisphere, temperate South America, and also South Africa....
(barleys - common barley, foxtail barley, etc)
Hystrix
(porcupine grass- bottlebrush grass)
Kengyilia
LeymusLeymus is a genus of the true grass family . The common name for this genus is "wild rye", however members of the genus Elymus are also sometimes given the same name...
(wild ryeWild rye is a term used for several grasses of the genus Leymus and Elymus. It is native to parts of North America and is valuable in the control of exotic invasive plants and as a rotation crop....
- American dune grass,lyme grass,etc)
Lophopyrum
(tall wheatgrass)
Malacurus
Pascopyrum
(western wheatgrass)
Peridictyon
Psathyrostachys
(Russian wildrye)
Pseudoroegneria (bluebunch wheatgrasses - beardless wheatgrass, etc)
SecaleSecale is a genus in the Triticeae tribe. The most known member is rye .This is used to treat chilbaines....
(Ryes - Cereal rye, Himalayan Rye,etc)
Sitanion
Stenostachys (New Zealand wheatgrasses)
Taeniatherum
(medusahead - medusahead)
Thinopyrum (intermediate wheatgrass, Russian wheatgrass, thick quackgrass)
Triticum
(Wheats - common wheatCommon wheat, Triticum aestivum, is a cultivated wheat species.- Nomenclature and taxonomy of the variety and its cultivars :-Evolution:...
, durumDurum wheat or macaroni wheat is the only tetraploid species of wheat of commercial importance that is widely cultivated today...
wheat, etc)
Cultivated or Edible Species
Aegilops
- Various species (rarely identifiable to species in archaeological material) occur in pre-agrarian archaeobotanical remains from Near Eastern sites. Their edible grains were doubtless harvested as wild food resources.
-
speltoides
- ancient food grain, putative source of B genome in bread wheat and G genome in T. timopheevii
tauschii
- Source of D genome in wheat
Elmyus
Various species are cultivated for pastoral purposes or to protect fallow
land from opportunistic or invasive species
canadensis
- edible, bread flour capable, fiddly seeds
trachycaulus
- pastoral cultivar
Hordeum
Many barley cultivars
vulgare
- common barley (6 subspecies, ~100 cultivars)
bulbosum
- edible seeds
murinum
(mouse barley) - cooked as piñole, bread flour capable, medicinal: diuretic.
Leymus
arenarius
(Lyme grass) - bread flour capable, possible food additive
racemosus
(Volga Wild Rye) - drought tolerant cereal, used in Russia
condensatus
(Giant Wild Rye) - Edible seeds, harvesting problematic small seeds
triticoides
(Squaw grass) - used in North America, seed hairs must be singed
Secale
Ryes
cereale
(Cereal Rye) - Livestock feed and sour dough bread - 6 subspecies.
cornutum
-ergot (Ergot of Spurred Rye) - herbal medicine at very low doses, deadly poisonous as food.
strictum
- actively cultivated
sylvestre
- (Tibetan Rye) - actively cultivated in Tibet and China highlands.
vavilovi
(Armenian Wild Rye) - edible seeds, thickener.
Triticum
(Wheat)
aestivum
(bread wheat) - (AABBDD Genome)
compactum
(club wheat)
macha
(hulled)
spelta
(hulled, speltSpelt is a hexaploid species of wheat. Spelt was an important staple in parts of Europe from the Bronze Age to medieval times; it now survives as a relict crop in Central Europe and has found a new market as a health food. Spelt is sometimes considered a subspecies of the closely related species...
)
sphaerococcum
(shot wheat)
monococcum
(Einkorn wheat) (A Genome)
timopheeviiTimopheev's Wheat is a tetraploid wheat that has both cultivated and wild forms. The domesticated form is restricted to western Georgia, while the wild form Timopheev's Wheat (Triticum timopheevii, also called Zanduri Wheat) is a tetraploid wheat that has both cultivated and wild forms. The...
(Sanduri wheat)
turgidum
(poulard wheat) (AB Genome)
carthlicum
(Persian black wheat)
dicoccoides
(wild emmer wheat)
dicoccum
(cultivated emmer wheat) - used to make Farro
durumDurum wheat or macaroni wheat is the only tetraploid species of wheat of commercial importance that is widely cultivated today...
(durum wheat)
paleocolchicum
polonicum
(Polish wheat)
turanicum
turgidum
Genetics
style="font-size:90%"| Genomes of some Triticeae genera and species
| |
Genera & Species |
1st |
2nd |
3rd |
|
|
Triticum boeoticum |
AA |
|
|
|
Triticum monococcum |
AMAM |
|
|
|
Triticum aurata |
AUAU |
|
|
|
Aegilops speltoidesAegilops speltoides is an edible plant in the Poaceae family native to Southeastern Europe and Western Asia, which is often used for animal feed, and it has grown in cultivated beds...
speltoides |
BB |
|
|
|
Aegilops caudata |
CC |
|
|
|
Aegilops tauschii |
DD |
|
|
|
Lophopyrum elongatum |
EE |
|
|
|
Hordeum vulgare |
HH |
|
|
|
Thinopyrum bessarabicum |
JJ |
|
|
|
Aegilops comosa |
MM |
|
|
|
Aegilops uniaristata |
NN |
|
|
|
Henradia persia |
OO |
|
|
|
Agropyrum cristatum |
PP |
|
|
|
Secale cereale |
RR |
|
|
|
Aegilops bicornis |
SS |
|
|
|
Amblyopyrum muticum |
TT |
|
|
|
Aegilops umbellulata |
UU |
|
|
|
Dasypyrum |
VV |
|
|
|
Psathyrostachys |
NsNs |
|
|
|
Psuedoregenia |
StSt |
|
|
|
Triticum zhukovskyi |
AA |
AMAM |
GG |
|
Triticum turgidum |
AA |
BB |
|
|
Triticum aestivum |
AA |
BB |
DD |
|
Triticum timopheevii Timopheev's Wheat is a tetraploid wheat that has both cultivated and wild forms. The domesticated form is restricted to western Georgia, while the wild form Timopheev's Wheat (Triticum timopheevii, also called Zanduri Wheat) is a tetraploid wheat that has both cultivated and wild forms. The...
|
AA |
GG |
|
|
Stenostachys sp. |
HH |
WW |
|
|
Elmyus canadensis |
HH |
StSt |
|
|
Elmyus abolinii |
YY |
StSt |
|
|
Thinopyrum Vjd =(V/J/D) |
JJ |
StSt |
VjdVjd |
|
Leymus tricoides |
NsNs |
XmXm |
|
Triticeae and its sister tribe Bromeae (possible cultivars:
Bromus mango S. America) when joined form a sister clade with Poeae
and Aveneae (oats). Inter-generic gene flow characterized these taxa from the early stages. For example, Poeae and Aveneae share a genetic marker with barley and 10 other members of Triticeae, whereas all 19 genera of Triticeae bear a wheat marker along with Bromeae. Genera within Triticeae contain diploid, allotetraploid and/or allohexaploid genomes, the capacity to form allopolyploid genomes varies within the tribe. In this tribe, the majority of diploid species tested are closely related to Aegilops
, the more distal members (earliest branch points) include Hordeum
(Barley), Eremian
, Psathyrostachys
. The broad distribution of cultivars within the Tribe and the properties of the proteins have implication in the treatment of certain digestive diseases and autoimmune disorders.
Evolution of the Tribe
One of the earliest branches in Triticeae, to Psuedoroegeneria
, produces the genome StSt and another Hordeum
then genome = HH. Allotetraploid combinations of Psuedoroegeneria
and HordeumHordeum is a genus of about 30 species of annual and perennial grasses, native throughout the temperate Northern Hemisphere, temperate South America, and also South Africa....
and are seen in Elmyus
(HHStSt), but also shows introgression from Australian and Agropyron wheatgrasses. Elymus contains mostly Psuedoroegeneria mtDNA.
Many genera and species of Triticeae are exemplary of allopolyploids, having more chromosomes than seen in typical diploids. Typically allopolyploids are tetraploid or hexaploid, XXYY or XXYYZZ. The creation of polyploid species results from natural random events tolerated by polyploid capable plants. Likewise natural allopolyploid plants may have selective benefits and may allow the recombination of distantly related genetic material facilitating at a later time a reversion back to diploid. Poulard wheat is an example of a stable allotetraploid wheat.
The Secale
(domesticated rye) may be a very early branch from the goat grass clad (or goat grasses are a branch of early rye grasses), as branch these are almost contemporary with the branching between monoploid wheat and Aegilops tauschii
. Studies in Anatolia now suggest Rye (SecaleSecale is a genus in the Triticeae tribe. The most known member is rye .This is used to treat chilbaines....
) was cultivated, but not domesticated, prior to the holoceneThe Holocene is a geological epoch which began approximately 11 700 years ago . According to traditional geological thinking, the Holocene continues to the present. The Holocene is part of the Neogene and Quaternary periods. Its name comes from the Greek words and , meaning "entirely...
and to evidence for the cultivation of wheat. As climate changed the favorablitiy of Secale
declined. At that time other strains of barley and wheat may have been cultivated, but humans did little to change them.
Goat Grasses and the Evolution of Bread Wheat
Tetraploidation in Wild Emmer Wheat
Aegilops
appears to be basal to several taxa such as Triticum
, Ambylopyrum
, and Crithopsis
. Certain species such as Aegilops speltoides
could potentially represent core variants of the taxa. The generic placement may be more a matter of nomenclature. Aegilops
and Triticum
genera are very closely related as the image to the right illustrates the Aegilops
species occupy most of the basal branch points in bread wheat evolution indicating that Triticum
genus evolved from Aegilops after an estimated 4 million years ago. The divergence of the genomes is followed by allotetraploidation of a speltoid goatgrass x basal wheat species Triticum boeoticum
with strains in the middle eastern region giving rise to cultivated emmer wheat.
Hexaploidation of tetraploid wheat
Hybridization of tetraploid wheat with Ae. tauschii
produced a hulled wheat similar to spelt, suggesting T. spelta
is basal. The tauschii
species can be subdivided into subspecies tauschii
(eastern Turkey to China or Pakistan) and strangulata
(Caucasus to S. Caspian, N. Iran). The D genome of bread wheat is closer to A.t. strangulata
than A.t. tauschii
. It is suggested that Ae. tauschii underwent rapid selective evolution prior to combining with tetraploid wheat.
Wild Triticeae use by humans
Intense use of wild Triticeae can be seen in the Levant as early as 23,000 years ago. This site, Ohala II (Israel), also shows that Triticeae grains were processed and cooked. Many cultivars appear to have been domesticated in the region of the upper Fertile Crescent, Levant and central Anatolia. More recent evidence suggests that cultivation of wheat from emmer's wheat
required a longer period with wild seeding maintaining a presence in archaeological finds.
Pastoral Grasses
Triticeae has a
pastoralPastoral, as an adjective, refers to the lifestyle of shepherds and pastoralists, moving livestock around larger areas of land according to seasons and availability of water and food. "Pastoral" also describes literature, art and music which depicts the life of shepherds, often in a highly...
component that some contend goes back to the Neolithic period and is referred to as the
Garden Hunting Hypothesis. In this hypothesis grains could be planted or shared for the purpose of attracting game animals so that they could be hunted close to settlements.
Today, rye and other Triticeae cultivars are used to grazing animals, particularly cattle.
Rye grasses in the New World have been used to selectively for use as fodder, but also
to protect grasslands without the introduction of invasive old world species.
Triticeae and health
Glutens (storage proteins) in the Triticeae tribe have been linked to
gluten-sensitive diseasesGluten sensitivity encompasses a collection of medical conditions in which gluten has an adverse effect. For individuals with gluten-sensitive enteropathy, removal of gluten generally results in the restoration of villus architecture or lower lymphocyte densities in the intestine...
. While it was once believed that [oat]s carried similar potentials, recent studies indicate that most-oat sensitivity is the result of contamination.
Triticeae glutensTriticeae glutens are seed storage proteins found in mature seeds of grass tribe Triticeae. Seed glutens of non-Triticeae plants have varieties of similar properties, but none singly can perform on a par with those of the Triticeae taxa, particularly the triticum species...
examines of the proteins of Triticeae, important in the link between gluten, gastrointestinal, allergic and autoimmune diseases Some of the recently discovered biochemical and immunochemical properties of these proteins suggest they evolved for protection against dedicated or continuous consumption by mammalian seed eaters. One recent publication even raises doubts about wheat's safety for anyone to eat Overlapping properties with regard to food preparation have made these proteins much more useful as cereal cultivars and a balanced perspective suggest a variable tolerance to Triticeae glutens reflects early childhood environment and genetic predisposition.
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