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Triticeae
From Wikipedia, the free encyclopedia
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Triticeae is a tribe within the Pooideae subfamily of grasses that includes genera with many domesticated species. Major crops are found in wheat (See Wheat taxonomy), barley, and rye; 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 Triticeae are implicated in various food allergies and intolerances.
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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.
Aegilops (goat grasses - jointed goatgrass, Tausch goatgrass,ovate goatgrass,barbed goatgrass, Persian goatgrass, etc)
Agropyron (crested wheatgrasses - Desert wheatgrass, quackgrass,western wheatgrass, etc)
Amblyopyrum (Slim wheat grass - amblyopyrum)
Australopyrum (Australian wheatgrasses - velvet wheatgrass,pectinated wheatgrass, etc)
Cockaynea
Crithopsis (delileana grass)
Dasypyrum (Mosquito grass)
Elymus (wild ryes - blue wildrye,squirreltail ryegrass,Texas ryegrass, etc) (Genome = StH)
Elytrigia
Eremium (Argentine desert ryegrass)
Eremopyrum (false wheatgrasses - tapertip false wheatgrass,Oriental false wheatgrass,annual wheatgrass, etc)
Festucopsis
Haynaldia
Henrardia
Heteranthelium
Hordelymus
Hordeum (barleys - common barley, arizona barley,foxtail barley, etc) (genome = H)
Hystrix (porcupine grass- bottlebrush grass)
Kengyilia
Leymus (wild rye- American dune grass,lyme grass,creeping rye,etc)
Lophopyrum (tall wheatgrass)
Malacurus
Pascopyrum(western wheatgrass)
Peridictyon
Psathyrostachys (Russian wildrye)
Pseudoroegneria (bluebunch wheatgrasses - bluebunch wheatgrass, beardless wheatgrass, etc) (Genome = St)
Secale (Ryes - Cereal rye, Himalayan Rye, Montana Rye,etc)
Sitanion
Stenostachys (New Zealand wheatgrasses) (Genome HW)
Taeniatherum (medusahead - medusahead)
Thinopyrum (intermediate wheatgrass, Russian wheatgrass, tall wheatgrass,thick quackgrass)
Triticum (Wheats - common wheat, durum wheat, etc)
- 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
- muticum - Source of T genome.
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
Many barley cultivars
- vulgare - common barley (6 subspecies, ~100 cultivars)
- bulbosum - edible seeds
- murinum (mouse barley) - cooked as piñole, breadable, medicinal: diuretic.
- 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
Ryes
- cereale (Cereal Rye) - Livestock feed and sour dough bread - 6 subspecies.
- cornutum-ergot (Ergot of Spurred Rye) - herbal medicine at very low doses,[1] deadly poisonous as food.
- strictum - actively cultivated
- sylvestre - (Tibetan Rye) - Actively cultivatedin Tibet and China highlands.
- vavilovi (Armenian Wild Rye) - edible seeds, thickener.
(Wheat)
- aestivum (bread wheat) - (ABD Genome)
- compactum (club wheat) -
- macha (hulled, )
- spelta (hulled, spelt)
- sphaerococcum (shot wheat)
- monococcum (Einkorn wheat) (A Genome)
- timopheevii (Sanduri wheat)
- turgidum (poulard wheat) (AB Genome)
- carthlicum (Persian black wheat)
- dicoccoides (wild emmer wheat)
- dicoccum (cultivated emmer wheat) - Edible-Farro
- durum (durum wheat)
- paleocolchicum
- polonicum (Polish wheat)
- turanicum
- turgidum
Triticeae and its sister tribe Bromeae (possible cultivars: Bromus mango S. America) form a 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.[2] Genera within Triticeae contain diploid, allotetraploid and/or allohexaploid genomes, the capacity for 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, Eremian, Psathyrostachys. Only three genera appear to be more distant from Aegilops. The danger in the phylogenetics is that it is known that allopolyploidy is common in the taxa, but the genetic studies typically focuses on the simpler diploid species and biases the conclusion.
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.[3] The divergence of the genomes is followed by allotetraploidation of a speltoid goatgrass x basal wheat species Triticum boeoticum with populations in the middle eastern region giving rise to cultivated emmer wheat.[4]
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 strangulata than tauschii. It is suggested that Ae. tauschii. underwent rapid selective evolution prior to combining with tetraploid wheat.
While it might be tempting to think that since Hordeum and Triticum were domesticated proximally, that these two are closely related in Triticeae. The Secale may be a very early branch from the goat grass clad or goat grasses are a branch of the rye grasses, this branch is almost contemporary with the branching between monoploid wheat and Aegilops tauschii. More distantly related are the Australian wheatgrasses. One of the oldest branches in Triticeae produces the Psuedoroegeneria (Genome = StSt) genera, and allotetraploid crosses with Hordeum (Genome = HH) and are seen in Elmyus (HHStSt),[5] but also shows introgression from Australian and Agropyron wheatgrasses.[6] Elymus contains mostly Psuedoroegeneria mtDNA.[7] Like other polyploid genomic Triticeae, Elymus represents also a number of prospective cultivars. Thus Hordeum cultivatable properties are not necessarily tied to the middle east or wheat domestication. Below is an examination of the proteins of Triticeae, this should be important as to why one does not consider gluten related diseases, diseases of wheat consumption, but disease of seed consumption of the Triticeae taxa as a whole, possibly extendable to the seeds of Bromeae and more basal taxa branchpoints (Such as Aveneae) as well. The importance of bread wheat is that it contains a larger proportion of these proteins and more isoforms resulting from three genomes from three members of a one major branch of Triticeae. The apparent lesson in Triciticeae domestication is to increase the number of genomes while reducing genes that interfere with industrial processing, the creation a polyploids is not difficult so much as picking the right two cultivars to cross. The Aegilopoidic species indicate that cultivating and selecting grasses prior to crossing (removing the undesirable traits in both stains) before crossing is one possibly way to simplify selection on the allopolyploid products.
Intense use of wild Triticeae' can be seen in the Levant as early as 23,000 years ago.[8] This site, Ohala II (Israel), also shows that Triticeae grains were processed and cooked.[9] Many cultivars appear to have been domesticated in the region of the upper Fertile Crescent, Levant and central Anatolia.[10][11]
Triticeae has a pastoral 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.
Glutens (storage proteins) in the Triticeae tribe have been linked with certainty to coeliac disease, and controversaly to other conditions. See Triticeae glutens for more detail
- ^ Eadie M (2004). "Ergot of rye-the first specific for migraine.". J Clin Neurosci 11 (1): 4-7. PMID 14642357.
- ^ Kubo N, Salomon B, Komatsuda T, von Bothmer R, Kadowaki K (2005). "Structural and distributional variation of mitochondrial rps2 genes in the tribe Triticeae (Poaceae).". Theor Appl Genet 110 (6): 995-1002. PMID 15754209.
- ^ Dvorak J, Akhunov ED, Akhunov AR, Deal KR, and Luo MC (2006). "Molecular characterization of a diagnostic DNA marker for domesticated tetraploid wheat provides evidence for gene flow from wild tetraploid wheat to hexaploid wheat.". Mol Biol Evol. 23 (7): 1386-1396. PMID 16675504.
- ^ >Heun M, Schäfer-Pregl R, Klawan D, Castagna R, Accerbi M, Borghi B, and Salamini F (1997). "Site of Einkorn Wheat Domestication Identified by DNA Fingerprinting.". Science 278 (5341): 1312-1314.
- ^ Mason-Gamer R (2004). "Reticulate evolution, introgression, and intertribal gene capture in an allohexaploid grass.". Syst Biol 53 (1): 25-37. PMID 14965898.
- ^ Liu Q, Ge S, Tang H, Zhang X, Zhu G, Lu B (2006). "Phylogenetic relationships in Elymus (Poaceae: Triticeae) based on the nuclear ribosomal internal transcribed spacer and chloroplast trnL-F sequences.". New Phytol 170 (2): 411-20. PMID 16608465.
- ^ Mason-Gamer R, Orme N, Anderson C (2002). "Phylogenetic analysis of North American Elymus and the monogenomic Triticeae (Poaceae) using three chloroplast DNA data sets.". Genome 45 (6): 991-1002. PMID 12502243.
- ^ Weiss E, Wetterstrom W, Nadel D, Bar-Yosef O (2004). "The broad spectrum revisited: evidence from plant remains.". Proc Natl Acad Sci U S A 101 (26): 9551-5. PMID 15210984.
- ^ Piperno D, Weiss E, Holst I, Nadel D (2004). "Processing of wild cereal grains in the Upper Palaeolithic revealed by starch grain analysis.". Nature 430 (7000): 670-3. PMID 15295598.
- ^ Lev-Yadun S, Gopher A, and Abbo S (2000). "(ARCHAEOLOGY:Enhanced:) The Cradle of Agriculture.". Science 288 (5471): 1602-1603.
- ^ Weiss E, Kislev ME, and Hartmann A (2006). "(Perspectives-Anthropology:) Autonomous Cultivation Before Domestication.". Science 312 (5780): 1608-1610.
Pubmed:Triticeae
Database of Edible Seed Plants
International Center for Agricultural Research in the Dry Areas (ICARDA) - An excellent resource for the ancestral genetics of Triticeae.
Aegilops (genome) Comparative Classification Table
Triticum (genome)Comparative Classification Table
Genomes in Aegilops, Triticum, and Amblyopyrum
Categories: Cereals | Grasses | Grains