Triticum (wheat) comprises six biological varieties at the diploid, tetraploid, and also hexaploid level (Table 1).

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From: Encyclopedia the Genetics, 2001

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S.O. Serna Saldivar, in Encyclopedia that Food and Health, 2016

Triticale (Triticum secale)

Triticale is the just plant varieties created by male who crossed wheat and rye. It was very first deliberately produced in 1876 although the very first varieties arised in the 1930s in Russia, however it was until the 1960s once it was commercially planted. Triticale is a hybrid result of the overcome of wheat (mother) and also rye (father) through the target of obtaining kernels v the best features of these cereals (gluten sensible and much better agronomic power or hardiness and also resistance to pests). Triticale has regained popularity during the previous 20 years. People production in 2013 (14.6 million tons) was around three times better than in 1993. However, many of the triticale right now grown does not satisfy gluten expectations and therefore is mostly used as forage or feed. In 2013, the triticale planted area was around 3.85 million hectare.


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Triticum types (Wheat)


J. Dvořák, in Encyclopedia the Genetics, 2001

Evolution


Triticum (wheat) comprises 6 biological species at the diploid, tetraploid, and hexaploid level (Table 1). The polyploid Triticum species originated by hybridization between Triticum and also the bordering genus Aegilops (goatgrass), as shown schematically in figure 1. The tetraploid species, T. Turgidum (genomes AABB) and T. Timopheevii (genomes AAGG), room polyphyletic. The A genomes the both varieties were added by T. Urartu. The B and G genomes are carefully related come the genome the Ae. Speltoides (S genome). The designation of these genomes as B and also G rather than as modified S genomes has been preserved for historical reasons. Since T. Turgidum is older 보다 T. Timopheevii, the B genome has diverged an ext from the S genome the Ae. Speltoides than the G genome. The G genome is virtually identical to the S genome in ~ the molecule level however it differs from it, as well as from the B genome, by significant structural chromosome rearrangements. Hexaploid T. Aestivum originated some 6000–7000 years earlier by the hybridization that tetraploid wheat, many likely cultivated emmer (T. Turgidum subsp. dicoccon), with Ae. tauschii. Ae. Tauschii subsp. strangulata in Transcaucasia was the principal resource of the wheat D genome gene swimming pool but, due to the fact that several hybridization events were responsible for the development of this gene pool, it cannot be excluded the Ae. Tauschii from other geographical regions, participated in shaping it. Hexaploid T. Zhukovskyi originated recently by interspecific hybridization of cultivated T. Timopheevii with cultivated T. Monococcum.


Table 1. Ploidy, domestication status, and also spike characteristics of Triticum varieties and subspecies


PloidyStatusSpikeSpeciesSubspecies
wildhulled, brittleT. Monococcumaegilopoides (wild einkorn wheat)
cult.hulled, nonbrittleT. Monococcummonococcum (cultivated einkorn wheat)
wildhulled, brittleT. Urartu
wildhulled, brittleT. Turgidumdicoccoides (wild emmer wheat)
cult.hulled, nonbrittleT. Turgidumdicoccon (cultivated emmer wheat) Paleocolchieum
naked, nonbrittleT. Turgidumdurum (durum), turgidum (pollard wheat), turanicum (Khorassan wheat), polonicum (Polish wheat), carthlicum (Persian wheat), isphahanicum
wildhulled, brittleT. Timopheeviiarmeniaeum (syn. araraticum)
cult.hulled, nonbrittleT. Timopheeviitimopheevii
cult.hulled, brittleT. Aestivummacha, tibetanum (Tibetan wheat)
hulled, partially brittleT. Aestivumspelta (spelt), vavilovii, yunanense (Yunan wheat)
naked, nonbrittleT. Aestivumaestivum (bread wheat), compactum (club wheat), sphaerococcum (Indian dwarf wheat), petropavlovskyi (Chinese rice wheat)
cult.hulled, nonbrittleT. Zhukovskyi

*

Table 2 summarizes genome relationships in the Triticum–Aegilops alliance. Genomes designated through the same capital letter re-publishing homologous chromosomes. Various superscripts attached come a common capital letter mark slightly identified (modified) version of a simple genome. Diploid resources of genomes designated together X and Y are currently uncertain, although part evidence argues that the X genome progressed from an ancient S genome. Table 2 additionally summarizes relationships amongst cytoplasms (plasmons) the the species in the Triticum–Aegilops alliance.


Table 2. Genome and plasmon constitution of species in the Triticum–Aegilops alliance


SpeciesPlasmonaGenomeb
T. MonococcumA2Am
T. Urartu?A
Ae. SpeltoidesS,G,G2S
Ae. SearsiiSvSse
Ae. BicornisSbSb
Ae. SharonensisS1S1
Ae. LongissimaS12S1
Ae. UniaristataNN
Ae. Comosa (incl. Ae. Heldreichii)M, MhM
Ae. CaudataCC
Ae. UmbellulataUU
Ae. TauschiiDD
Ae. Mutica (syn. Amblyopyrum muticum)T,T2T
T. TurgidumBAB (B is regarded S)
T. AestivumBABD
T. TimopheeviiGAG (G is regarded S)
T. ZhukovskyiGAGAm
Ae. CylindricaDDC
Ae. VentricosaDDN
Ae. CrassaD2DcX
Ae. CrassaD2DcXD
Ae. VaviloviiD2DcXSse
Ae. JuvenalisD2DcXU
Ae. TriuncialisU, C2UC
Ae. ColumnarisU2UY
Ae. Neglecta 4× (syn. Ae. Triaristata)UUY
Ae. Neglecta 6× (syn. Ae. Recta)UUYN
Ae. Geniculata (syn. Ae. Ovata)M° (T)UM°
Ae. BiuncialisUUM°
Ae. KotschyiSvUS1
Ae. Peregrina (syn. Ae. Variabilis)SvUS1

aSuperscripts show minor differentiation the a plasmon from the basic kind (for much more details view Wang et al., 1997).bModified native Dvořák (1998).

Abby J. Cuttriss, ... Barry J. Pogson, in advances in botanical Research, 2011

C Wheat

Triticum spp. Endosperm colour is crucial agronomic trait and also thus has been the emphasis of number of QTL studies. Lutein is the primary carotenoid in wheat endosperm tissue and also is frequently heavily esterified (Atienza et al., 2007; Howitt et al., 2009). A target molecular marker was occurred for the PSY1 gene top top wheat chromosome 7A, and found to co-segregate with yellow pigmentation in a collection of Chinese wheat cultivars (He et al., 2008). Further, the complete carotenoid pool size was found to it is in modulated by ɛLCY alleles and/or PSY-A1 summer sprouts variants (Howitt et al., 2009). Transgenic wheat expressing endosperm-specific PSY1 indigenous maize and also bacterial CRTI (desaturases) created a 10.8-fold rise (up to 4.96 μg g− 1 dry weight) in total seed carotenoid content (Cong et al., 2009). Thus, both targeted breeding and transgenic approaches are most likely to improve wheat lutein content, i m sorry is correlated with protection versus age-related macular degeneration (AMD) the the eye—the leading cause of remote in the arisen world. Whether such strategies have the right to increase provitamin A levels in wheat has not to be reported for this reason far.


SpeciesSubspeciesCommon namePloidyCultivation statusSpike morphology
Triticum urartu Tum. Ex GandilyanEinkorn2xWildHulled and also brittle
Triticum monococcum L.aegilopoides (Link) Thell.Einkorn2xWildHulled and brittle
monococcumEinkorn2xCultivatedHulled and nonbrittle
Triticum turgidum L.dicoccoides (Körn) Thell.Emmer4xWildHulled and brittle
dicoccon (Schrank) KörnEmmer4xCultivatedHulled and also nonbrittle
palaeocolchicum Löve and also Löve4xCultivatedHulled and also nonbrittle
durum (Desf.) Husn.Macaroni wheat4xCultivatedNaked and also nonbrittle
turgidumPollard wheat4xCultivatedNaked and also nonbrittle
turanicum Löve and LöveKhorassan wheat4xCultivatedNaked and nonbrittle
polonicum (L.) Thell.Polish wheat4xCultivatedNaked and nonbrittle
carthlicum (Nevski) Löve and LövePersian wheat4xCultivatedNaked and also nonbrittle
Triticum timopheevii (Zhuk.) Zhuk.armeniacum (Jakubz.) valve Slageren4xWildHulled and also brittle
timopheevii4xCultivatedHulled and also nonbrittle
Triticum aestivum L.aestivumBread wheat6xCultivatedNaked and nonbrittle
compactum (Host) MacKeyClub wheat6xCultivatedNaked and also nonbrittle
sphaerococcum (Percival) MacKeyIndian dwarf wheat6xCultivatedNaked and nonbrittle
spelta (L.) Thell.Spelt6xCultivatedHulled and semibrittle
vavilovii (Tum.) Thell.6xCultivatedHulled and also semibrittle
yunanense KingYunan river wheat6xCultivatedHulled and semibrittle
tibetanum ShaoSemi-wild Tibetan wheat6xFeralNaked and also brittle
macha (Dekapr. And also Menabde) MacKey6xCultivated/feralNaked and also brittle
Triticum zhukovskyi Menabd. And Ericz.6xCultivatedHulled and nonbrittle

aSome morphological forms have unjustifiably received varieties status in the past and also have no been reclassified as subspecies. This is true because that a tetraploid long-glume variant Triticum ispahanicum Heslot, free-threshing tetraploid Ethiopian wheat Triticum aethiopicum Jakubz., and also a hexaploid long-glume free-threshing variant Triticum petropavlovkyi Udacz. And also Migusch called Chinese rice wheat.


SpeciesPlasmonGenomea
Triticum monococcum L.A2Am
Triticum urartu Tum. Ex Gandilyan?A
Aegilops speltoides TauschS,G,G2S
Aegilops searsii Feldman and also Kislev ex HammerSvSse
Aegilops bicornis (Forssk.) Jaub. And also SpachSbSb
Aegilops sharonensis EigSlSsh
Aegilops longissima Schweinf. And Muschl.Sl2Sl
Aegilops uniaristata Vis.NN
Aegilops comosa Sm. In Sibth and Sm.M, MhM
Aegilops markgrafii (Greuter) HammerCC
Aegilops umbellulata Zhuk.UU
Aegilops tauschii Coss.DD
Amblyopyrum muticum (Boiss.) EigT,T2T
Triticum turgidum L.BBA (B is regarded S)
Triticum aestivum L.BBAD
Triticum timopheevii (Zhuk.) Zhuk.GGA (G = S)
Triticum zhukovskyi Menabd. And also Ericz.SGAAm
Aegilops cylindrica HostDDC
Aegilops ventricosa TauschDDN
Aegilops crassa Boiss. 4xD2DcX
Aegilops crassa Boiss. 6xD2DcXD
Aegilops vavilovii (Zhuk.) Chennav.D2DcXSse
Aegilops juvenalis (Thell.) EigD2DcXU
Aegilops triuncialis L.U, C2UC
Aegilops biuncialis Vis.UUMo
Aegilops columnaris Zhuk.U2UY
Aegilops neglecta Req. And Bertol. 4xUUY
Aegilops neglecta Req. And also Bertol. 6xUUYN
Aegilops geniculata RothMoMoU
Aegilops kotschyi Boiss.SvSshU
Aegilops peregrina (Hackel in J. Fraser) Maire and WeillerSvSl U

aThe genome that the parental varieties that added the cytoplasm and also was thus the female parental of the polyploid is listed an initial in the genome formulas of polyploid species.

Alessandro Bozzini(Retired), ... Vincenzo Natoli, in Durum Wheat (Second Edition), 2012

Polyploidization: A usual Evolutionary feature in Triticeae

The Triticum genus is facility and rich in species. A description of your characteristics and related genomes is presented in Morris and also Sears (1967), Kimber and Sears (1987), and also Bozzini (1988). However, because that the objectives of this chapter, the taxonomic group system of van Slageren (1994) will be followed. A “Triticum Comparative category Table” shows up at https://www.ksu.edu/wgrc/Taxonomy/taxintro.html.

When species grow in the exact same area, voluntary hybrids might be observed; countless examples space reported in the herbaria (Van Slageren 1994). Together interspecific hybrids space usually extremely sterile; the homeologous chromosomes of the two distinguished genomes carry out not pair uniformly during meiosis and produce nonviable unbalanced gametes. In part cases, though, meiosis alterations create the development of proud gametes (gametes transporting 2n = 14 chromosomes instead of the usual collection of n = 7 chromosomes). The mating of a 2n male gamete through a 2n woman gamete may bring about a new stable and also fertile polyploidy types (allotetraploid) that is composed of 2n=4x=28 chromosomes (Kihara and also Lilienfeld 1949, Xu and also Dong 1992). This ability to create unreduced gametes is genetically established and additionally observed in grew wheats (Zhang et al 2007).

Spontaneous polyploidy is usual in plants, and also many combinations in between diploid Triticeae genomes can be observed in nature (Van Slageren 1994). Interspecific allopolyploidization can also involve types with higher ploidy and can lead to hexaploidy. (Octoploidy and greater ploidy levels are rare in the Triticeae.)

In newly created polyploids, the homeologous chromosomes can still pair (mimicking autopolyploidy), leading to abnormalities in gamete formation and subsequently diminished fitness. Pairing between the different genomes have the right to lead to chromosome rearrangements. In T. Turgidum subsp. dicoccoides, a wild allotetraploid wheat (Badaeva et al 2007), together in T. Araraticum (T. Timopheevi subsp. armeniacum) (Jiang and also Gill 1994), high rates of diversity for chromosome rearrangements can be found in between individuals, consisting of reciprocal translocations and also chromosome inversions. The further stabilization the allopolyploids needs a restriction of pairing in between the homoeologous chromosomes (Cifuentes et al 2010). In polyploid wheats, mechanisms for repression the homeologous pairing space under genetic manage (Okamoto 1957, Riley and Chapman 1958, Sears 1976). Among these genes v a significant effect, Ph1 (pairing homeologous), has actually been recently established at the molecular level (Griffiths et al 2006).

Polyploidy appears to have arisen spontaneously in the Triticeae tribe in different periods that history. Divergent diploid genomes have actually been combined to produce brand-new polyploid varieties by voluntary hybridization between diploid (or diploid through tetraploid) Triticum or Aegilops species. For example, out of the 22 Aegilops wild types classified according to van Slageren (1994), just nine species, representing 6 divergent genomes, room diploid. Most of the remaining varieties are allotetraploid, and also a few are allohexaploid (Van Slageren 1994). The reality that high ploidy levels room observed in Triticeae strongly support the theory that the introduction of hereditary variability by multiple origins deserve to increase the ecological amplitude and also evolutionary success that allopolyploid species compared with their diploid progenitors, because that adaptation both in the wild and in agriculture (Meimberg et al 2009).


Trust Beta, ... Franklin Brian Apea-Bah, in Nuts and Seeds in health and disease Prevention (Second Edition), 2020

Abstract

Wheat (Triticum sp.) is a nutritionally important grain grain an international and is 2nd only come maize in regards to production and also utilization. It has broad application in the bakery and also pastry industries, and in pasta preparation. When the white and also red genotypes are the many common, various other colored genotypes such as the purple, blue and black species are used and studied to a lot lesser extent. Purple wheat seeds room a good source the anthocyanins which are natural plant pigments through potent antioxidant capacity. Their unique color and also potential to add health services to consumers is attracting the fist of researchers and food product developers. This thing looks in ~ the botanical description and historical growing of violet wheat, as well as their constituent phenolic compounds and also antioxidant properties. The presents valuable information on approaches of analyses that phenolic compounds and how lock are impacted by warm processing applications.


Youjie Xu, ... Donghai Wang, in incorporated Processing innovations for Food and farming By-Products, 2019

1 Introduction

Wheat (Triticum spp.) has actually a long background of crop domestication, which transformed human cultural evolution and also led come the introduction of human world (Carver, 2009). Modern wheat cultivars mostly consist of 2 polyploid varieties such as hexaploid bread wheat (Triticum aestivum) and also tetraploid hard or durum wheat (Triticum turgidum) used for macaroni and also low-rising bread. Another kind of cultivated diploid species einkorn wheat (Triticum momococcum) is a relic and only exist in some mountainous Mediterranean regions (Shewry, 2009). About 95% of the wheat right now grown global is hexaploid bread wheat and also the continuing to be 5% are largely tetraploid durum wheat (Shewry, 2009). Wheat is thought about as the world's largest and most important cereal crop for person staple food, v an yearly production of > 700 million tonnes created globally over the past couple of years (http://www.fao.org).

The many common features used to classify wheat cultivars is mostly based on kernel color and also kernel harness, often defined as red or white, and also hard or soft. Planting and also growing cycles are regularly used to determine wheat, such as winter wheat and also spring wheat (Carver, 2009). Wheat kernel is composed of 2%–3% germ, 13%–17% bran, and also 80%–85% endosperm (Šramková et al., 2009). Wheat germ is rich in protein (25%) and also lipid (8%–13%) and also also vital source of Vitamin E. Wheat bran provides a security layer to the kernel and also occupies over 8% of the full weight the the kernel. The endosperm provides up the major part (80%–85% through weight) of the kernel and consists of a protein and starch matrix. Wheat protein contents usually ranges from 10% to 18% of the complete dry matter.

In enhancement to human being food and also livestock feed, wheat and also wheat by-product indigenous wheat processing as well as wheat straws likewise gained attention as renewable resources for biofuels and bio-based products. Wheat is at this time the dominant feedstock for the manufacturing of bioethanol in the Europe (Brancoli et al., 2018), conversely, wheat straw as among the most abundant farming wastes has an excellent potential because that the manufacturing of liquid or gaseous biofuels (Lopez-Hidalgo et al., 2017). Besides, wheat straw also shows an excellent industrial applications for straw particleboard fabrication, arabinoxylans extraction, and also bioenergy production. In addition, milling industry by-products, wheat bran and germ, are necessary sources the health-enhancing bioactive components, at the same time wheat starch and protein are substantial biopolymers for creating platform chemicals.


In this chapter, we review the industrial and nonfood applications that wheat including bio-based assets from wheat straw such as particleboard production, xylans extraction, and bioenergy manufacturing; phytochemicals from wheat bran and germ such as phenolics, carotenoids, β-glucan, vitamins, and dietary fibers; and also biochemicals indigenous wheat protein and also starch such together biofilms and also bioadhesives, together demonstrated in the suggest wheat biorefinery ide for multiple commodities generation (Fig. 1).



T. aestivum probably generated spontaneously somewhere in the Iranian highlands or nearby areas. Historical finds show that this took place some 6000 years BC (Belderok, 2000). The unique milling and also baking properties of typical bread wheat space not found amongst the diploid and also tetraploid wheats. The preferable quality characteristics of bread wheats have actually been attributed preponderantly to the visibility of the D genome component (Belderok, 2000; Tonk et al., 2010). The an initial evidence because that wheat utilization originates from the Ohalo II website on the coast of the Sea the Galilee, Israel, wherein barley (Hordeum vulgare) and also brittle, wild tetraploid wild emmer wheat (Triticum dicoccum), dated as 19000 years old, were found, arguing the initial actions towards resolved and cereal farming (Kislev et al., 1992). Wheat and also barley were amongst the more quickly domesticated chop plants, domestication ensuing 10000 years back in the Pre-pottery Neolithic Near east (Lev-Yadun et al., 2000). The accumulation of excess food provides enabled huge settlements to it is in established, resulting in the emergence of western civilization. The earliest grew forms the wheat were basically landraces selected by farmer from wild populations since of their remarkable yield and other characteristics. However, domestication was also associated through the choice of hereditary traits that separated castle from their wild relatives. 2 of the most vital traits pursued throughout the domestication to be loss of smashing of the spike at maturity, which outcomes in seed loss at harvesting, and also presence of kernels in the free-threshing (naked) type (Shewry, 2009). In 2010, the manufacturing of wheat approached the of rice (Table 1.1) with 653.7 × 106 t (FAO/UN, 2012) developed worldwide. Relying on the climate, floor condition, variety, farming practices and also other conditions, wheat yields can range from 2.7 to 3.0 tonnes/ha (FAO/ UN, 2012). Nowadays, wheat yields global tend to be greater than 2.8 tonnes/ha on mean (FAO/UN, 2012) (Table 1.1). Wheat is grew in 123 countries and China is currently the world’s top wheat producer. Table 1.2 perform the peak 10 wheat-producing countries, end the five-year duration 2006–2010.


Table 1.1. Wheat and total grain grain production and also producer price in the people from 2000–2010


YearTotal wheat production (Mt)Total cereal production (Mt)aWheat together % of full grainsArea wheat harvest (Mha)Wheat productivity (t/ha)Producer price (US $/tonnes)
2000585.7204428.7215.42.7179.7
2001589.8209328.2214.62.7177.2
2002574.7207727.7213.82.7167.4
2003560.1226024.8207.72.7190.6
2004632.7224728.2216.92.9200.6
2005626.9221928.3219.72.8197.1
2006602.9233525.8211.22.8205.2
2007612.6250324.5216.72.8268.6
2008683.2247027.7222.83.0341.8
2009689.6247227.9224.63.0266.2
2010653.7241227.1217.23.0283.3
Average619.3228527.1216.42.8225.2

Source: Data native FAO/UN (2012).

aTotal cereal production has corn, rice, wheat, barley, sorghum, millet, oat, rye, combined grain.

Table 1.2. Wheat production estimates in the 10 leading developing countries; five-year average 2006–2010


RankCountryProduction (Mt)Area harvested (Mha)Wheat productivity (t/ha)World manufacturing (%)
1China89.018.94.713.7
2India63.623.52.79.8
3USA47.016.42.97.3
4Russian Federation40.018.72.16.2
5France29.64.46.74.6
6Chile24.15.14.73.7
7Hungary19.76.43.13.0
8Canada19.47.32.73.0
9Germany19.02.77.02.9
10Pakistan18.07.02.62.8
Total369.4110.43.3a57.0

aAverage the wheat yield amongst the 10 leading-producing countries.

Source: Data indigenous FAO/UN (2012).


Among the peak 10 wheat-producing countries, China contributed, throughout the duration 2006–2010, 13.7 % the the world wheat manufacturing from 8.6 % the the world’s wheat-growing area, when India contributed 9.8 % of the manufacturing from 10.7 % that the area. China produces a bigger amount that wheat 보다 India (89.0 compared to 63.6 million tonnes every year, 2006–2010) but from 4 % less wheat farming area (18.9 contrasted to 23.5 million hectares every year, 2006–2010). This is mainly as result of the high wheat productivity registered in China (4.7 tonnes/ha), second only come Germany and France with 6.7 and 7.0 tonnes/ha, dong (FAO/UN, 2012) (Table 1.2).Throughout the last 10 years, wheat production has slowly increased by roughly 10%, farming from 585.7 × 106 to 653.7 × 106 tonnes, mainly because of an boosted yield that has actually been boosted by ≈ 10%(Table 1.1).

As report in Table 1.1, the critical 10 years have seen wheat producer prices boost by 36.5%, moving from 179.7 united state $/tonnes to 283.3 us $/tonnes in 2010. Among the height 10 producer countries, Turkey and Russian Federation proved the highest possible (328.4 united state $/tonnes) and also the shortest (134.4 united state $/tonnes) producer price, respectively. Because that the leading producing nation China, the producer price for 2009 was same to 270.9 united state $/tonnes (FAO/UN, 2012).


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Dhan Pal Singh, ... Arti Singh, in tree Breeding and Cultivar Development, 2021

Triticum spp. (wheat)

The genus Triticum contains a polyploidy collection of varieties and hybrids ranging from diploids (2n=14) to hexaploid (2n=42). Triticum aestivum and T. Durum space widely grew species. Another species, T. Dicoccum is sparsely cultivated in details parts that India. There is enough evidence that the bread wheat has progressed in nature from three diploid species, T. Monococcum (AA), Aegilops speltoides (BB), and Aegilops squarrosa (DD) with intergeneric hybridization and genome building. The natural crossing in between T. Monococcum (2n=14) v A. Speltoides (2n=14) through chromosome doubling has actually resulted in evolution of tetraploid emmer wheat (AABB, 2n=28). The hybridization in nature between the tetraploid wheat through diploid A. Squarrosa (2n=14) following by copy of chromosome has actually resulted in the evolution of hexaploid wheat.


Different methods have been supplied for transferring genetic materials come bread wheat from various other cultivated varieties or indigenous wild relatives, which room both diploid and tetraploid. Whereby alien/donor varieties are very closely related to wheat and also carries one or more of the A, B, or D genomes, that is feasible to directly cross these species to wheat making use of special approaches of embryo culture to carry genes into wheat. Few of the diploids might be crossed through hexaploid or first crossed with tetraploid and then through the hexaploid. However, tetraploids can also be crossed straight with the hexaploid wheat. Homologous chromosome pairing and also crossing end would occur in the hybrids. The selection among result segregants would administer an possibility to isolate preferable segregants. Success was completed by hybridization of durum wheat (T. Durum=T. Turgidum) a tetraploid varieties with abdominal genomes to common wheat varieties which is hexaploid through ABD genomes. Because that example, high protein contents (Gpc-B1 gene) and condition resistance genes from T. Dicoccoides to T. Durum and also T. Durum to T. Aestivum have been transferred. Artificial wheat (hexaploids) are artificially produced by cross tetraploid (durum wheat, AABB genome) and also wild goatgrass (Aegilops tauschii, DD genome). Man-made wheat T. Turgidum, AABB) and also diploid wild goat grass (Aegilops tauschii, D’D’)>. The provides broader genetic base to hexaploid wheat, and also is a advantageous strategy to introduce agronomically advantageous traits right into hexaploid typical wheat indigenous wild genetic resources. Merezhko (1998) analyzed the influence of plant genetic resources on wheat breeding and also inferred that the most far-ranging results have been accomplished through hybridization v T. Durum and T. Dicoccum. Just a few bread wheat cultivars have been developed with the participation of T. Turgidum, T. Persicum, T. Timopheevi, T. Spelta, T. Compactum, and also T. Sphaerococcum. The wealthiest gene swimming pool of varieties belongs come Aegilops species. The move of an useful genes native the D genome the Aegilops is now much less complicated (Fig. 6.1). One amphidiploid with ad genome is synthesized which is cytogenetically stable and also can be crossed readily with A. Tauschii and bread wheat, and serves as intermediate bridge for introgressive hybridization.



Embryo rescue might be required in breakthrough of man-made wheat, and also regenerated plants are triploid, necessitating the use of colchicine to dual the chromosomes. In cross involving differing ploidy levels, geneticists introduce the usage of higher ploidy level together a female parent. Gill and Raupp (1987) suggested that the use of goatgrass (A. Tauschii or A. Squarrosa) might be suitable for direct gene transfer. They observed finish homology with small genetic interaction in between D genome that wheat and D genome that goatgrass. However, interspecific hybridization between the two types is challenging and only few tetraploid hybrids were reported. Researchers supplied A. squarrosa together female and noticed challenge in successful crossing, particularly F1 abortion, hybrid lethality, and also high male and also female sterility that F1 hybrids. However, if wheat is taken together female parental as argued in Fig. 6.2, far better results would be achieved. Genotypes, polyploidy level, crossing procedure, and cross direction are necessary to generate viable hybrids in Triticum, and previous study has shown that generally greater ploidy types should be supplied as a woman parent.


Some that the donor varieties are not very closely related come bread wheat and do not have a common genome v wheat. The pairing and also recombination would certainly not occur in such crosses. The usage of bridging cross and production the amphiploid would certainly be helpful. While newer examples are available, instances presented listed below are historically essential to demonstrate efforts prior to the usage of modern-day tools.

Sears (1956) used this method for the an initial time effectively to incorporate sheet rust resistance from Aegilops umbellulata to T. Aestivum. A. Umbellulata is a diploid (2n=14) wild grass native Mediterranean region having UU genome and also has no genome common with T. Aestivum. The cross in between T. Aestivum and also A. Umbellulata go not create viable seed. Therefore, that made a bridging cross in between A. Umbellulata and T. Dicoccoides (2n=28) and also produced F1 amphidiploid, which to be backcrossed twice v T. Aestivum and selection for sheet resistance was made. He properly developed enhancement line transporting the rust resistance gene on an additional A. Umbellulata chromosome. X-ray irradiation of this addition line resulted into translocation the a small segment of A. Umbellulata carrying resistance placed to 6B chromosome the wheat. The resistance line was called “Transfer.” The gene was moved from move to Thatcher wheat through backcrossing. Knott (1961) offered the procedure the Sears to move stem rust resistance indigenous Agropyron elongatum (EE, 2n=70) to T. Aestivum. One of the translocations to be transmitted typically through the gametes and also was provided as resource of stem rust resistance in Australian cultivar Eagle and Kite.

A similar technique was used by Driscoll and also Jensen (1964). They effectively transferred a sheet rust resistance and also a powdery mildew resistance gene from rye (Secale cereale) come bread wheat (T. Aestivum). Lock irradiated a sheet rust resistant wheat line delivering a rye chromosome followed by screening the result progenies to choose a line carrying an induced translocation that the desired kind called “Transec.” This line had two resistance gene from rye put into wheat chromosome 4A.


Surjani Uthayakumaran, Colin Wrigley, in cereal Grains (Second Edition), 2017

5.2 Wheat as a genus

Wheat (Triticum species) is one of the oldest food crops. It has actually been well-known to exist due to the fact that 10,000 BC as an agricultural species intentionally cultivated by man (Feldman, 2001; Gustafson et al., 2009; Morrison, 2016). Its popular stems in component from the adaptability of wheat together a cultivated chop suited for many different soils and climatic conditions. Most significantly, wheat is unique due to the fact that of the ability of wheat proteins to incorporate into the protein mass recognized as gluten (Békés and also Wrigley, 2016). Wheat is for this reason the just effective source of flour because that bread manufacturing in the people (Atwell, 2001; Moore, 2016). Its close relative, rye, shares some of the dough-forming capability of wheat, yet most rye bread is made from a grist that wheat and also rye flour (see Chapter 7).

5.2.1 Taxonomy

The genus Triticum includes a wide range of species, however only two types are grown commercially to a large extent:

Triticum aestivum—bread or common wheat, which is genetically hexaploid through genomes A, B and D;

Triticum durum—macaroni or durum wheat, gene tetraploid, with genomes A and also B (see Chapter 6).


Over 90% of the wheat grown an international is T. Aestivum. The is supplied for a wide variety of applications, consisting of bread, cakes, pastries, biscuits, puddings, thickeners and noodles. T. Durum (durum wheat) is mostly used for pasta production. In addition, little amounts the a few specialty wheats are grown: spelt wheat (a hexaploid wheat—T. Aestivum var. Spelta), Triticum monococcum (small spelt wheat) and also T. Timopheevii (Georgian wheat) (see Chapter 14).

T. Monococcum, Aegilops speltoides, T. Tauschii and also the wild Aegilops species, i beg your pardon is carefully related to the modern-day Ae. Speltoides, are ancestral diploid wheat species having seven pairs that chromosomes (2n = 14). The tetraploid T. Durum is obtained from the organic hybridisation of T. Monococcum (A genome) and the genealogical Ae. Speltoides (B genome) (Wrigley, 2009; Morrison and also Wrigley, 2016). Hexaploid bread wheat (2n = 42) is a an outcome of the herbal hybridisation the T. Dicoccoides (AABB) and T. Tauschii (DD) (Mangelsdorf, 1953; Shewry et al., 2003; Gustafson et al., 2009).

The common wheats of today are divided into red and also white wheats (based on the soot of red pigmentation in the particle coat), hard and soft wheats (based top top the resistance the the seed as soon as it is crushed), and also winter and spring species (differing in their necessity for a cold duration to hasten or allow normal breakthrough towards reproductive development) (Gooding, 2009) (see Chapter 18).

5.2.2 Origins

Man assumed control over his very own food production during the Neolithic Revolution. The pre-agricultural hunter–gatherer came to be familiar with nature’s periodicity and also with the life cycle of the dominant plants in his environment, finally succeeding come domesticate countless of them. Wheat is among the world most essential food crops to be domesticated. That is thought that wild loved ones of wheat very first grew in the center East, in the ‘Fertile Crescent’ (Feldman, 2001). Wheat was among the very first plants to it is in cultivated. It was grown around 11,000-years ago. Enormous changes in people’s lives occurred because the wheat being grown. People started growing their very own food, no longer needing come wander in search of food. Permanent settlements were established since wheat listed people through a secure food supply. Soon they grew sufficient wheat to feeding others from neighboring regions.

Once there to be extra wheat available, trade between various cultures developed. By 4000 BC, wheat farming had actually spread come Asia, Europe and North Africa. New species of wheat emerged because early farmers selected kernels from their ideal wheat plants to use as seed for planting the following year’s crop. In that way, only the best wheat characteristics were passed indigenous one generation to the next. Soon wheat became an essential worldwide crop.

Three key theories worrying the site of wheat domestication were proposed in the 19th century. Follow to the first theory, wheat was tamed in the near East. The evidence was indigenous the Chaldean priest, Berosus, who pointed out that wild wheat emerged in Mesopotamia at about 2700 BP (Syncellus, Frag. Hist. Graec., vol. 2, p. 416). Another theory in 1899 proposed the the farming of wheat began in central Asia. The 3rd theory suggest in 1908 said that wheat thrived wild in Europe and was later trained there (Feldman, 2001; Morrison, 2016).

5.2.3 genetic Constitution

Genetically, there space three main groups of grew wheat, namely, diploid, tetraploid and also hexaploid wheats (McIntosh, 2016). The wild progenitor of grew diploid wheat einkorn was uncovered in the center East, the progenitor because that tetraploid wheat emmer and also durum was discovered in the beginning of the 20th century. There are no equivalent progenitors for hexaploid wheat and it is clear the hexaploid wheats emerged from hybridisations in between cultivated tetraploid wheat and wild diploid species.

During the 20th century, breeders have emerged many new wheat genotypes. These brand-new types the wheat deserve to produce good yields the grain, v resistance to cold, disease, insects and also other crop threats. As a result, wheat production around the world has increased dramatically. Throughout the critical 30 years, there has been a tremendous increase in new knowledge that the biochemistry, genetics and also functional properties of wheat. Much more recently, molecular biology has actually helped to elucidate the functions of the genes that determine the an excellent diversity of wheat phenotypes (Jones et al., 2009; Akhonov, 2016; Henry, 2014, 2016).

Common or bread wheat (T. Aestivum) is hexaploid v 21 bag (2n = 42) that chromosomes consisting of three homoeologous (similar) genomes (AA, BB and also DD) each of 7 pairs. Durum and emmer wheats are tetraploids (2n = 28) possessing genomes, AA and BB, similar to these genomes in hexaploid wheat. Einkorn wheat is diploid (AA genome), supplying a variety of helpful uses in the person diet (Abdel-Aal and Hucl, 2014) (see Chapter 14).

5.2.4 Plant and Grain Morphology

An understanding of plant, head and also grain morphology (appearance, see Chapter 4) is beneficial for controlling the stages of serial production, and additionally for the assessment of grain quality to the extent that morphology have the right to be used for varietal identification—variety gift a an essential aspect of grain quality. Plant features are critical part that the mechanism for variety registration carried out by UPOV, the global Union because that the protection of new Varieties of Plants, because that the function of enforcing plant Breeders’ Rights. Registration calls for that a brand-new variety should exhibit the attributes of distinctness, uniformity and stability (DUS), mainly with respect come morphology.

The procedures and also attributes because that DUS testing of wheat are provided by Cook and Wrigley (2004) and on the UPOV website (www.upov.int). Number of books and review posts are easily accessible concerning the morphological features that are helpful for selection identification, some of them attach by to know descriptions and keys for the particular varieties in national variety collections as provided in Chapter 4, which provides a general description of morphology comparing the selection of cereal species, accentuating wheat.

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The wheat serial is botanically a single-seeded fruit, called a ‘caryopsis’ or ‘kernel’, arising within the glumes, which are modified leaves. The shape and also dimensions of the grain have actually the potential to provide evidence for distinguishing amongst varieties, as described further in Chapter 4. That is the inside endosperm that the wheat grain the is the resource of the flour created by milling (see Chapter 22) to provide the multitude of wheat-based foodstuffs (see Chapter 24).