Free-threshing Wheat Research Articles

Cultivated einkorn wheat (Triticum monococcum L. subsp. monococcum): the long life of a founder crop of agriculture

The first cultivated wheat, cultivated einkorn (Triticum monococcum L. subsp. monococcum), was domesticated in South-East Turkey during the Pre-Pottery Neolithic period. It then spread to the Middle-East, the Balkans and Caucasus, Turkmenistan, Central and Mediterranean Europe, North-Africa, and finally to Western and Northern Europe. In all these regions, it played an important role in the development of agriculture and was cultivated for several centuries before being replaced by free-threshing wheats. Today, cultivated einkorn is only present in isolated, mountainous areas of a few countries. However, there is renewed interest for this crop due to the nutritional qualities of its grain, its adaptation to low-input agriculture and high level of resistance to pests and diseases that represent advantages for organic farming. Cultivated einkorn is also a valuable reservoir of genes for wheat improvement. Its utilization, limited by its hulledness, low yield and especially by a poor knowledge of its diversity and its low crossability with bread and durum wheat, is expected to increase in the future, particularly with the need for wheat breeding to face newly emerging diseases through the use of genetic resistances. Considering these perspectives, the present review attempts to analyse the current and historical importance of einkorn cultivation and utilization in wheat breeding, tracing back to its origin and diffusion. The main traits of resistance to pest and diseases, and the nutritional qualities and technological characteristics of the grain are described. Einkorn genetic resources diversity exploration is reviewed and successful examples of introgression of useful einkorn traits into cultivated wheat are reported. Lastly, perspectives of einkorn cultivation development in low-input agriculture and use for wheat enhancement are discussed.

An integrated stable isotope study of plants and animals from Kouphovouno, southern Greece: a new look at Neolithic farming

This paper presents the first study that combines the use of ancient crop and animal stable isotopes (carbon and nitrogen) and Zooarchaeology Mass Spectrometry species identification (ZooMS) for reconstructing early farming practices at Kouphovouno, a Middle–Late Neolithic village in southern Greece (c. 5950–4500 cal. BC). Debate surrounding the nature of early farming predominantly revolves around the intensity of crop cultivation: did early farmers move around the landscape while practicing temporary farming methods such as slash and burn agriculture or did they create more permanent fields by investing high labor inputs into smaller pieces of land that produced higher crop yields? The need to address these questions using a direct assessment of the intensity and scale of cultivation is apparent, and an integrated stable isotope approach provides such an opportunity. The results of this study support the model of small-scale mixed farming, where crop cultivation and animal husbandry are closely integrated. The farmers directed their intensive management towards crops grown for human consumption (free-threshing wheat), while growing fodder crop (hulled barley) more extensively. Pulses were cultivated under a high-manuring/high-watering regime, likely in garden plots in rotation with free-threshing wheat. The diets of the livestock enable us to investigate which parts of the landscape were used for browsing and grazing and indicate that animal management changed in the Late Neolithic. The sheep and goats were now kept in smaller numbers and grazed together and new pasture grasses may have been sought for the grazing of cattle. This study demonstrates that beyond its applicability for palaeodietary reconstruction, analysis of stable isotopes of archaeological crop and animal remains has important implications for understanding the relationship between humans, plants and animals in an archaeological context.

PaleoIndian big-game hunters in North America: are we misreading the evidence?

This paper presents the first study that combines the use of ancient crop and animal stable isotopes (carbon and nitrogen) and Zooarchaeology Mass Spectrometry species identification (ZooMS) for reconstructing early farming practices at Kouphovouno, a Middle–Late Neolithic village in southern Greece (c. 5950–4500 cal. BC). Debate surrounding the nature of early farming predominantly revolves around the intensity of crop cultivation: did early farmers move around the landscape while practicing temporary farming methods such as slash and burn agriculture or did they create more permanent fields by investing high labor inputs into smaller pieces of land that produced higher crop yields? The need to address these questions using a direct assessment of the intensity and scale of cultivation is apparent, and an integrated stable isotope approach provides such an opportunity. The results of this study support the model of small-scale mixed farming, where crop cultivation and animal husbandry are closely integrated. The farmers directed their intensive management towards crops grown for human consumption (free-threshing wheat), while growing fodder crop (hulled barley) more extensively. Pulses were cultivated under a high-manuring/high-watering regime, likely in garden plots in rotation with free-threshing wheat. The diets of the livestock enable us to investigate which parts of the landscape were used for browsing and grazing and indicate that animal management changed in the Late Neolithic. The sheep and goats were now kept in smaller numbers and grazed together and new pasture grasses may have been sought for the grazing of cattle. This study demonstrates that beyond its applicability for palaeodietary reconstruction, analysis of stable isotopes of archaeological crop and animal remains has important implications for understanding the relationship between humans, plants and animals in an archaeological context.

Molecular Genetic Analysis of Domestication Traits in Emmer Wheat. I: Map Construction and QTL Analysis using an F2 Pupulation

ABSTRACTEmmer wheat (Triticum turgidum ssp. dicoccum) was a principal crop in the development and spread of Neolithic agriculture in the Old World. It represents the primitive situation in the domestication of AABB tetraploid wheat. To understand the genetic modifications underlying the early stage of tetraploid wheat domestication, QTL analysis was carried out using 144 F2 plants derived from a cross between the domesticated emmer wheat and the wild emmer wheat (T. turgidum ssp. dicoccoides). To our knowledge, this is the first report of molecular linkage map and QTL analysis of the domestication-related characters in emmer wheat. The linkage map with a total length of 2849.8 cM was constructed using 227 microsatellite (SSR) markers. Chromosomal location and effect of QTLs were estimated for ten domestication-related traits including whole plant and spike characteristics. Seventeen QTLs were detected on chromosomes 1B, 2A, 2B, 3A, 3B, 4A, 5B, and 7B. Two regions on chromosomes 2A and 3B have a large effect on rachis fragility. The estimated locations of these QTLs corresponded to those of the Br genes identified in the previous studies on a more adapted durum wheat (T. turgidum ssp. turgidum conv. durum). Our results indicate that selection and conversion of at least two Br loci (on chromosomes 2A and 3B) occurred during the domestication of emmer wheat prior to appearance of free-threshing wheat (e.g. durum). The map positions of nine QTLs for the traits related to seed production overlapped in two regions on chromosomes 2A and 5B. The result suggests that these chromosomal regions played an important role in increasing seed production during the domestication of emmer wheat.

Grindstones and related artefacts from Pre-Aksumite Seglamen, northern Ethiopia, and their wider implications

Although non-rotary grindstones (saddle querns) and related artefacts are not infrequently encountered on Holocene archaeological sites in many parts of Africa, they are rarely studied. This paper begins to remedy that omission by looking at the varied morphologies of some of the grind- and handstones found at the Pre-Aksumite site of Seglamen in highland northern Ethiopia and comparing these with similar artefacts from the Pre-Aksumite and Late Aksumite levels at the site of Kidane Mehret, near Aksum. A classificatory vocabulary is presented and it is shown that significant economic reconstructions can be derived from the study of these artefacts, including the probable correlation of a change in grindstone material and morphology with the introduction of modern free-threshing wheat.

The Origin of Spelt and Free-Threshing Hexaploid Wheat

It is widely believed that hexaploid wheat originated via hybridization of hulled tetraploid emmer with Aegilops tauschii (genomes DD) and that the nascent hexaploid was spelt, from which free-threshing wheat evolved by mutations. To reassess the role of spelt in the evolution of Triticum aestivum, 4 disomic substitution lines of Ae. tauschii chromosome 2D in Chinese Spring wheat were developed and one of them was used to map the Tg locus, which controls glume tenacity in Ae. tauschii, relative to simple sequence repeat (SSR) and expressed sequence tag loci on wheat chromosome 2D. The segregation of SSR markers was used to assess the presence of Tg alleles in 11 accessions of spelt, both from Europe and from Asia. Ten of them had an inactive tg allele in the D genome and most had an active Tg allele in the B genome. This is consistent with spelt being derived from free-threshing hexaploid wheat by hybridization of free-threshing wheat with hulled emmer. It is proposed that the tetraploid parent of hexaploid wheat was not hulled emmer but a free-threshing form of tetraploid wheat.

Evidence from principal component analysis for improvement of grain shape- and spikelet morphology-related traits after hexaploid wheat speciation

Grain shape and size are involved in the main components of the domestication syndrome in cereals. Wheat grain shape has been dramatically altered at each stage of the domestication of tetraploid wheat and through common wheat speciation. To elucidate the evolutionary change of wheat grain shape, principal component (PC) analysis of grain shape-related traits was first conducted using wild and cultivated tetraploid, synthetic hexaploid, and common wheat accessions. The synthetic hexaploid wheat lines were previously produced through interspecific crosses between two common wheat progenitors, tetraploid wheat and Aegilops tauschii, and produced grains similar to those of cultivated tetraploid wheat. To identify genetic loci related to the difference in grain shape between common wheat and the synthetic wheat, the 15 traits related to grain and spikelet shape were measured in 108 F(2) individuals between Norin 61 and a synthetic wheat line, and the first three PC values for the 15 traits, PC1, PC2 and PC3, were mapped as quantitative traits in the F(2) population. In total, six QTLs, found on chromosomes 1A, 5A, 1D, 2D and 7D, showed significant LOD scores. Among them, a QTL for PC2, located on the 2DS chromosomal region near the Ppd-D1 locus, mainly contributed to the phenotypic difference in grain shape. Tg-D1, controlling tenacious glume phenotype, was located at a similar region to the 2DS QTL, which suggested that the Tg-D1 locus pleiotropically affects not only glume toughness but also spikelet and grain shape in hexaploid wheat. Therefore, it was predicted that wheat grains were rapidly improved toward a shorter and rounder phenotype accompanied with free-threshing wheat formation.

Discrimination of alleles and copy numbers at the Q locus in hexaploid wheat using quantitative pyrosequencing

Speltoid spikes are characterized by pyramidal spike morphology featuring an elongated rachis and tenacious glumes. Speltoids are considered undesirable spike aberrants in wheat breeding leading to increased heterogeneity within a cultivar candidate. As a consequence, the presence of speltoids may result in rejection of a cultivar candidate during official field trials or denial of cultivar certification during seed multiplication. A reliable method is, thus, required to assess the occurrence of speltoids, early on in a wheat breeding program. The domestication gene Q located on the long arm of wheat chromosome 5A is known to suppress the speltoid phenotype in wheat. Here, a quantitative pyrosequencing assay was developed to distinguish between normal wheat plants, which possess two copies of the Q allele, and aberrants, which are either aneuploids lacking the correct number of chromosome 5A copies or plants which carry the primitive q allele. An accurate and reproducible determination of the Q gene copy number was achieved for different wheat genotypes based on homoeologous sequence quantification with two primer combinations at the Q locus. Single plants with one to four copies of the Q allele could be detected by quantitative pyrosequencing which corresponded to the occurrence of speltoid (1 Q allele), normal (2 Q alleles), and compact (more than 2 Q alleles) spikes. Q and q specific alleles could be differentiated at SNP position 2299 of the Q gene. This SNP is assumed to be related to the emergence of free-threshing wheat forms. To our knowledge this is the first report for detection of aneuploids and differentiation of Q alleles in bread wheat using pyrosequencing technology. In future, quantitative pyrosequencing assay can be applied in wheat breeding programs to carry out marker-assisted selection against the presence of speltoid spike aberrants.

Archäobotanische Funde aus der Kampagne 2009 in Qubur al-Walaydah

Abstract Early Iron Age archaeobotanical samples from Qub¯ur el-Wal¯eyide, with the majority falling into the phase IA and fewer into phase IB, have been analysed. Taphonomic conditions during carbonization of the plant remains seem to have been dominated by high burning temperatures, which are probably responsible for low find densities. The number of different taxa is,however, comparatively high,with barley representing the most frequent and numerous find, while most of the other sites in the area show dominance in free-threshing wheat, particularly in those with modern mean annual precipitation above 400 mm. Free-threshing wheat and lentil also occur at Qub¯ur el-Wal¯eyide in relatively high counts, while typical fruit crops of the Mediterranean, such as grape or olive do not occur in the samples. Amongst the wild plant species representatives of open and overgrazed landscapes are very frequent. Future investigations will have to clarify the representativeness of the model of barley dominance in settle...

Growth, Chlorophyll, and Cation Concentration of Tetraploid Wheat on a Solution High in Sodium Chloride Salt: Hulled Versus Free-Threshing Genotypes

ABSTRACT Based on the literature, under-utilized hulled wheats could be tolerant to some harsh environmental conditions. The effect of salt stress on chlorophyll content, leaf area, dry weight, and ion concentrations in eight genotypes of tetraploid wheat (Triticum turgidum) using a three-replicate completely random design indoor experiment was studied. These genotypes included six hulled wheat (HW), T. turgidum subspp. Dicoccum, and two free-threshing wheat (FTW), T. turgidum subspp. durum. Salt stress was induced by adding sodium chloride (NaCl) to a hydroponic medium to 40, 80, and 120 mM, in addition to control. Salinity reduced leaf content of chlorophyll a (chl-a) at 120 mM but had not significant effect on chlorophyll b (chl-b) content. Salt stress decreased plant leaf area by nearly 63%. Plant top dry weight declined by 52% with increasing salinity to 120 mM level. Plant top calcium (Ca2+) content was not affected, whereas plant top sodium (Na+) concentration increased and potassium (K+) and magnesium (Mg+) concentration decreased with increasing salinity, averaged over genotypes. No significant interaction of genotype × salinity was detected for traits studied in this experiment. When contrasted as two groups of genotypes, i.e., HW vs. FTW, the former group suffered more severe decreases in terms of chl-a, chl-b, leaf area, dry weight, and Mg2+ concentration and a more pronounced increase in Na+ compared to the FTW. Overall, no evidence of salt tolerance was found for hulled tetraploid wheats of central Iran.

Plant remains from the early Iron Age in western Sicily: differences in subsistence strategies of Greek and Elymian sites

For the early Iron Age Elymian town on Monte Polizzo, inland western Sicily, hulled barley was the dominant cereal, followed by emmer and free-threshing wheat. The dominant legume was Vicia faba. In the con- temporary Greek harbour town of Selinunte on the southern coast of western Sicily, free-threshing wheat was dominant, while hulled barley and the legume V. ervilia were sub- dominant. For Selinunte, an import of cereals from the Elymians is suggested. The investigated area around the agora (marketplace) yielded a processed cereal product and edible fruit as the predominantly consumed plant- based food in Selinunte. Its hinterland most probably pro- vided space for large-scale maintenance of horses and oxen as well as for stock breeding for consumption. At ''House 1'' on Monte Polizzo, the archaeobotanical record matches well with the archaeological interpretation of different rooms used for ritual consumption, everyday life, crop processing and crop storage. During feasts in the style of Greek symposia, grapes and figs were consumed. The Elymians most probably adopted olive cultivation quite late. The charcoal analyses, mainly of roof beams from Monte Polizzo residential contexts, point to a sufficient availability of undisturbed natural climax woodland for timberwork.

Urartian Plant Cultivation at Yoncatepe (Van), Eastern Turkey

Plant remains were recovered from an Urartian settlement, Yoncatepe, situated in the Van province of eastern Turkey and dating to the Iron Age period (first millennium B.C.E.). Large quantities of hulled barley (Hordeum vulgare L.) and of bread/macaroni wheat (free-threshing wheat) Triticum aestivum L./T. durum Desf.), both mixed with small quantities of domesticated emmer wheat (T. dicoccum Schubl.), were found in the storerooms of the Yoncatepe palace, indicating the storage of agricultural surplus. Rye (Secale cereale L.) grains occur very occasionally, while pulses include lentil (Lens culinaris Medik.), chickpea (Cicer arietinum L.), and bitter vetch (Vicia ervilia [L.] Willd.). Grape seeds unearthed in a tomb at Yoncatepe provide physical evidence supporting written records of vineyards. Numerous seeds of gold of pleasure (Camelina sativa [L.] Crantz), found in a storage vessel, provide evidence of the cultivation of this plant. It is likely, that the Urartians used the seeds for oil extraction.

The historical perspective of dryland agriculture: lessons learned from 10 000 years of wheat cultivation

Wheat is one of the founder crops of Western agriculture. This study reconstructs agronomic conditions, potential yields, and kernel weight in the beginnings of cultivation of domesticated free-threshing wheat, c. 8000 BC. The carbon and nitrogen stable isotope compositions and the dimensions of fossil grains of naked wheat (Triticum aestivum/durum) were analysed. Samples were collected in Tell Halula and Akarçay Tepe, two Neolithic archaeological sites from the Middle Euphrates (the claimed core area for wheat domestication). The samples analysed include the oldest reported remains of naked wheat. Consistently wetter conditions but lower kernel weights were found in the Neolithic compared with the present day. Besides, the estimated yields were clearly beyond what is expected from the gathering of wild stands of cereals. Patterns of phenotypic adaptation achieved by wheat after its diffusion through the Mediterranean were also assessed. On the one hand, the study looked at variation in morphophysiological traits as related to local climate in a set of 68 durum wheat landraces from the Middle Euphrates. On the other hand, an assessment was made of regional adaptation around the Mediterranean Basin in a set of 90 landraces, traditional varieties, and modern cultivars from different origins by characterizing agronomic and morphophysiological variability. Significant relationships were observed between phenotypic variation among landraces from the Middle Euphrates and both minimum temperatures and the ratio of precipitation to potential evapotranspiration of the sites of origin. In addition, consistent differences in grain yield, plant structure, and water status were found among genotypes following both north-south and east-west gradients across the Mediterranean. These differences are associated with contrasting environmental and selection pressures.

The spread of agriculture in northern Iberia: new archaeobotanical data from El Mirón cave (Cantabria) and the open-air site of Los Cascajos (Navarra)

This paper presents archaeobotanical results from the Neolithic levels (5,300–4,000 b.c.) of two recently excavated sites in northern Iberia: El Miron cave (Cantabria) and the open-air site of Los Cascajos (Navarra). A cereal grain from El Miron is currently the earliest domesticated plant remain from this region. Despite the large number of samples examined, plant remains are few. They include basically cereals (Triticum monococcum, T. dicoccum, T. aestivum/durum/turgidum and Hordeum vulgare) and some nuts and fruits (Corylus avellana, Quercus sp., Vitis sp., etc.). The presence of free-threshing wheats at El Miron opens up an interesting subject for debate, as until now naked wheats have been absent from the early Neolithic archaeobotanical record of the coastal Cantabrian region. Hulled wheat chaff is the main plant component from Los Cascajos, south of the Cantabrian Cordillera in Navarra, indicating waste from processing activities. The association of barley almost exclusively with both a burial and a ritual vase in Los Cascajos could be related specific rituals or ceremonies.

Plant stores at pottery Neolithic Höyücek, southwest Turkey

AbstractEleven samples comprising an estimated 39,000 plant remains were analysed from a burnt destruction level at the pottery Neolithic site of Höyücek, southwest Turkey (radiocarbon dated 7550–7350 uncalibrated bp, 6400–6100 calibrated BC). Large stores of emmer (Triticum dicoccum), free threshing wheat (Triticum aestivum/durum), lentils (Lens culinaris), bitter vetch (Vicia ervilia) and chickpea (Cicer arietinum) were identified and these plants were interpreted as crops. The low levels of weeds and crop processing by-products suggest most of the samples were remains of stores of human food. Two samples in which wild components (for example,Triticum boeticum, Medicago, Aegilops) dominated were interpreted as crop processing by-products, presumably stored for fodder. The presence of these stores in a structure interpreted as having a religious function shows that domestic activities also took place there. Comparison with other Neolithic and Chalcolithic sites of west central Turkey demonstrates a good correspondence in the range of crops. The poor representation of barley at Höyücek doubtless reflects the small number of samples from the site.

Identification of plant sterols in hexaploid and tetraploid wheats using gas chromatography with mass spectrometry.

Free sterols from hexaploid and tetraploid free-threshing wheats (Triticum aestivum L. and T. durum Desf.) and from their respective hulled wheats (T. spelta L. and T. dicoccon Schrank) were analysed by gas chromatography with mass spectrometry. The qualitative analysis of sterols showed a similar pattern either between hexaploid (T. aestivum, T. spelta) and tetraploid (T. durum, T. dicoccon) wheats or between free-threshing (T. aestivum, T. durum) and hulled (T. spelta, T. dicoccon) wheats. However, quantitative differences were found between tetraploid and hexaploid wheats, in that free sterol amounts in tetraploid wheats were 40% higher than in hexaploid ones. The mass spectra of the sterols were classified into four groups, taking into account the structural features of rings A and B. Typical mass spectral fragmentations of the four classes, and additional evidence related to the side chain of each molecule, were investigated together with their chromatographic behaviour, allowing identification of all the detected sterols.

Coexistence of Tetraploid and Hexaploid Naked Wheat in a Neolithic Lake Dwelling of Central Europe: Evidence from Morphology and Ancient DNA

Free-threshing wheat was a principal cereal in Neolithic cultures, as shown by the abundance of grains in the archaeological record. However, the morphology of the mainly charred preserved, prehistoric naked wheat grains is not characteristic of either tetraploid,Triticum durumDesf. andTriticum turgidumL., or of hexaploid, e.g.Triticum aestivumL. We analysed the morphology of charred naked wheat grains originating from a storage assemblage of an Early Cortaillod culture layer (3906–3906bc) at the Lake of Zürich, Switzerland and addressed their identification by molecular genetics. A fragment of the promoter region of the high-molecular-weight (HMW) subunit genes of glutenin was successfully amplified by the polymerase chain reaction. Sequences obtained from cloned PCR products are highly similar to modern sequences. The detection of the D genome allele suggests the presence of hexaploidT. aestivum. However, rachis remains from the same site as well as other contemporary sites were identified morphologically as tetraploid naked wheat.

Dynamics of Cereal Production at Tell el Ifshar, Israel during the Middle Bronze Age

A Middle Bronze Age IIA (MB IIA) storage complex (ca. 20th to 18th centuries B.C.) units of which were used for storing grain) was uncovered at Tell el Ifshar (Tel Hefer), Israel, in 1990. Analysis of charred plant remains from this complex, as well as from other locations on the tell, allows a broad discussion of MB IIA farming and agricultural decision making within a loosely centralized city-state. Villagers apparently sowed fields in low-lying alluvial resource zones rather than sandy clay zones. They planted legume and cereal crops well-suited to the physical environment, which also were short-term capital investments. Farmers planted both emmer and free-threshing wheat, but mainly emmer wheat—a species tolerant of environmental extremes and resilient to post-harvest loss despite greater processing cost and lower potential yield. Farmers also promoted field species-diversity and used various planting strategies to protect crops from environmental risk. In the Late Bronze Age and Iron Age, farmers risked higher production costs of free-threshing wheat in return for greater harvest potential and easier processing. Despite this overall trend, strategies varied over shorter time frames (e.g., within the Middle Bronze Age).

Archaeobotanical remains of hulled and naked cereals in the Iberian Peninsula

Archaeobotanical finds in Spain show differences in the representation of the different wheats and barleys. From the beginning of agriculture (around 5000 B.C.) onwards, all wheats and barleys can be found at the sites of the eastern Peninsula. But in later periods of the early Neolithic, free-threshing wheat becomes more important in the northeast and the southeast, compared to the hulled wheats (emmer and einkorn). Nevertheless, both naked and hulled barleys can be found in similar frequencies in this period. Seed analyses in the southeast and the east of Spain show the importance of naked barley compared with hulled barley in the third millenium uncal B.C. This is not the case in the northeast, where hulled barley has a similar frequency in this period until the Iron Age, when both hulled barley and free-threshing wheat are the most important taxa. The substitution of naked barley for hulled barley in the south-east Iberian Peninsula is very significant in the period of greatest growth of the Argar culture. Free-threshing wheat can be found at a similar frequency throughout the study area, and was an important human food source together with the barleys. Hulled wheats seem to have played a secondary role as food in all periods, although they are constantly present in our samples. Nevertheless spelt wheat does not appear until the Roman period, when it is only found on the Cantabrian north coast, where it is important.

The Macroscopic Plant Remains from Euesperides (Benghazi): an interim report

AbstractRecent excavations at the Greco-Libyan site of Euesperides, Benghazi, have included a sampling programme for the retrieval of macroscopic plant remains. Preliminary results are now available and help to shed some light on the economy of the site between the sixth and the third centuries BC. Barley is the principal cereal crop recorded, while both hulled and free-threshing wheats are present. Fruit remains generally dominate the samples and include frequent seeds of grape and fig. The grape pips are of interest in that they appear to be morphologically more wild than cultivated. It is thought that they may be of a variety which does not conform with the characteristics of better known northern Mediterranean varieties of grape.