Quality Characteristics of Twelve Advanced Lines of Avena magna ssp. domestica Grown in Three Contrasting Locations in Morocco.

The popularity of oats (Avena sativa) continues to increase in the cereal market due to their health benefits. The recent domestication of Avena magna, a Moroccan oat, presents an opportunity to enhance these benefits due to their higher nutritional composition. As the impact of microclimates on A. magna grain composition has not been explored, this study evaluates twelve A. magna ssp. domestica lines across three Moroccan locations, providing new data into microclimate effects on key grain characteristics. Significant variability is observed among lines and sites for nutrients, with mean protein, fat, and dietary fiber contents at 23.1%, 8.38%, and 7.23%, respectively. High protein levels, reaching 27.1% in Alnif and 26.5% in El Kbab, surpass the 'Avery' control (21.7% and 24.2%) in these environments. Groats from Bouchane exhibited elevated fat and fiber contents (10.2% and 9.94%) compared to the control (8.83% and 7.36%). While ß-glucan levels remain consistent at 2.53%, a negative correlation between protein content, fat, and starch was observed. A. magna lines exhibited higher levels of iron (7.50 × 10-3 g/100 g DM) and zinc (3.40 × 10-3 g/100 g DM) compared to other cereals. Environmental conditions significantly influence grain quality, with El Kbab yielding higher protein and ash contents, as well as Bouchane having increased fat, fiber, and starch. Stability analysis indicates that fat content was more influenced by the environment, while 25% of protein variability is influenced by genetics. Lines AT3, AT5, AT6, AT13, and AT15 consistently exceeds both the mean for protein and fiber across all sites, emphasizing their potential nutritional value. This study highlights the potential of A. magna ssp. domestica to address nutritional insecurity, particularly for protein, iron, and zinc in domestic settings.

A chromosome-scale assembly of the quinoa genome provides insights into the structure and dynamics of its subgenomes.

Quinoa (Chenopodium quinoa Willd.) is an allotetraploid seed crop with the potential to help address global food security concerns. Genomes have been assembled for four accessions of quinoa; however, all assemblies are fragmented and do not reflect known chromosome biology. Here, we use in vitro and in vivo Hi-C data to produce a chromosome-scale assembly of the Chilean accession PI 614886 (QQ74). The final assembly spans 1.326 Gb, of which 90.5% is assembled into 18 chromosome-scale scaffolds. The genome is annotated with 54,499 protein-coding genes, 96.9% of which are located on the 18 largest scaffolds. We also report an updated genome assembly for the B-genome diploid C. suecicum and use it, together with the A-genome diploid C. pallidicaule, to identify genomic rearrangements within the quinoa genome, including a large pericentromeric inversion representing 71.7% of chromosome Cq3B. Repetitive sequences comprise 65.2%, 48.6%, and 57.9% of the quinoa, C. pallidicaule, and C. suecicum genomes, respectively. Evidence suggests that the B subgenome is more dynamic and has expanded more than the A subgenome. These genomic resources will enable more accurate assessments of genome evolution within the Amaranthaceae and will facilitate future efforts to identify variation in genes underlying important agronomic traits in quinoa.

Homoeologous evolution of the allotetraploid genome of Poa annua L.

BACKGROUND: Poa annua (annual bluegrass) is an allotetraploid turfgrass, an agronomically significant weed, and one of the most widely dispersed plant species on earth. Here, we report the chromosome-scale genome assemblies of P. annua's diploid progenitors, P. infirma and P. supina, and use multi-omic analyses spanning all three species to better understand P. annua's evolutionary novelty. RESULTS: We find that the diploids diverged from their common ancestor 5.5 - 6.3 million years ago and hybridized to form P. annua ≤ 50,000 years ago. The diploid genomes are similar in chromosome structure and most notably distinguished by the divergent evolutionary histories of their transposable elements, leading to a 1.7 × difference in genome size. In allotetraploid P. annua, we find biased movement of retrotransposons from the larger (A) subgenome to the smaller (B) subgenome. We show that P. annua's B subgenome is preferentially accumulating genes and that its genes are more highly expressed. Whole-genome resequencing of several additional P. annua accessions revealed large-scale chromosomal rearrangements characterized by extensive TE-downsizing and evidence to support the Genome Balance Hypothesis. CONCLUSIONS: The divergent evolutions of the diploid progenitors played a central role in conferring onto P. annua its remarkable phenotypic plasticity. We find that plant genes (guided by selection and drift) and transposable elements (mostly guided by host immunity) each respond to polyploidy in unique ways and that P. annua uses whole-genome duplication to purge highly parasitized heterochromatic sequences. The findings and genomic resources presented here will enable the development of homoeolog-specific markers for accelerated weed science and turfgrass breeding.

A chromosome-scale reference of Chenopodium watsonii helps elucidate relationships within the North American A-genome Chenopodium species and with quinoa.

Quinoa (Chenopodium quinoa), an Andean pseudocereal, attained global popularity beginning in the early 2000s due to its protein quality, glycemic index, and high fiber, vitamin, and mineral contents. Pitseed goosefoot (Chenopodium berlandieri), quinoa's North American free-living sister species, grows on disturbed and sandy substrates across the North America, including saline coastal sands, southwestern deserts, subtropical highlands, the Great Plains, and boreal forests. Together with South American avian goosefoot (Chenopodium hircinum) they comprise the American tetraploid goosefoot complex (ATGC). Superimposed on pitseed goosefoot's North American range are approximately 35 AA diploids, most of which are adapted to a diversity of niche environments. We chose to assemble a reference genome for Sonoran A-genome Chenopodium watsonii due to fruit morphological and high (>99.3%) preliminary sequence-match similarities with quinoa, along with its well-established taxonomic status. The genome was assembled into 1377 scaffolds spanning 547.76 Mb (N50 = 55.14 Mb, L50 = 5), with 94% comprised in nine chromosome-scale scaffolds and 93.9% Benchmarking Universal Single-Copy Orthologs genes identified as single copy and 3.4% as duplicated. A high degree of synteny, with minor and mostly telomeric rearrangements, was found when comparing this taxon with the previously reported genome of South American C. pallidicaule and the A-subgenome chromosomes of C. quinoa. Phylogenetic analysis was performed using 10,588 single-nucleotide polymorphisms generated by resequencing a panel of 41 New World AA diploid accessions and the Eurasian H-genome diploid Chenopodium vulvaria, along with three AABB tetraploids previously sequenced. Phylogenetic analysis of these 32 taxa positioned the psammophyte Chenopodium subglabrum on the branch containing A-genome sequences from the ATGC. We also present evidence for long-range dispersal of Chenopodium diploids between North and South America.

Chromosome-Scale Genome Assembly and Annotation of Allotetraploid Annual Bluegrass (Poa annua L.).

Poa annua L. is a globally distributed grass with economic and horticultural significance as a weed and as a turfgrass. This dual significance, and its phenotypic plasticity and ecological adaptation, have made P. annua an intriguing plant for genetic and evolutionary studies. Because of the lack of genomic resources and its allotetraploid (2n = 4x = 28) nature, a reference genome sequence would be a valuable asset to better understand the significance and polyploid origin of P. annua. Here we report a genome assembly with scaffolds representing the 14 haploid chromosomes that are 1.78 Gb in length with an N50 of 112 Mb and 96.7% of BUSCO orthologs. Seventy percent of the genome was identified as repetitive elements, 91.0% of which were Copia- or Gypsy-like long-terminal repeats. The genome was annotated with 76,420 genes spanning 13.3% of the 14 chromosomes. The two subgenomes originating from Poa infirma (Knuth) and Poa supina (Schrad) were sufficiently divergent to be distinguishable but syntenic in sequence and annotation with repetitive elements contributing to the expansion of the P. infirma subgenome.

Chromosome-Scale Genome Assembly of the Hexaploid Taiwanese Goosefoot "Djulis" (Chenopodium formosanum).

Djulis (Chenopodium formosanum Koidz.) is a crop grown since antiquity in Taiwan. It is a BCD-genome hexaploid (2n = 6x = 54) domesticated form of lambsquarters (C. album L.) and a relative of the allotetraploid (AABB) C. quinoa. As with quinoa, djulis seed contains a complete protein profile and many nutritionally important vitamins and minerals. While still sold locally in Taiwanese markets, its traditional culinary uses are being lost as diets of younger generations change. Moreover, indigenous Taiwanese peoples who have long safeguarded djulis are losing their traditional farmlands. We used PacBio sequencing and Hi-C-based scaffolding to produce a chromosome-scale, reference-quality assembly of djulis. The final genome assembly spans 1.63 Gb in 798 scaffolds, with 97.8% of the sequence contained in 27 scaffolds representing the nine haploid chromosomes of each sub-genome of the species. Benchmarking of universal, single-copy orthologs indicated that 98.5% of the conserved orthologous genes for Viridiplantae are complete within the assembled genome, with 92.9% duplicated, as expected for a polyploid. A total of 67.8% of the assembly is repetitive, with the most common repeat being Gypsy long terminal repeat retrotransposons, which had significantly expanded in the B sub-genome. Gene annotation using Iso-Seq data from multiple tissues identified 75,056 putative gene models. Comparisons to quinoa showed strong patterns of synteny which allowed for the identification of homoeologous chromosomes, and sub-genome-specific sequences were used to assign homoeologs to each sub-genome. These results represent the first hexaploid genome assembly and the first assemblies of the C and D genomes of the Chenopodioideae subfamily.

Genome analysis in Avena sativa reveals hidden breeding barriers and opportunities for oat improvement.

Oat (Avena sativa L.) is an important and nutritious cereal crop, and there is a growing need to identify genes that contribute to improved oat varieties. Here we utilize a newly sequenced and annotated oat reference genome to locate and characterize quantitative trait loci (QTLs) affecting agronomic and grain-quality traits in five oat populations. We find strong and significant associations between the positions of candidate genes and QTL that affect heading date, as well as those that influence the concentrations of oil and ß-glucan in the grain. We examine genome-wide recombination profiles to confirm the presence of a large, unbalanced translocation from chromosome 1 C to 1 A, and a possible inversion on chromosome 7D. Such chromosome rearrangements appear to be common in oat, where they cause pseudo-linkage and recombination suppression, affecting the segregation, localization, and deployment of QTLs in breeding programs.

The mosaic oat genome gives insights into a uniquely healthy cereal crop.

Cultivated oat (Avena sativa L.) is an allohexaploid (AACCDD, 2n = 6x = 42) thought to have been domesticated more than 3,000 years ago while growing as a weed in wheat, emmer and barley fields in Anatolia1,2. Oat has a low carbon footprint, substantial health benefits and the potential to replace animal-based food products. However, the lack of a fully annotated reference genome has hampered efforts to deconvolute its complex evolutionary history and functional gene dynamics. Here we present a high-quality reference genome of A. sativa and close relatives of its diploid (Avena longiglumis, AA, 2n = 14) and tetraploid (Avena insularis, CCDD, 2n = 4x = 28) progenitors. We reveal the mosaic structure of the oat genome, trace large-scale genomic reorganizations in the polyploidization history of oat and illustrate a breeding barrier associated with the genome architecture of oat. We showcase detailed analyses of gene families implicated in human health and nutrition, which adds to the evidence supporting oat safety in gluten-free diets, and we perform mapping-by-sequencing of an agronomic trait related to water-use efficiency. This resource for the Avena genus will help to leverage knowledge from other cereal genomes, improve understanding of basic oat biology and accelerate genomics-assisted breeding and reanalysis of quantitative trait studies.

Improving phylogenetic resolution of the Lamiales using the complete plastome sequences of six Penstemon species.

The North American endemic genus Penstemon (Mitchell) has a recent geologic origin of ca. 3.6 million years ago (MYA) during the Pliocene/Pleistocene transition and has undergone a rapid adaptive evolutionary radiation with ca. 285 species of perennial forbs and sub-shrubs. Penstemon is divided into six subgenera occupying all North American habitats including the Arctic tundra, Central American tropical forests, alpine meadows, arid deserts, and temperate grasslands. Due to the rapid rate of diversification and speciation, previous phylogenetic studies using individual and concatenated chloroplast sequences have failed to resolve many polytomic clades. We investigated the efficacy of utilizing the plastid genomes (plastomes) of 29 species in the Lamiales order, including five newly sequenced Penstemon plastomes, for analyzing phylogenetic relationships and resolving problematic clades. We compared whole-plastome based phylogenies to phylogenies based on individual gene sequences (matK, ndhF, psaA, psbA, rbcL, rpoC2, and rps2) and concatenated sequences. We also We found that our whole-plastome based phylogeny had higher nodal support than all other phylogenies, which suggests that it provides greater accuracy in describing the hierarchal relationships among taxa as compared to other methods. We found that the genus Penstemon forms a monophyletic clade sister to, but separate from, the Old World taxa of the Plantaginaceae family included in our study. Our whole-plastome based phylogeny also supports the rearrangement of the Scrophulariaceae family and improves resolution of major clades and genera of the Lamiales.

A Chromosome-Scale Assembly of the Garden Orach (Atriplex hortensis L.) Genome Using Oxford Nanopore Sequencing.

Atriplex hortensis (2n = 2x = 18, 1C genome size ∼1.1 gigabases), also known as garden orach and mountain-spinach, is a highly nutritious, broadleaf annual of the Amaranthaceae-Chenopodiaceae alliance (Chenopodiaceae sensu stricto, subfam. Chenopodioideae) that has spread in cultivation from its native primary domestication area in Eurasia to other temperate and subtropical regions worldwide. Atriplex L. is a highly complex but, as understood now, a monophyletic group of mainly halophytic and/or xerophytic plants, of which A. hortensis has been a vegetable of minor importance in some areas of Eurasia (from Central Asia to the Mediterranean) at least since antiquity. Nonetheless, it is a crop with tremendous nutritional potential due primarily to its exceptional leaf and seed protein quantities (approaching 30%) and quality (high levels of lysine). Although there is some literature describing the taxonomy and production of A. hortensis, there is a general lack of genetic and genomic data that would otherwise help elucidate the genetic variation, phylogenetic positioning, and future potential of the species. Here, we report the assembly of the first high-quality, chromosome-scale reference genome for A. hortensis cv. "Golden." Long-read data from Oxford Nanopore's MinION DNA sequencer was assembled with the program Canu and polished with Illumina short reads. Contigs were scaffolded to chromosome scale using chromatin-proximity maps (Hi-C) yielding a final assembly containing 1,325 scaffolds with a N50 of 98.9 Mb - with 94.7% of the assembly represented in the nine largest, chromosome-scale scaffolds. Sixty-six percent of the genome was classified as highly repetitive DNA, with the most common repetitive elements being Gypsy-(32%) and Copia-like (11%) long-terminal repeats. The annotation was completed using MAKER which identified 37,083 gene models and 2,555 tRNA genes. Completeness of the genome, assessed using the Benchmarking Universal Single Copy Orthologs (BUSCO) metric, identified 97.5% of the conserved orthologs as complete, with only 2.2% being duplicated, reflecting the diploid nature of A. hortensis. A resequencing panel of 21 wild, unimproved and cultivated A. hortensis accessions revealed three distinct populations with little variation within subpopulations. These resources provide vital information to better understand A. hortensis and facilitate future study.

The genome of Chenopodium pallidicaule: An emerging Andean super grain.

PREMISE: Cañahua is a semi-domesticated crop grown in high-altitude regions of the Andes. It is an A-genome diploid (2n = 2x = 18) relative of the allotetraploid (AABB) Chenopodium quinoa and shares many of its nutritional benefits. Cañahua seed contains a complete protein, a low glycemic index, and offers a wide variety of nutritionally important vitamins and minerals. METHODS: The reference assembly was developed using a combination of short- and long-read sequencing techniques, including multiple rounds of Hi-C-based proximity-guided assembly. RESULTS: The final assembly of the ~363-Mbp genome consists of 4633 scaffolds, with 96.6% of the assembly contained in nine scaffolds representing the nine haploid chromosomes of the species. Repetitive element analysis classified 52.3% of the assembly as repetitive, with the most common repeat identified as long terminal repeat retrotransposons. MAKER annotation of the final assembly yielded 22,832 putative gene models. DISCUSSION: When compared with quinoa, strong patterns of synteny support the hypothesis that cañahua is a close A-genome diploid relative, and thus potentially a simplified model diploid species for genetic analysis and improvement of quinoa. Resequencing and phylogenetic analysis of a diversity panel of cañahua accessions suggests that coordinated efforts are needed to enhance genetic diversity conservation within ex situ germplasm collections.

Genomic insights from the first chromosome-scale assemblies of oat (Avena spp.) diploid species.

BACKGROUND: Cultivated hexaploid oat (Common oat; Avena sativa) has held a significant place within the global crop community for centuries; although its cultivation has decreased over the past century, its nutritional benefits have garnered increased interest for human consumption. We report the development of fully annotated, chromosome-scale assemblies for the extant progenitor species of the As- and Cp-subgenomes, Avena atlantica and Avena eriantha respectively. The diploid Avena species serve as important genetic resources for improving common oat's adaptive and food quality characteristics. RESULTS: The A. atlantica and A. eriantha genome assemblies span 3.69 and 3.78 Gb with an N50 of 513 and 535 Mb, respectively. Annotation of the genomes, using sequenced transcriptomes, identified ~ 50,000 gene models in each species-including 2965 resistance gene analogs across both species. Analysis of these assemblies classified much of each genome as repetitive sequence (~ 83%), including species-specific, centromeric-specific, and telomeric-specific repeats. LTR retrotransposons make up most of the classified elements. Genome-wide syntenic comparisons with other members of the Pooideae revealed orthologous relationships, while comparisons with genetic maps from common oat clarified subgenome origins for each of the 21 hexaploid linkage groups. The utility of the diploid genomes was demonstrated by identifying putative candidate genes for flowering time (HD3A) and crown rust resistance (Pc91). We also investigate the phylogenetic relationships among other A- and C-genome Avena species. CONCLUSIONS: The genomes we report here are the first chromosome-scale assemblies for the tribe Poeae, subtribe Aveninae. Our analyses provide important insight into the evolution and complexity of common hexaploid oat, including subgenome origin, homoeologous relationships, and major intra- and intergenomic rearrangements. They also provide the annotation framework needed to accelerate gene discovery and plant breeding.

Mitochondrial and chloroplast genomes provide insights into the evolutionary origins of quinoa (Chenopodium quinoa Willd.).

Quinoa has recently gained international attention because of its nutritious seeds, prompting the expansion of its cultivation into new areas in which it was not originally selected as a crop. Improving quinoa production in these areas will benefit from the introduction of advantageous traits from free-living relatives that are native to these, or similar, environments. As part of an ongoing effort to characterize the primary and secondary germplasm pools for quinoa, we report the complete mitochondrial and chloroplast genome sequences of quinoa accession PI 614886 and the identification of sequence variants in additional accessions from quinoa and related species. This is the first reported mitochondrial genome assembly in the genus Chenopodium. Inference of phylogenetic relationships among Chenopodium species based on mitochondrial and chloroplast variants supports the hypotheses that 1) the A-genome ancestor was the cytoplasmic donor in the original tetraploidization event, and 2) highland and coastal quinoas were independently domesticated.

Corrigendum: The genome of Chenopodium quinoa.

This corrects the article DOI: 10.1038/nature21370.

The genome of Chenopodium quinoa.

Chenopodium quinoa (quinoa) is a highly nutritious grain identified as an important crop to improve world food security. Unfortunately, few resources are available to facilitate its genetic improvement. Here we report the assembly of a high-quality, chromosome-scale reference genome sequence for quinoa, which was produced using single-molecule real-time sequencing in combination with optical, chromosome-contact and genetic maps. We also report the sequencing of two diploids from the ancestral gene pools of quinoa, which enables the identification of sub-genomes in quinoa, and reduced-coverage genome sequences for 22 other samples of the allotetraploid goosefoot complex. The genome sequence facilitated the identification of the transcription factor likely to control the production of anti-nutritional triterpenoid saponins found in quinoa seeds, including a mutation that appears to cause alternative splicing and a premature stop codon in sweet quinoa strains. These genomic resources are an important first step towards the genetic improvement of quinoa.

A Consensus Map in Cultivated Hexaploid Oat Reveals Conserved Grass Synteny with Substantial Subgenome Rearrangement.

Hexaploid oat ( L., 2 = 6 = 42) is a member of the Poaceae family and has a large genome (∼12.5 Gb) containing 21 chromosome pairs from three ancestral genomes. Physical rearrangements among parental genomes have hindered the development of linkage maps in this species. The objective of this work was to develop a single high-density consensus linkage map that is representative of the majority of commonly grown oat varieties. Data from a cDNA-derived single-nucleotide polymorphism (SNP) array and genotyping-by-sequencing (GBS) were collected from the progeny of 12 biparental recombinant inbred line populations derived from 19 parents representing oat germplasm cultivated primarily in North America. Linkage groups from all mapping populations were compared to identify 21 clusters of conserved collinearity. Linkage groups within each cluster were then merged into 21 consensus chromosomes, generating a framework consensus map of 7202 markers spanning 2843 cM. An additional 9678 markers were placed on this map with a lower degree of certainty. Assignment to physical chromosomes with high confidence was made for nine chromosomes. Comparison of homeologous regions among oat chromosomes and matches to orthologous regions of rice ( L.) reveal that the hexaploid oat genome has been highly rearranged relative to its ancestral diploid genomes as a result of frequent translocations among chromosomes. Heterogeneous chromosome rearrangements among populations were also evident, probably accounting for the failure of some linkage groups to match the consensus. This work contributes to a further understanding of the organization and evolution of hexaploid grass genomes.

The complete chloroplast genome sequences for four Amaranthus species (Amaranthaceae).

PREMISE OF THE STUDY: The amaranth genus contains many important grain and weedy species. We further our understanding of the genus through the development of a complete reference chloroplast genome. METHODS AND RESULTS: A high-quality Amaranthus hypochondriacus (Amaranthaceae) chloroplast genome assembly was developed using long-read technology. This reference genome was used to reconstruct the chloroplast genomes for two closely related grain species (A. cruentus and A. caudatus) and their putative progenitor (A. hybridus). The reference genome was 150,518 bp and possesses a circular structure of two inverted repeats (24,352 bp) separated by small (17,941 bp) and large (83,873 bp) single-copy regions; it encodes 111 genes, 72 for proteins. Relative to the reference chloroplast genome, an average of 210 single-nucleotide polymorphisms (SNPs) and 122 insertion/deletion polymorphisms (indels) were identified across the analyzed genomes. CONCLUSIONS: This reference chloroplast genome, along with the reported simple sequence repeats, SNPs, and indels, is an invaluable genetic resource for studying the phylogeny and genetic diversity within the amaranth genus.

Elevated Genetic Diversity in an F2:6 Population of Quinoa (Chenopodium quinoa) Developed through an Inter-ecotype Cross.

Quinoa (Chenopodium quinoa) is a seed crop of the Andean highlands and Araucanian coastal regions of South America that has recently expanded in use and production beyond its native range. This is largely due to its superb nutritional value, consisting of protein that is rich in essential amino acids along with vitamins and minerals. Quinoa also presents a remarkable degree of tolerance to saline conditions, drought, and frost. The present study involved 72 F2:6 recombinant-inbred lines and parents developed through hybridization between highland (0654) and coastal (NL-6) germplasm groups. The purpose was to characterize the quinoa germplasm developed, to assess the discriminating potential of 21 agro-morpho-phenological traits, and to evaluate the extent of genetic variability recovered through selfing. A vast amount of genetic variation was detected among the 72 lines evaluated for quantitative and qualitative traits. Impressive transgressive segregation was measured for seed yield (22.42 g/plant), while plant height and maturity had higher heritabilities (73 and 89%, respectively). Other notable characters segregating in the population included panicle and stem color, panicle form, and resistance to downy mildew. In the Principal Component analysis, the first axis explained 74% of the total variation and was correlated to plant height, panicle size, stem diameter, biomass, mildew reaction, maturation, and seed yield; those traits are relevant discriminatory characters. Yield correlated positively with panicle length and biomass. Unweighted Pair Group Method with Arithmetic Mean-based cluster analysis identified three groups: one consisting of late, mildew-resistant, high-yielding lines; one having semi-late lines with intermediate yield and mildew susceptibility; and a third cluster consisting of early to semi-late accessions with low yield and mildew susceptibility. This study highlighted the extended diversity regenerated among the 72 accessions and helped to identify potentially adapted quinoa genotypes for production in the Moroccan coastal environment.

C-Banding of Plant Chromosomes.

C-banding is used to differentially stain metaphase chromosomes in organisms having appreciable amounts of constitutive heterochromatin. Its primary benefits are that it is an inexpensive and a relatively fast method of identifying individual chromosomes and morphological or karyotypic variation, including large chromosomal rearrangements and aneuploidies. We currently employ this technique with considerable effect in genome analysis of oat (Avena sativa) and related grass species, though it has been most extensively used for chromosome analysis of wheat (Triticum aestivum) and its relatives of the Triticeae.