Tritordeum Ascherson Research Articles

Wx Gene in Hordeum chilense: Chromosomal Location and Characterisation of the Allelic Variation in the Two Main Ecotypes of the Species

Starch, as the main grain component, has great importance in wheat quality, with the ratio between the two formed polymers, amylose and amylopectin, determining the starch properties. Granule-bound starch synthase I (GBSSI), or waxy protein, encoded by the Wx gene is the sole enzyme responsible for amylose synthesis. The current study evaluated the variability in Wx genes in two representative lines of Hordeum chilense Roem. et Schult., a wild barley species that was used in the development of tritordeum (×Tritordeum Ascherson et Graebner). Two novel alleles, Wx-Hch1a and Wx-Hch1b, were detected in this material. Molecular characterizations of these alleles revealed that the gene is more similar to the Wx gene of barley than that of wheat, which was confirmed by phylogenetic studies. However, the enzymatic function should be similar in all species, and, consequently, the variation present in H. chilense could be utilized in wheat breeding by using tritordeum as a bridge species.

Selenium-Fertilized Tritordeum (× Tritordeum Ascherson et Graebner) as Dietary Selenium Supplement in Laying Hens: Effects on Egg Quality.

The aim of the present study was to investigate the effect of adding selenium (Se) in cereal production by fertilization on Se concentration in laying hen eggs. Tritordeum (×Tritordeum Ascherson et Graebner), a new cereal from the cross between durum wheat and a wild barley species having accreditation as natural crop species, was produced using selenate as Se-fertilizer. Hy-Line Brown laying hens were randomly allocated to two dietary treatments and fed for 10weeks. Hens were fed two corn-soybean meal-based diets comprising a control basal diet including Tritordeum (100g/kg diet) cv. Aucan grown without Se fertilization (containing background Se only from premix supplying 1,0 times birds' requirements) and a test-diet containing Se-enriched Tritordeum at the same level of the control diet. No difference was observed among dietary treatments on feed consumption and efficiency, egg mass, and laying rate, whereas egg yolk Se and vitamin E contents as well as liver and plasma Se levels were significantly influenced by dietary Se-enriched Tritordeum. Based on our findings, Se-enriched Tritordeum improved egg quality without affecting hens' productive performance. Thus, Se-fertilized Tritordeum may represent a valuable natural source of Se compared to conventional dietary supplements.

Carotenoid profiling of Hordeum chilense grains: The parental proof for the origin of the high carotenoid content and esterification pattern of tritordeum

The outstanding high carotenoid content of the tritordeum (×Tritordeum Ascherson et Graebner) grains, a promising novel cereal derived from the crossing of durum wheat and the wild barley Hordeum chilense, has previously been assigned as a character derived from the genetic background of its wild parent. The carotenoid profile of H. chilense, especially the lutein esters presented in this study, provide biochemical evidences to confirm this affirmation, being the first time that the individual carotenoid profile of this cereal has been characterized. The total carotenoid content (6.14 ± 0.12 μg/g) and the individual carotenoid composition were very similar to the tritordeum grains, with lutein being the major carotenoid (88%; 5.38 ± 0.11 μg/g) and very low levels of β-carotene. In contrast to tritordeum, H. chilense presented a considerable amount of zeaxanthin (12%; 0.74 ± 0.01 μg/g). Up to 55% of lutein was esterified with palmitic (C16:0) and linoleic (C18:2) acids, presenting a characteristic acylation pattern, in agreement with the tritordeum one, and composed by four monoesters (lutein 3′-O-linoleate, lutein 3-O-linoleate, lutein 3′-O-palmitate and lutein 3-O-palmitate) and four diesters (lutein dilinoleate, lutein 3′-O-linoleate-3-O-palmitate, lutein 3′-O-palmitate-3-O-linoleate, lutein dipalmitate). These data may be useful in the field of carotenoid biofortification of cereals.

Lutein esterification in wheat endosperm is controlled by the homoeologous group 7, and is increased by the simultaneous presence of chromosomes 7D and 7Hch from Hordeum chilense

The high carotenoid content in tritordeum (×Tritordeum Ascherson et Graebner) grains is derived from its wild parent, Hordeum chilense Roem. et Schulz. Phytoene synthase 1 (Psy1) is located on chromosome 7HchS and plays a major role in this trait. This study investigates the impact of the introgression of chromosome 7Hch into common wheat background on carotenoid composition, including xanthophylls esterified with fatty acids (monoesters and diesters). All of the genetic stocks carrying Psy1 from H. chilense increased their carotenoid content relative to common wheat. In addition, significant changes in the carotenoid profile were detected in different genetic stocks. The most relevant was the increase in content of lutein diesters when both 7Hch and 7D were present, which indicates the existence of genes involved in the esterification of xanthophylls in both chromosomes. Furthermore, our results suggest that 7Hch genes preferentially esterify lutein with palmitic acid, whereas 7D is either indifferent to the fatty acid or it prefers linoleic acid for lutein esterification. The involvement and complementarity of 7Hch and 7D are highly significant considering the scarcity of previous results on lutein esterification in wheat.

Molecular characterization of two novel alleles of Hordoindoline genes in Hordeum chilense Roem. et Schult.

Grain texture is an important trait in wheat quality, and is related to the presence or absence of puroindolines a and b. In barley, these proteins are synthesised by the Hordoindoline (Hin) genes, orthologs of the Puroindoline (Pin) genes present in bread wheat and Aegilops species. In this study, the variation of Hin genes has been characterized in two representative lines of Hordeum chilense Roem. et Schult., a wild barley species that has been used in the development of a new man-made cereal (tritordeum, ×Tritordeum Ascherson et Graebner). Two novel alleles were detected in this material, one for the Hina-Hch1 gene and another for the Hinb-Hch1 gene. These alleles demonstrated high similarity to the Pin genes of bread wheat, which may explain the soft grain texture of tritordeum. This suggests that the variation present in H. chilense could be utilized in wheat breeding through the use of tritordeum as a bridge species, to extend the range of different textures.

Increase in transcript accumulation of Psy1 and e-Lcy genes in grain development is associated with differences in seed carotenoid content between durum wheat and tritordeum

Carotenoid rich diets have been associated with lower risk of certain diseases. The great importance of cereals in human diet has directed breeding programs towards carotenoid enhancement to alleviate these deficiencies in developing countries and to offer new functional foods in the developed ones. The new cereal tritordeum (×Tritordeum Ascherson et Graebener) derived from durum wheat (Triticum turgidum ssp. durum) and the wild barley Hordeum chilense, naturally presents carotenoid levels 5-8 times higher than those of durum wheat. The improvement of tritordeum properties as a new functional food requires the elucidation of biosynthetic steps for carotenoid accumulation in seeds that differ from durum wheat. In this work expression patterns of nine genes from the isoprenoid and carotenoid biosynthetic pathways were monitored during grain development in durum wheat and tritordeum. Additionally, a fine identification and quantification of pigments (chlorophylls and carotenoids) during grain development and in mature seeds has been addressed. Transcript levels of Psy1, Psy2, Zds, e-Lcy and b-Lcy were found to correlate to carotenoid content in mature grains. The specific activation of the homeologous genes Psy1, e-Lcy from H. chilense and the high lutein esterification found in tritordeum may serve to explain the differences with durum wheat in carotenoid accumulation.

High-throughput genotyping of wheat-barley amphiploids utilising diversity array technology (DArT)

BackgroundHordeum chilense, a native South American diploid wild barley, is one of the species of the genus Hordeum with a high potential for cereal breeding purposes, given its high crossability with other members of the Triticeae tribe. Hexaploid tritordeum (×Tritordeum Ascherson et Graebner, 2n=6×=42, AABBHchHch) is the fertile amphiploid obtained after chromosome doubling of hybrids between Hordeum chilense and durum wheat. Approaches used in the improvement of this crop have included crosses with hexaploid wheat to promote D/Hch chromosome substitutions. While this approach has been successful as was the case with triticale, it has also complicated the genetic composition of the breeding materials. Until now tritordeum lines were analyzed based on molecular cytogenetic techniques and screening with a small set of DNA markers. However, the recent development of DArT markers in H. chilense offers new possibilities to screen large number of accessions more efficiently.ResultsHere, we have applied DArT markers to genotype composition in forty-six accessions of hexaploid tritordeum originating from different stages of tritordeum breeding program and to H. chilense-wheat chromosome addition lines to allow their physical mapping. Diversity analyses were conducted including dendrogram construction, principal component analysis and structure inference. Euploid and substituted tritordeums were clearly discriminated independently of the method used. However, dendrogram and Structure analyses allowed the clearest discrimination among substituted tritordeums. The physically mapped markers allowed identifying these groups as substituted tritordeums carrying the following disomic substitutions (DS): DS1D (1Hch), DS2D (2Hch), DS5D (5Hch), DS6D (6Hch) and the double substitution DS2D (2Hch), DS5D (5Hch). These results were validated using chromosome specific EST and SSR markers and GISH analysis.ConclusionIn conclusion, DArT markers have proved to be very useful to detect chromosome substitutions in the tritordeum breeding program and thus they are expected to be equally useful to detect translocations both in the tritordeum breeding program and in the transference of H. chilense genetic material in wheat breeding programs.

Selection of the Wheat Genotypes and Related Species with Resistance to Mycosphaerella Graminicola

During 2008-2012, field tests of resistance to Mycosphaerella graminicola (Fuckel) J. Schröt. were conducted on a set of selected wheat varieties and related forms. Various M. graminicola isolates obtained from the Crop Research Institute in Prague were used for infection. Resistance of genotypes to three different isolates was tested in each year with the exception of 2009 and 2010, when identical isolates were used. A variant without artificial infection was used as control. Assorted varieties of winter and spring wheat, synthetic hexaploid wheat (SW), tritordeum (×Tritordeum Ascherson et Graebner), and one sample of haynaldoticum (×Haynaldoticum sardoum Meletti et Onnis) were tested. The aim was to select potential donors of resistance. The average infection rate for the set of spring wheat varieties over the 5 years was 6.7% (con-trol 0.5%), for tritordeum it was 0.3% (control 0.1%), for SW it was 0.7% (control 0.1%), and for haynaldoticum it was 1.7% (control 0.2%). The infection of winter wheat was 18.6% (control 3.8%). High average resistance was found in tritordeum, haynaldoticum, and some forms of SW. Lower resistance was found in conventional wheat varieties. The results were influenced by the degree of isolate virulence, growing season, and developmental stages of plants at the time of inoculation.

Isolation and identification of lutein esters, including their regioisomers, in tritordeum (×Tritordeum Ascherson et Graebner) grains: Evidence for a preferential xanthophyll acyltransferase activity

Liquid chromatography in conjunction with UV–visible spectroscopy and atmospheric pressure chemical ionisation (APCI) mass spectrometry has been used for the structural assignment of the lutein esters, including the regioisomeric forms, naturally occurring in the endosperm of tritordeum (×Tritordeum Ascherson et Graebner), a novel cereal. The distinctive mass spectrometry fragmentation pattern of lutein, characterized by a favored loss of the moieties at the position 3′ of the ε-end ring, allowed an unambiguous structural identification of four monoesters (lutein 3′-O-linoleate, lutein 3-O-linoleate, lutein 3′-O-palmitate, lutein 3-O-palmitate) and four diesters (lutein dilinoleate, lutein 3′-O-linoleate-3-O-palmitate, lutein 3′-O-palmitate-3-O-linoleate, lutein dipalmitate). This is the first time that the regioisomers of carotenoid esters have been identified in a cereal. Evidences for a preferential xanthophyll acyltransferase activity regarding the position (3 or 3′) and the acyl moiety are discussed. Further studies should be carried out in order to identify the acyltransferase enzymes and the acyl donor molecules involved in the xanthophyll esterification process.

Exploitation of nuclear and cytoplasm variability in Hordeum chilense for wheat breeding

Hordeum chilense Roem. et Schultz. is a diploid wild barley native to Chile and Argentina. The high crossability of this species with other members of the Triticeae tribe promoted the development of the new species × Tritordeum Ascherson et Graebner. Hexaploid tritordeum was developed from the hybrid derived from the cross between H. chilense (used as female parent) and durum wheat. The interest of H. chilense is based on the presence of traits potentially useful for wheat breeding, including high endosperm carotenoid content, septoria tritici blotch resistance and abiotic stress tolerance. Besides, the variability at cytoplasm level is also important in this species. The development of common wheat–H. chilense alloplasmic lines (nucleus from wheat and cytoplasm from H. chilense) results in fertile or male sterile genotypes, depending on the accession donating the cytoplasm. Furthermore, these alloplasmic lines constitute an ideal system for deepening our knowledge on nuclear–cytoplasm interactions. In conclusion, H. chilense is an interesting source of variability for wheat breeding.

Tritordeum: a new crop of potential importance in the food industry

The grain characteristics and breadmaking potential of the amphiploid Hordeum-Triticum was studied. To that end, tests commonly used for evaluating breadmaking potential in cereals were performed on lines of triticale (x Triticosecale Wittmark), durum wheat (Triticum turgidum conv. durum) and bread wheat (T. aestivum), and tritordeum (x Tritordeum Ascherson et Graebner). The tritordeum showed similar quality characteristics to that of medium quality bread wheat varieties commonly used in Spanish breadmaking industry. The notable intraspecific genetic variability showed by the tested lines means that this cereal may have potential to be used as a new food source.

Tritordeum: a new crop of potential importance in the food industry

The grain characteristics and breadmaking potential of the amphiploid Hordeum-Triticum was studied. To that end, tests commonly used for evaluating breadmaking potential in cereals were performed on lines of triticale (x Triticosecale Wittmark), durum wheat (Triticum turgidum conv. durum) and bread wheat (T. aestivum), and tritordeum (x Tritordeum Ascherson et Graebner). The tritordeum showed similar quality characteristics to that of medium quality bread wheat varieties commonly used in Spanish breadmaking industry. The notable intraspecific genetic variability showed by the tested lines means that this cereal may have potential to be used as a new food source.

Effects of reciprocal crosses on agronomic performance of tritordeum

Tritordeums (Tritordeum Ascherson et Graebner) are the amphiploids derived from the crosses between Hordeum chilense and durum or bread wheats. Primary tritordeums are obtained using H. chilense as female parent and therefore they exhibit H. chilense cytoplasm. The effect of wheat cytoplasm on agronomic performance of tritordeums was investigated. We developed four pairs of reciprocal F1 lines only differing in their cytoplasm, donated from wheat or H. chilense alternatively. The agronomic performance of reciprocal F1 lines contrasting for their cytoplasm was evaluated. The following traits were assessed: leave and tillers number one month after sowing, plant height, anthesis date, total number of ears, number of spikelets per spike, fertility of the main spike, length and wide of the flag leaf in the main stem and thousand kernel weight. Reciprocal F1 lines did not differ for any of the agronomic traits evaluated with the exception of anthesis date in the pair THC1726/HTC1727. Therefore, both wheat and H. chilense cytoplasms can be used in tritordeum breeding.

Variability and Genetic Diversity for Gliadins in Natural Populations of Hordeum Chilense Roem. et Schult.

Hordeum chilense Roem. et Schult. is wild diploid barley that has been used for the synthesis of the new cereal, tritordeum (× Tritordeum Ascherson et Graebner). This species is distributed in Chile and Argentina where it is possible to find in natural populations. In this work, the gliadin fraction of the seed storage protein have been used for evaluating the genetic diversity in nine natural populations of H. chilense. The total diversity (Ht) in the nine populations was 0.879 (ranging from 0.926 for the ω-gliadins to 0.795 for the β-gliadins). Data showed that the 71.3% of this genetic diversity was between populations, whereas the 28.7% was within populations. This species is considered as self-pollinating, where gene flow within populations was mainly attributed to seed dispersal because of these materials appear distributed in cattle zones where the pasturing could be an efficient mechanism of dispersion.

Genome discrimination and chromosome pairing in the Hordeum chilense × Aegilops tauschii amphiploid

Tritordeum (X Tritordeum Ascherson et Graebner) is a synthetic amphiploid belonging to the Triticeae tribe, which resulted from crosses between Hordeum chilense and wheat. It presents useful agronomic traits that could be transferred to wheat, widening its genetic basis.

Linkage relationships between prolamin genes located on chromosome 1Hch in Hordeum chilense.

The endosperm storage proteins of Hordeum chilense Roem. et Schult., a species used in the synthesis of the amphiploid tritordeum (x Tritordeum Ascherson et Graebner), have a great effect on the gluten strength of this amphiploid. We have analysed electrophoretically the heredity of these proteins, which are synthesised by genes located on chromosome 1H(ch), and detected up to five loci in a cross between two lines of H. chilense. These loci present a certain homology with loci synthesising the same proteins in wheat. The genetic distances between these loci were calculated.

Análise comparativa da qualidade de panificação e rendimento de grãos entre tritórdeo hexaplóide e outros cereais de inverno

A duplicação cromossômica dos híbridos entre Hordeum chilense e Triticum turgidum conv. durum originou o tritórdeo hexaplóide (X Tritordeum Ascherson et Graebner), um novo cereal cujas características estão sendo avaliadas. Com o objetivo de obter maiores informações sobre o potencial do tritórdeo para a qualidade de panificação e componentes do rendimento de grãos, foi instalado em 1996 em Córdoba, Espanha, um experimento de campo com três repetições. O desempenho de três linhagens de tritórdeo foi comparado com o rendimento de duas variedades comerciais de trigo, duas de trigo duro e quatro de triticale. O conjunto de resultados indicou perspectivas do tritórdeo para o desenvolvimento de variedades altamente produtivas com aceitável qualidade de panificação, especialmente por se tratar de uma espécie nova e ainda pouco melhorada.

Preliminary evaluation of grain yield components in hexaploid tritordeum

Chromosome duplication of Hordeum chilense and Triticum turgidum conv. durum hybrids created a new cereal with favorable characteristics for planting: the hexaploid tritordeum (X Tritordeum Ascherson et Graebner). A field experiment with three replications was carried out in Cordoba, Spain, to obtain more information on the potential yield of tritordeum for grain yield and its components. The performance of two advanced tritordeums was compared with the yield of two commercial wheat varieties, two durum wheats and four triticales. Results showed that tritordeum has a great potential for the development of highly productive varieties, especially because it is a new and rarely bred species.

Variation in the high-molecular-weight glutenin subunits coded at the Glu-Hch1 locus in Hordeum chilense

Hordeum chilense Roem. et Schult. is a native South American diploid wild barley included in the section Anisolepis Nevski. H. chilense occurs exclusively in Chile and Argentina and has been used in the synthesis of a new amphiploid named tritordeum (×Tritordeum Ascherson et Graebner). The HMW glutenin subunits of H. chilense have a great influence on gluten strength of tritordeum. The variability of these proteins has been analysed electrophoretically, and up to ten allelic variants have been detected in a world collection of this species. This genetic variability has been included in 121 lines of tritordeum and could be used for widening the genetic basis of tritordeum and wheat.

The Rheological Properties and Baking Performances of Flours from Hexaploid Tritordeums

Abstract Hexaploid tritordeum (X Tritordeum Ascherson et Graebner) is the amphiploid obtained from the cross between a South American wild barley ( Hordeum chilense Roem. et Schulz.) and durum wheat ( Triticum turgidum conv. durum Desf. em. M.K.). The bread making characteristics of eight lines of hexaploid tritordeum have been analysed, together with those of one bread wheat cultivar. The results indicated that, in general, the tritordeums yielded flours with quality properties similar to those of bread wheat, although their rheological and baking characteristics were slightly poorer. Despite the small number of samples, a range of variation was shown for some quality characters. This intra-specific variability suggests that, using well-established breeding procedures, it may be feasible to produce better quality tritordeums.