Production and meiotic pairing behaviour of new hybrids of winter wheat (Triticum aestivum) x winter barley (Hordeum vulgare).

New winter wheat (Triticum aestivum L.) x winter barley (Hordeum vulgare L.) hybrids produced using cultivated varieties (wheat 'Martonvásári 9 krl'(Mv9 krl) x barley 'Igri', Mv9 krl x 'Osnova', 'Asakazekomugi' x 'Manas') were multiplied in tissue culture because of the high degree of sterility and then pollinated with wheat to obtain backcross progenies. Meiotic analysis of the hybrids Mv9 krl x 'Igri' and 'Asakazekomugi' x 'Manas' and their in vitro regenerated progenies with the Feulgen method revealed 1.59 chromosome arm associations per cell in both initial hybrids. The number of chromosome arm associations increased after in vitro culture to 4.72 and 2.67, respectively, in the two combinations. According to the genomic in situ hybridization (GISH) analysis, wheat-barley chromosome arm associations made up 3.6% of the total in the initial Mv9 krl x 'Igri' hybrid and 6.6% and 16.5% of the total in in vitro regenerated progenies of the 'Asakazekomugi' x 'Manas' and Mv9 krl x 'Igri' hybrids, respectively. The demonstration by GISH of wheat-barley chromosome pairing in the hybrids and especially in their in vitro regenerated progenies proves the possibility of producing recombinants between these two genera, and thus of transferring useful characters from barley into wheat. In vitro conditions caused an increase in chromosome arm association frequency in both combinations and in fertility in some regenerants.     

A core genetic map of Hordeum chilense and comparisons with maps of barley (Hordeum vulgare) and wheat (Triticum aestivum)

The first genetic map of the wild South Ameri- can barley species Hordeum chilense is presented. The map, based on an F₂ population of 114 plants, contains 123 markers, including 82 RAPDs, 13 SSRs, 16 RFLPs, four SCARs, two seed storage proteins and two STS markers. The map spans 694 cM with an average distance of 5.7 cM between markers. Six additional SSRs and seven additional SCARs which were not polymorphic were assigned to chromosomes using wheat/H. chilense addition lines. Polymorphisms were revealed by 50% of the RAPD amplifications, 13% of wheat and barley SSR primers, and 78% of the Gramineae RFLP anchor probes. The utility of SSR and RFLP probes from other Gramineae species shows the usefulness of a comparative approach as a source of markers and for aligning the genetic map of H. chilense with other species. This also indicates that the overall structure of the H. chilense linkage groups is probably similar to that of the B and D genomes of wheat and the H genome of barley. Applications of the map for tritordeum and wheat breeding are discussed. Received: 20 August 2000 / Accepted: 22 September 2000     

Repeated DNA sequences isolated by microdissection. II. Comparative analysis in Hordeum vulgare and Triticum aestivum

The genomic organization of two satellite DNA sequences, pHvMWG2314 and pHvMWG2315, of barley (Hordeum vulgare, 2n=14, HH) was studied by comparative in situ hybridization (ISH) and PCR analysis. Both sequences are members of different RsaI families. The sequence pHvMWG2314 is a new satellite element with a monomer unit of 73 bp which is moderately amplified in different grasses and occurs in interstitial clusters on D-genome chromosomes of hexaploid wheat (Triticum aestivum, 2n=42, AABBDD). The 331-bp monomer pHvMWG2315 belongs to a tandemly amplified repetitive sequence family that is present in the Poaceae and preferentially amplified in Aegilops squarrosa (2n=14, DD), H. vulgare and Agropyron elongatum. (2n=14, EE). The first described representative of this family was pAs 1 from Ae. squarrosa. Different sequences of one satellite DNA family were amplified from Ae. squarrosa, A. elongatum and H. vulgare using PCR. Characteristic differences between members of the D and H genome occurred in a variable region which is flanked by two conserved segments. The heterogeneity within this element was exploited for the cytogenetic analysis of Triticeae genomes and chromosomes. Comparative ISH with pHvMWG2315 identified individual wheat and barley chromosomes under low (75%) and high (85%) hybridization stringency in homologous and heterologous systems. We propose the designation Tas330 for the Triticeae amplified sequence (Tas) satellite family with a 330 bp average monomer length.     

Analysis of recombination and gene distribution in the 2L1.0 region of wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.)

Both wheat and barley belong to tribe Triticeae and are closely related. High-density detailed comparison of physical and genetic linkage maps revealed that wheat genes are present in physically small gene-rich regions (GRRs). One of the largest GRRs is located around fraction length 1.0 of the long arm of wheat homoeologous group 2 chromosomes termed the "2L1.0 region." The main objective of this study was to analyze the structural and functional organization of the 2L1.0 region in barley in comparison to wheat. Using the 29 physically mapped RFLP markers for the region, wheat and barley consensus genetic linkage maps of the 2L1.0 region were generated by combining information from 18 wheat and 7 barley genetic linkage maps. Comparative analysis using these consensus maps and other available wheat and barley mapping resources identified 227 DNA markers and ESTs for the region. The region accounted for 58% of the genes and 68% of the arm's recombination in wheat. However, the corresponding region in barley accounted for about 42% of the genes and 81% of the recombination. The kb/cM ratio for the region was 122 in barley compared to 244 in wheat. Distribution of genes and recombination varied between the two species even though the gene order and density were similar.     

Molecular organization of the barley (Hordeum vulgare) genome]

Studies in peculiarities of the DNA secondary structure in barley by means of thermal denaturation and renaturation shows that there are three types of the nucleotide sequences organization in DNA. More than 95% of the genome composition contain distributed repetitive sequences, in one part of the concentration of the repetitive sequences being higher as compared to bulk of them. About 3.5% of DNA is enriched with A-T pairs and contains no repetitive sequences. There is no "unique" part in the barley genome, which is natural for animals. Slowly renaturation sequences repeat 4 times.     

Characterization of a family of chlorophyll-deficient wheat (Triticum) and barley (Hordeum vulgare) mutants with defects in the magnesium-insertion step of chlorophyll biosynthesis.

During thylakoid membrane biogenesis, chlorophyll (Chl) biosynthesis and the accumulation of Chl-binding proteins are tightly linked, light-regulated processes. We have investigated the consequences faced by mutant plants with defects in Chl biosynthesis by studying a series of five homeologous allelic chlorina mutants in wheat (Triticum) and one phenotypically related barley (Hordeum vulgare) mutant that express the same pleiotropic mutant phenotype but to different extents. These mutants accumulate Chl at different rates, with the most severely affected plants having the slowest rate of Chl accumulation. Analysis of precursor pools in the Chl synthesis pathway indicates they have a partial block in Chl synthesis and accumulate protoporphyrin IX (Proto), the last porphyrin compound common to both heme and Chl synthesis. The affected plants with the most severe phenotypes accumulate the most Proto. Chloroplasts isolated from these mutants exhibit a lower activity of the enzyme Mg-chelatase, which catalyzes the first committed step in Chl synthesis. The most severely affected plants exhibit the greatest reduction in Mg-chelatase activity. Heme levels and protoporphyrinogen oxidase activity were the same for mutant and wild-type plants. We suggest that a block in Mg-chelatase activity in these mutants could account for the other traits of their pleiotropic phenotype previously described in the literature.     

An embryo-specific protein of barley (Hordeum vulgare).

An immunological approach has been used to identify embryo-specific products that can be used as molecular markers of embryogenesis. Immunoadsorption of antisera to remove antigens common to embryos, meristematic cells and callus, revealed one major embryo-specific antigen, a polypeptide of 17 kDa. The antigen appeared at mid-stages of zygotic embryo formation and remained at similar levels up to six days post-germination of the seedling. The polypeptide could not be detected by protein staining, suggesting it is a non-abundant product. Appearance of the antigen could be induced by culture of zygotic embryos in vitro on abscisic acid (1 microM) or mannitol (9% mass/vol.). Cross-reactive products of near-identical molecular mass were observed in embryos of wheat, rye and oats but not distantly related cereals, nor embryos from dicotyledonous species. The timing of the appearance of the antigen was different in embryos formed from microspores during anther culture in vitro. In the cultured material, the 17-kDa polypeptide preceded the appearance of morphologically distinct embryonic structure.     

An RFLP map of diploid Hordeum bulbosum L. and comparison with maps of barley (H. vulgare L.) and wheat (Triticum aestivum L.)

This paper describes the first extensive genetic map of Hordeum bulbosum, the closest wild relative of cultivated barley. H. bulbosum is valuable for haploid production in barley breeding, and because of desirable agronomic characteristics, it also has potential for trait introgression into barley. A H. bulbosum map will assist introgression and provide a basis for the identification of QTLs for crossability with barley and other potentially useful genes. The present study used a population of 111 individuals from a PB1×PB11 cross to develop a genetic linkage map of diploid H. bulbosum (2n=2x=14) based on barley, wheat and other ”anchor” cereal RFLP markers previously mapped in other species. Because of the cross-pollinating and highly polymorphic nature of H. bulbosum, up to four alleles showed segregation at any one locus, and five different segregation types were found. This enabled maps to be developed for the PB1 and PB11 parents, as well as a combined map. In total, 136 RFLP loci were mapped with a marker coverage of 621 cM. The markers were generally colinear with barley but H. bulbosum had less recombination in the centromeric regions and similar or more in the distal regions. Cytological studies on pollen mother cells at metaphase-I showed marked distal localization of chiasmata and a frequency consistent with the genetic map length. This study showed that H. bulbosum was highly polymorphic, making it suitable for trait analysis and supplementing maps of barley. Received: 20 November 2000 / Accepted: 5 January 2001     

Control of early seedling growth in varietal lines of hexaploid wheat (Triticum aestivum), durum wheat (Triticum durum), and barley (Hordeum vulgare) in response to the phthalimide growth regulant,AC 94,377

AC 94,377 caused elongation of seedlings of Triticum aestivum, Triticum durum, and Hordeum vulgare when applied to the soil, or the soil plus seed at planting. Affected were the leaf sheathes and the coleoptiles, and at high compound rates there was premature elongation of the stem internodes. As exemplified by the response of T. aestivum var. Fidel, the influence on coleoptile elongation was greatest under conditions whereby the coleoptile was naturally stimulated to elongate, i.e., when growth was in the dark and temperatures were cool (15°C). All of the stem internodes were capable of elongation except the one below the coleoptile node. The effect on leaf sheath elongation was prolonged when compared to activity of gibberellic acid.Several varieties of the three cereal species were examined in the greenhouse for sensitivity to AC 94,377 in order to evaluate the extent of the response. All of the barley varieties examined were sensitive to AC 94,377, elongating regardless of the planting conditions. Two such conditions were established, including incubation under warm (28/20°C) conditions following planting the grains 1 cm deep, and incubation under cool (22/16°C) conditions following planting the grains 6 cm deep. Wheat varieties distributed into two general categories, those which were sensitive and those which were not. The insensitivity correlated well to the presence of the reduced height (Rht) and GA-insensitive (Gai) genes in Triticum aestivum and Triticum durum, respectively. Thus, AC 94,377 can be used conveniently to evaluate varietal lines for the presence of this phenotype. This correlation also lends support to the notion that the Rht/Gai mutations in wheat are either at the level of a gibberellin receptor or at a step in the signal transduction pathway.     

Genetical analysis of microspore derived plants of barley (Hordeum vulgare)

Summary From an F₁ hybrid between the two barley (Hordeum vulgare L.) cultivars Golden Promise and Mazurka a series of doubled haploid (DH) lines were generated both from microspores by anther culture and from immature zygotic embryos after hybridization withH. bulbosum. The DH lines from both sources were used to monitor the segregation of the five major genes, rachilla hair length, DDT susceptibility, height, C hordein polymorphism and mildew resistance. Whereas the microspore-derived samples showed significant departures from the expected 11 ratio for three of the five genes, theH. bulbosum lines showed deviation for only one gene. Analysis of linkage data also showed differences between the two series of DH lines. Cytogenetic analysis revealed a mean chiasma frequency in theH. bulbosum lines which was very similar to the F₁ hybrid. In contrast, four of the ten microspore derived lines examined showed a reduced chiasma frequency. One showed evidence of translocation heterozygosity.     

Molecular analyses of a repetitive DNA sequence in wheat (Triticum aestivum L.).

A repetitive sequence designated WE35 was isolated from wheat genomic DNA. This sequence consists of a 320-bp repeat unit and represents approximately 0.002% of the total wheat DNA. It is unidirectionally distributed either continuously or discretely in the genome. Ladder-like banding patterns were observed in Southern blots when the wheat genomic DNA was restricted with endonuclease enzymes EcoRI, HincII, NciI, and NdeI, which is characteristic for tandemly organized sequences. Two DNA fragments in p451 were frequently associated with the WE35 repetitive unit in a majority of lambda wheat genomic clones. A 475-bp fragment homologous to the 5'-end long terminal repeat (LTR) of cereal retroelements was also found in some lambda wheat genomic clones containing the repetitive unit. Physical mapping by fluorescence in situ hybridization (FISH) indicated that one pair of wheat chromosomes could be specifically detected with the WE35 positive probe p551. WE35 can be considered a chromosome-specific repetitive sequence. This repetitive unit could be used as a molecular marker for genetic, phylogenetic, and evolutionary studies in the tribe Triticeae.     

Characterization and localization of cryptic satellite DNAs in barley (Hordeum vulgare)

Summary Three satellites on the heavy side of the main band and two satellites on the light side were isolated in a pure from by preparative ultracentrifugation of H. vulgare DNA in Ag⁺/Cs₂SO₄ density gradients. The satellites were characterised in terms of their buoyant densities in CsCl and their thermal dissocation temperature in both native and reassociated forms to Cot 4. In CsCl gradients, heavy satellites formed a single peak whereas light satellites resolved into more than one component. Thermal transitions of some satellites indicated the presence of more than one molecular species. The multicomponent nature of thermal denaturation profiles was evident on differential analysis. Radioactive RNAs complementary to the three heavy satellites of H. vulgare were localised by in situ hybridization onto its nuclei and chromosomes. One heavy satellite (H₃) was found to be distributed on all chromosomes, although one pair showed less hybridization compared to the others. The other satellite (H₁) appeared to be present in a much lower amount on the chromosomes.     

Senescence-induced iron mobilization in source leaves of barley (Hordeum vulgare) plants

? Retranslocation of iron (Fe) from source leaves to sinks requires soluble Fe binding forms. As much of the Fe is protein-bound and associated with the leaf nitrogen (N) status, we investigated the role of N in Fe mobilization and retranslocation under N deficiency- vs dark-induced leaf senescence. ? By excluding Fe retranslocation from the apoplastic root pool, Fe concentrations in source and sink leaves from hydroponically grown barley (Hordeum vulgare) plants were determined in parallel with the concentrations of potential Fe chelators and the expression of genes involved in phytosiderophore biosynthesis. ? N supply showed opposing effects on Fe pools in source leaves, inhibiting Fe export out of source leaves under N sufficiency but stimulating Fe export from source leaves under N deficiency, which partially alleviated Fe deficiency-induced chlorosis. Both triggers of leaf senescence, shading and N deficiency, enhanced NICOTIANAMINE SYNTHASE2 gene expression, soluble Fe pools in source leaves, and phytosiderophore and citrate rather than nicotianamine concentrations. ? These results indicate that Fe mobilization within senescing leaves is independent of a concomitant N sink in young leaves and that phytosiderophores enhance Fe solubility in senescing source leaves, favoring subsequent Fe retranslocation.     

Cytogenetics of an unstable trisomie in barley (Hordeum vulgare).

The origin, identification, meiotic chromosome behavior, and breeding behavior of an unstable trisomic barley were studied. The extra chromosome originated by breakage and fusion of an acrocentric chromosome 3 in a plant from an F2 population of a cross between acrotrisomic 3L3S (2n = 14 + 1 acro3L3S) and a balanced lethal stock, xc. (xantha) ac (albino). The F2 population segregated only for the albino trait. The genotypic constitution of the trisomic plant was ac ac (for both normal chromosome 3) and Ac (for the unstable metacentric chromosome). The unstable extra metacentric chromosome was designated as metacentric 3B (abbreviated as meta3B). Meiotic chromosome behavior in plants with 2n = 14 + 1 meta3B differed from plant to plant and within spikes. Some plants showed only trisomic cells with a chromosome configuration of 1 III + 6 II and 7 II + 1 I at metaphase I, whereas other plants showed both trisomie and disomic cells (7 II) that resulted from the elimination of the extra meta3B. The frequency of ring trivalents was low (6.8%). An average transmission rate of unstable meta3B ranged from 4.3 to 12.9%. The elimination of meta3B, and hence loss of the dominant Ac allele, resulted in albino seedlings as well as white stripes on plants, leaves, and spikes. Chromosome numbers of albino seedlings in the progeny of 2n = 14 + 1 meta3B were all diploid (2n = 14), while green seedlings contained 2n = 14 + 1 meta3B. However, progenies of some spikes of one trisomic plant showed a low frequency of green diploids and metatrisomics (2n = 14 + 1 meta3B), which was attributed to crossing-over.     

Cytogenetics of the trigeneric hybrid, (Hordeum vulgare ×Triticum aestivum) ×Secale cereale

Summary Chromosome pairing was studied in hybrids of (Hordeum vulgare ×Triticum aestivum) ×Secale cereale. Chiasma frequency per cell varied from 1.94 to 3.16 between the different hybrids. This variation was attributed to genetic variability in rye parents which affected homoeologous pairing. The pairing of rye chromosomes as revealed by Giemsa C-banding was a combination of nonhomologous association between rye chromosomes and associations with chromosomes of wheat and barley. Contribution No. 634 Ottawa Research Station     

A molecular,isozyme and morphological map of the barley (Hordeum vulgare) genome

A map of the barley genome consisting of 295 loci was constructed. These loci include 152 cDNA restriction fragment length polymorphism (RFLP), 114 genomic DNA RFLP, 14 random amplified polymorphic DNA (RAPD), five isozyme, two morphological, one disease resistance and seven specific amplicon polymorphism (SAP) markers. The RFLP-identified loci include 63 that were detected using cloned known function genes as probes. The map covers 1,250 centiMorgans (cM) with a 4.2 cM average distance between markers. The genetic lengths of the chromosomes range from 124 to 223 cM and are in approximate agreement with their physical lengths. The centromeres were localized to within a few markers on all of the barley chromosomes except chromosome 5. Telomeric regions were mapped for the short (plus) arms of chromosomes 1, 2 and 3 and the long (minus) arm of chromosomes 7.This research was also supported by other members of the NABGMP: K. Kasha, Department of Crop Science, University of Guelph, Guelph, Ontario, Canada NIG 2W1; W. Kim, Agriculture Canada Research Station, 195 Dafoe Road, Winnipeg, Manitoba, Canada R3T 2M9; A. Laroche, Agriculture Canada Research Station, P.O. Box 3000 Main, Lethbridge, Alberta, Canada,TU 4B1; S. Molnar, Plant Research Centre Agriculture Canada, Central Experimental farm, Ottawa, Ontario, Canada K1A 0C6; G. Scoles, Department of Crop Science, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N OWOThis research is part of the North American Barley Genome Mapping Project, R. A. Nilan and K. Kasha, Coordinator and Associate Coordinator, respectively Permanent address: Department of Plant Genetics, NI Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow     

RAPD-based analysis of introgression of barley genetic material into the genome of alloplasmic wheat lines (Hordeum geniculatum All./ Triticum aestivum L.)

Genomes of three alloplasmic wheat lines obtained on the basis of barley--wheat hybrid Horderum geniculatum All. (2n = 28) x Triticum aestivum L. (2n = 42)(Pyrotrix 28) were examined using random amplified polymorphic DNA (RAPD) analysis. Line L-29 was obtained after first backcross of the initial hybrid with the wheat variety Pyrotrix 28 and ten subsequent self-pollinating generations. This line was represented by euploid plants with typical to the common wheat chromosome number (2n = 42), as well as by aneuploids, which contained an additional telocentric chromosome in the main karyotype (2n = 42 + t). Lines L-26 and L-27 were obtained by two backcrosses of one BC1 plant with the wheat variety Novosibirskaya 67 and one subsequent self-polination of one BC3 plant. Chromosome number in all these plants corresponded to 2n = 40 + 4t. RAPD analysis was carried out using seven primers, which were previously proved to be effective for identification of the barley genome fragments within hybrid genomes of alloplasmic lines. The presence of barley genome fragments in line L-29 was revealed by use of five primers, while in lines L-26 and L-27 these fragments were detected by use of one primer. The significant difference in the number of barley RAPD fragments in the genomes of alloplasmic lines obtained at different backcrossing stages suggests more intense displacement of barley genome during backcrossing compared to self-pollination in BC1 plants.     

Identifying inflorescence phytoliths from selected species of wheat (Triticum monococcum, T. dicoccon, T. dicoccoides, and T. aestivum) and barley (Hordeum vulgare and H. spontaneum) (Gramineae)

Analysis of microfossil silica phytoliths is becoming an increasingly important research tool for taxonomists, archaeobotanists, and paleoecologists. Expanded use of phytolith analysis by researchers is dependent upon development of phytolith systematics. In this study phytoliths produced by the inflorescence bracts from four species of wheat, Triticum monoccocum, T. dicoccon, T. dicoccoides, and T. aestivum, and two species of barley, Hordeum vulgare, and H. spontaneum, were analyzed using computer-assisted image and statistical analysis with the intent to develop taxonomic tools to distinguish among the taxa. A classification key based on significant differences among the mean morphometries of the inflorescence phytoliths produced by each species was created and tested. Discriminant analysis of the morphometries of several morphotypes of phytoliths was also conducted to determine whether this computer-assisted statistical procedure could be used as another method to classify the taxa and to determine which morphotypes have measurements that can best be used in discriminant functions. Test results indicated that, at the genus level, both the classification key and discriminant analysis of certain morphotypes of phytoliths were relatively reliable tools for distinguishing among phytoliths produced in the inflorescence bracts of the taxa considered. For distinguishing among the taxa at the species level, the classification key was most reliable. Of the discriminant analyses tested, that based on all the phytolith morphotypes combined was more reliable than those based on only one morphotype.     

The genotoxic effects of Logran on Hordeum vulgare L. and Triticum aestivum L

In the present study, the cytogenetic effects of the herbicide Logran on root tip cells of Triticurn aestivum L. and Hordeum vulgare L. and changes of total protein content in root tip meristems were studied. The seeds of plants were treated with various concentrations of Logran (125, 250, 500 microg/ml) for 3 and 6 h. The percentages of abnormal cells were seen to increase with increasing treatment period and concentrations. The most dominant types of observed abnormalities were C-mitosis, distributed metaphase and anaphase, stickiness. All the used concentrations of Logran significantly induced a number of chromosomal aberrations in root tip cells of Hordemrn vulgare L. and Triticum aestivum L. Logran also decreased mitotic index. The decrease of protein content in root tips of Triticum aestivum L. is significant at all the treated concentrations and treatment periods when compared with control.