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Introduction Fusarium head blight (FHB), caused by the fungus Fusarium graminearum Schwabe (Gibberella zeae), is a devastating disease that not only causes yield reduction but also decreases grain quality. It [...], Elymus repens (L.) Gould (2n = 6x = 42, StStStStHH) is a hexaploid perennial wheatgrass species from the tribe Triticeae, distantly related to bread wheat Triticum aestivum L. (2n = 6x = 42, AABBDD). As a potential source of resistance to Fusarium head blight (FHB), E. repens was crossed to common wheat to transfer resistance genes. The progeny were advanced to homozygosity by single seed descent. A total of eight [BC.sub.1][F.sub.9] progeny lines were selected and characterized in this study. The chromosome numbers of these derived lines ranged from 42 to 56, including lines with 44, 52, and 54 chromosomes. All of the lines were cytologically stable in terms of meiotic chromosome behavior. The univalent frequency in the lines varied between 0.34 and 2.36 per cell. Similarly, the multivalent frequency did not exceed 1% in any of the lines. GISH analysis revealed that the number of intact wheat chromosomes in the various lines varied between 40 and 44. Numerous translocated chromosomes were detected in all lines. The translocations involved chromosomal segments from wheat, and the St and H genomes of E. repens. Furthermore, trigenomic translocated chromosomes were detected in some of the lines. The introgression into wheat chromosomes included not only terminal types but also interstitial segments. The Fusarium head blight resistance of the eight lines, following point inoculation, varied from 5.65% infected florets to 11.46% compared with the check cultivars T. aestivum 'Roblin' and T. aestivum 'Crocus' at 100% and 85%, respectively. Key words: Fusarium head blight, Elymus repens, genomic in situ hybridization, common wheat, cytogenetic analysis. L'Elymus repens (L.) Gould (2n = 6x = 42, StStStStHH) est une agropyre hexaploide perenne de la tribu des Triticeae et un lointain parent du ble tendre Triticum aestivum L. (2n =6x = 42, AABBDD). A titre de source potentielle de resistance a la fusariose de l'epi, l'E. repens a ete croise au ble tendre afin de transferer des genes de resistance. La descendance a ete fixee par filiation monograine. Au total, huit lignees [BC.sub.1][F.sub.9] ont ete choisies et caracterisees au cours de ce travail. Le nombre de chromosomes au sein de ces lignees variait entre 42 et 56 incluant des lignees a 44,52 et 54 chromosomes. Toutes les lignees etaient stables sur le plan du comportement cytologique et meiotique des chromosomes. La frequence des univalents variait entre 0,34 et 2,36 par cellule et, similairement, la frequence de multivalents n'excedait pas 1 % chez ces lignees. Des analyses GISH ont revele que le nombre de chromosomes intacts du ble variait entre 40 et 44. De nombreuses translocations ont ete detectees chez toutes les lignees. Les translocations impliquaient des segments chromosomiques du ble et des genomes St et H de l'E. repens. De plus, des chromosomes portant des translocations trigenomiques ont ete detectes chez certaines lignees. Les introgressions au sein des chromosomes du ble incluaient non seulement des segments terminaux mais aussi des segments internes. La resistance a la fusariose chez ces huit lignees, telle que mesuree par inoculation ponctuelle des epis, variait entre 5,65 % et 11,46 % d'epillets infectes, tandis que les cultivars temoins T. aestivum 'Roblin' et T. aestivum 'Crocus' en presentaient respectivement 100 % et 85 %. [Traduit par la Redaction] Mots-cles: fusariose de l'epi, Elymus repens, hybridation genomique in situ, ble tendre, analyse cytogenetique.

Very few sources of resistance to Fusarium head blight (FHB) of wheat have been identified. Thinopyrum elongatum (Host) D.R. Dewey (2n = 14, EE genome), a wild relative of wheat, carries resistance to FHB on the long arm of its chromosome 7E (7EL). In this report, a strain of Fusarium graminearum Schwabe, the principal causal agent of FHB, transformed to produce green fluorescent protein (GFP), was used to characterize the resistance carried by 7EL when expressed in the susceptible background of 'Chinese Spring' (CS) wheat. Inoculated spikelets of the addition line CS-7EL showed less infection than those of the parental line, CS. This was associated in CS-7EL with upregulation of many genes predicted to be involved in plant defence and downregulation of genes associated with salicylic-acid-induced defence. The difference between CS and CS-7EL in the progression of infection was striking; the fungus spread easily and extensively from the inoculated spikelet into the node and adjacent spikelets in CS, but was effectively blocked from spreading in CS-7EL. Microscopic data showed that fungal growth was inhibited within the inoculated spikelet in CS-7EL, and spread was completely blocked by the node tissue. The blocking of fungal growth through the node into the rachis correlates with the deposition of an unidentified substance in CS-7EL. Additionally, longer internode segments in CS-7EL versus CS may contribute to limiting fungal spread. Our results suggest that the resistance displayed by CS-7EL is multifaceted, involving both physical and chemical factors. Key words: Triticum aestivum, Fusarium graminearum, gene expression, green fluorescent protein, infection spread, wheat rachis. On a identifie jusqu'ici tres peu de sources de resistance a la fusariose de l'epi (FE) chez le ble. Le Thinopyrum elongatum (2n = 14, genome EE), une espece sauvage voisine du ble, porte la resistance a la FE sur le long bras de son chromosome 7E (7EL). Les auteurs ont utilise une souche du F. graminearum, principal agent causal de la FE, transformee pour exprimer une proteine fluorescente verte (PFV) afin de caracteriser la resistance portee par le 7EL lorsqu'exprimee dans la base susceptible du ble Chinese Spring (CS). L'inoculation des epillets de l'addition CS-7EL montre moins d'infection que ceux de la lignee parentale, CS. Ceci s'accompagne chez le CS-7EL d'une regulation a la hausse de plusieurs genes previsibles pour leur implication dans la defense de la plante et une regulation a la baisse de genes associes a la defense induite par l'acide salicylique. La difference de progression de l'infection entre le CS et le CS-7EL est frappante; le champignon s'etend facilement et extensivement a partir de l'epillet inocule dans le noeud et les epillets adjacents chez le CS, mais son etalement se trouve efficacement bloque chez le CS-7EL. Les donnees microscopiques montrent que la croissance fongique est inhibee dans les epis inocules chez le CS-7EL, et le passage a ete completement bloque dans les tissus nodaux. Le blocage de la croissance fongique a travers le noeud vers le rachis correspond a la deposition d'une substance non identifiee chez le CS-7EL. De plus, les segments internodaux, plus longs chez le CS-7EL versus le CS, peuvent contribuer a limiter la croissance du champignon. Les resultats suggerent que la resistance deployee par le CS-7EL comporte plusieurs facettes, impliquant a la fois des facteurs physiques et chimiques. Mots-cles : Triticum aestivum, Fusarium graminearum, expression genetique, proteine fluorescente verte, etalement de l'infection, rachis du ble. [Traduit par la Redaction], Introduction Fusarium head blight (FHB) is a major disease of wheat, barley, and corn in all temperate regions of the world, which causes significant yield losses as well as reduction [...]

[Traduit par la Redaction] Introduction Rye (Secale cereale L. and Secale strictum (C. Presl) C. Presl) (formerly Secale montanum Guss) offers the potential to increase the genetic variability and to [...], The PI 386148 triticale from Russia is among the highest resistant line to the Russian wheat aphid (RWA) (Diuraphis noxia (Mordvilko)). This triticale line was used as the male parent in crosses with Lamar wheat (Triticum aestivum L.). The [F.sub.1] plants were backcrossed to Lamar wheat. The progenies were tested for RWA biotype 1 reaction for at least eight backcross and selfing generations. Five lines from these selections were identified for their resistance to the RWA and their seeds were increased for agronomic and other characterizations. Molecular and cytological analyses of these lines were performed using genomic in situ hybridization and rye chromosome-specific microsatellites markers. Three lines were cytologically stable and carried a pair of rye (Secale strictum (C. Presl) C. Presl) chromosomes as disomic addition lines of 1R. One line was unstable and showed a moderate level of mixoploidy with monosomic additions of 1R. Duplication of rye chromosome 1R was also identified. No wheat-rye chromosome interchange was detected, suggesting little homology between S. strictum and T. aestivum chromosomes. Specific microsatellite primers were used to identify the rye chromosomes present in each line. One rye chromosome, 1R, from the donor species contains genes for RWA resistance. Grain yield and test weight of three of the lines were similar to some adapted released wheat varieties under stress conditions. Key words: wheat, rye, chromosome addition, genomic in situ hybridization (GISH), microsatellite markers, Russian wheat aphid resistance. Le triticale PI 386148, provenant de la Russie, est parmi les plus resistants au puceron ruse du ble (Diuraphis noxia (Mordvilko)). Cette lignee de triticale a ete croisee (comme parent male) avec la ble Lamar (Triticum aestivum L.). Les descendances ont ete testees pour leur resistance au biotype 1 du puceron pendant au moins huit generations (retrocroisements ou autofecondations). Cinq lignees resistantes ont ete identifiees au sein de ces progenitures et ont ete multipliees pour des fins de caracterisation agronomique et autres. Des analyses moleculaires et cytologiques ont ete effectuees sur ces lignees au moyen d'hybridations genomiques in situ et de l'emploi de microsatellites specifiques des chromosomes du seigle (Secale strictum (C. Presl.) C. Presl). Trois lignees etaient stables du point de vue cytologique et portaient une paire de chromosomes du seigle sous forme d'addition disomique du chromosome 1R. Une lignee etait instable et presentait un niveau modeste de mixoploidie avec des additions monosomiques de 1R. Une duplication du chromosome 1R du seigle a egalement ete observee. Aucun chromosome resultant de l'echange de sequences ble-seigle n' a ete detecte ce qui suggere une faible homologie entre les chromosomes du S. strictum et du T. aestivum. Des marqueurs microsatellites ont ete employes pour identifier les chromosomes du seigle qui sont presents dans chaque lignee. Un chromosome du seigle, 1R, contient des genes conferant la resistance au puceron ruse du ble. Le rendement et le poids specifique des trois lignees etaient semblables a ce qui est rencontre chez des varietes de ble adaptees sous des conditions de stress. Mots-cles : ble, seigle, addition chromosomique, hybridation genomique in situ (GISH), marqueurs microsatellites, resistance au puceron ruse du ble.

Introduction Cultivated barley (Hordeum vulgare) (2n = 2x = 14) is one of the major cereal crops in world acreage along with wheat, corn, and rice. There are about 32 [...], Wild species in the Triticeae tribe are very valuable resources for agronomic improvement in cereal crop species. Intergeneric hybrids were produced between several barley cultivars and perennial species in the genera Elymus, Thinopyrum, and Pseudoroegneria. Caryopsis formation and subsequent plantlet regeneration from embryo culture were variable depending on the hybrid combinations. Chromosome numbers and hybrid identity were confirmed by GISH analysis on the somatic cells of the hybrids. While the hybrids showed very robust vegetative growth and exceeded the parental spikes in size, their floral morphologies resembled that of the wild species. Meiotic chromosome analysis revealed that the bivalent formation frequency per cell ranged from 0.06 in Hordeum vulgare 'Betzes' x Elymus curvatus to 3.0 in Elymus humidus x H. vulgare 'Manley'. By GISH analysis on the meiocytes of the hybrid E. humidus x 'Manley', the frequency of autosyndetic bivalents exceeded the allosyndetic bivalent formation, which gave an insight into the genome constitution of E. humidus as an autoallohexploid species. Regardless of the low allosyndetic chromosome pairing between barley and E. humidus, this combination may be useful for further input, since E. humidus is known to carry many valuable genes for biotic and abiotic stress tolerance. Key words: Hordeum, Elymus, perennial Triticeae, intergeric hybrid, autosyndesis, allosyndesis, GISH. Les especes sauvages au sein de la tribu des bordees constituent une ressource trEs precieuse pour l'amelioration des caracteres agronomiques chez les cereales cultivees. Des hybrides intergeneriques ont ete produits entre plusieurs cultivars d'orge et des especes perennes au sein des genres Elymus, Thinopyrum et Pseudoroegneria. La formation de caryopses et la regeneration subsequente de plantules par sauvetage d'embryons se sont averees variables selon les hybrides. Le nombre de chromosomes ainsi que l'identite des hybrides ont ete confirmes par analyse GISH sur les cellules somatiques des hybrides. Alors que les hybrides montraient une croissance vegetative trEs vigoureuse et excedaient les parents en ce qui a trait a la taille des epis, leur morphologie florale ressemblait a celle des espEces sauvages. L'analyse des chromosomes meiotiques a revele que la frequence de bivalents variait entre 0,06 par cellule chez l'hybride H. vulgare 'Betzes' x E. curvatus et 3,0 par cellule chez l'hybride E. humidus x H. vulgare 'Manley'. En analyse GISH sur les meiocytes de l'hybride E. humidus x H. vulgare 'Manley', la frequence de bivalents autosyndetiques excedait celle des bivalents allosyndetiques, ce qui porte a croire que la constitution genomique de PE. humidus correspond a celle d'un autoallohexaploide. Sans egard a la faible frequence d'appariement chromosomique allosyndetique entre l'orge et l'E. humidus, cette combinaison pourrait s'averer propice a de futurs efforts puisqu'il est rapporte que PE. humidus porte plusieurs gEnes utiles pour la resistance aux stress biotiques et abiotiques. Mots-cles : Hordeum, Elymus, bordees perenne, hybrides intergeneriques, autosyndEse, allosyndEse, GISH. [Traduit par la Redaction]