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Resistance to both barley yellow dwarf virus (BYDV) and cereal yellow dwarf virus (CYDV) has been demonstrated in wheat genetic stocks with Thinopyrum intennedium chromatin. A number of resistance-bearing translocations have been reported on chromosome arm 7DL from two independent Th. intermedium sources; one source is the addition line Ll and the other is the spontaneous substitution line P29. Another source of resistance in wheat cytogenetic stocks is available as a 2Ai(2D) substitution line. We used a set of 38 molecular markers and the available deletion stocks to compare the size of the 7DL translocations more comprehensively than has been done previously. We also compared the efficacy of BYDV resistance of the various genetic stocks both before and after transfer to a common genetic background. TC14 was confirmed as carrying the smallest translocation, replacing about 20% of the distal end of 7DL. TO and TC10 had 90% of the chromosome arm replaced by Th. intermedium chromatin; the proximal 10% corresponded to wheat chromatin. YW642 appeared to have the whole 7DL replaced by Th. intennedium chromatin, as confirmed by the co-dominant marker cfd68 mapping on the bin nearest the centromere. Translocation line P961341 had bins 3, 7, and 8 replaced by Th. intermedium chromatin, making this the second smallest translocation with BYDV and CYDV resistance. The translocation sizes reported here differ from some of the previous estimates. The translocated Th. intennedium segments appeared to be bigger than the replaced wheat 7DL fragments. All the resistances derived from the Ll and P29 group 7 chromosomes and the 2Ai#2 chromosome were effective in reducing the number of infected plants and the mean virus titre, regardless of the background. Some evidence is discussed suggesting the long arm of the Th. intermedium group 7 chromosome 7Ai#1 carries two resistances, the distal Bdv2 and a proximal second gene. Key words: Luteovirus, intermediate wheatgrass, CYDV, alien translocations, EST derived markers. La resistance au virus de la jaunisse nanisante de l'orge (BYDV) et au virus de la jaunisse nanisante des cereales (CYDV) a ete documentee chez des lignees de ble possedant de la chromatine provenant du Th. intennedium. Plusieurs translocations conferant la resistance ont ete rapportees sur le chromosome 7DL en provenance de deux sources independantes du Th. intennedium. L'une de celles-ci est la lignee d'addition Ll et l'autre est la substitution spontanee P29. Une autre source de resistance au sein des stocks genetiques du ble est disponible sous la forme d'une substitution 2Ai(2D). Les auteurs ont employe 38 marqueurs moleculaires et les deletions disponibles pour comparer la taille des translocations 7DL de maniere plus precise que cela n'avait ete fait anterieurement. Les auteurs ont egalement compare l'efficacite de la resistance au BYDV chez les diverses lignees avant et apres leur introduction dans un meme fond genetique. TC14 a ete confirmee comme etant la translocation la plus petite puisqu'elle remplace environ 20 % de l'extremite distale de 7DL. Chez TC5 et TC10, 90 % du bras chromosomique a ete remplace par la chromatine du Th. intermedium; le 10 % proximal etant constitue de chromatine du ble. Au sein de YW642, la totalite de 7DL semble avoir ete remplacee par la chromatine du Th. intermedium tel que confirme par le marqueur codominant cfd68, lequel est situe dans le segment le plus rapproche du centromere. Dans la translocation P961341, les intervalles (<< bins >>) 3, 7 et 8 etaient remplaces par la chromatine du Th. intermedium, ce qui en fait la seconde plus petite translocation conferant la resistance au BYDV et au CYDV. Les tailles des translocations rapportees dans ce travail different de certaines des estimations anterieures. Les segments provenant du Th. intermedium semblent plus grands que les regions remplacees au sein du bras 7DL du ble. Toutes les resistances examinees, derivees des chromosomes du groupe 7 chez Ll et P29 ainsi que du chromosome 2Ai#2, permettaient de reduire le nombre de plantes infectees et la charge virale moyenne sans egard au fond genetique. Les auteurs discutent certaines evidences suggerant que le bras long du chromosome de groupe 7 chez le Th. intennedium (7Ai#1) porterait deux resistances, le gene distal Bdv2 et un second gene proximal. Mots-cles : Luteovirus, agropyron intermediaire, CYDV, translocations interspecifiques, marqueurs derives d'EST. [Traduit par la Redaction], Introduction The cereal diseases caused by barley yellow dwarf viruses are now known to be caused by two related species, Barley yellow dwarf virus (BYDV, genus Luteovirus, family Luteoviridae) and [...]

We describe a striking new species of Grallaria antpitta from wet, upper subtropical forest in the upper Rio Chinchipe drainage, provincia Zamora-Chinchipe, Ecuador. Notes on its natural history and molecular systematics are presented along with spectrograms of its voice. The species is readily diagnosed by its large size, unique white facial markings, and voice. Initial results from DNA sequence analyses place the new species in a well-supported clade that includes Grallaria nuchalis (which is syntopic with the new species), G. hypoleuca, G. watkinsi, and G. ruficapilla.

The dependence of the structural, magnetic, electrical and optical properties of epitaxially grown ilmenite-hematite (IH) films on their oxygen stoichiometry is described. The IH films have shown both the semiconducting transport and ferrimagnetic properties.

Ilmenite-hematite [[(FeTi[O.sub.3]).sub.1-x]-[([Fe.sub.3][O.sub.3]).sub.x]] is a solid solution system displaying intrinsic ferromagnetic and semiconductor properties. Magnetic force microscopy is used for detecting the domain structure in the thin ilmenite-hematite films.