Monospore isolates of Mycosphaerella graminicola considered to originate from one ascus were analysed by the polymerase chain reaction (PCR) with 32 RAPD primers. Eighteen of these revealed three classes of polymorphisms, which enabled a RAPD-based tetrad analysis. Four pairs of isolates resulting from a single diploid nucleus were determined. A procedure to cross these isolates was developed to investigate the mating system. Three of six crosses were successful, and the segregation of mating types in accordance with the tetrad analysis strongly points to a bipolar heterothallic mating system in M. graminicola. Random ascospore progenies from the successful crosses, each comprising 54 isolates, were studied with three primers to determine the mode of inheritance of the RAPD markers. Mendelian segregation and recombination of RAPD markers was observed in all progenies.

International audienceWith standardised near isogenic line (NIL) differentials co-operators were able to present the first comprehensive virulence survey of the European wheat leaf rust population (1996-1999). The work included pathotype identification of 2608 isolates and field tests of NILs. Lr9 and Lr19 were very effective all over Europe. Lr24, Lr25, and Lr28 were also effective, but in some countries and locations substantial virulence frequencies were observed. In addition, the genes Lr12, Lr13, Lr22a, Lr34, Lr35 and Lr37 were effective at the adult plant stage, but locally less so. In general, the indoor seedling tests and adult plant field tests showed good agreement. Virulence to Lr1, Lr2a, Lr24, Lr25, Lr28 and Lr29 tended to increase in the period, for the other Lr-genes the virulence frequency remained more or less stable. Among the 105 pathotypes identified none was clearly predominant in Europe.La situation en Europe pour la virulence de la rouille brune chez le blé. L'utilisation d'une gamme d'hôtes différentiels commune composée de lignées isogéniques (NIL) a permis aux auteurs de réaliser le premier inventaire exhaustif de la population européenne de rouille brune du blé (1996-1999). Deux mille six cent huit isolats ont été identifiés et les NIL ont été évaluées au champ. Lr9 et Lr19 se sont révélés efficaces dans toute l'Europe. Lr24, Lr25 et Lr28 ont également été efficaces, mais la fréquence des virulences correspondantes était non négligeable dans certains pays et certains lieux. Les gènes Lr12, Lr13, Lr22a, Lr34, Lr35 et Lr37 ont été efficaces au stade adulte, excepté dans quelques lieux. En général, les résultats des tests au stade plantule en conditions contrôlées ont été cohérents avec ceux obtenus au stade adulte au champ. Les fréquences de virulence sont demeurées stables au cours de la période étudiée, sauf pour Lr1, Lr2a, Lr24, Lr25 et Lr29, dont les fréquences de virulence correspondantes tendaient à augmenter. Aucun des 105 pathotypes identifiés n'est apparu clairement dominant en Europe

Beyond and below what was once Czechoslovakia lie the deep Balkans. They are, it has been said, a sort of hell paved with the bad intentions of the powersBy the beginning of the twentieth century Europe had added to its repertoire of Schimpfwörter, or disparagements, a new one which turned out to be more persistent than others with centuries old traditions. "Balkanization" not only had come to denote the parcelization of large and viable political units but also had become a synonym for a reversion to the tribal, the backward, the primitive, the barbarian. In its latest hypostasis, particularly in American academe, it has been completely decontextualized and paradigmatically related to a variety of problems.

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