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

The determination of the gluten index is a widely used method for analysing the gluten strength of bread wheat and spring durum wheat genotypes. The present work was carried out to study the effect of the genotype, meteorological factors (temperature, precipitation and number of days with T max C 30°C) and agronomic treatments (N fertilisation and plant protection) on the gluten index of winter durum wheat varieties and breeding lines. The results indicated that the gluten index had little dependence on the environment, being determined to the greatest extent by the genotype. Compared with varieties having weak gluten, those with a strong gluten matrix responded less sensitively to changes in environmental conditions. Among the meteorological factors, high temperature at the end of the grain-filling period caused the greatest reduction in the mean gluten index of three varieties (R 2 = 0.462), while the fertiliser was found to be a significant factor affecting the gluten strength of winter durum wheat varieties. Using selection based on the gluten index, the gluten strength of winter durum wheat lines can be improved sufficiently to make them competitive with high quality spring varieties.

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In artificial infection experiments carried out in the nursery in Martonvasar in 1991Martonvasar in , 1992Martonvasar in and 1993, studies were made on the bunt infection of wheat varieties bred in Martonvasar and of monogenic lines containing known resistance genes (Btl to BllO, respectively). This was followed in 1993 by tests on the frost resistance of healthy wheat seedlings and wheat seedlings artificially infected with bunt in the frosttesting chamber of the Martonvasar phytotron.During the period of the experiment, the local pathogen population was avirulent to genes Bl9 and BllO, and virulent to Bt7. Monogenic lines containing resistance genes Bt4, Bl5, Bt6 and Bt8 had good resistance, while that of lines containing Bll, Bl2 and Bt3 was only moderate. Among the cultivated varieties, only three proved to be moderately resistant ('Martonvasari 17', 'Martonvasari 23', 'Fatima 2'), while the remainder were susceptible or very susceptible. The frost resistance of plants infected with bunt was significantly lower, over an average of the varieties, than that of healthy plants. A close (r = 0.890) correlation was found between the bunt susceptibility of the varieties tested and the increase in frost kill due to infection, while no correlation was observed in this respect for monogenic lines containing various resistance genes (Bi).

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In recent years viral diseases have become more frequent on cereals in Hungary. In the breeding nursery of the Martonvásár Institute, which contains stocks with very diverse genetic backgrounds, wheat suffered major attacks by viruses in 1972, 1976, 1980, 1981, 1982, 1986, 1990, 1996 and 1998. The winter barley plots incurred great damage in 1989 and 1990, while a large proportion of the durum wheat was destroyed in 1996. In 1982 barley yellow dwarf virus caused an epidemic in Fejér County and on many farms the damage was so great that the fields had to be ploughed up. The following nine viruses, which impose a threat to cereals, have been identified in Hungary to date: 1966: barley yellow dwarf luteovirus (BYDV), 1984: barley stripe mosaic hordeivirus (BSMV), 1985: wheat streak mosaic tritimovirus (WSMV), 1986: brome mosaic bromovirus (BMV), cocksfoot mottle sobemovirus (CfMV), 1988: wheat dwarf mastrevirus (WDV), 1989: barley yellow mosaic bymovirus (BYMV), 1990: agropyron mosaic rymovirus (AgMV) and ryegrass mosaic rymovirus (RyMV). The most frequent and widespread of these are BYDV and WDV, which are thus able to cause the greatest quantitative and qualitative damage. On the basis of six years’ data (1994–2000), neither BYDV nor WDV could be isolated from 35.7% of 1163 samples exhibiting leaf yellowing and dwarfness. This indicates that other viruses pathogenic to cereals can induce similar symptoms. Among the plants showing symptoms of virus infection, 47.3% were attacked by WDV alone, in proportions ranging from 28.8% in barley to 69.7% in triticale. The degree of infection changed from year to year: WDV was isolated from 0.0% of symptom-exhibiting plants in 1999, from 48.5% in 1997 and from 94.0% in 2000. Barley yellow dwarf virus was only isolated alone from 9.5% of the samples, while it was isolated together with wheat dwarf virus from 7.5% of the samples. Considerable differences were observed between the cereal species: only 5.6% of the durum wheat samples were infected with BYDV, while this figure was 28.1% for oats. There was also a significant year effect. In 1996 triticale was not infected, while in 2000 5.0% of the plants exhibited symptoms and in 1994 45.5% of the plants were hosts to the BYD virus. Under Hungarian conditions all five known serotypes can be found, though in different proportions depending on the cereal species and the year. The most frequent is RPV (27.4%), followed by PAV (26.9%), SGV (15.6%), MAV (15.3%) and RMV (14.8%). In samples collected from oats only the PAV serotype was found. The MAV serotype has never been isolated from triticale. The dominant serotype was RPV (60.7%) in wheat samples, SGV (36.0%) in durum wheat and RMV (29.1%) in barley.

AbstractŠVEC M., SZUNICS L., MIKLOVIČOVÁ M., SLOVÁKOVÁ T., TISOVÁ V., HAUPTVOGEL P. (2002): Identification of genes for resistance to wheat powdery mildew in Hungarian, Polish and Slovak wheat cultivars. Plant Protect. Sci., 38: 64-72.The objective of the study was to identify genes for resistance to powdery mildew in wheat cultivars and land races from Poland, Slovakia and Hungary. The presence and distribution of resistance genes was compared to powdery mildew virulence structure in these countries. The different strategies in breeding for resistance were expressed in a different distribution of resistance genes, especially among Polish and Hungarian cultivars. In 20 of the 29 Hungarian common wheat cultivars the resistance gene Pm8 was found. Of the 32 Polish cultivars investigated, 16 possess a combination of genes Pm2+6. Resistance gene Pm4b did not occur in any Hungarian cultivar tested, and resistance gene pm5 was not detected in any Polish cultivar. Virulence in wheat powdery mildew populations was influenced by differences in distribution of resistance genes in host genotypes. The most significant difference was found between Polish and Hungarian powdery mildew populations. The two populations differed mainly in virulence against Pm2. Resistance gene MlAr was detected in three old Slovak cultivars.

Under phytotronic conditions investigations were made on the effect of important environmental factors, such as temperature, water and an increasing concentration of atmospheric C02, on the hardening of young cereal plants .In all the varieties derived from the major wheat growing regions of the world the hardening process was favourably influenced by a doubling of atmospheric CO2 content, so that a significantly larger number of plants survived the frost test than for plants of the same variety raised under normal conditions .A reduction in freezing temperature and an increase in soil moisture content caused a slight reduction in survival % for varieties with excellent frost resistance and a great reduction for those with medium or poor frost resistance .Predictions suggest that in Central Europe, as the result of global climatic changes, there will be a reduction in the quantity of winter precipitation, a considerable rise in winter temperatures and an increase in atmospheric CO2 concentration . Judging by the experimental results, these changes could improve the overwintering of winter cereals ; at the same time, however, a number of factors (mainly the reduction of precipitation) leading to yield losses must be expected during the vegetation period .