Powdery Mildew (Erysiphe graminis f. sp. hordei) Resistance in Moroccan Barley Landraces
J. H. CZEMBOR and H. J. CZEMBOR
Plant Breeding and Acclimatization Institute, Plant Breeding and Genetics Department, Radzikow, 05-870 Blonie, Poland
CZEMBOR, J. H. and H. J. CZEMBOR, 2000. Powdery mildew (Erysiphe graminis f. sp. hordei) resistance in Moroccan barley landraces. Bulg. J. Agric. Sci., 6: 271-284
Eight barley (Hordeum vulgare L.) landraces were tested for resistance to powdery mildew (Erysiphe graminis f. sp. hordei) and new sources of resistance to a large number of virulence genes were identified. Landraces were collected in four expeditions between 1984-1990 in Morocco and originated from the collection of the International Centre for Agricultural Research in the Dry Areas (ICARDA), Aleppo, Syria. In 1998 all tested landraces showed resistance to natural infection of powdery mildew in IHAR Radzikow, Poland. From these landraces 21 single-plant lines were selected and tested at the seedling stage with 23 differential isolates of powdery mildew. The isolates were chosen according to their virulence spectra as observed on the 'Pallas' isoline differential set and on 8 additional differential cultivars and had collectively virulences to all major resistance genes used in the past and currently in Europe. Lines 379-1-3 and 379-2-3 were identified with resistance to 22 (95.7%) from 23 isolates used. These lines were characterized by resistance reaction type 0 which was observed for inoculation with most isolates. Five lines expressed infection type 0 for inoculation with more than 50% of the isolates. Only one line showed resistance infection type 2 for most isolates used. About 70.2% of all infection types observed among tested lines were classified as powdery mildew resistance. The most frequent (40.8%) resistant infection type was 0 (immunity). The infection type 2 occurred with frequency 24.4% and infection type 1 (hypersensivity) with frequency of 5% respectively. In 14 tested lines it was impossible to determine which specific allele or alleles for resistance are present. Allele Mla1 was postulated to be present in 5 (23.8%) lines either alone or in combination with other unknown genes. In two lines presence of alleles Mla6 and Mla14 was postulated. The use of identified sources of resistance to a large number of powdery mildew virulence genes in barley breeding was discussed.
Key words: barley, Erysiphe graminis f. sp. hordei, genetic resources, genes for resistance, Hordeum vulgare, landraces, Morocco, powdery mildew