Resistance of some barley cultivars at leaf diseases

Abstract

Plant genetic resistance at diseases is a decisive factor for the productivity of every species. The diseases produced by fungi in barley crops had a large virulence spectrum and an infection intensity, which depended on the ecological conditions from the cultivation zone and the biological status of the genotype. The study has involved investigations conducted in the experimental field, under the climatic conditions of the years 2001 and 2006 on 42 barley genotypes (lines, varieties and landraces) from the Suceava Genebank collection. The biologic material was studied by the methodology of evaluation resistance within the European Project Genres CT98-104, in which Romania was a partner (1999-2002). The leaf diseases developed on plants were powdery mildew (Erysiphe graminis f.sp. hordei), leaf stipe (Pyrenophora graminea), spot bloth (Drechslera sorokiniana), leaf rust (Puccinia recondita) and scald (Rhynchosporium secalis). The infection degree on the leaf area was estimated for every studied genotype. The assessments were made during the vegetation period, by using the FAO notation and percentage. The results obtained in both years were pointed out by the different reaction of cultivars to diseases. Some genotypes developed immunity to fungi, like Pyrenophora graminea, Erysiphe graminis var. hordei, Rhynchosporium secalis, while others were extremely resistant at every identified fungus, pointing out the main role of the genotype in the resistance reaction. The climatic conditions of the two years, characterized by water deficit and normal temperatures, were a relevant factor in assessing the infection degree at diseases in the studied cultivars. The extremely resistant and immune genotypes could be used as a resistance source in the barley breeding programs.