ETUDE DE LA TOLERANCE DE CULTIVARS D’ORGE A LA TACHE HELMINTHOSPORIENNE

Abstract

This study was conducted to assess tolerance of barley (Hordeum vulgare) cultivars to spot blotch. The barley cultivars Parkland, Bonanza and Laurier inoculated with spores of Bipolaris sorokiniana developed approximately the same level of spot blotch symptoms in the field. Natural disease development was minimal in plots treated with mancozeb; it was intermediate in uninoculated and untreated plots. Reduction of grain yield and grain weight differed with each cultivar. Disease had the most depressing effects on Parkland. Disease severity was highest on Laurier which suffered the least decrease in grain yield and grain weight compared to the checks. Yield and seed weight of Bonanza were not affected by low or moderate disease levels (checks) but were reduced when symptoms were severe (inoculations).Key words: Barley, cultivars, spot blotch, Bipolaris sorokiniana, tolerance, mancozeb