Nitrogen and Phosphorus Salts Treatment Effect to Spot Blotch Development on Barley

The paper presents the data on seedling and adult resistance to dark-brown leaf spot blotch (Bipolaris sorokiniana) in barley samples described in modern literature as resistant to the disease and in varieties allowed growing in the territory of Russian Federation. All 32 samples and 69 varieties under study were highly susceptible to the blotch at both growth stages. This fact indicates to urgent need in developing new methodes for dark-brown leaf spot blotch protection. Treatment of barley plants varieties with mixture of nitrogen and phosphorus salts solution reduced the disease development on seedlings of 13 commercial varieties and on adult plants of 36 varieties (52 % out of all studied). For all these 36 varieties weight of 1000 grains was significantly higher on treated plots compared to untreated ones for 11–108 %. The mechanism of nitrogen and phosphorus salts effect on the dark-brown leaf spot blotch development (changing virulence/aggressiveness of the pathogen) indicates that change of the salts concentrations and their ratio in the solution could expand the set of host plants genotypes on which this treatment will decrease the disease development.