V. Ivanova*, S. Doneva, Z. Petrova

Dobroudzha Agricultural Institute, 9520 General Toshevo, Bulgaria

Abstract. During 2009 – 2011 at Dobroudzha Agricultural Institute, General Toshevo, Bulgaria the response of 365 new common winter wheat lines to the cause agents of brown rust (Puccinia triticina Eriks.), powdery mildew (Blumeria graminis f. sp. tritici) and stem rust (P. graminis f. sp. tritici) was investigated. The resistance of the released 84 lines was also followed with regard to the separate pathotypes of Puccinia triticina at stage 2nd leaf under controlled climatic conditions. The lines were divided into six groups according to the class of resistance they were referred to for each pathogen. The biochemical indices characterizing grain quality, protein and the limiting amino acid lysine were studied. The lines with the highest content of lysine and protein were pointed out for each group. The released lines possess important properties from breeding and practical point of view. These lines combine complex resistance to the three economically most important diseases on wheat in Bulgaria: brown rust, powdery mildew and stem rust. The high immunity of the new common winter wheat lines is combined with high biochemical grain index, an equally valuable property of wheat. The content of raw protein in grain and the amount of lysine will focus the breeding efforts on developing new wheat varieties with high grain quality. In this sense the new lines of common winter wheat can be interesting sources of genes since disease resistance and grain quality are priorities in modern wheat breeding.