Marker-Assisted Selection and resistance gene pyramiding in barley

The soil-borne barley yellow mosaic virus complex (BaMMV-BaYMV), the aphid-borne barley yellow dwarf virus (BYDV) and the seed-borne fungus Pyrenophora graminea (leaf stripe) are the most serious diseases for the barley crop in Southern Europe. Moreover, resistance to BaYMV, still not present in Czech Republic, is a target of quarantine breeding for this as well as for other Eastern European Countries, and resistance to leaf stripe an increasingly important trait for organic barley crop in Europe. Nevertheless, breeding for multiple diseases encounters several economical and technical problems, and cultivars resistant to all the former diseases are not yet available. In this view, two schemes of marker-assisted selection (MAS) have been followed in winter barley to develop high yielding advanced lines: an assisted pedigree by introducing the two virus resistances, and a "gene pyramiding" scheme to introduce four loci of resistance - two to leaf stripe, and one each to BYDV and BaYMV. STS and SSR markers have been selected for the aim and applied to segregating progenies together with phenotypic selection for agronomic traits.Results of the two MAS processes are here presented, including yield performances of the advanced breeding lines