Mapping of Rym16, the second soil-borne virus-resistance gene introgressed from Hordeum bulbosum

Rym16 Hb , a gene conferring resistance to soil-borne viruses, was introgressed from Hordeum bulbosum to barley chromosome 2HL. Mechanical inoculation with BaMMV and field tests on a plot contaminated with different viruses demonstrated that Rym16 Hb is effective against all European viruses of the soil-borne virus complex (BaMMV, BaYMV-1, -2). Genetic analysis revealed a dominant inheritance of the resistance controlled by Rym16 Hb . Using 2HL anchor markers, the size of the introgression was estimated to be about 30 M. In its proximal part, the introgression was characterized by a rearrangement of markers Xbcd266, ABC153 and ABC252, accompanied with pronounced linkage drag by factor 4 in segregating mapping populations. The introgression was found to be associated with a recessive lethality factor, l Hb , which was closely linked to the markers mentioned above. Recombination occurring within the introgressed H. bulbosum segment allowed us to separate l Hb from Rym16 Hb and to reduce the size of the introgression to 23 cM or less. © Springer-Verlag 2006.