GENETICS AND MAPPING OF BARLEY STRIPE MOSAIC-VIRUS RESISTANCE IN BARLEY

The inheritance of resistance to barley stripe mosaic virus (BSMV) in barley was investigated in the Steptoe/Morex doubled haploid populatio n developed by the North American Barley Genome Mapping Project. The n umber of resistant (66) and susceptible (84) progeny approximated a 1: 1 ratio, indicating that a single gene was involved in conferring resi stance to BSMV strain CV42 in Morex barley. This resistance gene was m apped to the centromeric region of the plus (short) arm of chromosome 1, based on its linkage to molecular markers on the Steptoe/Morex map, and was found to cosegregate with restriction fragment length polymor phism (RFLP) marker ABC455. Marker ABG011 was located 6.1 centimorgans (cM) distal to the resistance locus. The nearest opposite flanking ma rker mapped was Amy2, located at a distance of 8.1 cM and on the other side of the centromere. The identification of a cosegregating marker may facilitate both the selection for BSMV resistance in barley breedi ng programs and the high resolution mapping of the centromeric region in the vicinity of this locus.