Molecular markers linked to the Aegilops variabilis-derived root-knot nematode resistance gene Rkn-mn1 in wheat

Aegilops variabilis no. 1 is the only known source of resistance to the root-knot nematode Meloidogyne naasi in wheat. Previous studies showed that a dominant gene, Rkn-mn1, was transferred to a wheat translocation line from the donor Ae. variabilis. Random amplified polymorphic DNA (RAPD) analysis was performed on the wheat cultivar 'Lutin', on AE. variabilis, on a resistant disomic addition line and on a resistant translocation line. For genetic and molecular studies, 114-117 BC3F2 plants and F-3-derived families were tested. Five DNA and one isozyme marker were linked to Rkn-mn1. Three RAPD markers Ranking the Rkn-mn1 locus were mapped at 0 cM (OpY16(-1065)), 0.8 cM (OpB12(-1320)) and 1.7 cM (OpN20(-1235)), respectively. Since the Rh-n-mn1 gene remained effective, its introduction into different wheat cultivars by marker-assisted selection is suggested.