Identification and physical mapping of three Haynaldia villosa chromosome-6V deletion lines

Abstract

Three deletion lines (del6V?2S-1, del6V? 2L-1, and del6V?2L-2) of Haynaldia villosa chromosome 6V added to wheat were identified by C-banding and characterized by RFLP analyses. The breakpoints were located at fraction lengths (FL) 0.58 in del6V?2S-1 in the short arm, and FL 0.66 in del6V?2L-1 and FL 0.64 in del6V?2L-2 in the long arm. Thirty-one Triticeae homoeologous group-6 DNA probes were used to map RFLP loci in the deletion lines and the wheat-H. villosa disomic substitution (DS) line 6V?2(6A). Nine probes failed to detect polymorphism between Chinese Spring and DS6V?2(6A). Ten of sixteen polymorphic short-arm loci were not detected in del6V?2S-1. Thus, the loci are located in the deleted distal chromosome region. Six RFLP markers were mapped in the proximal 58% of 6VS. Of 20 DNA markers specific for 6VL, six mapped in the distal 36% of the long arm, and nine mapped in the proximal 64% of 6VL. The breakpoint of the short arm of 6V?2 occurs between Xpsr106 and Xcdo270, and that of the long arm between Xpsr915 and Xmwg934. The powdery mildew resistance gene Pm21 is located on the short arm of chromosome 6V?2. Pm21 is present in del6V?2S-1, and can be further mapped in the proximal 58% of 6V?2S.