Identification of microsatellite markers linked to leaf rust resistance gene Lr25 in wheat
Singh, A.; Pallavi, J.K.; Gupta, P.; Prabhu, K.V.
Journal of Applied Genetics 53(1): 19-25
ISSN/ISBN: 2190-3883 PMID: 22033869 DOI: 10.1007/s13353-011-0070-0
The leaf rust resistance gene Lr25, transferred from Secale cereale L. into wheat and located on chromosome 4B, imparts resistance to all pathotypes of leaf rust in South-East Asia. In an F(2)-derived F(3) population, created by crossing TcLr25 that carries the gene Lr25 for leaf rust resistance with leaf rust-susceptible parent Agra Local, three microsatellite markers located on the long arm of chromosome 4B were found to be linked to the Lr25 locus. The donor parent TcLr25 is a near-isogenic line derived from the variety Thatcher. The most virulent pathotype of leaf rust in the South-East Asian region, designated 77-5 (121R63-1), was used for challenging the population under artificially controlled conditions. The marker Xgwm251 behaved as a co-dominant marker placed 3.8 cM away from the Lr25 locus on 4BL. Two null allele markers, Xgwm538 and Xgwm6, in the same linkage group were located at a distance of 3.8 cM and 16.2 cM from the Lr25 locus, respectively. The genetic sequence of Xgwm251, Lr25, Xgwm538, and Xgwm6 covered a total length of 20 cM on 4BL. The markers were validated for their specificity to Lr25 resistance in a set of 43 wheat genetic stocks representing 43 other Lr genes.