Registration of spring wheat sources of leaf rust resistance genes Lr53, Lr56, Lr59, and Lr62

Spring wheat (Triticum aestivum L.) germplasm with the alien derived leaf rust (caused by Puccinia triticina Erikss.) resistance genes Lr53, Lr56, Lr59, and Lr62 has been developed over many years, initially at the University of Stellenbosch (South Africa), and then at the Cereal Research Centre (Agriculture and Agri-food Canada), and North Dakota State University (USA). A Thatcher near-isogenic line carrying Lr53, Thatcher-Lr53 (Reg. No. GS-185, PI 682091), was derived, while, following allosyndetic pairing induction, numerous recombinants of the translocations carrying Lr56, Lr59, and Lr62 have been produced and mapped. The shortest and potentially most useful recombinants were identified and named Lr56-157 (Reg. No. GS-186, PI 682092), Lr59-151 (Reg. No. GS-187, PI 682093) and Lr62-129 (Reg. No. GS-188, PI 682094). The four resistance genes may be homeo-allelic since they have similar locations at the telomeric ends of either chromosome 6AS or 6BS, appear to give strong racespecific resistance to a wide range of P. triticina races, occur in the proximity of the Xdupw217 simple sequence repeat marker locus, and, except for Lr59 (which is derived from a smaller primary introgression), were loosely associated with a stripe rust (caused by P. striiformis Westend. f. sp. tritici Erikss.) resistance locus in the original translocations. This study serves to confirm the potential effectiveness of the genes retained in the shortened translocations by testing with 11 representative, current US races of P. triticina.