Mapping of a new stripe rust resistance locus Yr57 on chromosome 3BS of wheat Mandeep S. Randhawa • Harbans S. Bariana • Rohit Mago • Urmil K. Bansal Received: 8 November 2014 / Accepted: 27 January 2015 / Published online: 1 February 2015 Ó Springer Science+Business Media Dordrecht 2015 Abstract A common wheat landrace, AUS27858, from the Watkins collection showed low seedling stripe rust response against Australian Puccinia striiformis f. sp. tritici pathotypes. Genetic analysis of stripe rust resistance indicated the involvement of two indepen- dent resistance loci YrAW1 and YrAW2. YrAW1 was mapped in chromosome 4AL and formally named Yr51. Ninety seeds of a heterozygous F 3 line (HSB#5474; YrAW2yrAW2) were grown individually to produce a segregating population referred to as single gene segregating population #5474 (SGSP#5474) to map YrAW2. Monogenic segregation at the YrAW2 locus was confirmed among the SGSP#5474. YrAW2 was located in chromosome 3BS through DArT-based bulked segregant analysis. SGSP#5474 was advanced to F 6 generation and was phenotyped for detailed mapping. Test of allelism with Yr4, previously located on chromosome 3BS, showed 5.2 ± 1.3 % recombi- nation between YrAW2 and Yr4. Since there is no other stripe rust resistance gene located in the distal part of chromosome 3BS, YrAW2 was formally named Yr57. Markers gwm389 and BS00062676 flanked Yr57 at genetic distances of 2.0 and 2.3 cM, proximally and distally, respectively. These markers were genotyped on a set of Australian and Indian wheat cultivars and the absence of resistance-linked alleles of gwm389 and BS00062676 markers was shown in cultivars known to lack Yr57. These markers would be useful in marker- assisted pyramiding of Yr57 with other marker-tagged major and minor genes. The genetic stock carrying Yr57 singly has been deposited with the Australian Winter Cereal Collection, Tamworth, Australia, and it is accessioned as AUS91463. Keywords Wheat  Stripe rust  Molecular mapping  Validation of markers Introduction Wheat (Triticum aestivum L.) is affected by three rust diseases; stripe rust, leaf rust and stem rust. Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is currently the most damaging wheat disease world- wide. During the mid-1980s, stripe rust caused significant losses in the eastern wheat belt of Australia (Wellings 2007). An epidemic of stripe rust occurred in eastern Australia during 2003 due to a new pathotype that was first detected in Western Australia in 2002 (Wellings et al. 2003). Due to this incursion, annual crop protection costs were estimated to be A$40–90 million (Wellings 2007). Annual losses of M. S. Randhawa  H. S. Bariana  U. K. Bansal (&) Faculty of Agriculture and Environment, The University of Sydney PBI-Cobbitty, PMB 4011, Narellan, NSW 2567, Australia e-mail: Urmil.bansal@sydney.edu.au R. Mago CSIRO Agriculture Flagship, GPO 1600, Acton, ACT 2601, Australia 123 Mol Breeding (2015) 35:65 DOI 10.1007/s11032-015-0270-0