Chromosome location of leaf rust resistance gene Lr43 from Aegilops tauschii in common wheat

Wheat leaf rust resistance gene Lr43 was recently transferred from Aegilops tauschii Coss. to common wheat (Triticum aestivum L.) to produce hard red winter wheat germplasm line KS92WGRC16. Monosomic and telocentric analyses were used to determine the chromosomal and chromosome arm location of Lr43. KS92WGRC16 was crossed with each of the seven D-genome monosomic lines. The F2 families were inoculated with race PBJL of the leaf rust fungus. Puccinia recondita Roberge ex Desmaz. f. sp. tritici (Eriks. and E. Henn.) D.M. Henderson. The number of resistant to susceptible seedlings did not deviate significantly from a 3:1 ratio in crosses involving 1D, 2D, 3D, 4D, 5D, or 6D monosomic lines. However, the 7D monosomic-derived F2 deviated significantly from a 3:1 ratio (x2 = 32.2, P 0.001) indicating that Lr43 is located on this chromosome. Twenty resistant F2 plants from the critical cross were progeny tested, and results confirmed the location of Lr43 on chromosome 7D. Telocentric analysis showed that Lr43 is on the short arm of chromosome 7D (7DS) and it is unlinked to the centromere. This information may facilitate development of molecular markers and result in more efficient breeding for resistant cultivars