Marker-assisted selection for leaf rust resistance gene LR 37 in the Martonvásár breeding programme.

The Lr37 (Bariana, 1991) resistance gene was translocated from Aegilops ventricosa (syn. Triticum ventricosum) chromosome 2NS to the short arm of wheat chromosome 2AS together with the tightly linked resistance gene Yrl7 against yellow rust and the Sr38 gene against stem rust. STS (CslVrgal3'F/R) (Seah el al., 2001) and SCAR (SC-Y15 F/R) markers (Robert et al., 1999) were used to verify the presence of the Lr37 resistance gene. Blaszczyk et al. (2004) found that the microsatellite marker Xgwml 176 was relatively close to the Lr37 STS marker, with a linkage distance of 4.1 cM, but the exact location of the Lr37 gene is still unknown (Blaszczyk et al., 2004). Although rust races with virulence to Yrl7 and Lr37 have been identified in various countries (Robert et al., 1999) this gene cluster provides reliable resistance to a wide range of races and is very useful in gene combinations (Helguera et al., 2003). The winter wheat cultivar, VPM-1 (Ae. ventricosa / T. lurgidum var. carthlicum (syn. persicum) // 3*1 aestivum cv. Marne), carrying Lr37, was developed in France, and was first selected for resistance to eyespot caused by Pseudocercosporella herpotrichoides (Doussinault et al., 1981), like its derivatives Flyak, Madsen, Rendezvous, etc. Recently, the cluster of resistance genes Lr37-Yrl7-Sr38 was identified in more than 35 cultivars and lines (Robert, O. et al., 1999, Ambrozkova et al., 2002, Blaszczyk et al., 2004). According to seedling tests, the cluster of Lr37, Yrl7 and Sr38 conferred more resistance at 17 ± 2°C than at normal temperature (Bariana 1991, Bariana and Mcintosh, 1993), so the classification of populations would be easier at low temperature. The Lr37 gene provides adult plant resistance (APR) (Mcintosh et al., 1995). It can be very beneficial in combinations, particularly with genes that provide resistance in both seedlings and adult plants such as Lr9, Lr24 or Lrl9.