QTL Mapping For Adult-plant Resistance Gene To Leaf Rust In Chinese Wheat Line Fuyu 3 And Romanian Wheat Line Fundulea 900

Wheat leaf rust is one of the devastating diseases in common wheat(Triticum aestivum L.) worldwide. Using resistant wheat cultivars is the most economic, effective and environmentally friendly approach to reduce the losses caused by the diseases.Currently, the genes in resistant cultivars utilized in the production were race-specific, this kind of resistance was easily lost when new virulent races emerge or increase and may finaly cause servere yield loss. Therefore identidying and mapping leaf rust resistance genes especially slow rusting genes of leaf rust was with significant magnitude in breeding durable resistant varieties. The aim of this study was to identify slow rusting QTL for leaf rust in Chinese wheat Fuyu 3/Zhengzhou 5389 F2:3 population and Romanian wheat Fundulea 900/Thatcher F2:3 population. The main results are summarized as follows:1. Three leaf rust resistance QTLs were detected in Fuyu 3/Zhengzhou 5389 F2:3 population using ICIM. They are located on chromosome 1BL, 2BS and 7BL, and were designated as QLr.hbu-1BL, QLr.hbu-2BS and QLr.hbu-7BL, respectively, and all resistance alleles were contributed by Fuyu 3.2. QLr.hbu-1BL located on chromosome 1BLwas proved to be Lr46. The loci was stably expressed in all the environments, and explained 12.0-19.2 % of the phenotypic variance. The QTL on chromosome 2BS was a mojor loci, and also could be detected in all the enviroments, expalianed 22.3-38.9 % of the phenotypic variance. This QTL might be a new one. The third QTL QLr.hbu-7BL with minor effect was located on chromosome 7BL, and only can be detected in 2012. The QTL expalianed 4.1-4.3% of the phenotypic variance and might be known leaf rust gene Lr68.3. Wang found that Lr34 was present in Fundulea 900. In Fundulea 900/Thatcher F2:3 population, a total of 3 QTL for leaf rust resistance were detected on chromosome 1BL, 2DS and 7DS, and designated as QLr.hebau-1BL, QLr.hebu-2DS and QLr.hebu-7DS, respectively. QLr.hebu-7DS from Fundulea 900 with major effect and explained 35.3-72.8% of the phenotypic variance in all the environments. The loci proved to be Lr34;The second QTL QLr.hebau-1BL derived from Fundulea 900 which proved to be Lr46 was detected in 2012 and 2013 cropping seasons, and explained 4.6-11.4% of the phenotypic variance.4. As Lr34 with large effect depressed the express of other genes, lines with Lr34 were excluded for further analysis. When analysising with the remaining 70 Fundulea 900/Thatcher F2:3 population with absence of Lr34, QLr.hebau-1BL(Lr46) could be detected in all the three environments, and explained 20.4-23.4% of the phenotypicvariance which was major compared with analysising with the whole Fundulea900/Thatcher F2:3 population. The expreesion level of Lr46 was suppressed by Lr34. Another QTL QLr.hebu-2DS on chromosome 2DS derived from Thatcher was detected in 2012 and 2013 cropping seasons, and explained 20.4-23.4% of the phynotypic variance. The loci was located nearby Lr22 b which was identified in Thatcher, but show some difference with Lr22 b, and the resistance of QLr.hebu-2DS might be provided by the residue resistance of Lr22 b.