QTL Mapping For Adult-plant Resistance Gene To Leaf Rust In Chinese Wheat Cultivar Lantian9

Wheat leaf rust, caused by Puccinia tirticina(Pt), is a devastating disease that cancause severe yield loss. Growing resistant cultivars are the most efficient, economic andenvironmentally-friendly way for reducing the losses caused by the disease. Wheat leafrust resistance can be divided into major gene resistance and minor gene resistance.Wheat variety Lantian9is a winter wheat variety selected by Lanzhou agriculturalschool. It has good agricultural traits such as high and stable yield, cold and droughtresistance, resistance to wheat leaf rust and stripe rust and wide adaptability. Previousreport showed that Lantian9was susceptible to most of chinese leaf rust pathotypes inseedling stage, but showed high resistance in the adult stage. Therefore, Lantian9maycontain adult slow rusting resistance genes, the objective of the study was to identify theslow rusting genes in Lantian9.In the study,197F2:3lines derived from Lantian9/Huixian Hong cross was used tomap leaf rust QTL. The population was inoculated by three pathotypes designated asTHTT, THTS and THTQ, respectively, and then phenotyped for FDS in the field during2010-2011,2011-2012and2012-2013cropping seasons. A total of1232SSR markerswere used to screen between resistant parent Lantian9and susceptible parent HuixianHong. The polymorphic markers were then used to detect the whole population.Phenotypic and genotypic data were combined to map adult plant resistance QTLs inLantian9and Huixian Hong using QTL softwares Map Manager QTXb20andIcimapping3.2.Results showed that five QTL were detected in the population, and five QTL werederived from Lantian9. The QTL located on chromosome2B was stablely identified inthree cropping seasons, tentatively designated QLr.hbau-2BS, explained9.1%,6.0%and9.0%of the phenotypic variations in three years, respectively. The other four QTLs wereidentified in only one cropping season, include two QTLs on chromosome1B,tentatively designated QLr.hbau-1BL.1detected in2011-2012crop season andQLr.hbau-1BL.2detected in2012-2013crop season, one on chromosome4B, tentativelydesignated QLr.hbau-4BS detected in2011-2012crop season, one on chromosome3A,tentatively designated QLr.hbau-3A detected in2011-2012crop season, explained11.7%,7.7%,8.5%and5.6%of the phenotypic variation, respectively. QLr.hbau-1BL.1comesfrom Huixian Hong, the other four QTL come from Lantian9.All of these results confirmed that leaf rust resistance of the population of Lantian9/Huixian Hong cross was controlled by multiple minor QTL. In2011-2012cropping season, four leaf rust QTL were detected and the total penotype variance reached to31.8%. one and two QTL was detected in2010-2011and2012-2013cropping seasons,and explained PVE to9.1%and16.8%, respectively. More SSR markers or marker withSNP can be used to detect more QTL in the future.Leaf rust QTL identified in the study and their closely linked molecular markers canbe used for molecular breeding resistence in wheat cultivars with durable resistance inMAS(marker-assisted selection).