Excavation And Molecular Mapping Of New Resistance Gene To Stripe Rust In Common Wheat

On the basis of previous resistance assessment to stripe rust, we selected forty cultivars with high resistance to stripe rust from more than 200 native and modern varieties. Using five prevalent races of yellow rust CY27, CY29, CY30, CY31, CY32, the forty varieties were evaluated to stripe rust repeatedly. The results showed that Heshang mai, Shanhan 8675, Lumai 19 and Yumai 13 were immunity~high resistance to all the races. So chromosomal location of resistance genes in these varieties was carried out using SSR and AFLP techniques. Yumai18 is susceptible to all the races except CY27, but Yumai 18 has good qualities. So we used Yumai 18 to cross with Heshang mai. We inoculated CY32 on F2 and F9 individuals, the results indicated that one recessive gene controlled the resistance of heshang mai to the race CY32. We also used the method of microsatellite markers to locate the resistance gene in Heshang mai. After screening 290 wheat microsatellite primers, we found five markers Xwmc216, Xgdm126, Xgwm153, Barc188 and Barc81 were linked to the resistance gene in Heshang mai. The nearest genetic distance is 14.7cM. According to http://shigen.lab.nig.ac.jp/wheat/komugi/maps/markerMap, all the markers are on the long arm of Chromosome 1B. Because the resistance gene YrHe is between the xwmc216 and Xgdm 126, so we can conclude that the resistance gene-Yrhe is located on chromosome 1BL.The order among centromere, markers and gene is centromere---Xwmc216---YrHe---Xgdm126---Xgwm153---Barc188---Barc81. Based on the origin of resistance gene and gene analysis, we deduced that YrHe is a new resistance gene to stripe rust. A resistance gene to stripe rust in cultivar Shanhan 8675 was tagged using a RILs developed from Shanhan8675 and Yanzhan No1. After screening 290 wheat microsatellite primers, we found two markers Xwmc170 and CFA2043 were linked to the resistance gene in Shanhan 8675 with genentic distance of 9.8cM and 15.0cM, respectively. The order among centromere, markers and gene is centromere-CFA2043-Xwmc170-YrSh. Based on the results of mapdraw 2.0 and mapmaker 3.0, we can conclude that the resistance gene-YrSh is located on chromosome 2AL. According to the map position and resistance spectrum, we deduced that YrSh is a new resistance gene to stripe rust. A resistance gene to stripe rust in cultivar Lumai 19 was tagged using a RILs derived from Lumai 19 and Yanzhan No 1. After screening 290 wheat microsatellite primers, a marker Xwmc170 linked to the resistance gene in Lumai 19 with the genetic distance of 3.8cM was found. According to the information in http://shigen. lab. nig. ac.jp/ wheat/ komugi/ maps/ makermap, Xwmc170 was located in chromosome 2AL. So we can deduce that the resistance gene-YrLu is located on chromosome 2AL. The AFLP primer pairs-M62P19 which completely linked to the resistance gene to stripe rust Yr32 was used in our materials, but we didn't find polymorphism among parents, resistant bulk and susceptible bulk. So we concluded that Yr32 is different from the resistance gene in Lumai 19. According to gene postulation, resistance spectrum and map position, we concluded that YrLu is a new resistance gene to stripe rust. In our research, we assessed the resistance to stripe rust in F5 individuals derived from Yumai13 and Yanzhan No 1 using CY31, and the result showed that two genes controlled the resistance to stripe rust in Yumai 13. We also used the SSR technique to locate the resistance gene in Yumai 13. After screening 290 primers, we found that the linked molecular markers with the resistance genes in Yumi 13 distributed on chromosome 2B and 3B. On the chromosome 2B, there were 6 markes linked with resistance gene ; and two linked markers were on 3B. Next step, we should consider how to calculate the genetic distance among resistance genes and markers. From the genetic analysis and chromosome location, we can deduce that there are two resistance gene to control the resistance to the race CY31 in Yumai 13.