Genetic Analysis And Chromosomal Location Of Yellow Rust Resistance Gene In ’Gusongdalongxu’ Of Sichuan Wheat Landraces

Wheat stripe rust, caused by Puccinia striiformis f. sp. tritic, is one of the fungal diseases in production of wheat. Sichuan Province is a place where the incidence of wheat stripe rust is very high. So it is very important for breeders to find out new resistance genes to improve wheat varieties. The new wheat varieties not only can resist diseases but also can adapt to the environment of Sichuan Province.This research is to identify the genetic characteristics of stripe rust resistance gene in Sichuan wheat landrace, Gusongdalongxu. We screened molecular markers to do genetic analysis and chromosomal location between F₂ populations derived from the hybrid of resistant parent Gusongdalongxu and infected parent Taichung 29. Below are the main results:1. Inoculate pathogenic physiology races mixture in field to identify the yellow rust resistance in Sichuan landrace wheat Gusongdalongxu. Genetic analysis of F₁, F₂ and F_2:3 hybrid generations of Gusongdalongxu and Taichung29 showed that the stripe rust resistance of Gusongdalongxu is controlled by a single dominant gene, temporarily named Yrgsdlx.2. Using RGAP, SRAP and SSR 3 molecular marker technologies analyzed F₂ hybrid generation of Gusongdalongxu and Taichung 29. Seven linked molecular markers were found, including 1 RGAP molecular markers （S1/NLRR-INV2）,3 SRAP molecular markers （F-me7/R-me 18、F-me7/R-me20、F-me8/R-me12）,3 SSR molecular markers （Xwmc438、Xgpw2160、Xgdm130）. Combined with the specificity of the SSR markers position on chromosome, the single stripe rust resistance gene Yrgsdlx was positioned on the chromosome 7D. Calculated the genetic distance among markers through software JoinMap 4 and drew the genetic map by software Mapdraw V2.1. The order of seven markers in the genetic map is F-me7/R-mel8,F-me7/R-me20、F-me8/R-me12、 S1/NLRR-INV2、Xgdm130、Xwmc438 and Xgpw2160. The closest flanking makers of Yrgsdlx were Xgdm130 and S1/NLRR-INV2with the genetic distances of 12.7 cM and 19.9 cM, respectively.3. Using Diversity Arrays Technology （DArT） to scan F₂ population, we found nine linked markers and located them on the chromosome 7DS. The closest flanking makers of Yrgsdlx were D8025 and D4454with the genetic distances of 2.0 cM and 2.2 cM, respectively.4. We analyzed Yrgsdlx and other Yrgenes（Yr18, Yr33, YrY212, YrM8003 and YrWV） located on chromosome 7DS from pedigree, resistance level and common markers, gene Yrgsdlx is diffierent from them. So Yrgsdlx probably is a novel stripe rust resistance gene.