Investigation Of Resistance Of Chinese Wheat Cultivars (Lines) To Wheat Leaf Rust And QTL Mapping For Adult-Plant Resistance Of CIMMYT Wheat Cultivar Saar To Wheat Leaf Rust

Wheat leaf rust is an important disease in wheat production,screening and breeding for resistance cultivars are considered to be the most economical,environmental and effective appropriate strategy to reduce damages due to this disease.Therefore,it is an important basis for utilizing the resistance cultivars,and is very reasonably to make clear the constitute and genetic characteristics of the resistance genes in our country's wheat production cultivars and important germplasm.The resistance against wheat leaf rust can be expressed in seedling stage or adult stage.Commonly the seedling resistance controlled by monogene is the quality trait with high resistant to leaf rust,but it may be overcame by the changing of the Puccinia recondite f.sp.tritic.The adult plant resistance controlled by polygenes is the quantity trait which is durable relatively.So,to understand the resistance completely,research on the resistance to wheat leaf rust should be from two respects of seedling and adult plant period,further analysis of QTL(quantitative trait loci)should be done to the materials which have slow rusting resistance.In this study,adult plant resistance of those 206 wheat cultivars(lines)which mainly came from Henan,Shandong, Heibei,Shanxi,Gansu,Hubei,Anhui,Jiangsu,Sichun,Guizhou and Yunnan was identified using THTT Puccinia triticina pathotype in the field.24 isolates of Puccinia recondite f.sp.tritic were used for the identification of leaf rust resistant ability and the postulation of leaf rust resistance genes in 96 cultivars(lines)of these materials.And Marker-assisted Selection(MAS)was used to study the leaf rust resistance genes.As a result,the resistance to leaf rust of the tested materials was preliminarily clear,some cultivars(lines)representing slow leaf rusting were ascertained.To analyse the genetic constitution of the sow leaf rusting,it need a appropriate cross population,also it is workload,so in this research CIMMYT wheat Saar as a typical cultivar was used to study the slow leaf rusting,QTL mapping,contribution rate,closely linked molecular markers were determined in this research.1.Resistance genes against wheat leaf rust were detected by Marker-assisted Selection (MAS)and comparing the infection types on Near-isogenic Lines and the tested cultivars(or lines)induced by 24 isolates of Puccinia recondite f.sp.tritic which were previously characterized of avirulence or virulence gene combination.Lr1,Lr9,Lr3bg, Lr3ka,Lr14ab,Lr17,Lr18,Lr21,Lr24,Lr26,Lr30,Lr34,Lr39,Lr40,Lr43and Lr45 were tested to be present in 55 cultivars(lines).Lr26 was present in 22 cultivars(lines);Lr1 was present in 21.cultivars(lines);Lr18 was present in 17 cultivars(lines);Lr3bg was present in 11 cultivars(lines);Lr17 was present in 10 cultivars(lines);Lr34 was present in 9 cultivars(lines);Lr24 was present in 4 cultivars(lines);Lr9 waspresent in 3 cultivars (lines);Lr21 was present in 3 cultivars(lines);Lr30 was present in 3 cultivars(lines);Lr40 was present in 3 cultivars(lines);Lr39 was present in 2 cultivars(lines);Lr43 was present in 2 cultivars(lines);Lr45 was present in 2 cultivars(lines)and unknown resistance gene (or genes)in 28 cultivars.No genes for leaf rust resistance in the seedling stage were found in 24 cultivars.2.Adult plant resistance of 206 wheat cultivars(lines)was identified using THTT Puccinia triticina pathotype in the field.49 cultivars displayed low infection type,and the FDS was less than 10%,the rAUDPC was less than 0.28;Slow-rusting resistance was displayed in at least 25 cultivars(lines),the infection type was 3 or 4,but the FDS was less than 15%,the rAUDPC was less than 0.23.Seventeen cultivars(lines)displayed mid-resistance to leaf rust with FDS between 15%～40%,the rAUDPC was less than 0.45.3.A total of 142 SSR and 209 DArT(Diversity Arrays Technology)markers were used to map QTL for the resistance to leaf rust in a recombinant inbred line(RIL)population with 109 F₆ families derived from the cross Avocet/Saar.Five QTLs for the resistance to leaf rust were detected on chromosomes 1BL,2DS,5BL,6AL and 7DS,explaining 4.5%～6.4%,12.2%～12.5%,4.9%～11.2%,4.9%～7.8%and 14.0%～67.6%of phenotypic variance,respectively.Nine closely linked molecular markers were identified in this study, they are Xhbe248 on 1BL;Xbarc124 on 2DS;XDuPw395 on 5BL;Xgwm617a,Xgwm169 on 6AL;and XcsL V34,Xgwm295,Xswm10,Xgwm1220 on 7DS,respectively.