Evaluation Analysis And Molecular Mapping Of Resistance To Stripe Rust And Yield-related Traits In The Middle And Lower Reaches Of The Yangtze River Wheat Landraces

The wheat landraces as an important genetic resource,it has developed and domesticated for a long time,through natural and artificial selections.They show specific characteristics,adaptability to complex environmental conditions,genetic diversity,and grain traits.The middle and lower reaches of the Yangtze River wheat region is the main wheat production area,and it is also the main epidemic area of stripe rust in China.To identify excellent stripe-rust resistance and yield-related traits wheat landraces,a panel of210 accessions derived from the middle and lower reaches of the Yangtze River were resistance and yield-related traits evaluated in whole growth period.Based on our result,Anyuehong and Yibinzhuermai were selected from the middle and lower reaches of the Yangtze River wheat landraces and were used as resistance parents,respectively.The genetic linkage map for recombinant inbred lines(RILs)populations of them were conducted,using the 55 K SNP array.Combining phenotypic datasets from multiple field experiments with high-quality genetic linkage map were mapped QTL for controlling stripe rust resistance and yield-related traits from these two wheat landraces.The potentially novel QTL regions located in adult-stage resistance and yield-related traits may be useful to improve stripe-rust resistance and yield-related traits in current wheat cultivars.Major exploration results were obtained as follows:1.Based on the 342 stripe rust resistance genes / sites / segments previously reported,the genetic map of wheat molecular markers constructed by Maccaferr and Andrzej was used as a reference map to construct a meta-quantitative trait loci(MQTL)map of wheat stripe rust resistance was constructed based on the meta-analysis technique.The map covers 194 wheat stripe rust resistance MQTL,among which 81 MQTL are associated with disease severity(DS),31 with the infection type(IT),15 with the area under the disease progress curve(AUDPC),and 44 with DS and IT,6 with DS and AUDPC,13 with IT and AUDPC,and 4 with other stripe rust resistance traits.These stripe rust resistant consistent MQTL were projected on 21 chromosomes in wheat,which were unevenly distributed,and12 clusters were discovered on chromosomes 2A,4A,5A,1B,2B,3B,5B,6B,7B,1D,2D and 7D,respectively.A comparative analysis with published permanently named stripe rust resistance genes revealed that most of the permanently named genes were lied in MQTL cluster segments,indicating that these MQTL cluster segments are likely to be hotspots for controlling wheat stripe rust resistance.2.Identification of stripe rust disease resistance of 210 accessions derived from themiddle and lower reaches of the Yangtze River were inoculated with a mixture of Chinese Puccinia striiformis f.sp.tritici races(PST)and resistance evaluated at seedling stage,in2017 and 2018,mixed PST races were used in Chongzhou and Mianyang of Sichuan province respectively to identify the adult stage and yield-related traits analysis.The results showed that 4 wheat landrace germplasms(Hongmaozao,Zaowutian,Guangtoumai,and Yuanzhuimai are near-immunity at seedling stage(IT = 0 and 0;),accounting for1.90% of all germplasms.102 wheat landrace germplasms are stable resistance at the adult stage,accounting for 48.57% of all.Based on the analysis of resistance phenotypes at the seedling stage and the adult plant stage,the three materials are resistance during the whole growth period,accounting for 1.43%.Analysis of yield-related traits shows that the wheat regions in the middle and lower reaches of the Yangtze River are rich phenotypic variation in both environments.Based on the analysis of stripe rust resistance and yield-related traits,6 wheat endemic germplasms with excellent stripe rust resistance and outstanding yield-related traits were identified: Daheshangtou(Anhui),Feixisanyuehuang(Anhui),Linpingyang wheat(Zhejiang),Yibinzhuermai(Sichuan),Anyuehong wheat(Sichuan)and Meishanguangtou wheat(Sichuan).3.The phenotypic identification of stripe rust resistance at seedling stage and adult stage showed that Anyuehong wheat landrace(AYH)stripe rust resistance was adult stage resistance and controlled by quantitative trait loci(QTL).A wheat 55 K SNP chip was used to scan the whole genome of AYH / Taichuang 29(TC29)recombinant inbred lines(RILs)to construct a high-density SNP genetical linkage map.A total of 1143 SNP markers were anchored,covering 21 chromosomes in wheat,with a total length of 2822.05 c M.Based on the final disease severity of stripe rust(FDS),infection type(IT)and area under disease progress curve(AUDPC)in adult plant stage,QTL mapping of resistance against stripe rust in adult plant stage was performed.A total of 5 QTL controlling stripe rust resistance at the adult plant stage were detected,which were located on chromosomes 1D,2A,5B,and 7D,respectively,which are named QYr AYH.Sicau-1D.1,QYr AYH.Sicau-2A.1,QYr AYH.Sicau-5B.1,QYr AYH.Sicau-7D.1 and QYr AYH.Sicau-7D.2,and the Explainable phenotypic variability is from 6.10 to 31.65%.Compared with the analysis of the rust consistency map and the Chinese spring physics map found that QYr AYH.Sicau-7D.2 and QYr AYH.Sicau-5B.1 may be potential novel QTL for controlling resistance to wheat stripe rust in the adult plant stage.Genetic effect analysis showed that these QTL or their combinations can significantly reduce the FDS of adult plant stage stripe rust.In response to the detection of two potential novel QTL,competitive allele-specific PCR markers(KASP),KASP?AX-109750388,and KASP?AX-110527974 were developed that can effectively identify QYr AYH.Sicau-7D.2and QYr AYH.Sicau-5B.1 respectively.Combined with 63 cultivars in Sichuan province KASP analysis of result,it was found that only a few cultivars have the identified adult plant stripe rust resistance QTL.4.The constructed SNP high-density genetic linkage map was used to perform yield-related traits QTL analysis,such as spikelet number(SPN),spike length(SL),productive tiller number(PTN),kernel number per spikelet(KNL),kernel number per spike(KNS),kernel weight per spike(KWS),and thousand kernel weight(TKW).A total of 32 QTL controlling wheat yield-related traits were detected,which could explain the phenotypic variation rate from 4.67 to 24.43%,among which 25 QTL can explain the phenotypic variation rate of more than 10%,which are distributed on 1A,2A,2B,2D,3A,3D,4A,4D,5A,5D,6B,6D,and 7D chromosomes,and QSLAYH.Sicau-4D.1 located on the 4D chromosome controls SL,can be stable expressed in both environments.It was also found that 1A,3A,and 4D chromosomes each carried a QTL with one factor and multiple effects,among which the chromosome 1A AX-111216460-AX-108728119 region simultaneously controls PTN,KNL and TKW,the chromosome 3A AX-110922897-AX-111072779 region simultaneously controls panicle number and grain weight,and the 4D chromosome AX-109564839-AX-109449898 segment controls wheat length and number simultaneously.5.The phenotypic identification of stripe rust resistance at seedling stage and adult plant stage showed that Yibinzhuermai wheat landrace(YBR)stripe rust resistance was adult plant stage resistance and controlled by QTL.A wheat 55 K SNP chip was used to scan the whole genome of YBR / TC29 recombinant inbred line population to construct a high-density SNP genetical linkage map.A total of 1487 SNP molecular markers were anchored,covering 21 chromosomes of wheat,with a total length of 3526.69 c M.QTL mapping analysis of stripe rust resistance at adult plant stage of FDS,IT and AUDPC was made.A total of 5 QTL controlling stripe rust resistance in adult plant stage were detected,which were located on chromosomes 2A,2B,5B,and 7D respectively,which are named QYr YBR.Sicau-2A.1,QYr YBR.Sicau-2B.1,QYr YBR.Sicau-5B.1,QYr YBR.Sicau-7D.1,and QYr YBR.Sicau-7D.2,and the explainable phenotypic variability is 4.94?19.81%.Based on the constructed consistent quantitative trait loci map of wheat stripe rust and comparative genomics findings,QYr YBR.Sicau-7D.1,QYr YBR.Sicau-5B.1,and QYr AYH.Sicau-7D.1,QYr AYH.Sicau-5B.1 in AYH co-located in the same interval,indicating that the two wheatlandraces may have the same QTL for controlling stripe rust in adult plant stage.Genetic effect analysis showed that these QTL or their combinations can significantly reduce the severity of wheat stripe rust of the adult plant stage.6.The constructed SNP high-density genetic linkage map was used to perform yield-related traits QTL analysis,spikelet number(SPN),spike length(SL),productive tiller number(PTN),kernel number per spikelet(KNL),kernel number per spike(KNS),kernel weight per spike(KWS),and thousand kernel weight(TKW)on YBR / TC29 RIL recombinant inbred lines.A total of 31 QTL controlling wheat yield-related traits were detected,which could explain the phenotypic variation rate from 4.79% to 16.39%,among which 13 QTL can explain the phenotypic variation rate of more than 10%,which are distributed on 1A,2B,3B,4B,5A,5B,6B and 7A chromosomes,and AX-110360226-AX-110938645 lied on the 5A chromosome controls SL and SPN,while the AX-108902579-AX-08847997 on 7A chromosome control KNL and TKW simultaneously.