| Wheat is one of the most important crops worldwide and is the primary source of human sustenance and calories.The main long-term goal of wheat breeding is to breed new wheat varieties with high and stable yields.In order to explore more QTLs,this study determined 18 plant architecture and spike traits using the recombinant inbred line population of “Tainong 18×Linmai 6”(TL-RIL).Combining with the high-density genetic map constructed previously,QTL analysis was performed using three software,Win QTLCart,Ici Mapping and Map QTL.The aim is to locate the key QTL loci affecting these traits and provide a theoretical basis for further gene cloning and wheat breeding.The main results are as follows:(1)Phenotypic variation and correlation analysis showed that all traits showed large variations(4.41-59.96%).Among these,the number of sterile spikelet number per spike(SSS)had the largest variation.The variation of total spikelet number per spike(TSS)was the smallest.Among the observed plant architecture traits,the coefficient of variation for flag leaf width(FLW)showed a minimum value of 7.54%,while length-width ratio of flag leaf(FLFW)showed a maximum value of 20.9%.Among the three factors of yield,the coefficient of variation of thousand grains weight(TGW)was the smallest,while the coefficient of variation of SN was the largest,and the coefficient of variation of grain number per spike(GNS)was17.84%.Except for some individual traits,the correlations were significant between most traits.The correlations were significant between the three factors of yield,thousand grains weight(TGW),spike number(SN)and grain number per spike(GNS).(2)A total of 209 QTLs were detected on all 21 chromosomes.The additive effects of111 QTLs were positive,indicating that the increased effects were from the female parent,Tainong 18.The additive effect of 98 QTLs was negative,indicating that the increased effect came from the male parent,Linmai 6.Among them,14 QTLs were mapped for angle between stem and the base of flag leaf(ABSFL),7 QTLs for flag leaf length(FLL),15 QTLs for flag leaf width(FLW),4 QTLs for Length-width ratio of flag leaf(FLFW),11 QTLs for flag leaf area(FLA),3 QTLs for angle between stem and the base of second leaf(ABSSL),6 QTLs for second leaf length(SLL),12 QTLs for second leaf width(SLW),11 QTLs for length-width ratio of second leaf(SLFW),10 QTLs for the second leaf area(SLA),17 QTLs for stem diameter(SD),13 QTLs for spike lenghth(SL),20 QTLs for total spikelet number per spike(TSS),16 QTLs for sterile spikelet number per spike(SSS),17 QTLs for maximum grain number per spikelet(MGPS),5 QTLs for grain number per spike(GNS),17 QTLs for thousand grains weight(TGW),and 11 QTLs for spike number(SN).(3)A munber of 27 major QTLs(the contribution rate of three QTL analysis software was more than 10%)were detected.Among them,nine were related to plant architecture traits,including ABSFL,SLW,SLA,SD;twelve traits were involved in panicle traits,including SL,TSS,SSS,and MGPS.Six of them were related to three yield components,including TGW,GNS and SN.(4)A total of 21 QTL clusters(C1-C21)consisting of 44 QTLs associated with 15 traits were detected on 12 chromosomes: 1A,1B,1D,2A,2D,4B,5A,5B,6A,6D,7A,7D.There is an important QTL cluster(C9)on chromosome 4B,which is composed of two QTLs and is related to MGPS and SSS.QMgps-4B.2 was a major QTL with a contribution rate more than20%.(5)A total of 123 candidate genes were located with 66 candidate genes related to plant architecture traits,44 candidate genes related to panicle traits,and 13 candidate genes related to yield traits.Of these,4 QTLs were mapped to 2 candidate genes,115 QTLs were mapped to 1 candidate gene,and 90 QTLs were not mapped to candidate genes.At the same time,we predicted that Traes CS4B02G047100 could be a potential candidate for controlling SN. |
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