| Ensuring stable production of wheat(Triticum aestivum L.)is the key to ensuring food security in China.The discovery of QTL loci controlling important traits can lay the genetic foundation for wheat variety improvement.In this study,198 RIL lines were genotyped using 50K chip SNP markers in the combination of "Xinong 1376 / Xiaoyan 81",and a high-density genetic map covering 21 chromosomes of wheat was constructed.The RIL population was planted in Yangling District,Shaanxi Province in two consecutive years in 2018/2019 and in Nanyang City,Henan Province in 2018/2019 to phenotypically identify the stem and plant-type related traits and uncover their associated QTL during the reproductive period of wheat.The purpose of this study was to identify the main effect QTL that existed stably in different environments or molecular markers that co-segregated with them,and to provide a reference for fine mapping and selective breeding based on molecular markers.1.A genetic map covering 21 chromosomes of wheat was constructed.The total length of the genetic map was 3605.53cM,which was composed of 2685 bin markers,including 13571 polymorphic markers and 28 linkage groups.The average distance between markers was 1.34cM,the average marker density was 0.75cM,the shortest linkage group was 24.25cM,and the longest linkage group was 261.39cM.The distribution of the number of markers constituting the genetic map in the wheat genome is A>B>D.2.A total of 52 stem-related QTL loci were identified by QTL testing for stem-related traits,mainly on chromosomes 1A,2A(2),3A(2),and 5A(6)in the A genome,chromosomes 3B(1),4B(5),5B(5),and 7B in the B genome,and chromosomes 1D(2),2D(8),3D(2),4D(6),5D(8),6D(2),and 7D chromosomes,with a single locus explaining0.53-34.56% of the phenotypic variation,of which 26 multi-environment stable QTLs were distributed on the 1D,2A,2D(5),3A,4B(2),4D(4),5A(4),5D(5),and 7D chromosomes.The phenotypic variation of 14 major QTL loci contributed more than 10% in at least a single environment,affecting SD1(2),BIL1(3),PD1(2),SD2(4),SS2 and LD,respectively.3.A total of 17 QTL loci for plant-type related traits were found in this study.They were mainly distributed in 2D(2),3A,3B,4B(2),4D(4),5B(2),5D,6A,6B(3),these included 3 QTL affecting PT,4 QTL affecting the SNL,and 10 QTL affecting PH,a single QTL locus explained 0.67% to 48.31% of the phenotypic variation.There were 7 major QTLs that accounted for more than 10% of phenotypic variation in at least a single environment.4.In this paper,QTL clusters containing multiple traits were identified,mainly distributed on chromosomes 2D,4B,4D,5A,5B,and 5D.Among them,QTL loci located within the interval AX-179557748 and AX-109871849 on chromosome 2D can affect traits such as PH,SD1,PD1,SS1,and SNL simultaneously with QTL close to or closely linked to the plant height gene Rht8.QTL clusters found on chromosome 4B influence PH,PT,and BIL.QTL clusters located near Rht-D1 b on chromosome 4D can affect PH,SNL,BIL1,BIL2,PT,and LD. |
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