| As an important and worldwide food crop,improving the yield and quality of wheat are of great significance to people's life.Many agronomic characters of wheat are belongs to quantitative characters,which are controlled by multiple loci,and the phenotypic values are determined by environment and gene interaction.So constructing a genetic linkage map with high density,and QTL studies of agronomic and yields traits,locating its position on the chromosome and the effect,have important significance for the genetic improvement of common wheat.In this study,we conducted QTL studies about the important agronomic and yield traits in RIL population developed from “Weimai 8×Annong 91168”,while SNP genotyping techniques were used to construct a high density genetic map.The main results as follows:1.A genome-wide genotyping study of Weimai 8,Annong 91168 and RIL populations using SNP chips,resulting in a genetic linkage map containing 2,000 markers,which covered 2506.98 cM,genetic distance between markers was 1.25 cM on average.The map contains a total of 24 linkage groups,including 21 chromosomes of wheat.2.The number of days to flowering in Weimai 8 and Annong 91168 were 200 days,and RIL population ranging from 197 to 207 days,and mateials growing in the low nitrogen environment flowering 1 day in advance.Totally 14 QTL linked with number of days to flowering were located and which were distributed on chromosomes 2D,3B,4B,5A,5B,5D,6A,6D,and 7A.Nine QTL could explain more than 10% of the phenotypic variation,and two QTL could detected in different enviorments.3.The height,uppermost internode,the third internodes,the fourth internodes length of Weimai 8 was significantly higher than that of the Annong91168;Under the low nitrogen treatment plant height and internode length were significantly lower than the normal water conditions.Under the low nitrogen condition,height and internode length of WA population were significantly lower than in control conditions.QTL analysis of RIL populations revealed a total of 65 QTL related to plant height traits,of which 43 QTL explained more than 10% phenotypic variability,and 10 QTL could be repeated more than 2 times.4.The leaf length and leaf area of Wei'mai 8 were significantly lower than that of Annong 91168,leaf width was higher than that of Annong 91168.Under the low nitrogen treatment,the parent Wei'mai 8 flag leaf length,width and area were higher than those of the other parent.Under the low nitrogen treatment,the flag leaf length,width and area of the RIL population were less than that of the control environment.The flag leaves and stem angle were all greater than the control environment under the low nitrogen treatment.QTL analysis of flag leaf correlations in RIL populations resulted in 41 QTL related to flag leaf traits,of which 31 QTL explained more than 10% of phenotypic variation,and 7 QTL could be detected repeatedly.5.The panicle length,spikelet number per panicle,grains per panicle of Weimai8 were significantly higher than that of Annong 91168,while the sterile spikelet number is lower thatn Annong 91168.In low nitrogen environment,panicle length,spikelet number per panicle and grain number per panicle were significantly lower than those in control environment.A total of 34 QTL loci were obtained by QTL analysis,of which 20 QTL were the major loci,and 8 QTL could be detected repeatedly in multiple transitions.6.The grain length of Weimai 8 were significantly lower than that of Annong 91168,while the grain width and grain weight higher of Weimai 8 were significantly higher than that of Annong 91168,under the low nitrogen treatment all of the phenotypes values were significantly lower than that of control environment.Grain traits showed transgressive segregation in 4 environments,suggesting that dominant alleles that control related traits were randomly distributed on parent chromosomes.QTL analysis of RIL populations containing 144 families revealed a total of 60 additive QTL related to grain traits,and 18 QTL could be repeated more than 2 times7.A pleiotropic effect QTL refers to a highly relevant trait that exhibits a regionalized distribution or the presence of a common QTL.In this experience,23 pleiotropic effect QTL were detected distributed on chromosomes 1A,1B,2D,3A,3D,4B,5A,5D,6A,6B,6D and 7A,and all of them explained more than 10% of phenotypic variation,covering the length in 0.18-25.14 cM.Meanwhile,a stable expression of a pleiotropic effect QTL was detected in 3A,4B and 5D chromosomes. |
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