| Barley(Hordeum vulgare L.)is a crucial raw material for feed industry,brewing industry and modern health food.Lodging is the main factor affecting the production and development of barley,which not only affects the grain and stem yield and quality,but also increases the difficulty of harvesting.Therefore,the analysis of the genetic mechanism of lodging resistance traits in barley stem can provide theoretical support for lodging resistance breeding in barley.In this study,based on 64 barley germplasm resources and DH population of“Huaai11×Huadamai6”.The cell wall components and lodging resistance related traits of 94 barley cultivars were measured.Meanwhile,we evaluated the lodging resistance traits of 13 barley stems for 2 consecutive years.The high-density genetic linkage map constructed in the laboratory was used to map QTLS for 13 lodging resistance traits.And the candidate genes were predicted.The main results are as follows:1.Through the detection of cell wall components(cellulose,acid-soluble lignin,acid-insoluble lignin,total lignin)in stems of natural germplasm and 30 of DH population,statistical analysis and correlation analysis were carried out in combination with lodging resistance related traits(main stem length,main stem fresh weight,third internode break force,lodging index).Among the cell wall components,cellulose content had the lowest coefficient of variation(5.92%),and acid soluble lignin had the highest coefficient of variation(13.94%).Among lodging resistance related traits,the coefficient of variation of main stem breaking length was the lowest(15.76%),and the coefficient of variation of breaking force between the three stem segments was the highest(38.23%).Lodging index was positively correlated with length of main stem(MSL)and cellulose content with correlation coefficients of 0.61and 0.41,respectively.There was a significant negative correlation between lodging index and third internode breaking force(TIBF),the correlation coefficient was-0.75.Cellulose content was the main intrinsic factor affecting lodging resistance,while the TIBF and MSL were the main phenotypic traits affecting lodging resistance of barley.2.Phenotypic analysis and heritability evaluation were evaluated on 13 lodging resistance traits(Uppermost node diameter(UND),Second node diameter(SND),Third node diameter(TND),Uppermost internode length(UIL),Second internode length(SIL),Third internode length(TIL),Uppermost internode diameter(UID),Second internode diameter(SID),Third internode diameter(TID),Third internode breaking force(TIBF),Stem fresh weight(SW),Length of main stem(MSL)and Lodging index(LI))of 122 DH lines and their parents for two consecutive years.The13 traits were normally distributed for two years,with coefficients of variation8.09%～33.29%in 2021,and 8.45%～34.11%in 2022.The h~2ranged from 67.00%to97.29%.Except for the TIBF and UND,there were significant differences in other traits between the parents.LI was positively correlated with SW,UIL,SIL,TIL and MSL,the correlation coefficients were 0.55,0.75,0.89,0.91 and 0.91,respectively.LI has a significant negative correlation with TIBF,and the correlation coefficient is-0.39.3.Based on the established high density genetic linkage map,QTL mapping of13 lodging resistance traits were performed for 2 consecutive years by inclusive composite interval mapping.A total of 49 stable QTLs were identified,including 5,3,5,2,4,2,4,5,5,4,4,4 and 2 stable QTLs for UND,SND,TND,UIL,SIL,TIL,UID,SID,TID,TIBF,SW,MSL and LI,respectively.The PVE and LOD of the stable QTLs ranged from 4.50%to 50.01%and 3.05 to 34.11.There were 27 major QTLs with PVE exceeding 10%.4.A total of 22 QTL enrichment hotspots were identified by integrating a large number of linkage intervals of different lodging resistance traits,involving 288 QTLs,among which 1,6,6,3,2,1 and 3 hot spots were found on 1H,2H,3H,4H,5H,6H and 7H chromosomes,respectively.At the same time,the annotation of each gene in major QTLs by Ensembl database,22 candidate genes related to cell division and plant development were identified.Among them,12 candidate genes were related to stem node diameter and internode diameter,and 10 candidate genes were related to internode length.In conclusion,64 barley germplasm resources and 122 barley DH populations were used as materials in this study,which laid a foundation for fine mapping or mapping cloning of lodging resistance related traits in stem,and provided a reference for the study of lodging resistance mechanism and breeding of new barley varieties. |
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