Genome-Wide Association Studies For Forage Yield And Quality Traits In Triticale

Object: Triticale is a new type of high-quality forage for the development of animal husbandry.Breeding high-yield and high-quality new forage-type triticale varieties are the main goals of its breeding.Mining the genes related to the yield and quality traits of triticale forage grass can provide a basis for the subsequent genetic improvement of triticale forage grass yield and quality traits.Methods: This study used 300 hexaploid triticale germplasm resources from many countries around the world as a natural population,and systematically investigated the fresh forage weight per plant,dry forage weight per plant,crude protein content,neutral detergent fiber content,acidity detergent fiber content,and relative feed value.Combined with simplified genome sequencing,we carried out a genome-wide association analysis of hexaploidy triticale forage yield and quality traits,revealed the genetic diversity of hexaploidy triticale germplasm resources,mined SNP loci,and candidate genes related to forage yield and quality traits.Results:1.The 300 copies of hexaploid triticale originated from 6 continents and 20 major producing countries of triticale,and its sources were extensive;the genetic diversity was rich,and its forage yield and quality traits had extensive genetic variation and diversity among varieties.The coefficient of variation ranged from 5.01%to 24.31%,the coefficient of variation of fresh forage weight per plant was the largest,and the content of neutral detergent fiber was the smallest;the fresh hay yield and content of neutral detergent fiber of winter triticale were higher than those of spring black.However,the crude protein content and relative feed value of spring triticale were higher than those of winter triticale.The difference in value was very significant.H390,B 4081,Nutri Seeds I-18,Eronga 83,Beetle,etc.20 had higher comprehensive evaluation D values and the best comprehensive performance.2.The results of genome-wide association analysis showed that at the P < 0.00001 level,a total of 382 SNP loci associated with forage yield and quality traits were detected.Among them,the loci significantly correlated with fresh forage weight per plant,dry forage weight per plant,crude protein,neutral detergent fiber,acid detergent fiber,and relative forage value was 74(in chr1 A,chr1B,chr2 A,chr3A,chr3 B,chr4A,chr5 A,chr6B,chr7 A,chr1R,chr2 R,chr3R,chr5 R,chr6R,and chr7R),41(in chr3 A,chr3B,chr5 A,chr7A,chr1 R,chr2R,chr3 R,chr4R,chr6 R,and chr7R),40(in chr5 A,chr1R,chr3 R,chr4R,and chr5R),12(chr2A,chr3 B,chr3R,and chr5R),274(in chr1 A,chr1R,and chr3R),and 30(in chr1 A,chr3R,and chr5R),respectively.81 pleiotropic SNPs were detected,32 SNPs were significantly associated with fresh forage weight per plant and dry forage weight per plant,19 SNPs were significantly associated with crude protein content and acid detergent fiber content,and 21 SNPs were significantly associated with acid detergent fiber content and relative feed value,2 SNPs were significantly associated with neutral detergent fiber content and relative feed value,6 SNPs were significantly associated with neutral detergent fiber content,acid detergent fiber content,and relative feed value,and crude protein content,neutral detergent there was 1 SNP significantly associated with fiber content,acid detergent fiber content and relative feeding value.49 candidate genes were screened,and the candidate genes related to fresh forage weight per plant,dry forage weight per plant,crude protein,neutral detergent fiber,acid detergent fiber and relative forage value wwas22,16,7,3,11 and 6.Among them,there were 16 pleiotropic genes,there were 10 genes related to fresh forage weight per plant and dry forage weight per plant,3 genes related to neutral detergent fiber content and relative feed value,and 3 genes related to acid detergent fiber content and relative feed value.TRITD3Av1G019730 and TRITD3Bv1G151350 genes are candidate genes for fresh forage weight per plant and dry forage weight per plant,TRITD5Av1G170840 gene is a candidate gene for crude protein content,Sc WN5R01G661100.1gene is a candidate gene for neutral detergent fiber content and relative feed value,Sc WN3R01G253300.Gene 1 is a candidate gene for acid detergent fiber content and relative feeding value.Conclusion: In this study,excellent resources for the traits related to yield and quality of triticale forage grass were screened out.The significant association loci of forage yield and quality traits of triticale identified by genome-wide association analysis can lay a foundation for the gene mining of forage yield and quality traits of triticale and the cultivation of new varieties of triticale in the future.