Genome-wide Association Analysis Of Seed-related Traits In Flax

Research on seed characters and oil content of flax flax is of great significance for flax flax breeding.In this study,the 1000-grain weight,seed length,seed width,ratio of seed length to width,seed area and oil content of 269 flax flax germplasm were tested repeatedly in the northeast suburb of Hohhot,southwest suburb of Hohhot and Jining,and the genetic variation of seed related traits was revealed by statistical analysis.The phenotypic data of SNP genotypes and seed-related traits obtained by our research group were used for association analysis,and SNP loci and candidate genes significantly associated with target traits were mined,providing scientific basis for genetic improvement of flax flax.1.The statistical analysis results of seed traits and oil content of 1.269 flax germplasm showed that the coefficient of variation of seed traits ranged from 2.78% to13.91%,among which the coefficient of variation of 1000-grain weight was the largest(13.91%),and the coefficient of variation of seed length-width ratio was the smallest(2.78%).The phenotypes of seed characters and oil content were different in the three environments.The average 1000-grain weight(5.97±0.85g),seed area(6.69±0.70mm2),ratio of seed length to width(1.91±0.05),seed length(4.21±0.22mm),seed width(2.22±0.12mm),and seed oil content(38.51%±0.02)in the southwest suburb of Hohhot The mean value of seed circumference(10.60±0.54mm)in the northeastern suburbs of Hohhot was the largest.The generalized heritability range of flax seed characters was65.23%～78.35%.The total effects of seed circumference,seed length,seed width and oil content on 1000-grain weight(Y)were more than 89.15%.2.Genome-wide association analysis of seed traits and oil content showed that 30 SNP loci and 46 candidate genes were obtained for 6 seed traits and oil content of flax flax,including 4 SNP and 5 candidate genes for 1000-grain weight,7 SNP and 11 candidate genes for seed area,and 4 SNP and 7 candidate genes for seed circumference.There were 4 SNPS and 6 candidate genes in seed length,4 SNPS and 5 candidate genes in seed width,4 SNPS and 7 candidate genes in seed length-width ratio,3 SNPS and 5candidate genes in seed oil content.3.Two candidate genes related to seed oil content were verified by RT-q PCR.The results showed that LUSG00015572 gene had the highest expression level(0.3081)in the early seed development of flax with high oil content(France308 line).The expression level of flax flax with low oil content(Hungary247)was the highest at the late stage of seed development(0.1730).LUSG00024705 gene expression in the early,middle and late stages of seed development of flax flax with high oil content(France308strain)was significantly higher than that of flax flax with low oil content(Hungary247).