Genome-wide Association Study On Starch Content And Composition In Chinese Wheat Landraces

We reported the test of starch contents and compositions of 468 Chinese wheat grown in five different environments from ten zones of China,and further conduct genome-wide association analysis of starch contents based on Wheat660 SNP and Wheat55 SNP markers.The main results are shown as below:The results showed that the average value of total starch content of 272 Chinese wheat landraces was 56.45% in five environments ranged from 37.86% to 70.02%.And the average apparent amylose content of 272 Chinese wheat landraces was 12.50% ranged from 7.19% to 18.49%.The average total starch content of 196 Sichuan wheat accessions was 57.35% in Chongzhou in 2017 ranged from 53.20% to 62.88%,and the average apparent amylose content of 196 Sichuan wheat was 12.99% ranged from 9.16% to 16.41%.Using the genotypic data of the Wheat660 chip,a genome-wide association analysis of starch content was performed on 272 Chinese wheat varieties.All the 29 SNP markers associated with total starch content were detected in at least two environments,locating within nine novel QTL segments,distributed on chromosomes 5A,6A,7A,1B,3B,6B and 5D.The phenotypic variation contribution rate(R2)ranged from 7.7% to 11.4%.A total of ten SNP markers associated with apparent amylose content were detected in at least two environments,locating within three novel QTL segments,distributed on chromosomes 2D,3B and 1A.The phenotypic variation contribution rate(R2)ranged from 8.3% to 12.2%.Using the genotypic data obtained from the Wheat55 chip,a genome-wide association analysis of starch content was performed on 169 Sichuan wheat varieties.A total of 33 SNP markers associated with total starch content were detected in Chongzhou in 2017,14 novel QTL segments,distributed on chromosomes 1A,5A,7A,4B,5B,7B,and 5D.The phenotypic variation contribution rate(R2)ranged from 6.0% to 10.2%.A total of 16 SNP markers in nine novel QTL segments associated with apparent amylose content were detected in Chongzhou in 2017 and distributed on chromosomes 1A,3A,1B,4B,7B,1D,3Dand 5D.The phenotypic variation contribution rate(R2)ranged from 5.9% to 8.7%.there are no common QTL segments detected between the different GWAS,because the genetic background of two wheat varieties and the marker density of two gene chips are different.By analyzing the variance of QTL haplotypes,ten favorable haplotypes and 13 unfavorble haplotypes were detected.