| Foxtail Millet is a gramineae plant whose seeds are called millet after being husked.It is found in northern China.In this study,435 germplasm resources of foxtail millet were used as experimental materials,which were planted in three ecological zones of north,middle and south of Shanxi province.The bristle length,tiller number,thousand seed weight and folic acid content in foxtail millet grains were investigated.By means of normal distribution,general descriptive statistics,correlation,regression,principal component analysis and GGE analysis,the variation characteristics of the three main agronomic traits and folic acid content were analyzed.Genome-wide association analysis was conducted in combination with population genotypes to predict and screen out SNPs significantly associated with each trait and folic acid content,and further select candidate genes associated with these traits in foxtail millet.The main research results are as follows:1.Normal distribution analysis was conducted on the bristle length,tiller number and thousand seed weight of 435 foxtail millet germplasm resources from six ecological sites in three localities in 2019-2020,and it was found that the thousand seed weight traits in Datong ecological area,Jinzhong ecological area and Jincheng ecological area in 2020 presented normal distribution law.Correlation analysis showed that 6 traits were significantly correlated with each other.According to the principal component analysis,three principal components were obtained from Datong,Jinzhong and Jincheng ecological areas,and the cumulative interpretation rate of principal components was 0.835.A total of 18 characters were divided into four categories according to their similarity in the three ecological areas.2.Folic acid content in grains of 435 millet germplasm resources from different ecological regions and analysis showed that folic acid content in grains of Datong ecological region and Jinzhong ecological region presented normal distribution law in 2019 and 2020.Correlation analysis showed that 6 traits were significantly correlated with each other.Principal component analysis showed that two principal components were obtained,and the cumulative interpretation rate of principal components was 0.792.GGE analysis showed that folic acid content of B400,B13 and B217 had a better performance in all ecological regions.3,GWAS analysis results showed that 117 QTL were detected,15176 SNPS,are distributed in all 9 chromosomes,in the section of the genomes of SNP sites near 50 kb find 1111 candidate genes related to the length of the bristles,360 candidate genes associated with tiller number,610 candidate genes associated with grain,224 candidate genes associated with folic acid content.The expression pattern analysis of candidate genes showed that gene Si9g52810 had the highest expression level in ear,and the expression level showed a decreasing state from S1 to S5,which was consistent with the decreasing trend of folic acid content in ear tissue of foxtail millet.Si9g52810 is a member of the folate transporter MRP family,named as SIMRP21.Further analysis of the sequence characteristics,molecular evolution and expression pattern of this family suggested that SIMRP21 may be involved in folate accumulation and transport in millet grains.To sum up,this study analyses the variation characteristics of foxtail millet agronomic characters,found B40,B400,B13 advantage varieties,obtained with foxtail millet bristles length,tiller number and thousand seed weight and folic acid content in the relevant candidate genes,foxtail millet and foxtail millet folic acid metabolism gene mining for follow-up study provides a theoretical basis. |
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