Mapping Quantitative Trait Loci Underlying Agronomic Traits In Maize With An SNP Marker Linkage Map

Maize is one of the most important food crops in China. It plays a vital role in agricultural economy of China. Agronomic traits have significant influence on stability and adaptability in maize production. So understanding the genetic basis of these traits highlights the theoretical value and practical significance in maize. A linkage map was constructed by SNP markers using one F2 family derived from DH1M×T877 respectively. QTL analysis was carried out to determine the relationship between marker genotype and the traits evaluated. The major research results were as follows:1. Analysis of the phenotype date, we found these 12 agronomic traits were in accordance with normal distribution in the population. Many traits showed strong correlation or moderate correlation, including plant height, ear height, tassel branch number, tassel length and stem diameter,2. This map included 1174 polymorphic SNP markers respectively, covering 10 chromosomes of total maize and its total length was 1294.6cM respectively with an average interval of 1.1 cM. The number of makers on each chromosome was 150,85,93,178,155,106, 107,125,99,76 with average interval length between markers on each chromosome 1.22cM, 1.64cM,1.61cM, 0.70cM,0.96cM,1.01cM,1.21cM,0.92cM and 1.08cM and 1.20cM respectively.3. The phenotypic data of plant characters of the population was used to detect QTLs by using the Composite Interval Mapping (CIM) and Interval Mapping (IM) of WinQTLCart2.5. In total,25 QTLs were identified using the CIM on chromosomes 1,2,3,4,5,7,8,9 and 10, ranging from 5.28% to 14.30% of the total phenotypic variation.16 QTLs were identified using the IM on chromosomes 1,2,3,5,7,8,9 and 10, ranging from 5.91% to 13.01% of the total phenotypic variation.The number of QTLs associated with plant height was 2 on chromosome 8,10. These QTLs accounted for 6.11-7.17% of the phenotype variations. The number of QTLs associated with ear height was 3 on chromosome 1,3,9. These QTLs accounted for 6.65-8.57% of the phenotype variations. The number of QTLs associated with tassel branch number was 2 all on chromosome 2. These QTLs accounted for 6.59～14.30% of the phenotype variations. The number of QTLs associated with tassel length was 2 all on chromosome 1. These QTLs accounted for 6.32～13.22% of the phenotype variations. The number of QTLs associated with stem diameter was 2 on chromosome 1,5. These QTLs accounted for 5.47～9.25% of the phenotype variations. The number of QTLs associated with leaf angle (t) was 3 on chromosome 2,7. These QTLs accounted for 6.62～8.87% of the phenotype variations. The number of QTLs associated with leaf angle (m) was 3 on chromosome 3,8. These QTLs accounted for 5.72～7.11% of the phenotype variations. The number of QTLs associated with leaf angle (b) was 1 on chromosome 7. This QTL accounted for 9.57% of the phenotype variations. The number of QTLs associated with leaf area (t) was 3 on chromosome 1,2. These QTLs accounted for 6.30～6.86% of the phenotype variations. The number of QTLs associated with leaf area (m) was 6 on chromosome 3,8,9. These QTLs accounted for 5.41～6.52% of the phenotype variations. The number of QTLs associated with leaf area (b) was 1 on chromosome 10. This QTL accounted for 12.12% of the phenotype variations. The number of QTLs associated with brace root number was 5 on chromosome 3,4,8,10. These QTLs accounted for 5.28～11.25% of the phenotype variations.