| Based on the F2 population with 120 plants derived from interspecific cross of N10×Daqingjie [Setaria viridis Beauv.×Setaria italica Beauv.], a SSR linkage map of foxtail millet was constructed, which was made up of 10 linkage groups, including 46 markers, covering 916cM in total with an average interval of 19.91cM between the adjacent loci. As for the different linkage groups, the length ranged from 22.6cM to 179.7cM with an average length of 91.6cM, and the number of markers contained in each linkage group varied from 2 to 9.Composite interval mapping method of Windows QTL Cartographer V2.5 was used in QTL analysis of five agronomically important traits of foxtail millet. A total of twelve QTLs was detected with LOD≥2.0.Three QTLs affecting plant height were detected on three different linkage groups and contribute 27% to the tatol phenotypic variation. One is located between GTDZ8-82-2 and FM01.1-2-2 on LG3 and contributes 10% to phenotypic variance. It is 11.9cM away from FM01.1-2-2. Its additive effect is -5.04 and dominat effect is 8.52. The second is located between AGDZ2-17-2 and TG400-2 on LG3 and is 13.9cM away from AGDZ2-17-2 with the additive effect being -5.53 and the dominant effect being 6.11, accounting for 13% of phenotypic variance. The third is located in ACXV1-41-1～TG507-2 interval on LG4 and is 9.2cM from ACXV1-41-1. It can explain 4% of phenotypic variance and the additive effect is -3.39 with the dominant effect being -7.10.Two QTLs for panicle neck length are detected locating on LG3 and LG4 respectivly, with 21% contribution to phenotypic variance. The first one located between AGDZ2-17-2 and TG400-2 on LG3 and is 13cM away from AGDZ2-17-2, this locus explains 20% of phenotype effect with additive effect being -3.77 and dominant effect being 3.54. The other is located between ACXV1-41-1and TG507-2 on LG4 and is 8cM away from ACXV1-41-1.There are two QTLs found contributed to 9% of their tatol variation of stem node number, which located between AGDZ2-17-2 and TG400-2 on LG3 and between ACXV1-41-1 and TG507-2 on LG4 respectivaely. The first one on LG3 is 14.6cM away from AGDZ2-17-2 and contributes 4% to the tatol phenotype variance, with its additive effect being -0.25 and dominant effect being 0.35. The other is 5.5cM away from ACXV1-41-1 and the phenotype variance explained by this QTL is 5%, with its additive effect of -0.29 and the dominant effect of -0.46.Three QTLs were found to be responsible for panicle length with the contribution to phenotypic variance being 12%. Located between AC209-1-1 and CTDZ3-24 on LG1, the first QTL locus is 7.7cM away from CTDZ3-24 and its additive effect is -0.23 and dominant effect is -0.7, contributing 1% to panicle length phenotype variance. The second is located between AGDZ1-36-4-2 and TG518-1 on LG3 and contributes 11% to the phenotype variance. The additive effect of this locus is -0.95 and the dominant effect is 0.29. The third is located in TG518-1～P24 interval on LG3 and is 4.2cM from TG518-1. It can explain 10% of phenotypic variance and the additive effect is -0.95 with the dominant effect being 0.24.Two QTLs were found to be responsible for seed shattering, with total contribution to phenotypic variance being 31%. Located in AGDZ23-35 and GTDZ7-74 interval on LG2, the second QTL is 19.5cM away from AGDZ23-35 and contributes 25% to phenotypic variance. Its additive effect is -1.78 and dominant effect is -1.30. The second one is located in GDZ22-59 and FM2.1-1 interval on LG8 and is 18.1cM away from AGDZ22-59. The contribution of this locus to phenotypic variance is 7%, with its additive effect being 1.74 and dominant effect being -0.74.Moreover, we found that QTLs affecting plant height, panicle neck length and the number of stem node number are located on the same positions and this is consistent with the result of correlation among those three morphological traits.The genetic map, which is constructed based on a F2 population in this study, is the first SSR linkage map of foxtail millet, which provides a framework for the advance of gene mapping, map-based gene cloing and molecular-assisted selection of this crop. The QTLs detected contrituting to five important traits of foxtail millet in this research will accelerate functional genomic study of this crop.
|
PDF Full Text Request