| Spider mites are one of the main pests that affect maize yield.Maize spider mites have the characteristics of difficult control,strong outbreak,and serious damage.Spider mites generally reduces maize yield by 10-50%,and even more than 70%.So far,most of the solutions to the spider mite problem have been focused on prevention and control.But the researches on the genetic breeding of corn resistance to mites,such as the positioning of anti-mite QTL and the discovery of anti-mite genes,are very limited.In this study,the highly resistant inbred line BSSS53-B and the highly sensitive mite inbred line Mo 17-476 were used as parents to generate F1 generation through orthogonal and reverse crosses.The F5 and F6 populations of the cross line were used as materials,and the genetic linkage map was constructed using polymorphic SSR molecular markers,and the QTL of corn anti-mite resistance was located in combination with the complete interval mapping method to discover the main anti-mite QTL.The results are as follows:1.The total length of the genetic linkage map and the average interval of molecular markers of the two generations including six populations are:the total length of F5 orthogonal population is 2211.21cM,and the average marker interval is 14.64cM.The total length of the F5 reciprocal population is 2241.92cM,and the average marker interval is 15.43cM.The total length of the F5 forward and reverse cross mixed population is 2472.48cM,and the average marker interval is 15.55cM.The total length of the F6 orthogonal population is 2704.64cM,and the average marker interval is 19.32cM.The total length of the F6 reciprocal population is 2813.02 cM,and the average marker interval is 19.14 cM.The total length of the mixed population of F6 forward and reverse crosses is 2905.57cM,and the average marker interval is 19.24cM.2.The total 33 QTLs from different groups in different generations whose LOD value is more than or equal to 3.0 and the contribution rate is more than 10%,are distributed in 15 positioning intervals of 9 chromosomes except chromosome 6.The LOD value is 3.0～13.5,the contribution rate is 10.2%～33.0%,and the marker interval is 4.0～27.0cM.3.Within the umc1506F-bnlg2190 marker interval of chromosome 10,there is a group of common QTLs whose LOD is more than or equal to 3.0 and a contribution rate greater than 10%.The QTL from the F5 orthogonal population is named qZmSWR8-5,and the LOD value is 3.4,the contribution rate is 12.6%,and the mark spacing is 21.0cM.The QTL from the F5 reciprocal group,named qZmDMR13-2,has a LOD value of 3.5,a contribution rate of 13.9%,and a mark spacing of 14.0 cM.4.SWR,DMR,SWRa3,SWRa5,DMRa3,DMRa5,SPDI3,and SPDI5 related to maize anti-mite QTL have a total of 8 traits that are skewed.Based on this,QTLs with LOD values and PVEs greater than 10 are located,which means Maize anti-mite traits may be controlled by major genes.5.Two QTLs with a LOD and a contribution rate greater than 10 were located on chromosomel and in the same positioning interval umc1703F-umc1972F with the same marker intervals:4.0cM.They are named qZmDMR9-1 and qZmSPDI514-1.The LOD value of qZmDMR9-1 is 13.1 and the contribution rate is 33.0%.The LOD value of qZmSPDI514-1 is 13.5 and the contribution rate is 17.9%. |
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