Screening Of SSR Markers And QTL Mapping Of Resistant Gene To Northern Corn Leaf Blight

Northern corn leaf blight is oneof the most popular disease in the world,which is an important cause of maize yield reduction.The resistant genes of northern corn leaf blight based on major and pleiotropic genes,which is very sensitive to the influence of natural environment and artificial selection.However,the monotonicity in the genetic background of modern maize varieties and the homogenization of the maizebreeding pattern,has promoted the formation ofdominant physiological race of Setosphaeria turcicapathogen,and accelerated the reduction of resistant genes of northern corn leaf blight in maize varieties.At the same time,the traditionalresearch on the resistance tonorthern corn leaf blight was limited to the conventional progressfor genes selection and breeding of maize materials,but the researches on the resistant genes of northern corn leaf blight through molecular marker technology is the development direction.Therefore,it is of great significance to study the quantitative trait location with resistant genesof northern corn leaf blight.In the current study,we constructed a F2 segregation populationand a F2:3 families segregation population including 248 members based on the susceptible parent AM293 and the resistant parentLV958.Based on the artificial inoculation of the corn leaf residue which is infected with Setosphaeria turcicapathogen,and construction of the genetic linkage map of segregating population by capillary electrophoresis with SSR molecular markers,we located the quantitative trait locus with resistant genes of northern corn leaf blight by combining the phenotypic traits of northern corn leaf blight in the field and genotype data using Inclusive composite interval mapping.The main results are as follows:1.We built a F2 mapping population with resistant genes of northern corn leaf blight which contains 248 members,and a F2:3 families population with resistant genes of northern leaf blight which contains 248 inbred lines.That laid a foundation for the establishment on the population of recombinant inbred lines about the resistant genes of northern corn leaf blight.2.There were 8 pairs of SSR primers which were closely linked to the resistant genes of northern corn leaf blight had been screened from 387 primers.We screened 2 pairs of SSR primers which were closely linked to the resistant genes of northern corn leaf blight on the first chromosome,respectively named bnlg439,bnlg2331;We screened 2 pairs of SSR primers which were closely linked to the resistant genes of northern corn leaf blight on the second chromosome,respectively named blng1335,bnlg1138;We screened3 pairs of SSR primers which were closely linked to the resistant genes of northern corn leaf blight on the eighth chromosome,respectively named bnlg2235,bnlg1812,umc2199;We screened1 pair of SSR primers which were closely linked to the resistant genes of northern corn leaf blight on the tenth chromosome named umc2163.3.There were 4 quantitative trait locus related with resistant genes of northern corn leaf blight were detected by conjoint analysis on both phenotypic data and genotype data through 2 years' performance.We located 3 quantitative trait locus related with resistant genes of northern corn leaf blight in the year 2015,qRnclb-1-1 were located in the first linkage group,which was between bin=1.03 and bin=1.11,with a LOD value of 4.13,with an additive effect of-15.08% and could explain the phenotypic variance 42.37%;qRNCLB-2-1 was located in the second linkage group,which was between bin=2.06 and bin=2.07,with a LOD value 3.94,with an additive effect of-8.96% and could explain the phenotypic variance of 6.49%;qRNCLB-8-1 is located in the eighth linkage groups,which was between bin=8.02 and bin=8.05,with a LOD value of 9.03,with a additive effect of-10.35%,and could explain the phenotypic variance 19.06%.We located 2 quantitative trait locus and a pair of SSR primers related with resistant genes of northern corn leaf blight in the year 2016,qRnclb-1-1 were located repeatedly in the first linkage group,which was between bin=1.03 and bin=1.11,with a LOD value of 7.27,with an additive effect of-12.57% and could explain the phenotypic variance 29.45%;qRNCLB-8-2 were located repeatedly in the eighth linkage group,which was in bin=8.05,with a LOD value of 4.87,with an additive effect of-7.38% and could explain the phenotypic variance 8.67%.