| Maize (Zea mays) is one of the important food crop in china, CornCurvalaria Leaf Spot is a new leaf disease in Northern China in recent years, the diseasemainly damaged leaf, sometimes it can also infect the leaf sheath and bracts, the leaves arefull of disease spots when the disease become serious and the production of corn decreasedseriously. It have occurred in Henan, Hebei, Liaoning province and so on. Now, the diseaseis becoming more serious and have threatened to safety in production. Scholars at homeand abroad have conducted some researches in the incidence regularity, control method,resistance identification, the pathogen biologic characteristic and so on, but there are lessreports on genetics of resistance. So it is of practical guiding significance to construct themaize genetic linkage map, map QTLs for Corn Curvalaria Leaf Spot. This study was aimed to analyze the resistant genetic mechanism for seedling stageand adult-plant stage using the major gene plus polygene mixed genetic model, Theexperiment was conducted using four generations (P1、P2、F1、F2) from a cross of Qi319(resistance)×Chang7-2(susceptible). The genetic linkage map constructed using SSRmarkers and F2generation, QTL (quantitative trait loci) mapping analysis about theresistance of Corn Curvalaria Leaf Spot was performed by QTL Icimapping v3.2whichbased an inclusive composite internal mapping. The detailed results were available asfollows:（1）Based on genetics analysis of the four generations, the results showed that theresistance of Qi319to Corn Curvalaria Leaf Spot appeared to be quantitative inheritance.The resistance of seedling stage and adult-plant stage were controlled by two major genes.the resistant heredity of seedling stage was fit two pair of additive-dominance major gene+additive-dominance polygene model; the resistant heredity of adult-plant stage was fit twopair of additive major gene+additive-dominance polygene model.（2）Both additive and dominant genetic effects controlled the resistance of seedlingstage, Furthermore, the two major genes of resistant of seedling stage displayed negativepartial dominance. While dominant genetic effects was absent among the resistance ofadult-plant stage. The heritability of major gene of seedling stage and adult-plant stage was65.14%and83.98%, respectively, The heritability of polygene of seedling stage andadult-plant stage was13.44%and13.21%, respectively.（3）To construct the maize genetic linkage map and map QTLs for Corn CurvalariaLeaf Spot using QTL Icimapping v3.2.31SSR markers were mapped on3linkage groupsusing the MAP in QTL IciMapping v3.2and the average number of SSR makers per everylinkage group ranged from9to12. The linkage genetic map was covered548.30cM and theaverage interval between two SSR markers was17.69cM on the linkage map. Then scaningF2generation using the BIP in QTL IciMapping v3.2,One QTL was identified onchromosome7th for controlling the resistance of Corn Curvalaria Leaf Spot. This QTL waslocated between SSR marker umc1134and phi116and regulated by major gene, it couldexplain phenotypic variation44.19%. The Additive effect value is0.0227and the dominanteffect value is3.2558. |
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