Molecular Mapping For Resistance To Bipolaria Maydis And Leaf Traits In Maize

As an important grain crop, corn is only subordinate to rice and wheat, and plays animportant role in grain productin. Southern Corn Leaf Blight （SCLB） which is causede byBipolaria maydis is a current prevalent disease in both abroad and domestic corn areas. Inrecent years, the disease is one of the three major diseases in our cron areas. It has beengradually increasing the thrend of serious and causing great decrease for maize production. Itwas confirmed that breeding resistant varieties to SCLB is a fundamental way to solve thisproblem. So far, absolutely resistant varieties are foud in production. Therefore, it isbecoming very important to do further studies on inheritance and the molecular markerslinking to Bipolaria maydis, and to breed highly resistant varieties to SCLB.In this study a small blotch resistance were significantly different in four ordinary maizeinbred lines as parents prepared a four cross hybrids to four cross-mapping population of F₂plant to build SSR marker linkage map, with the interval mapping method in the maize genomewas detected on corn leaf blight resistance QTL and leaf trait QTL. The main results are asfollows:1.map construction based on SSR markerIn this study, four Zhongkai University of Agriculture and Engineering, Institute of CropBreeding ordinary maize inbred PT01, PT02, PT03, PT04for the hybrid parent materials,preparation of four crosses （PT01/PT02//PT03/PT04）, won the228F₂plants of four-crossmapping population, for the first3leaves of maize number of lesions per unit area, the totalnumber of lesions, leaf length, leaf width and leaf area mOLECULAR MARKERS. With250pairs of SSR primers polymorphic between the parents. With Joinmap3.0software to meet therequirements of the97loci linkage analysis. Get one with97sites,10linkage groups, length1114.8cM, average distance between markers SSR markers11.49cM maize genetic linkagemap, and according to the maize genome sequence information of the10linkage groups weremapped to the corresponding chromosomes.2.QTL mapping for resisitance to Southern Corn Leaf BlightThe228four cross F1resistant trait data in conjunction with molecular marker linkagemap information, using interval mapping method in the maize genome was detected on maizeleaf spot disease small number of lesions per leaf area and the number of lesions QTL. Theresults were as follows:In the10detected on chromosome6number of lesions per unit area QTL, located in thefirst2,4,6,7maize chromosomes. Which, qSCLB1-2-1is located on chromosome2, the first additive effect of-1.93,3.09second additive effect on the phenotype of the contribution rate of8.9%. qSCLB1-4-1and qSCLB1-4-2is located on chromosome4, the first additive effect of-2.12,-1.88, second additive effect of2.64,3.32, phenotypic contribution rates were12.5%and14.3%. qSCLB1-6-1and qSCLB1-6-2located on chromosome6, the first additive effectswere2.72,-7.58, second additive effects were7.43,1.48, phenotypic contribution rates were36.2%and37.2%. qSCLB1-7-1is located on chromosome7, the first additive effect was3.87,and the second additive effect of2.47phenotypic contribution rate of53.7%.Number of lesions detected five QTL, located on chromosomes2,4,6in corn.qSCLB2-2-1and qSCLB2-2-2located on chromosome2, phenotypic contribution rate was11.1%and20.0%; first additive effect of-0.70,-0.94, second additive effect of0.35,0.23.qSCLB2-6-1and qSCLB2-6-2located on chromosome6, phenotypic contribution rates were28.0%and10.7%respectively; first additive effect was0.60,-0.90, second additive effect was1.26,-0.36. qSCLB2-4-1is located on chromosome4, phenotypic contribution rate of45.2%;first additive effect of-1.07, second additive effect was0.51.3.QTL mapping for leaf traitOn chromosome3,2leaf length QTL （qLL-3-1and qLL-3-2）. Phenotypic contributionrates were21.9%and33.8%in the first additive effect-0.13,0.18, second additive effect of0.47,0.12.A leaf width QTL was got, locating on chromosome2（qLW-2-1）, the contribution ofphenotypic8.4%, the first additive effect of-0.02, second additive effect of-0.05.On chromosome3and6,2leaf area QTL （qLA-3-1, qLA-6-1）, phenotypic contributionrate is7.6%and24.7%; first additive effect of0.26,-0.84, the second additive effect was0.51,-1.76.The results of this study are expected to maize breeding for disease resistance andmolecular marker-assisted selection to provide a theoretical reference.