QTL Analysis Of Resistance To Head Smut Caused By Sphacetotheca Reiliana(Kühn) Clint In Waxy Maize

By head smut hazards of conventional corn and waxy maize production have suffered huge losses. One of the most effective way to solve the problem is the breeding of resistance to maize head smut corn varieties for popularization and application. Using molecular markers to study the technology of corn head smut resistance gene can greatly improve the efficiency of disease resistance breeding. In this study,we use high head smut infection of waxy maize male parent inbred lines of Jinuo B4 and resistance to head smut female parent inbred lines Jinuo 2325 as test material, and the waxy maize leaf DNA extraction method and waxy maize SSR- PCR reaction system was optimized, that for waxy maize molecular breeding experiment laid theoretical basis. Then using F2 mapping population and F2:3 resistance evaluation population, and the composite interval mapping method is adopted for QTL preliminary localization of waxy maize resistance to head smut, which provides the theoretical foundation For waxy maize head smut resistance gene mapping and marker-assisted selection breeding and related research. The results of the study are as follows:(1) SSR-PCR( Simple Sequence Repeat- Simple Sequence Repeat) system of the method of orthogonal design with 5 levels of 6 factors was used to establish the optimal reaction amplification systems and procedures. In a total volume of 20μL SSR-PCR system, it contains template 1.5U DNA polymerase, 1.0nmol/μL Mg2+, 80 ng DNA template, 0.1pmol/μL primers, 0.15μLmol/μL d NTPs, and 1×PCR buffer. Each reaction component of waxy maize SSR- PCR amplification reaction influence size order for d NTPs> primers> Mg2+> DNA polymerase> DNA template.(2) With the optimal experimental system and use the F2 mapping population with 199 individuals which was derived from the cross of two elite inbreds( Jinuo 2325 ×Jinuo B4), building a genetic linkage map containing 83 SSR marker.Detected in changchun, jilin province, a total of seven QTl loci at 1, 2, 3, 4, 8 and 9 chromosome; Three QTL loci were detected in dandong, liaoning province, which located on chromosomes 1, 2, 4. Pooled analysis based on the two environments was condueted, a total of 4 QTL loci detected and located on chromosomes 1, 2, 4, 8. three QTL loci located at 1, 2, 4,on chromosome has been repeated detected,which proves that waxy maize head smut resistance genes have consistency. the second chromosome markers for QTL loci bnlg1520 contribution rate reached the highest in both sites,were 15.4% and 18.1% respectively. Their acting showed dominant and additive effect respectively.