QTL Mapping And Genetic Analysis For Mite Resistance And Major Agronomic Traits Based On Crossing And Reciprocal Crossing F₂ Populations

Identifying the genetic effects of major agronomic traits in maize and combining with molecular marker-assisted selection techniques have important reference value for improving the yield traits,improving the quality of maize,excavating existing genetic resources and breeding new maize varieties.Through QTL mapping,we initially mapped the traits related to corn mites and analyzed their genetic effects,developed closely linked molecular markers,and explored the key chromosome segments containing the major anti-mite QTLs with high contribution rates Molecular Mechanism and Promotion of Development of Anti-mite Molecular Breeding.In this study,maize inbred lines BSSS53-B and Mo17-476 with obvious difference in traits were used to construct 186 positive and negative F2 populations.A total of 186 pairs of SSR primers were used to amplify the cross between the groups Thirteen traits of anti-mite,plant and ear were collected from the population and the breed of reciprocal cross combination to construct the genetic map.A total of 99 QTLs were detected in the F2 population,of which 38 QTLs were detected in the Orthogonal population,belonging to 11 traits and 1 to 8 loci per trait respectively;41 QTLs and 13 There were 1 to 6 loci detected in each trait,and 20 QTL loci were detected in the reciprocal crossed hybrids,belonging to 10 traits,with 1 to 6 loci detected in each trait.A total of 36 QTLs with a contribution rate of more than 10 were detected.Among them,QTLs with high contribution rates were detected in plant traits and ear traits,and 12 QTLs with a contribution rate of more than 5 were also detected in spider mite traits.For example,qZmEH1-1,qZmEH1-2,qZmEH1-3,qZmEH3-1,qZmEH3-3,qZmEH5-1,qZmEH8-1,qZmEH9-1 are explained on chromosomes with different distributions.Explanations of traits The phenotypic variation rates were 14.49%,21.51%,26.69%,10.53%,13.97%,10.21%,11.83%and 11.75%,respectively.The genetic distance of their positions was 10cM,9cM,9cM and 18cM,17 cM,9.5 cM,5 cM,9.5 cM.These results will provide foundations for precise mapping of the major QTLs exploited in present study,and the improvement of important traits by MAS through developing molecular markers specific to mite-reisistant and major agronomic traits.