QTL Mapping And Epistasis Assay Of Yield-related Traits Using Z3HBILs Of Maize (zea Mays L.)

Yield-related traits are typical quantitative traits, are dominated by a set of minoradditive quantitative traits loci (QTL) with board genetic or environmental interactions.Z3HBILs was a set of chromosome segment substitute lines, which were developedusing Zong3as receptor and HB522as the donor. Z3HBILs was permanent mappingpopulation used to detected QTL for yield-related traits and epistasis interaction. Sixyield-related traits including ear length (EL), ear diametra (ED), kernels per row (KPR),100-kernel weight (KW), ear grain weight (GW) and grain rate (GR) were phenotypied attwo locations across3years under four environments. Genotypes were screened bygenome-wide SSR markers. QTL was identified using the modified composite intervalmapping. Moreover, to validate epistasis, a new two-locus segregation population wasdeveloped by pairwise crossing among chromosome segment substitute lines. The mainlyresults of this study are as follow:1. QTL for yield-related traits were detected on ten chromosomes of maize. Total of84QTL for yield-related traits were identified in4environments. Of which,26QTL werenot noticed in other studied.11QTL,16QTL,14QTL,21QTL,10QTL and12QTL weredetected for ear length (EL), ear diameter (ED), kernel number per row (KPR), ear weight(EW) and grain rate (GR), respectively. Total of24major-effects QTL were identified for6yield-related traits defined as the phenotype donation is above10%, of which4QTL forEL,3QTL for ED,2QTL for KPR,5QTL for KW,6QTL for GW and4QTL for GR.2. Eight stable QTL for6yield-related traits were detected, which were qEL1-2,qED1-2, qKPR3-1, qKW4-2, qKW1-2, qKW6-1; Among them qGW2-1, qGR4-1, qEL3-1,qKPR3-1, qKPR3-2, qGW2-1, qGR3-2and qGR6-1were not reported previously.3. Yield-related traits of maize was controled by lest major-effects QTL and lots ofmicro-effects QTL. Additive effects, dominance effects, and over-dominance effects ofthese QTL played important role on yield-related traits of maize.4. Three hundred and thirty pairs of QTL interactions locating10chromosomes forsix yield related traits were detected.60pairs,65pairs,44pairs,81pairs,35pairs and45pairs of QTL interactions for EL, ED, KPR, KW, GW and GR were detected, respectively.A total of23pairs significant QTL interactions were detected, including5pairs major-effects QTL interactions. The interactions among major-effects QTL, micro-effectsQTL and other chromosome fragments effected yield related traits totally.5. QTL interactions is real. In field study,6interaction groups were built using4significant QTL each other in according GriffingⅡdiallel cross. The study indicated thatthe QTL interactions between qKW1-2and qKW1-3, qKW1-2and qKW6-1, qKW1-2andqKW9-2and qKW6-1and qKW9-2were real. The interaction patterns were dominance×dominance, dominance×additive and additive×additive. The study also indicated thatit was real that qKW1-3and qKW6-1has no interaction detected by ICIM. The interactionbetween qKW1-3×qKW9-2was not real.