Construction Of A Set Of SSSLs In Maize And QTL Mapping On The Plant-type And Flowering Related Traits

Chromosome single-segment substitution lines(SSSLs)are powerful tools for detecting and precisely mapping quantitative trait loci(QTLs)and evaluating the action of genes as single Mendelian factors.In our study,A set of chromosome single-segment substitution lines derived from two sequenced elite maize inbred lines was constructed used MAS.Each SSSL contained a single substituted chromosome segment that was derived from donor strain Zong 3 in the genetic background of the recipient Xu178 strain.Based on those SSSLs,one hundred and five SSSLs,which covered 47.85% of the entire maize genome,were used to identify the QTLs of maize plant type and flowering related traitor in two environments.The main results are as follows:1.239 SSSLs,which included 158 uniquely substituted segments,were developed from an advanced backcross procedure with the marker-assisted selection using the elite maize inbred line Xu178 as the recipient and Zong 3 as the donor.The 158 substituted segments were unevenly distributed on ten maize chromosomes,and the substituted segment length ranged from 0.95 centimorgan(c M)to 186.05 c M with an average of 47.67 c M.The total length of the 158 substitution segments was 11,394.22 c M,which covered 4,481.74 c M(67.56%)of the entire maize genome.2.Through the phenotypic characterization of maize plant type and flowering related traitor in two environments,a total of 196 QTLs were identified,including 32,20,21,26,17,12,21,14,16,17 QTLs for plant height,ear height,ear height/ plant height,leaf number,leaf number above ear,leaf number above ear / leaf number,leaf area,49 QTLs(25.00%)were detected in different environments.The major QTL of maize plant type and flowering related traitor with the same gene effect directions which detected in at two environments,were qPH-1-2,qPH-1-3,qPH-2-4,qPH-5-2,qPH-9-2,qEH-2-3,qEH-2-4,qEH-3-2,qEH-5-2,qEH-9-1,qEH/PH-2-4,qEH/PH-2-5,qEH/PH-3-1,qEH/PH-3-4,qLN-1-4,qLN-2-4,qLANE-1-1,qLANE-2-1,qLANE/LN-2-3,qLANE/LN-2-4,qLANE/LN-5-1,qLA-2-3,qLA-4-1,qDPOLL-2-2,qDSILK-2-1,qDSILK-2-3,qDASI-2-3,qDASI-4-1,qDASI-4-3 and qDASI-6-1,respectly.3.QTLs detected for plant-type and flowering related traits in this study tended to be clustered together.For example,QTL related to plant height,ear height,ear height/ plant height,leaf number above ear,leaf number above ear / leaf number,leaf area,anthesis,silking,ASI all can bedetected in the same region at bin2.04-2.06,bin5.05,bin9.04 suggest different QTLs may clustered together and this region might be a hot plot for plant type and flowering related traitor.These QTLs which were in the same marker interval of the same chromosome and related to different traits of plant type or flowering can greatly improve the efficiency of MAS as we could select one but in favour of multi-effect.These chromosomal regions will be focused in the further studies.