| Sesame (Sesamum indicum L.) is a high-quality oil and specialized economic crop grownworldwide which has a long cultivated history. It’s low-yielding crop compared with other crops. Itremains the breeding goal to increase the yield per unit area and stress resistance of sesame. Plantheight is an important agronomic trait which serious affected the yield, anti-lodging ability anddensity in sesame, so it is necessary to conduct researches on inheritance and molecular biology toplant height related traits. Up to now, there is no there is no report about inheritance and mappingQTLs associated with plant height related traits.In this study, a multi-family generations (P1, F1, P2, B1, B2, and F2(Ⅰ)derived from a cross ofZhongzhi No.11（high-stalk,♀）×2289（dwarf,♂）, another multi-family generations (P1, F1, P2, B1,B2, and F2)(Ⅱ) derived from a cross of Zhongzhi No.11（high-stalk,♀）×2748（dwarf,♂）and anatural population with216accessions were used, and the mixed major-gene plus polygeneinheritance model and molecular marker technology were used to study the above aspects, includinggenetic analysis, association mapping, linkage groups constitution and QTL mapping. The mainresults were as follows:1. A mixed major gene plus polygene inheritance model was used to perform the genetic analysisof plant height and the main traits related to it with six generations derived from crossⅠ and cross Ⅱ.The joint segregation analysis results showed that: For plant height and stem height from base to firstcapsule, the best fitting genetic models were all polygenes model in two crosses; For top lengthwithout capsule, the best fitting genetic model was polygene model in cross Ⅰa ndone major geneplus polygenes in cross Ⅱ; Capsule zone length and number of capsule node pairs on main stem, thebest fitting genetic models were all polygene model in cross Ⅰ and were all onemajor genes plusploygenes model in crossⅡ; For internode length, the best fitting genetic model was one major geneplus polygenes in cross Ⅰ andtwo major genes plus polygenes in cross Ⅱ. Plant height related traitswere all controlled by one major gene or two major genes plus polygenes or polygenes. Thedifference in the same trait indicated the complicacies of inheritance.2. Total of216accessions in sesame core-collection were used to study the variation andinterrelationship of plant height constitutions. All accessions were scanned with79pairs of EST-SSR,AFLP and SRAP primers, and the loci related to plant height constitutions were predicted byassociation mapping. Result show that all traits of plant height constitutions presented a trend ofcontinuous change, meanwhile, they had abundant variation types and the coefficient of variation(CV) were all above10%. Correlation analysis and multiple regression analysis showed that stemheight from base to first capsule and capsule zone length were the main factors affect plant height. Intotal,34loci related to plant height constitutions simultaneously in2010and2011were detected byassociation analysis based on GLM(Q) model and MLM(Q) model. These loci explained1.89%to5.29%of phenotypic variation with average of2.82%. Among these loci, two were pleiotropic thataffected two traits respectively detected by GLM(Q) model, only one locus M20E12-3associating with stem height from base to first capsule was identified both by two models. Result also showedthat sesame plant height constitutions were affected by genotype, environment and their interactionsignificantly.3. A genetic linkage map of sesame was constructed with Zhongzhi No.11(high-stalk,♀)×2289(dwarf,♂), their F2populations and primers (SSR, InDel, InDel-SSR, EST-SSR), which consisted of10linkage groups with34molecular markers.The map was291.3cM in length and the averagedistance between adjacent markers was8.8cM. A total of26additive QTLs for7plant height relatedtraits were identified by using the software of WinQTLCart2.5and QTLNetwork2.0, distributed onLg1, Lg2, Lg5, Lg8and Lg10. The results of both methods were consistent, yet the differencebetween the two methods showed the inheritance of traits related to plant height constitutions arecomplicated. Primer sse200was related with the number of capsule node pairs on main stem detectingby association mapping, and it was consistent with the result of QTL mapping having the sameintervals between the marker of ID0089-ZMM0628.The linkage groups construction and QTLs for the related traits of plant height related traits wereall haven’t been reported in China and abroad. The results were valuable to further researches ongenetic improvement and molecular biology of sesame height related traits. |
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