QTL Mapping For Spike Length And Four Spike Related Trairs In Wheat

To explore the genetic mechanism of panicle characters, for instance, spike length(SL), grains per spike (SGN), spikelet per spike (SPS), and compactness (SC) in wheat. Acluster of the crossbreed F2population was constructed through hybridizing betweenLankao906and Xiaoyan81. The parents and the plants of F2population were cultivated in2012cropping seasons in Yangling, Shanxi province and assessed for some spike related traits.1150SSR molecular markers were used in this study. QTLs analyses were identified with thesoftware of QTL IciMapping version3.2based on the method of inclusive composite intervalmapping. And acquired the following major results:1．The genetic linkage map was constructed using the crossbreed F2populationorigined from the hybridization between Lankao906and Xiaoyan81and135SSR markerscovered21chromosomes. The length of the genome was2885.91cM, with an averagedistance of single marker per21.37cM and the shortest genetic distance of3.3cM/marker.2．In total, up to22putative additive QTLs for spike related traits were detected inthe Lankao906/Xiaoyan81F2population, which were situated on different chromosomalintervals of1B、2B、3A、3B、4A、4D、5B、5D. A single QTL explained1.47%～41.78%of the phenotypic variations. Of these,2major QTLs (QSps-2B1、 QSps-2B2) for SPS weresituated on different chromosomal intervals of2B, respectively, with genetic contribution rateof41.78%、23.30%. A major QTL (QSc-1B) for SC was situated on1B chromosome, withgenetic contribution rate of12.55%. A total of17pairs of epistatic QTLs for SL, SGN, SPS,and SC were detected on different chromosomes,1B、1D、2A、3A、3B、4A、4D、5A、5B and7A, explained35.35%、20.66%、26.88%and41.49%，respectively.3． The Xwmc291-Xwmc808interval on chromosome3B, the Xgpw2279～Xbarc236、Xwmc707～Xwmc680intervals on chromosome4A had three QTL clusters. Theanalysis of QTL cluster indicated the Xwmc291～Xwmc808interval on chromosome3B hadthe uniform orientation of increasing effects on SGN, SPS, and SC, which tended to have pleiotropism and achieved the genetic improvement of SGN, SPS, and SC simultaneously.And the synergistic alleles all derived from Xiaoyan81.