Genetic Mapping Of QTLs Related To Heading Date On Wild Emmer Chromosome 4AL

Heading date is one of the important target traits in wheat breeding, its sooner or later and will directly or indirectly affect the yield, quality, stress resistance and many other important agronomic characters, in some areas also affect seeding time of following crop, after which affect the output of crops. Based on wheat chromosome arm substitution lines(CASLs) of wild emmer in the background of common wheat specie Chinese Spring(CS), a F2 population derived from a cross of the earlier CASL3 AL,7BS and the later 4AL was used for QTL analysis for heading date under four environments,in order to screen QTLs that can be stably expressed.The method of composite interval mapping(CIM) was used for QTL mapping of heading date and obtained the main results are as follows:1.Field experiment found that CASL3 AL, CASL7 BS head earlier than receptor parent CS and CASL4 AL later than CS in different sowing date. From the autumn sowing(September 2014) to winter(February 2015), CASLs heading date drop from 180 days to 100 days.2.Phenotypic analysis of heading date in F2 mapping population and their parents showing significant difference. The range of variation among F2 population and their parents in two environment was respective large. The F2 populations present near normal distribution in two years, and in favor of the earlier heading.3.A genetic linkage map containing 19 SSR markers which were assigned to the chromosome 4AL,using MAPMAKER/Exp version 3.0 software,was finally constructed, which was comprising 19 sites, with the whole genome length of 67.8 cM and a average distance of 3.6 cM between adjacent markers. Based on the genetic linkage map, the software WinQTLcart 2.5(with composite interval mapping method) was used to conduct QTL(LOD>2.5) of the heading date. The results indicated that 4 QTLs were detected,among which 3 QTLs were repeatedly detected within the same marker interval(Xbarc170-Xwmc262) in three different mapping populations, explaining 13.06%,18.84% and 34.27% of observed phenotypic variation respectively.The results established the foundation to select excellent wheat variety of suitable maturity period by molecular marker-assisted selection, will do great help to further fine mapping and cloning of the heading date gene in the future.