QTLs Mapping Analysis For Traits Associated With Drought Tolerance In Wheat Seedling

160 RIL lines of wheat (Jinmai47 × Yumai18) were used for genetic research material in this study, using SSR markers constructed a genetic linkage map and seven important traits including seed high (SH), root number (RN), maximum root length (MRL), root fresh weight (RFW), root dry weight (RDW), ratio of root fresh weight to shoot fresh weight (RFW/SFW) and ratio of root dry weight to shoot dry weight (RDW/SDW) were measured in different environment under drought tolerance and well-watered conditions in wheat seedling. Quantitative trait loci and genetic and environmental interactions for these traits were performed by ICIM (Inclusive Composite Interval Mapping). The main results were as the following.1 The test results show that the seven traits in the recombinant inbred lines group characterized by continuous variation, and variation range is larger, there is an obvious two-way transgressive segregation phenomenon, showing the number of typical traits genetic characteristics. The RIL population could be used for QTL mapping analysis.2 The genetic linkage map, with 19 linkage groups, was constructed using 95 SSR markers and 1EST-SSR marker with polymorphism, with the whole genome length of 1243.23cM and an average distance of 13.51cM between markers, and the number of markers on chromosomes being 2-14, was suitable for QTL mapping.3 In total,54 additive QTLs,38 epistatic QTLs,48 QTLs with additive and environment interaction effect and 29 QTLs with epistatic and environment interaction effect were mapped,36 of which can explain at least 10% of the phenotypic variation in different environment, being major QTLs.4 We detected a major QTL QSh qau - 4 d that were found in the interval between Xbarc80 - Xcfd54 on chromosome4D. The contribution of individual QTL for phenotypic variation were 10.4% and 17.9% respectively, the additive effects of 1.71 and 1.66 respectively under the condition of two kinds of water stable expression, synergistic alleles from yumai 18, have lower genetic effects of plant height. Xbarc80 and Xcfd54 can be used for wheat drought resistance of marker-assisted selection breeding.5 Many of the traits shared the same QTL, which seven important QTL clusters were detected in this study. The first QTL cluster located on chromosome 1B between Xcfd61-Xwmc120, related to the plant root number, root length and root dry weight; The second QTL cluster located on chromosome 2A between Xgwm47-Xwmc170, related to the maximum root length, root fresh weight and ratio of root fresh weight to shoot fresh weight; The next QTL cluster located on chromosome5D between Xgwm292-Xgdm63, related to the maximum root length, root dry weight and ratio of root dry weight to shoot dry weight; The next QTL cluster located on chromosome 7D between Xgwm437-Xgdm67, related to the seedling height, root fresh weight, ratio of root dry weight to shoot dry weight; The third QTL cluster located on chromosome2B between Xwmc317-Xbarc55, related to the maximum root length, root fresh weight and ratio of root fresh weight to shoot fresh weight;The third QTL cluster located on chromosome 1A between Xbarc213 - Xbarc158, related to the seedling height, root fresh weight, root dry weight; The last QTL cluster located on chromosome1B between Xgwm312-Xgwm140, related to the root fresh weight, root dry weight and ratio of root dry weight to shoot dry weight.