Mapping QTLs For Physiological Traits Associated With Cold-resistance In Winter Wheat

Common wheat (Triticum asetivum L.) as the main food crop in the world, almost all winter wheat cultivation happen cold damage and freeze injury, which becomes one of the largest natural disasters of wheat production. Studying on heredity and gene location for physiological indexes associated with cold-resistance in winter wheat is of great importance to provide the foundation and the genetic resources in cold-resistance breeding. In this study, the map population, which was consisted of double haploid lines from the cross Huapei3×Yumai57, was constructed a genetic linkage map. In three growth stages (pre-wintering stage, over-wintering stage and late-wintering stage) and three enviroments of every stage, cell membrane permeability (the A value, physiological index associated with cold-resistance in wheat) of leaf was determined by low temperature (?18℃). QTL analyses on cell membrane permeability of leaf in wheat were further performed by using composite interval mapping mixed linear model based software Icimapping 2.2, which will provide reference information for gene cloning and molecular marker assisted selection associated with cold-resistance in wheat. The results are as follows:1. The correlation coefficient (the r value) between the cell membrane permeability of leaf treated by low temperature (?18°C) and the survey data of field freeze was 0.8806, which was remarkably positive correlation.According to the size of cell membrane permeability of leaf in wheat under the low temperature treatment, it can judge the freeze degree in winter wheat.2. A total of 324 SSR markers were mapped on 24 linkage groups. Chromosome 5A, 5B and 7B contain two linkage groups. The total coverage of the map is 2485.7 cM, the average genetic distance between marks is 7.67 cM.3. A total of 51 additive QTLs associated with the cell membrane permeability of leaf in winter wheat were detected, which were distributed on 15 chromosomes: 1A, 1B, 2A, 2D, 3A, 3B, 4D, 5A, 5B, 5D, 6A, 6B, 6D, 7B and 7D. 13 QTLs with phenotypic contributions higher than 10% could explain 11.28%%-34.96% of the phenotypic variation. In pre-wintering stage, the major genes were distributed on chromosomes 1B, 3B and 5B. A common locus in the Xgwm213-Xswes861.2 interval on chromosome 5B was detected in the three environments of the stage, with 0 cM genetic distance from Xswes861.2. In over-wintering stage, the major genes were distributed on chromosomes 2D, 3B and 6B. In late-wintering stage, the major genes were distributed on chromosomes 1B, 6B and 7D.