QTL Analysis For Stem Strength And Its Correlated Traits In Wheat

Improving the quality of stem strength is an important way to increase yield potential of wheat. A DH population with 113 lines, derived from the cross of CA9613xH1488, was used to identify QTLs for stem strength and its correlated traits in this study. The results are summarized as follows:1. The correlationships between stem strength and anatomic traits, lodging index were significant. Stem strength and anatomic traits were positively correlated (r = 0.40-0.48). On the other hand, the correlation index between stem strength and lodging index were negtively correlated (-0.48).2. The linear correlationship between stem strength and fresh weight of stem and spike, 1st and 2nd internodes under spike, biomass yield, and the dry weight of spike were significant, respectively. As the results of correlation and regression analysis, it was suggested that fresh weight of spike and biomass yield should be considered as important traits for breeding lodging resistance.3. The result of genotype analysis for the DH population with 54 polymorphic loci showed that 7 loci (12.96%) skewed significantly from the expected 1:1 gene segregation rate. A genetic linkage map was constructed by Mapmaker program, which covering 11 chromosomes with an average interval length of 16.2cM. The chromosomes were 2A, 2B, 2D, 3A, 3B, 3D, 4B, 5A, 5B, 6A, 7B.4. QTLs for stem strength were located on chromosome 5B and 2D, and detected each QTL could explain 8.17-12% phenotype variance. The two parents, CA9613 and HI488, carried genes enhancing stem strength. QTLs for fresh weight were located on chromosome 4B and 2B, spike fresh weight on 4B, both of fresh weight of 2nd internode under spike and biomass yield on 5B, fresh weight of 3rd and 4th internodes under spike on chromosome 2A, 2B, 5B, dry weight of internode under spike onchromosome 2B, 5B, 7B, height on chromosome 2B and 7B, internode length on 2B, 5B, 7B, internode diameter on chromosome 3B, 4B, 5B, 5A, internode pith diameter on 3B, respectively.5. All QTLs detected in this study were affected by epistasis of additivexadditive and interactions of QTLsxE.