Segregation analysis of the mixed genetic model of major gene plus polygene was used to identify the major genes for cotton yield-related traits using six generations P1,P2,F1,B1,B2,and F2 generated from the cross of Baimian 1×TM-1.In addition to boll size and seed index,the major genes for the other five traits were detected:one each for seed yield,lint percentage,boll number,lint index;and two for lint yield.Quantitative trait locus/loci(QTL)mapping was performed in the F2 and F2:3populations of above cross through molecular marker technology,and a total of 50 QTL(26 suggestive and 24 significant)for yield-related traits were detected.Four common QTL were discovered:qLP-3b(F2)/qLP-3(F2:3)and qLP-19b(F2)/qLP-19(F2:3)for lint percentage,qBN-17(F2)/qBN-17(F2:3)for boll number,and qBS-26b(F2)/qBS-26(F2:3)for boll size.Especially,qLP-3b(F2)/qLP-3(F2:3),not only had LOD scores>3 but also exceeded the permutation threshold(5.13 and 5.29,respectively),correspondingly explaining 23.47 and 29.55%of phenotypic variation.This QTL should be considered preferentially in marker assisted selection(MAS).Segregation analysis and QTL mapping could mutually complement and verify,w hich provides a theoretical basis for genetic improvement of cotton yield-related traits by using major genes(QTL). Segregation analysis of the mixed genetic model of major gene plus polygene was used to identify the major genes for cotton yield-related traits using six generations P1, P2, F1, B1, B2, and F2 generated from the cross of Baimian 1 × TM- 1.In addition to boll size and seed index, the major genes for the other five traits were detected: one each for seed yield, lint percentage, boll number, lint index; and two for lint yield.Quantitative trait locus / loci (QTL ) mapping was performed in the F2 and F2: 3populations of above cross through molecular marker technology, and a total of 50 QTL (26 suggestive and 24 significant) for yield-related traits were detected. Four common QTLs were discovered: qLP-3b (F2: 3) for boll number / qLP-3 (F2: 3) and qLP-19b (F2) / qLP-19 (F2: 3) for boll size. Especially, qLP-3b (F2) / qLP-3 (F2: 3), not only had LOD scores> 3 but also exceeded the permutation threshold (5.13 and 5.29, respectively), correspondingly explaining 23.47 and 29 .55% of phenotypic variation. This QTL should be considered preferentially in marker assisted selection (MAS). Segregation analysis and QTL mapping could mutually complement and verify, w hich provide a theoretical basis for genetic improvement of cotton yield-related traits by using major genes (QTL).