Fine‐mapping a fibre strength QTL QFS ‐ D 11‐1 on cotton chromosome 21 using introgressed lines

An initial F 2 mapping population of 223 plants of the cross between TM ‐1 ( G ossypium hirsutum L .) ×  H 102 ( G ossypium barbadense L .) was used to map QTL s controlling fibre strength in cotton. A genetic linkage map with 408 SSR markers was constructed with a total length of 3872.6 cM. Multiple‐ QTL model of the software MapQTL version 5.0 was used to map QTL s related to fibre strength of the F 2 : 3 population. QTL QFS ‐ D 11‐1 conferring fibre strength was mapped between NAU 2950 and NAU 4855 on chromosome 21 ( C hr. 21) which explained 23.4% of phenotypic variation. Introgressed lines ( IL s), that is, IL ‐ D 11‐1, IL ‐ D 11‐2 and IL ‐ D 11‐3 were obtained through marker‐assisted backcrossing in TM ‐1 background. An F 2 population of 758 plants derived from cross IL ‐ D 11‐2 ×  TM ‐1 was used for fine‐mapping QTL QFS ‐ D 11‐1 . QFS ‐ D 11‐1 was mapped between markers NAU 2110 and NAU 2950, adjacent to its initial interval NAU 2950– NAU 4855 with phenotypic variation explaining 35.8%. QFS ‐ D11‐1 was further mapped to 0.6 cM from the flanking marker NAU 2950. The results will give a basis for marker‐assisted selection of QFS ‐ D 11‐1 in cotton breeding and to lay the foundation for cloning QFS ‐ D 11‐1 .