QTL mapping for agronomic and fibre traits using two interspecific chromosome substitution lines of Upland cotton

CS-B14Sh and CS-B22Sh are cotton interspecific chromosome substitution (CS)-B lines, in which a pair of short arms of chromosome 14 and chromosome 22 were introgressed from Gossypium barbadense doubled-haploid line 3-79 with the background of Gossypium hirsutum line TM-1, respectively. These two CS-B lines were crossed with TM-1, and segregating progenies (F-2 and F-2:3, respectively) were obtained. Phenotypic data of lint yield, yield-related traits and fibre-quality traits were collected from two trials. In the cross CS-B14SH X TM-1, QTL for boll weight (BW), lint percentage (LP), fibre upper half mean length (UHML), micronaire reading (MIC), and fibre breaking tensile strength (STR) were repeatedly detected. Alleles from 3-79 decreased BW and MIC, but increased UHML and STR. In the cross CS-B22Sh X TM-1, QTL for BW, LP, UHML, MIC, STR, fibre elongation (EL),seed weight(SW), node of first fruiting branch (NFB) and fibre uniformity index (UI) were repeatedly detected, and alleles from 3-79 decreased UHML, UI and STR, but increased NFB, SW, MIC and EL. QTL clusters were found in both populations.