QTL mapping for salt tolerance at seedling stage in the interspecific cross of Gossypium tomentosum with Gossypium hirsutum

Soil salinity negatively affects growth and development as well as yield and fiber quality of cotton. The identification of quantitative trait loci (QTLs) for traits related to salt tolerance could facilitate the development of cotton cultivars with salt tolerance. The objective of this study was to map QTLs for salt tolerance in an F-2:3 population derived from an interspecific cross between an upland cotton, CRI-12 (G09091801-2), of upland cotton (Gossypium hirsutum) and an accession, AD(3)-00 (P0601211), of wild cotton Gossypium tomentosum. 1295 simple sequence repeat markers, which amplified 1342 loci, distributed on 26 chromosomes and covered 3328.24 cM with an average inter-marker distance of 3.0 cM, were utilized for molecular genotyping. Salt tolerance was evaluated in a hydroponic at a young seedling stage for 2 weeks at 150 mM NaCl concentration in three environments. Mapping of QTLs related to salt tolerance was carried out on 7 traits by composite interval mapping using Windows QTL Cartographer 2.5. Eleven consistent QTLs were detected on 8 chromosomes (9, 11, 15, 16, 21, 23, 24 and 26) in at least two environments. qRL-Chr16-1 for RL was a major QTL explaining the Phenotypic variance of 11.97 and 18.44 % in two environments. Of the 11 QTLs, 10 were located on the D subgenome, indicating that genes responsible for salt tolerance in the allotetraploid cotton AD genome were mainly derived from the D subgenome. The information derived from these studies may be useful in facilitating breeding of salt tolerant cotton lines.