marker-assisted selection in wheat - ictsd

68Marker-assisted selection – Current status and future perspectives in crops, livestock, forestry and fishSummaryWithin the framework of a cotton breeding programme, molecular markers are used toimprove the efficiency of the introgression of fibre quality traits of Gossypium barbadenseinto G. hirsutum. A saturated genetic map was developed based on genotyping dataobtained from the BC 1 (75 plants) and BC 2 (200 plants) generations. Phenotypic measurementsconducted over three generations (BC 1 , BC 2 and BC 2 S 1 ) allowed 80 quantitative traitloci (QTL) to be detected for fibre length, uniformity, strength, elongation, fineness andcolour. Positive QTL, i.e. those for which favourable alleles came from the G. barbadenseparent, were harboured by 19 QTL-rich regions on 15 “carrier” chromosomes. In subsequentgenerations (BC 3 and BC 4 ), markers framing the QTL-rich regions were used toselect about 10 percent of over 400 plants analysed in each generation. Although BC plantsselected through the marker-assisted selection (MAS) process show promising fibre quality,only their full field evaluation will allow validation of the procedure.