Plant biomass is a complex trait which is the combined function of many plant characteristics, including the number of stalks, stem diameter and plant height. In the present study, we used three F2:3 populations, derived from crossing three diverse paternal lines and a common maternal line (Grassl), for the genetic dissection of biomass and biomass-related traits in sorghum. The parental lines were selected in such a way to maximize the diversity of both cellulosic types and geographic origins and the phenotypes deemed suitable for cellulosic sorghum improvement. High-quality SNPs generated by the genotyping-by-sequencing (GBS) method were used for mapping quantitative trait loci (QTL) associated with the traits studied. QTLs detected were compared among the population used in this study, as well as with previously reported QTLs for non-random correspondence. Several major QTLs with significant potential contributions towards improving the traits were detected, which can be useful in MAS for bioenergy sorghum improvement.