Key message: A population developed from an exotic line with supernumerary spikelets was genetically dissected for eight quality traits, discovering new genes/alleles with potential use in wheat breeding programs. Abstract: Identifying new QTLs and alleles in exotic germplasm is paramount for further improvement of quality traits in wheat. In the present study, an RIL population developed from a cross of an elite wheat line (WCB414) and an exotic genotype with supernumerary spikelets (SS) was used to identify QTLs and new alleles for eight quality traits. Composite interval mapping for 1,000 kernels weight (TKW), kernel volume weight (KVW), grain protein content (GPC), percent of flour extraction (FE) and four mixograph-related traits identified a total of 69 QTLs including 19 stable QTLs. These QTLs were located on 18 different chromosomes (except 4D, 5D, and 6D). Thirteen of these QTLs explained more than 15 % of phenotypic variation (PV) and were considered as major QTLs. In this study, we identified 11 QTLs for TKW (R2 = 7.2–17.1 %), 10 for KVW (R2 = 6.7–22.5 %), 11 for GPC (R2 = 4.7–16.9 %), 6 for FE (R2 = 4.8–19 %) and 31 for mixograph-related traits (R2 = 3.2–41.2 %). In this population, several previously identified QTLs for SS, nine spike-related and ten agronomic traits were co-located with the quality QTLs, suggesting pleiotropic effects or close linkage among loci. The traits GPC and mixogram-related traits were positively correlated with SS. Indeed, several loci for quality traits were co-located with QTL for SS. The exotic parent contributed positive alleles that increased PV of the traits at 56 % of loci demonstrating the suitability of germplasm with SS to improve quality traits in wheat.