Wheat (Triticum aestivum) is among the most important staple crops to safeguard the food security of the growing world population. To bridge the gap between genebank diversity and breeding programs, we developed an advanced backcross-nested association mapping plus inter-crossed population (AB-NAMIC) by crossing three popular wheat cultivars as recurrent founders to 20 germplasm lines from mini core collection. Selective backcrossing combined with selection against unadapted traits and extensive crossing within and between sub-populations created new opportunities to detect unknown genes besides increasing the frequency of beneficial alleles in the AB-NAMIC population. We performed phenotyping of 594 AB-NAMIC lines and a natural panel (NP) comprised of 476 cultivars for six consecutive growing seasons and genotyped these 1,070 lines with a 660K SNP array. Genome-wide association studies in both panels for plant development and yield traits demonstrated improved power and resolution of AB-NAMIC over NP. Notably, GWAS in AB-NAMIC detected the candidate gene TraesCS7B03G1216700, having high homology to rice SWEET6b gene, that exerts strong effects on adaptation and yield traits. The commercial release of three derived AB-NAMIC lines attested to its direct applicability in wheat improvement. Our research provides an excellent framework for fast-tracking exploration and accumulation of beneficial alleles stored in genebanks. We also present a wheat genomics-assisted breeding (WheatGAB) pipeline that will help breeders to devise strategies to achieve superior combinations of alleles/haplotypes associated with traits that are crucial for sustainable increase in wheat productivity.