To probe into the opportunities for breaking the barriers of wheat yield using synthetic hexaploid wheat (SHW)

two sets of recombinant inbred lines (RILs)

S12 (SynCD780×Chuanyu12

131 lines) and S16 (SHWderived variety Chuanmai42×Chuannong16

127 lines)

were planted in multienvironments (year×site) in 2006-2008. Phenotypic data were collected for fifteen agronomic traits of both S12 and S16 and 280 microsatellite markers were employed to genotype lines of S16. Continuous variation and transgressive segregation for all tested traits were observed. Grain yield of superior lines in S12 was 64% higher than Chuanyu12 achieved by increasing kernel weight (≈ 10%). Average grain yield of the top ten highyielding lines in S16 was up to 79 t/hm2

181% higher than Chuannong16 by increasing both kernel weight and grains m-2. Using singlemarker regression and interval mapping

a total of 55 putative QTLs with a LOD score ＞30 based on S16 were detected

of which 7 were for grain yield

40 for yield components

and 8 for rates of grain and biomass production. For 38 (691%) of them

alleles from the SHWderived variety Chuanmai42 were associated with a positive effect on yieldrelated traits. The present studies indicated that breaking barriers of wheat yield using SHW is feasible.