Eight sunflower inbred lines were crossed in 8×8 diallel fashion (without reciprocal) and 28 F1 were developed at Oilseed Research Centre (ORC), Bangladesh Agricultural Research Institute (BARI), Gazipur in Rabi season, 2018. All F1 and their parents were planted in Rabi season 2019 to estimate general combining ability (GCA) and specific combining ability (SCA) effects for yield and yield attributes. The highly significant mean squares for genotypes for all the studied characters indicating wide variability in the parental materials. The highly significant GCA effects for stem diameter, days to maturity, number of seeds/head, 1000-seed weight and SCA effects for days to 50 flowering, days to maturity, head diameter, number of seeds/head, 1000-seed weight and seed yield were observed. The greater ratio of GCA/SCA implies the predominance of additive gene effect for all the studied characters. The parents, P1, P2, P3, P6 and P8 were found as good general combining parents for short duration, early maturity, lodging resistant, and 1000 seed weight. Crosses with the best SCA effects for some characters were found from the interaction of low × low, high × low, low × high or high × average combining parents. Further investigation on superiority and stability of good combining parents and hybrids over different years and locations is needed.

Keywords: Sunflower; Griffing’ method; Diallel cross; GCA; SCA