Heterosis (or hybrid vigor) is a phenomenon in which hybrid progeny exhibit superior performance over their parents.It was described by Charles Darwin (1876) and observed in many plant and animal species.Heterosis is widely used in many crops and vegetables to make high-yielding cultivars,and yield increase in hybrids ranges from 15 to 50%.However the molecular mechanism underlying heterosis is still to be elucidated and there is no consensus model.As most crucifer vegetable cultivars use F1 hybrid seed production systems,these species should show heterosis in particular parental combinations.However there are few reports analyzing heterosis in crucifer vegetables.