Abstract: 【Objective】 To reveal the effects of different exogenous hormones on the seed number and photosynthetic performance in common buckwheat.【Methods】 Varieties of “BZS” and“CT1” as experimental materials and treated with different concentrations（100,150,200 mg/L） of paclobutrazol（PP₃₃₃） and 6-benzyl adenine（6-BA） at different time of seedling stage to study the effects of different treatments on pollen fertility,stigma receptivity,photosynthetic parameters,flowering number and the seed number of common buckwheat.【Results】 Compared with the control（water）,PP₃₃₃ treatment at 100 mg/L and 6-BA at 150 mg/L,the seed numbers reached maximum increased respectively 20.3% and 47.9%. The net photosynthetic rate and intercellular CO₂ concentration during full booming stage were both increased when spraying PP₃₃₃ and 6-BA compared with CK at different stage of common buckwheat. The transpiration rate was increased and stomatal conductivity was decreased when spraying PP₃₃₃ compared with CK but the effect of spraying 6-BA was opposite to that of spraying PP₃₃₃.【Conclusion】 In the second true leaf stage of common buckwheat,PP₃₃₃ 100 mg/L or 6-BA 150 mg/L treatments could improve pollen fertility,stigma receptivity,seed number per plant,and photosynthetic performance.

Key words: Common buckwheat, Fruiting, Pollen fertility, Stigma receptivity, Photosynthetic performance