Effects of gibberellin on the growth,fruiting and yield of tartary buckwheat

【Objective】To explore the effect of gibberellin (GA₃) on the promotion of tartary buckwheat growth and development,so as to provide a theoretical basis and technical support for high-yielding tartary buckwheat cultivation.【Method】Chuanqiao No.1 was used as the test material. Plants were sprayed at the beginning of flowering with different concentrations(0, 25, 50 and 75 mg/L) of GA₃ solution, where the 0 mg/L treatment consisted of spraying with an equal amount of water as a control(CK). The effect of the different treatments on tartary buckwheat growth, photosynthetic physiology, flowering and yield effects were analyzed.【Result】Compared with the CK group, different concentrations of GA₃ treatment were able to promote tartary buckwheat plant growth. With the increase in GA₃ concentration, plant height showed a significant increase (P<0.05, the same below), and the number of main stem branches first increased and then decreased, but the number of main stem nodes did not change significantly (P>0.05). Exogenous GA₃ was seen to significantly improve tartary buckwheat photosynthesis and treatment with 50 mg/L produced the best effect. Compared with CK, tartary buckwheat treated with 50 mg/L showed a 26.0% increase in SPAD value at the late-filling stage(30 d after treatment) and increases in the rates of net photosynthesis, stomatal conductance and transpiration rate of 28.6%, 31.3% and 16.1%, respectively, at the mid-filling stage. Conversely, the intercellular CO₂ concentration was decreased by 12.3% with this treatment. Exogenous GA₃ also promoted tartary buckwheat flowering and fruiting. Relative to the CK group, the fruiting rate, total number of flowers, number of mature seeds and dead flowers were increased by 19.5%,13.8%, 30.0% and 38.4%, respectively, accompanied by a 41.4% reduction in the number of dead grains. Tartary buckwheat grain weight and yield with the increase in GA₃ concentration showed a trend of increase to 50 mg/L, followed by a decrease. Relative to the CK group, the maximum increases in grain weight and yield were 16.1% and 21.8%, respectively.【Conclusion】Foliar spraying of GA₃ can significantly improve photosynthesis and promote flowering and fruiting, with increased yields from Chuanqiao No.1. The best effect can be achieved by spraying 50 mg/L at the first flowering stage.