Investigation Effect of Different Amount and Time of Apply a Bio-Regulator on Growth Indices of Vicia faba L.

BACKGROUND: Gibberellins may play a key role in many metabolic pathways affecting these characteristics, such as chlorophyll production and degradation, translocation of assimilates, nitrogen metabolism, and nitrogen redistribution. OBJECTIVES: The current study was conducted to assess the effect of different amount and time of apply Gibberellin acid on growth curves and crop production of Broad bean. METHODS: This research was done via factorial experiment based on randomized complete blocks design with three replications along 2010 year. The treatments included different concentration of Gibberellin (nonuse of Gibberellin or control, 5 ppm, 50 ppm and 250 ppm) and time of application Gibberellin (Vegetative growth before flowering, flowering until pod emergence, Pod emergence until grain filing). RESULT: Result of analysis of variance revealed effects of different amount, time of apply Gibberellin acid and interaction effect of treatments on seed yield was significant at 5% probability level. Compare different level of Gibberellin acid concentration revealed maximum amount of seed yield (2761 kg.ha-1), leaf area index (2.43), total dry matter (3750 gr.m-2), relative growth rate (0.049 gr.gr.day-1), crop growth rate (34 gr.m-2.day-1) and net assimilation rate (7.5 gr.m-2.day-1) belonged to 50 ppm Gibberellin acid and lowest ones was for control treatment. Also among different time of apply Gibberellin acid, maximum amount of mentioned traits was for Vegetative growth before flowering phase and the lowest one belonged to pod emergence until grain filing. CONCLUSION: Consume 50 ppm Gibberellin acid concentration at vegetative growth before flowering phase had the highest amount of crop production and growth indices and it can be advised to farmers.