The effect of seed pretreatment with gibberellic acid on germination and early establishment of grain sorghum

Abstract

The effect of presoaking grain sorghum seed in gibberellic acid (GA,) on germination was studied in petri dishes at 10,15, and 20°C. There was no effect at 20°C, a slight stimulation at 15°C and a marked speeding up of germination at 10°C. Seed of grain sorghum presoaked in GA3 gave more rapid emergence in pots and in the field. Greatest acceleration of emergence occurred with early (September) sown sorghum when soil temperatures were lowest. Higher seedling mortality usually gave lower final plant stand .with GA3 ptesoaked seed. The fungicide thiram improved sorghum establishment specially at low soil temperatures and gave no interaction with GAS presoaking of grain sorghum seed.