Breaking seed dormancy in black mulberry (Morus nigra L.) by cold stratification and exogenous application of gibberellic acid

Experiments were done to determine the effects of cold stratification (0, 20, 40, 60, 80 or 100 days), application of gibberelic acid (GA(3)) (0, 250, 500, 1000 or 2000 mg/l) and the combination (GA(3) + stratification) on seed germination of black mulberry. Application of 1000 mg/l GA3 proved more effective than any of the other concentrations of GA3 applied. Seeds stratified for 100 days showed 88% germination. The combined treatment of 250 mg/l GA(3) and 100 days of stratification yielded 96% germination of seeds. The relationships between GA3 concentration and seed germination (r = 0.93), and between stratification duration and seed germination (r = 0.91) of black mulberry were linear.