Alleviation of seed dormancy in kala zeera (Bunium persicum) through chilling and phytohormones

Kala zeera (Bunium persicum) is a high-value medicinal spice plant. The seeds and extracts are used for culinary, perfumery, flavouring food and medicinal purposes. The commercial cultivation of kala zeera is hampered due to poor seed germination and deep physiological dormancy. To break the dormancy of kala zeera, three phytohormones, gibberellic acid (100 µmol L-1), 6-benzylaminopurine (10 µmol L-1) and thidiazuron (6.3 µmol L-1) were tested individually and in combination, under two temperature levels: continuous chilling at 4°C and one week chilling at 4°C followed by incubation at room temperature. The combined application of the three phytohormones under continuous chilling (4°C) improved the germination from 11.25 to 93.25% and reduced the mean germination time 60 to 50 days. The lowest mean germination time (34.78 days) and high mean daily germination (1.57 seeds day-1) with a high coefficient of germination velocity (2.88), were found under combined application of phytohormones as compared to their individual application. The findings have implications in successful propagation and systematic cultivation of this high-value medicinal spice plant.