In vitro and in vivo A. ligtu hybrid seed germination tests were conducted at different treatments: soaking in gibberellic acid (GA3) or salicylic acid (SA) (0, 100, 200 and 400 mg.l-1) and Potassium nitrate (KNO3) (0.1, 0.2, 0.4 and 0.8%) with and without stratification in 5±1 °C. Stratification had a significant effect on seed germination (p < 0.05). Maximum germination (86.67%, 96.50% after 16.44, 15.05 days under in vivo and in vitro conditions, respectively) was found in 100 mg.l-1 GA3 + 21 days of stratification and was followed by 0.8% KNO3 and 100 mg.l-1 SA along with 21 days of stratification. Mean germination time (MGT) decreased with duration of stratification and GA3, SA and KNO3 application, respectively. The present results indicated that, GA3, SA and KNO3 stimulated various growth aspects of Alstroemeria seedlings growth in both under in vitro and in vivo, but seeds treated in 100 mg.l-1 GA3 soulation was more effective. Seeds treated with SA and KNO3 without stratification and control had no germination. A.ligtu hybrid species probably exhibits a combination of physiological dormancy. Stratification at 5±1 °C for 21 days or GA3 + 21 days of stratification overcame seed dormancy and increased the germination percentage of A.ligtu hybrid seeds. Seedlings growth in vivo conditions was higher as compared with in vitro conditions.
