Effect of Gibberellic Acid and Standard Seed Treatments on Mountain Snowberry Germination

Abstract

Acid scarification, warm stratification, cold stratification, and soaks in gibberellic acid (GA₃) were effective in promoting germination in mountain snowberry (Symphoricarpos oreophilus Gray [Caprifoliaceae]) from New Mexico, but treatment levels and interactions were important. The combination of a 30-min acid soak, 21-d warm stratification treatment, and 84-d cold stratification treatment (the shortest duration evaluated) was highly effective in promoting germination. Increasing cold stratification from 84 to 168 d increased germination, as did incubation in all concentrations (250 to 1000 ppm) of GA₃, but the benefit of longer cold stratification and GA₃ incubation was reduced for acid-scarified seeds. Acid scarification breaks physiological dormancy of the embryo and may allow maturation of the embryo during cold stratification to begin sooner. Timing of GA₃ application was also important. For seeds undergoing acid scarification followed by warm stratification followed by cold stratification, application of GA₃ prior to warm stratification resulted in less germination compared to application following warm stratification. In snowberry, early GA₃ application may result in GA₃ catabolism during warm stratification, reducing the concentration available during cold stratification.