Effect of various stratification regimes on seed germination in cold-hardy garden roses
Garden roses have notoriously low and lengthy seed germination, which is a serious limitation to the effectiveness of breeding protocols. A series of experiments have been conducted at Vineland, Canada, to study the effect of achene acid scarification and enzyme maceration, as well as the synergetic effect of these techniques combined with various warm and cold stratification regimes on rose seed germination. In this experiment (2011-2012), we studied the germination response of four very hardy rose cultivars to eight stratification treatments (T) (three replications per treatment; 50 achenes per replication). Achenes from 'Cape Diamond', 'Champlain', 'Frontenac', and 'Morden Sunrise' were subjected to: T1, 5 weeks warm stratification (5WWS) + 6 weeks cold stratification (6WCS); T2, 5WWS + 9WCS; T3, 5WWS + 12WCS; T4, 5WWS + 15WCS; T5, 8WWS + 6WCS; T6, 8WWS + 9WCS; T7, 8WWS + 12 WCS; and T8, 8WWS + 15WCS. Hips in identical ripening stage were harvested on October 26, 2011, and the achenes from all treatments received uniform pre-treatment with cellulase (0.5% for 38 h) followed by leaching in water for 48 h. None of the cultivars responded to T1 or T5. 'Cape Diamond' had a gradual increase of germination in response to longer warm and cold stratification regimes, with the best performance of 23% in T8. 'Morden Sunrise' had best germination of 20% in T4. 'Champlain' and 'Frontenac' had almost identical germination responses - 17 and 19%, respectively to T3; 28 and 29%, respectively, to T4; 23 and 24%, respectively, to T7; and 25 and 24%, respectively, to T8.
Sandhu, P. and Conev, R. (2016). Effect of various stratification regimes on seed germination in cold-hardy garden roses. Acta Hortic. 1127, 231-236
seed dormancy, enzymes, cellulase, warm and cold stratification