Biometric, ultrastructural, and seed germination analysis of Etlingera elatior (Jack) R.M. Smith

Torch ginger is a tropical species of ornamental/landscape, medicinal, and gastronomic use in several countries. The ideal physiological conditions for its seed development are unknown, which precludes sexual reproduction for propagation of seedlings and genetic improvement of the species. Thus, the objective of this study was to understand the morphological and biometric traits of its fruits and seeds and to evaluate the effect of temperature on the germination, storage, emergence, and seedling growth of two cultivars of torch ginger to contribute to future research on the propagation of the species. The color of the fruits suffices to distinguish the cultivars, while the other biometric and ultrastructural traits are similar between cultivars. The seeds of the two cultivars showed a higher percentage of germination in the dark under a thermoperiod of 35°C for 16 h and 25°C for 8 h. The Red Torch cultivar tolerated storage for up to 30 days, while the Pink Torch seeds could be stored for up to 90 days. The emergence in substrate was greater under the thermoperiod of 35/25°C, being 30% and 20% for the Red and Pink Torch cultivars at 30 days of thermal induction, respectively, but greater seedling growth occurred at 30/25°C