Influence of Seasonal Variation and Growth Conditions on Seed Germination of Ebolo (Crassocephalum crepidioides and Crassocephalum rubens) Vegetables

Background and Objective: Crassocephalum crepidioidesand C. rubens are plants indigenous to tropical Africa. They are important orphan crops that are highly nutritious but are still mainly harvested from the wild. One major challenge that limits the cultivation of these crops is the high degree of seed dormancy, which makes it difficult to propagate through seeds. This study aimed to investigate the effects of growth conditions, media, and seasonal variation on the seed germination capacity of C. crepidioidesand C. rubens.Materials and Methods:Crassocephalum crepidioidesand C. rubensseeds were cultivated in the greenhouse across two growing seasons: Winter and summer. Seed germination tests were conducted using two different growth media: Filter paper and half-strength Murashige and Skoog (½MS) medium. Seeds were incubated at varying temperatures (21 and 25°C), light intensities (30, 80 μmoL/m²/sec), in the dark, and long-day photoperiod (16 hrs of light/8 hrs of darkness). Results: Both species exhibited a high degree of seed dormancy in the dark, but light and temperature promoted germination, with light having a stronger effect on seed germination of C. rubens.Germination was faster on filter paper for both species compared to ½MS medium. Notably, C. rubens seeds harvested in the winter exhibited higher dormancy than C. crepidioides, while summer-harvested C. crepidioides seeds showed increased dormancy compared to C. rubens. Conclusion: Overall, C. crepidioidesexhibited higher dormancy compared to C. rubens and required light and temperature to break out of dormancy. Improved seed germination was observed on filter paper, while seasonal variation influenced the dormancy level in Crassocephalumseeds.