Seed germination and seedling morphology of three cultivated pitaya (Hylocereus undatus, Hylocereus polyrhizus and Selenicereus megalanthus)

Hylocereus undatus, H. polyrhizus, and Selenicereus megalanthus possessed higher economic value. Identification of the differences in seed germination and the seedling morphology will contribute to the efficient breeding and planting of three cultivated pitaya. A series of seed germination and seedling morphology experiments were conducted to investigate differences in the parameters among Hylocereus undatus, H. polyrhizus, and Selenicereus megalanthus. Results indicated that H. undatus and H. polyrhizus had significantly higher seed germination percentage than S. megalanthus under the same treatment conditions; however they had significantly lower seedling fresh weight than S. megalanthus on the 14^th day after pregermination. Seedling fresh weight and seedling length of S. megalanthus were significantly higher than those of H. undatus and H. polyrhizus, but no differences were presented in the root total length of the seedlings among H. undatus, H. polyrhizus, and S. megalanthus on the 60^th day after seedling transplantation.