HortScience (Sep 2023)
‘Taoyuan No. 3-Spring Red’ and ‘Taoyuan No. 4-Red Glory’, the New Cultivars of Cherry Blossom in Subtropical Area
Abstract
Cherry blossoms belong to the genus Prunus within the family Rosaceae. There are ∼100 species of indigenous plants, mainly distributed in temperate regions of the Northern Hemisphere, and there are more than 200 cultivated varieties (Obha et al. 2007). For blooming successfully in spring, it is necessary for those deciduous trees to undergo a period of chill beforehand. During the flowering period, the entire tree is devoid of leaves while the flowers blossom profusely on the branches, making it more aesthetically valuable. Cherry blossom viewing holds significant cultural importance in many temperate countries and plays a crucial role in international tourism activities (McClellan 2005). Taiwan is located at the junction of the subtropical and tropical climatic zones in the Northern Hemisphere, with the Tropic of Cancer, at the latitude of 23.5°, passing through the southern regions of Taiwan’s main island. The central and northern regions of Taiwan are characterized by a subtropical climate. According to the Flora of Taiwan (Editorial Committee of the Flora of Taiwan 1993), there are 11 native species of the Prunus genus in Taiwan. Among them, Taiwan cherry (Prunus campanulata Maxim) is distributed in southern China, Ryukyu Islands, and Japan, as well as in broad-leaved forests at high elevations (500–2000 m) throughout Taiwan (Editorial Committee of the Flora of Taiwan 1993). The native Taiwan cherry, displaying a range of flower colors from light pink to deep purple red, naturally blooms from January to March. Due to the mild winter climate in lower altitude areas of Taiwan, the selection of cherry blossom cultivars for landscape applications has been limited. Seed-propagated seedlings have been widely used for landscape purposes in urban and suburban areas, particularly in low-altitude regions (<500 m) (Newsroom Compilation 2006) in northern Taiwan. Within the population of Taiwan cherry trees, prolonged hybridization has contributed to a significant level of genetic diversity, resulting in individual specimens with variations in flower color, flower morphology, and heat and cold tolerance (Liou 2018). Previous studies and evidence have indicated the essentiality of the chill accumulation during the winter for the budbreak of deciduous woody plants (Arora et al. 2003; Erez et al. 1979). Insufficient chill accumulation has been found to result in incomplete development of floral bud organs (Fadón et al. 2021; Wang et al. 2016; Yamane et al. 2011), as well as a reduction in the germination of dormant buds (Erez and Couvillon 1987; Ferlito et al. 2021). The smaller quantity of flowers or variations in flowering periods among landscape Taiwan cherry trees in the same area was often observed. The new cultivars, Taoyuan No. 3-Spring Red and Taoyuan No. 4-Red Glory, were selected from local races in the central and northern regions of Taiwan. Through single plant selection, line observation, and comparative trial, these two cultivars were selected for their low chilling requirement for earlier flowering habits, good ratio of tree height to width, and high adaptability to local terroir, making them suitable for landscape applications in subtropical areas.
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