Scientia Horticulturae 211 (2016) 248–254 Contents lists available at ScienceDirect Scientia Horticulturae journal homepage: www.elsevier.com/locate/scihorti In vitro proliferation and ex vitro rooting of microshoots of commercially important rabbiteye blueberry (Vaccinium ashei Reade) using spectral lights Cao Dinh Hung a,b,∗ , Chang-Hee Hong a,b,∗ , Seon-Ki Kim a , Kyu-Han Lee a , Jea-Young Park a , Cao Dinh Dung c , Min-Woo Nam a , Dae-Ho Choi a , Hye-In Lee a a LED Agri-bio Fusion Technology Research Center (LAFTRC), Chonbuk National University, Iksan Campus, 79 Gobong-ro, Iksan-si, Jeollabuk-do 570–752, Republic of Korea b Laboratory for Horticultural Lighting and Monitoring (Satellite lab of LAFTRC), National University of Science, Linh Trung Campus, Thu Duc District, Ho Chi Minh City, Vietnam c Potato, Vegetable and Flower Research Center, Institute of Agricultural Science for Southern Vietnam, 79 Ho Xuan Huong Street, Ward 12, Dalat City, Lamdong Province, Vietnam a r t i c l e i n f o Article history: Received 2 March 2016 Received in revised form 2 August 2016 Accepted 2 September 2016 Keywords: Clonal propagation Enhanced ventilation LED-light Root regeneration Shoot growth Vaccinium ashei a b s t r a c t Efficient protocols for in vitro shoot growth and ex vitro root formation from in vitro-derived shoots under light-emitting diodes (LEDs) with simple ventilation were developed for rabbiteye blueberry cv. ‘Titan’. Red LEDs promoted shoot elongation while blue LEDs induced short shoots with enhanced accumulation of leaf chlorophyll contents. A combined treatment of 80% red with 20% blue LEDs was found the most suitable for plant growth, and more effective than 50% red mixed with 50% blue LEDs or fluorescent lamps as the control treatment. The use of ventilated vessels with ambient CO 2 enrichment from a growth chamber resulted in healthy plants having greatly improved shoot length, leaf expansion, leaf chlorophyll contents and dry weight of both shoots and roots. In vitro-cultured shoots could be directly rooted at 100% under non-sterile conditions using a perlite-peat mixture with careful controls of high humidity. These results suggest that LEDs, particularly when coupled with ventilated vessels, should be used as a primary light source for replacing conventional fluorescent tubes in large-scale production of rabbiteye blueberries. © 2016 Elsevier B.V. All rights reserved. 1. Introduction The rabbiteye blueberry (Vaccinium ashei syns. V. virgatum, V. amoenum), a member of the family Ericaceae, is native to the North American subtropical regions and mostly found in the southeastern United States (Prodorutti et al., 2007; Yadong et al., 2003). Similar to other Vaccinium species including highbush blueberry (V. corym- bosom), lowbush blueberry (V. angustifolium) and half-highbush blueberry (V. corymbosum × V. angustifolium), rabbiteye blueberry Abbreviations: B, 100% blue LEDs; FL, Fluorescent lamps; LEDs, Light-emitting diodes; R, 100% red LEDs; R5B5, 50% red plus 50% blue LEDs; R8B2, 80% red plus 20% blue LEDs; MS, Murashige and Skoog; MW, Medium containing 50% MS plus 50% WPM; WPM, Woody Plant Medium. ∗ Corresponding authors at: LED Agri-bio Fusion Technology Research Center, Chonbuk National University, Iksan Campus, 79 Gobong-ro, Iksan-si, Jeollabuk-do 570-752, Republic of Korea. E-mail addresses: caodinhhungvn@yahoo.com (C.D. Hung), chhong@jbnu.ac.kr (C.-H. Hong). shrubs are of commercial importance, owing to their small fruits containing high contents of antioxidant phenolic compounds for human health benefits, such as anthocyanins, flavonols and phe- nolic acids (Debnath, 2007, 2009; Howell, 2009; Tetsumura et al., 2012). Despite this similarity, rabbiteye blueberry cultivars can pro- duce tall plants of up to 20 feet with much longer fruitful lives (approx. 20 years) and lesser vulnerability to diseases than those of other blueberry species (Prodorutti et al., 2007; Yadong et al., 2003). Propagation of blueberry crops using true seeds exhibits high rates of heterozygosity (Prodorutti et al., 2007; Sedlak and Paprstein, 2009). Therefore, blueberry bushes are conventionally propagated vegetatively by stem nodal cuttings for preserving their genetic structure and uniformity, however, this conven- tional method is costly, labour-intensive, time-consuming, and commonly faces challenges in rooting capacity (Litwi ´ nczuk, 2013; Litwi ´ nczuk et al., 2005; Meiners et al., 2007; Zhao et al., 2011). These shortcomings can be overcome through the use of in vitro propagation techniques to allow rapid multiplication of elite geno- http://dx.doi.org/10.1016/j.scienta.2016.09.003 0304-4238/© 2016 Elsevier B.V. All rights reserved.