Horticultural Science and Technology ISSN:1226-8763(Print) 2465-8588(Online) 원예과학기술지

This study was carried out to investigate a method for producing cultured virus - free ovules for breeding high - quality Citrus cultivars. Ovules from the immature fruits of three Citrus cultivars native to Jeju (Dongjeongkyool, Cheongkyool, and Jikak) and two cultivars of Citrus unshiu Marc. (Miyagawa wase and Haryejosaeng) that were thought to be infected with Citrus tristeza virus (CTV) were cultured on MS2 medium (Murashige - Skoog [MS] basal medium containing 500 mg·L^-1 malt extract, 50 g·L^-1 sucrose, 1.0 mg·L^-1 kinetin, and 8 g·L^-1 agar). After four weeks of culture, 10, 21, 13, 5, and 7 somatic embryos and 2, 4, 2, 4, and 5 white callus cells (surrounding green somatic embryos) were obtained from Dongjeongkyool, Cheongkyool, Jikak, Miyagawa wase, and Haryejosaeng, respectively. After six weeks of culture, somatic embryos were obtained from cultured cells grown on MT basal medium supplemented with malt extract (500 mg·L^-1), lactose (70 g·L^-1), and agar (16 g·L^-1). Over 60% of the somatic embryos from Citrus cultivars native to Jeju developed into normal plants on MS basal medium supplemented with malt extract (500 mg·L^-1), sucrose (50 g·L^-1), and agar (8 g·L^-1) after 10 weeks of culture. Normal plants were regenerated from two Citrus unshiu Marc. cultivars on MT basal medium supplemented with sorbitol (1.0 M), galactose (1.0 M), GA3 (1.0 mg·L^-1), and Gelrite (3 g·L^-1). The absence of virus in plants generated from cultured ovules was confirmed by RT - PCR and antigen - antibody reactions. Therefore, virus - free Citrus cells can be obtained for breeding high - quality Citrus cultivars using the biotechnological technique evaluated in this study.