Thidiazuron-induced somatic embryogenesis and changes of antioxidant properties in tissue cultures of half-high blueberry plants

An efficient protocol of somatic embryogenesis (SE) has been developed for the first time in four half-high blueberry (Vaccinium corymbosum L. × V. angustifolium Ait.) cultivars. Thidiazuron (TDZ), a plant growth regulator with potential activities for shoot regeneration and shoot proliferation, was found most effective for somatic embryo formation when added to a nutrient medium at high concentration (9 µM). Although TDZ was also best for embryo germination at low concentration (2.3 µM), it was followed by zeatin at 4.6 µM for the same. Plantlets developed from SE were removed from the nutrient medium and transferred on a peat: perlite medium where 100% survival rate was acquired following the acclimatization process in a greenhouse. The concentrations of total phenolic and flavonoid contents were higher in greenhouse-grown conventionally cutting-propagated donor mother plants than those of respective SE plants for ‘St. Cloud’, ‘Patriot’ and ‘Northblue’ but not for ‘Chippewa’. The effect of propagation method and/or the older age of donor mother plants were clearly visible exclusively as the 15-year-old donor plants showed higher level of 2,2-diphenyl-1-picrylhydrazyl scavenging activity than the eight-weeks-old SE plants in all four cultivars.