Camellia sinensis (L.) O. Kuntze is a woody perennial, evergreen shrub or small tree native to Southwest China, whose leaves are processed into various types of teas for consumption. Harvesting mature tea seeds typically requires 12 to 14 months, with an additional 2 to 3 months needed for germination using traditional methods. In an effort to expedite this breeding cycle, we conducted aseptic germination experiments on immature embryos of Camellia sinensis fruits collected from different months, spanning from May to September. Visible embryos were observed in immature fruits harvested in late July, exhibiting an average size of 2.17 ± 0.33 cm, and demonstrated germination capabilities only after mid-August. These embryos were excised and cultured on Murashige and Skoog (MS) medium supplemented with 3% sucrose and 0.65% agar. Cultures were maintained in a growth chamber set at 24°C under a 16-hour photoperiod. To enhance the germination process, cultures were kept in darkness for the initial two weeks. Immature embryos initiated germination approximately one to two weeks after the initiation of culture. After two months, plantlets were transplanted into a substrate consisting of peat moss and perlite (1:1 v/v) and acclimatized in a mist system within a greenhouse. Five month post-culture initiation, the average shoot length, root length, and leaf number of transplanted plantlets were recorded as 2.24 ± 0.89 cm, 5.61 ± 4.58 cm, and 8.36 ± 2.84, respectively. Preliminary findings suggest promising outcomes, demonstrating the feasibility of in-vitro embryo germination in tea plants. This methodology holds the potential to mitigate late-term abortion of hybrid embryos and significantly shorten the breeding cycle, critical aspects in breeding triploid tea varieties through crossbreeding diploid and tetraploid tea plants.
