The study aimed to determine the developmental characteristics of explants from lavender cultivars and samples during prolonged in vitro maintenance under different conditions (darkness or low light) and subsequent growth recovery, as well as to assess their genetic stability. The source material comprised cultivars and samples of Lavandula angustifolia Mill.—Stepnaya, Sineva, Vdala, Volna, Krymchanka, Galleya, No. 12-95, No. 372-44, and D-356. We analyzed the development of explants (stem segments with a node) after 6, 9, and 12 months of storage at 6–8°C in darkness or under illumination of 150–300 lx, and after their regrowth in vitro at 24–26°C and 2.3 klx illumination. The number of viable explants after one year of storage under illumination (20.8–63.3%, depending on genotype) exceeded that in darkness (16.3–38.9%). All analyzed parameters varied considerably depending on the cultivar and sample. During storage, 44.5–49.8% of explants developed shoots. Upon regrowth after one year of storage under illumination, the proportion of viable explants in the first subculture reached 85.5–98.5%, whereas in darkness it ranged from only 30.0–60.0%. Morphometric parameters and multiplication coefficients were comparable to those observed during clonal micropropagation. For the cultivars Stepnaya, Sineva, and Vdala, analysis using seven molecular genetic markers (RAPD and ISSR) demonstrated no genetic divergence after one year of in vitro storage compared with the source plants. These results allowed optimization of lavender storage regimes (illumination, duration of storage, and subsequent regrowth) and confirmed the preservation of genetic stability.
Yegorova et al. (Fri,) studied this question.