Uman National University | today: 05/30/2026
| Author(s) |
Стефанюк В. Й., , , Гапоненко А. М., , , Коховська І. В., , , Павлюк Н. В., , , |
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| Category | The Agronomy | ||
| year | 2026 | issue | Issue 108 part 1 |
| pages | 289-301 | index UDK | 633.81:631.531.02:581.142 | DOI | 10.32782/2415-8240-2026-108-1-289-301 (Link) |
| Abstract | Aims. To determine the level of photoblastic potential realization in seeds of various stevia cultivars under the influence of alternative light regimes and to identify the most adaptive cultivars. Methods. The research material consisted of the seed fund of five common stevia cultivars (Stevia rebaudiana Bertoni): Berehynia (Control), Slavutych, Kateryna, Maryna, Halyna. Factor B (Light regime) included: total darkness (B1) – seeds were sown at a depth of 0.5 cm in the substrate and additionally isolated with light-proof covering (simulation of the absence of photostimulation); constant light (B2) – 24/0 round-the-clock illumination using LED phyto-emitters with a power of 40 W/m²; natural photoperiod (B3) – cyclic lighting according to the 16 hours light / 8 hours dark scheme (long-day simulation); spectral light (B4) – monochromatic red light (wavelength λ = 660 nm) aimed at activating the phytochrome system of the seeds. Results. The study established that light regime parameters are the determining factor for the realization of the photoblastic potential of stevia (Stevia rebaudiana Bertoni) seeds. It was found that a complete lack of photostimulation in the dark variant (B1) leads to a state of deep seed dormancy, where germination is 0%, and the level of infestation by pathogenic microflora (molding) increases to 19.3–28.4%. The highest quality indicators were obtained under the influence of monochromatic red light (λ = 660 nm), where laboratory germination reached 82–86%. It was determined that the optimization of the light regime contributes to the improvement of morphometric parameters: the length of the primary root increased to 3.20–4.10 cm, and the hypocotyl length to 2.8–3.5 cm, depending on the genotype. The Berehynia cultivar showed the highest resistance to phytopathogenic pressure and the best response to photostimulation, ensuring a minimum level of molding (0.5%) and the highest Relative Light Requirement (RLR) index. Analysis of variance (ANOVA) proved that the share of the light factor's influence on the formation of germination energy and germination rate is 61.6%, while the contribution of cultivar characteristics is 24.8%. The coefficient of variation of the studied indicators did not exceed 4.2%, which confirms the high reliability of the results. It was established that the use of rational light regime parameters not only maximizes seed germination but also performs a fungistatic function, reducing the risk of seedling death in the early stages of ontogeny. Conclusions. The photoblastic nature of stevia seeds requires mandatory light stimulation for successful germination. Red light (λ = 660 nm) is the most effective regulator of germination and immune status. Among the studied genotypes, the Berehynia cultivar is recommended for intensive seedling technologies due to its high adaptability and resistance to fungal pathogens. | ||
| Key words | photosensitivity, germination, viability, infestation, light | ||