Optimization of the composition of growth regulators to stimulate vegetative propagation of saffron (Crocus Sativus L.) in in vitro culture

Abstract

Goal. To determine the optimal composition of growth regulators of vegetative organs of saffron to stimulate its reproduction in an in vitro culture. Methods. The study was conducted in 2023–2024 in a microclonal laboratory using the following methods: visual (conducting phenological observations), measuring-weight (determining biometric indicators and productivity), chemical (establishing qualitative indicators), mathematical statistical (determining the reliability of the results obtained), as well as dispersion and regression analysis (mathematical processing of experimental data). Results. The positive reaction of saffron explants (Crocus sativus L.) to its cultivation by in vitro method was established. Auxins of the nutrient medium activated the cells before division, while the division itself was initiated by cytokinins. In other words, under the conditions of dual hormonal control, induction mechanisms were triggered in explants, which led to the beginning of the formation of callus culture. The growth hormones used were: 6-benzylaminopurine (BAP), b-pindolylbutyric acid (PBA), and b-naphthylacetic acid (NAA). The highest incidence of true shoots (up to 21%) was observed with BAP (1.0 mg/L), and PBA (0.5 mg/L). The combination of BAP, 1.0 mg/L, with PBA, 1.0 mg/L, was effective for inducing root formation. Conclusions. It was determined that different combinations of components of the nutrient medium influenced not only the survival rate of explants, but also the dynamics of their morphogenetic development. The first to awaken were the lateral apical buds, from which leaves were formed. Generative apical and small lower buds were activated a little later. Optimal for the activation of physiological processes was the medium with a combination of phytohormones BAP (1.0 mg/l) + PBA (0.5 mg/l), in which on the 120th day the share of recovered regenerated explants was the largest — 58%.