Effects of spectral quality on the micropropagation of Dendrocalamus asper (Schult. & Schult.f.) Backer and genetic fidelity analysis by ISSR

The use of different spectral qualities in the micropropagation of plant species has been extensively studied due to their effects on the morphogenesis of different tissues. In addition, the action of these lights has provided benefits such as a reduction in microbial contaminants and an increase in shoot vigour. For bamboo species, studies of the effects of spectral quality are still scarce, which, in addition to the economic importance of this species, justifies the need to understand the dynamics of in vitro development and establish routine protocols for large scale micropropagation. This study evaluated the effect of different spectral qualities: fluorescent, white, blue, red and a blue:red combination in equal proportions, on the micropropagation of Dendrocalamus asper . The experiment was conducted using nodal segments as explants, with five replicates per treatment and 20 explants per replicate, totalling 100 explants per condition. Growth parameters such as shoot length, number of leaves and contamination were recorded. The results showed that blue:red LEDs (1:1 ratio) significantly enhanced leaf formation and shoot elongation, with an average shoot length increase of 35 %, compared to fluorescent light. The red LED treatment reduced bacterial contamination by 40 %, demonstrating its effectiveness during the inoculation stage. However, none of the spectral conditions significantly improved adventitious rooting. Genetic fidelity analysis using ISSR markers confirmed the absence of somaclonal variation among the treatments, ensuring the clonal stability of the regenerated plants. • The stages of elongation and adventitious rooting in vitro of Dendrocalamus asper occur simultaneously. • Red light promotes the establishment of tissues and reduces fungal contamination. • There is a stimulus in the production of shoots with the combination of blue and red light. • Broader spectral ranges, such as white LED and fluorescent light, stimulate in vitro adventitious rooting. • Clones of Dendrocalamus asper can be produced through in vitro cultivation, maintaining genetic fidelity with the selected adult plant.