La caracterización de los recursos genéticos, es de vital importancia para su aprovechamiento en programas de fitomejoramiento. En Stevia rebaudiana Bert., se demandan genotipos con atributos químicos y agronómicos deseables; por ello, el objetivo de la investigación fue, caracterizar morfoagronómicamente 25 clones de estevia, derivados del cruzamiento al azar entre plantas de la variedad Morita II, mediante la aplicación de descriptores (11 características cuantitativas y ocho cualitativas), sobre cinco plantas al azar de cada genotipo, teniendo en consideración la moda y frecuencia de cada descriptor, el análisis de componentes principales y un dendograma mediante el método de Ward. Las características agronómicas hábito de crecimiento erecto, rendimiento de follaje y número de días a floración superior a los 50 días, permitieron la selección de los clones 04, 09, 13, 16, 18, y 19. A su vez, se identificaron dos componentes que explicaron un 69.41% de la varianza, el primero aportando un 47,74% y el segundo, un 21,67% de la variación total, soportado por caracteres relacionados con el rendimiento, lo que resulta de interés para adelantar programas de mejoramiento genético en la especie

Cultivating Limnospira maxima, renowned for its abundant proteins and valuable pigments, faces substantial challenges rooted in the limited understanding of its optimal growth parameters, associated high costs, and constraints in the procurement of traditional nitrogen sources, particularly NaNO₃. To overcome these challenges, we conducted a comprehensive 4 × 3 factorial design study. Factors considered included white, red, blue, and yellow light spectra, along with nitrogen sources NaNO₃ and KNO₃, as well as a nitrogen-free control, for large-scale implementation. Optimal growth, measured by Optical Density, occurred with white and yellow light combined with KNO₃ as the nitrogen source. These conditions also increased dry weight and Chl-a content. Cultures with nitrogen deprivation exhibited high values for these variables, attributed to carbon accumulation in response to nitrogen scarcity. Phycocyanin, a crucial pigment for nutrition and industry, reached its highest levels in cultures exposed to white light and supplemented with KNO₃, with an impressive content of 384.11 g kg⁻¹ of dry weight. These results highlight the efficacy and cost-efficiency of using a combination of white light and KNO₃ for large-scale L. maxima cultivation. This strategy offers promising opportunities to address global food security challenges and enhance the production of industrially relevant pigments.

Conventional fertilizers often result in the accumulation of chemical residues in the environment with a significant threat to ecosystems, with leaching to the groundwater disrupting the delicate balance of ecosystems. To mitigate the adverse effects of chemical residues, we need new methods and the use of eco-friendly alternatives. Cyanobacteria could play a crucial role in sustainable agriculture by reducing the partial/complete use of synthetic fertilizers. This study assessed the impacts of different concentrations of Limnospira maxima extract on the physiological aspects of Vigna unguiculata, Stevia rebaudiana, and Solanum melongena. The gas exchange parameters, chlorophyll a fluorescence, and phenotypic characteristics were measured. The net photosynthesis (A_N) of V. unguiculata, S. rebaudiana, and S. melongena increased by 23%, 40%, and 44%, respectively, upon the application of cyanobacteria extracts. Furthermore, the quantum yield of photosystem II showed that the extract application enhanced this response in the three species by 8.7%, 4.8%, and 11.3%, respectively. Similar results were found in the total plant biomass production with significant increases of 17%, 130%, and 80% with respect to the control. Moreover, a positive correlation was observed between A_N and the majority of the evaluated parameters, which could illuminate the plant’s responses to the studied treatments. The promising potential of this cyanobacteria as a biofertilizer was accentuated.

Fusarium wilt, caused by Fusarium oxysporum f. sp. cubense tropical race 4 (Foc TR4), threatens banana and plantain production throughout South America. Because Colombian biosafety regulations restrict in vitro work with Foc TR4, we tested the antifungal activity of Nostoc commune against F. oxysporum race 2 isolated from cv. ‘Manzano’ (Musa AAB). An ethanolic extract of the cyanobacterium (EEC) was profiled by gas chromatography and evaluated with a Kirby–Bauer assay (1000–4000 ppm; n = 4). Synthetic Sico^® and botanical Timorex^® served as positive controls, and solvent-free plates were the negative control. Growth reduction (GR) and percentage inhibition of radial growth (PIRG) were analysed with Student’s t-test (α = 0.05). Forty-two compounds—mainly fatty and carboxylic acids associated with antifungal activity—were detected. Sico achieved complete inhibition (100 ± 0%), Timorex suppressed 76 ± 2%, and 4 000 ppm EEC curtailed mycelial expansion by 45 ± 3% (p < 0.01). Although less potent than commercial fungicides, EEC impeded F. oxysporum growth, demonstrating that N. commune synthesises bioactive metabolites. Optimising cyanobacterial cultivation and formulation could yield a sustainable biocontrol alternative for managing Fusarium wilt in the region.

Limnospira maxima is widely cultivated due to its abundance of proteins, carbohydrates, vitamins, minerals, essential fatty acids, and phycobiliproteins. However, limited information, high production costs, and nitrogen source limitations have hindered the optimal utilization of this cyanobacteria. The main goal of this study was to address these limitations by identifying ideal cultivation parameters to maximize yields, reduce costs, and contribute to global food security. It was demonstrated that the white and yellow light spectra are the most suitable for cultivating L. maxima, and the use of KNO3 as a nitrogen source proved to be the most cost-effective on a large scale. Nitrogen deficiency stimulates the production of dry biomass but also affects the concentration of key pigments such as chlorophyll and phycocyanin. A notable characteristic of L. maxima is its adaptability and survival capability in various environmental conditions, including nitrogen-deficient environments. This resilience is achieved through the degradation of phycobilisomes and the storage of glycogen. By identifying the optimal growth conditions and understanding the physiological responses of L. maxima, cultivation practices can be improved to be more efficient and sustainable.

The cyanobacteria Nostoc commune contains bioactive compounds with antimicrobial activity and high potential to control of phytopathogens. The objective of this work was to determine the in vitro effect of sonicated biomass of these cyanobacteria on the growth of Fusarium oxysporum. The biomass of N.commune was dissolved in sterile distilled water and subjected to centrifugation processes and ultrasound-assisted cell rupture. The antifungal effect was evaluated using the disk diffusion technique (Kirby-Bauer) in a PDA (Potato Dextrose Agar) medium. In the center of the Petri dish, an agar disk (0.7 cm) with pure mycelium of the fungus was placed in the center of the Petri dish and, around it, four filter paper disk impregnateed with the algae extract (0.7 cm) were placed. The radial growth of the pathogen was measured in the presence and absence of N. commune, until the control covered the entire Petri dish to assess the Percentage of Radial Inhibition of the pathogen (PICR %). The growth rate of the fungus was lower in the initial stages of measurement and the PICR fluctuated between 33 and 58%. However, there were no inhibition halos in the growth of the fungus, it is assumed that the antifungal effect of the cyanobacteria was not permanent over the time, but it could be potentiated by improving the extraction process of the extract.