Resumen

PILATUNA QUISHPE, María Fernanda; GONZALEZ-PARRA, Marilú Manuela; MERO GARCIA, Manuel Efraín  y  RISCO ARIAS, David. Agronomic evaluation of nitrogen-fixing bacteria isolated from Andean soils in lettuce and tomato seedlings. Investig. Agrar. [online]. 2021, vol.23, n.1, pp.47-52. ISSN 2305-0683.  https://doi.org/10.18004/investig.agrar.2021.junio.2301680.

The prolonged use of synthetic chemical fertilizers produces negative effects on the fertility of the soil. As an alternative, the use of microorganisms in agriculture has been proposed in recent years. The objective of this trial was to evaluate the agronomic efficiency of isolates of microorganisms from different soils with native Andean crops in the germination and growth of tomato and lettuce plants. To do this, free-living nitrogen-fixing bacteria were isolated and selected using Ashby medium in soils and rhizosphere of amaranth (Amaranthus quitensis Kunth), blackberry (Rubus glaucus Bentham), white carrot (Arracacia xanthorriza Bancr.) And mashua (Tropaeolum tuberosum Ruiz & Pav.). Subsequently, physiological and biochemical tests were carried out to select bacteria that resembled the genus Azotobacter sp., and were inoculated in greenhouse crops of lettuce and tomato, from February to April 2018, where the days to germination, plant height, and number of leaves were measured, and an analysis of variance and Tukey’s test were performed to assess whether there were statistical differences between the treatments. In the inoculation of 3 strains in the tomato crop, a significant advance in the germination time of 3-4 days was observed. In 9 of the treatments, a significant increase in the height of both tomato and lettuce plants was observed, and the number of leaves significantly increased in 6 lettuce and 3 tomato treatments. The bacterial strain that obtained the best results was isolated in the rhizosphere of the blackberry crop.

Palabras clave : Azotobacter sp.; Lactuca sativa; Solanum lycopersicum; ammonium fixation; germination.

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