Torulaspora globosa: Rhizosphere yeast promoting lettuce growth on seedlings and under field conditions

Abstract

Among soil microorganisms, one group stands out as beneficial to agricultural activities: a plant growth-promoting rhizobacteria (PGPM). These microorganisms support plants through phytohormone production, nutrient provision and plant health maintenance. Among these PGPM, yeasts have a high potential, which is still not very well known.This study aimed to evaluate the effect of inoculation with the rhizosphere yeast Torulaspora globosa (strain 5S55) on development of lettuce (cv. Crocantela). The first research consisted of inoculating seeds with yeast (100 cells/seed), and inoculating seeds, 7 and/or 15 days after emergence (DAE) (1x106 cells/plant). The second one consisted of transplanting seedlings from the first experiment to field. Inoculation of seeds and seedlings provided a significant increase of seedling root dry mass; we observed the significant increase of 27% in productivity of lettuce under field conditions, of shoot fresh mass and a raise of number of leaves per plant. However, studies on inoculation methods, inoculum formulation, cell concentration are essential to optimize the results in growth promotion and to establish technology.