Resumo

CRIOLLO, Paola Jimena; OBANDO, Melissa; SANCHEZ M., Leonardo  e  BONILLA, Ruth. Effect of plant growth-promoting rhizobacteria (PGPR) associated to Pennisetum clandestinum in the altiplano cundiboyacense. Corpoica cienc. tecnol. agropecu. [online]. 2012, vol.13, n.2, pp.189-195. ISSN 0122-8706.

Pennisetum clandestinum (kikuyo) is a common pasture in the altiplano cundiboyacense silvopastoral systems, which possesses high nutritional value. Therefore, studies to improve the production process in both economic and environmental terms are very important. The role of inoculation with plant growth- promoting bacteria was evaluated on the growth of kikuyu grass. The 4K and 5B strains were identified, through amplification and analysis of their 16S rDNA, as members of the Stenotrophomonas and Pseudomonas genera, respectively. They were characterized in vitro for their efficiency of biological nitrogen fixation, production of indole compounds, and phosphate solubilization. Four treatments were evaluated under greenhouse conditions. Furthermore, the biomass was evaluated at different stages of the plant (70, 100 and 130 days). The 4K strain demonstrated a root dry weight that increased by 50% at 70 and 100 days and the 5B strain showed a statistically significant behavior for plant and root dry weight with an increase of 50% at 130 days. The most important effect was presented after 100 d where treatments, TQ, TB1 and TB2, exceeded more 80% to absolute control in the fresh weight of the air. These results showed that inoculation with PGPR represents a biotechnological alternative to promote growth of P. clandestinum, as we observed relevant effects on biomass production 100 days after planting.

Palavras-chave : silvopastoral system; grasses; biological nitrogen fixation; indolic compounds; phosphate solubilization.

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