Compost as a source of rizobacteria to stimulate the growth of micropropagated sugarcane plants

Compost is a source of microorganisms with different functions in plants. The objective was to evaluate the effect of rhizobacterial strains isolated from filter cake and chicken manure compost on micropropagated sugarcane plants during greenhouse acclimatization. Strains from composts obtained from mix of filter cake + chicken manure (C1 = 25:75 v/v; C2 = 50:50 v/v; C3 = 75:25 v/v and C4 = 100:0 v/v) were isolated by the technique of dilutions and spreading in plates. The isolated strains were evaluated for their ability to produce auxins and solubilize phosphates. The best strains were identified at the molecular level and inoculated into micropropagated sugarcane seedlings. 63 bacterial strains were isolated, of which 14 that presented growth promotion mechanisms were selected. The identified bacterial strains were highly similar to 7 genera: Bacillus, Enterobacter, Acinetobacter, Achromobacter, Paenarthrobacter, Weizmannia, and Staphylococus. The inoculation of rhizobacteria in sugarcane plants, during the acclimatization phase, showed that Achromobacter xyloxosidans CPOC56 and Acinetobacter viviannii CPOC48 significantly increased height (40 %), leaf area (107 %), root volume (124 %), dry weight (93 %), nitrogen (115 %) and phosphorus (133 %) content, compared with the control. The filter cake and chicken manure compost was a reservoir of plant growth-promoting rhizobacteria, the 14 selected strains with beneficial attributes belonged to 11 different species. The Achromobacter xyloxosidans CPOC56 and Acinetobacter vivianii CPOC48 strains are a good option to promote growth during the acclimatization phase of micropropagated sugarcane plants.