This study was designed to evaluate the efficiency, select the best performing bacteria and fungi isolates for phosphate solublization and yield attributes of coffee seedlings under nursery condition. The study was conducted at Jimma Agricultural Research Center during February to August 2019, in plastic pots. This study was carried out in CRD in three replications per treatments. The experiment has 4 sets where set 1 had the bio-inoculant factors and phosphate factor combined factorially. Set 2 had 3 factors (3PSF, 3PSB and 2 p levels) in factorial combinations. Set 3 has single factor (the 6 inoculants under basal VC (300g/1.5kg soil). Set 4 was a two factor trial: PSF (3 levels) and PSB (3 levels) combined factorially under basal VC. All sets had negative and positive (rec. NP) controls, and set 3 and 4 had sole VC as additional control unit. Bio-inoculant and phosphate combination were significantly responded to all growth attributes. Moreover, co-inoculation of RSCF1.19 with three bacterial isolates (RCHVCB1, RScB1.19, and RMaB2.11) in combination with phosphate led to significantly higher tested growth parameters. Similar increase in growth attributes were observed in both single and dual inoculation due to VC used when compared with both positive and negative control. Non-significant but higher NPK-uptake were observed in a combination of bio-inoculants and phosphate fertilizer compared to the positive and negative control. The combination of VC with RSCF1.19 and RLVCF2 fungal isolates can be recommended as bio-inoculants for solublizing inorganic phosphate and to obtain vigor and healthier coffee seedlings in south west soil of Ethiopia for coffee Arabica cultivation.
