Effect of endophytic bacterial inoculation on banana, Musa x paradisiaca 'Lakatan'

The effectiveness of endophytic bacteria (EB) inoculation on banana cv. 'Lakatan' was evaluated under nursery and field conditions. Preliminary observations on EB inoculation with isolate MUCp 12 showed that it can significantly affect plant height (PH) and pseudostem diameter (PD) of banana. In addition, EB inoculation was comparable to inorganic fertilizer (IF). The root dry weight and total dry matter weight yield (TDMY) were also enhanced significantly. Inoculation with bacterial endophytes did not have a significant effect on the N content of banana. In contrast, a highly significant effect was observed in the total P and total K content of inoculated plants. Nutrient uptake by banana revealed that EB inoculation significantly increased the P uptake as also seen in the total P. The interaction effect of EB inoculation and IF application was also determined. PH was not significantly increased. Nevertheless, the interaction effect was able to enhance this parameter. In contrast, there was a significant effect on the PD of banana. The T60 + MUCp 14 treatment performed best. However, the effect of this treatment was not significantly different from inoculation with isolate MUCp 12 and inoculation combined with lower rate of IF application. This suggests that inoculation alone can increase PD. Results showed that there were no significant differences among treatments in terms of biomass yield. However, inoculation with isolate MUCp 12 and MUCp 14 increased the shoot dry weight and TDMY of banana. The significant effect on P content was attributed to inoculation with isolate MUCp 14. However, the effect seemed to be detrimental when combined either the T30 or T60 treatments. In terms of N content, same observation was seen when isolate MUCp 12 was used. In terms of the N, P and K uptake of banana, no significant differences were observed among treatments. Overall observations on the growth parameters of banana under field conditions revealed that there were highly significant differences among treatments. Generally, treatment T60 had the greatest effect in enhancing PH followed by the treatments T60 + MUCp 12 and T30 + MUCp 12. In contrast, PD was enhanced by the treatment T60 + MUCp 12. In terms of LAI, it was increased when isolate MUCp 12 was coupled with either the lower or higher rate of IF application. Results showed that inoculation with isolate MUCp 12 significantly increased the total N, total P and total K contents of banana leaves. However, its combination with either the T30 of T60 rate of IF resulted to lower values. It was observed and recorded that treatment T30 + MUCp 12 was the first to manifest signs of flowering and fruiting followed by treatment T60 then T30. The improved growth and development of the inoculated plants could possibly be due to the production of growth promoting substances by the endophytic bacteria. Based on the results, EB inoculation is recommended at the nursery stage for seedling establishment. Proper identification and characterization of the bacterial endophytes through bioassays are highly advised. Moreover, this study requires further research to verify the outcome of the experiments. Testing in other crops and modification in inoculation methods will be of great help.