Growth Promoting Rhizobacterium Effects on Coffea arabiga Scion onto Robusta Rootstock

Abstract

Context: No reports about the response of the main Coffea arabica L. genotypes grafted onto Coffea canephora in the presence of plant growth promoting rhizobium have been found yet. Aim: To evaluate the effect of Rhizobium alamii Rpr2 on C. arabica L. development while grafted onto C. canephora (Robusta). Methods: The trial was conducted under a randomized block design, with a 4x2 factorial arrangement, in four replicas. The factors were four C. arabica L. genotypes. (Isla 6-14, Isla 5-15, Isla 6-11, and San Ramón), and two rhizobium application levels (with rhizobium or without it). The days to inosculation were evaluated, along with the percentage of graft inosculation, graft height, graft stem height, number of graft leaf pairs, foliar area, dry leaf mass, root growth, root volume, and root dry mass. Results: The results showed the interaction between the grafted C. arabica species, and strain R. alamii Rpr2. The inoculated scion Isla 6-14/Robusta showed a better response than the other treatments and the control, which makes it a suitable variant for coffee growing. Conclusions: The utilization of plant-growth promoting bacteria is an effective alternative for grafting stimulation and development, which might lead to greater availability of plantlets ready for large-scale planting in the field.

Keywords

• genotypes
• rhizobium
• plant nursery