Strains and doses of rhizobia influence the germination and growth of coffee plants in the pre-germinator

Abstract

The use of plant growth-promoting rhizobia is an interesting alternative to stimulate the development of coffee plants in the pre-germination phase, in the context of sustainable agriculture. The objective of this work was to evaluate the inoculation of strains and doses of rhizobia in coffee plants in pre-germination beds. The cultivars ‘Isla 5-15’ (Coffea arabica L.) and ‘Robusta’ (Coffea canephora Pierre ex Froehner) were used. A complete randomized design with a 3×3 factorial arrangement was used with additional treatment (control without rhizobia), using three strains (Rhizobium sp. Rpd16, Rhizobium sp. C1, and Bradyrhizobium elkani ICA 8001) and three application rates (0.1, 0.5 and 1.0 mL per seed) as factors. The experiment was conducted in two phases: during germination and seed development. The percentage of emergence, emergence index and emergence velocity index of the seed were evaluated in the first phase. In the second phase, seedling height and root length were evaluated. The combination of strains and rhizobia doses influenced the two cultivars in the germination phase and showed little effect in the growth phase under pre-germination conditions. The strains that showed the best response in the two cultivars were Rhizobium sp. (Rpd16) and B. elkani (ICA 8001). The doses had effects only in the germination phase and were dependent on the strains evaluated in the different indices. These results suggest the use of rhizobial strains for the integrated management of coffee plants in their initial stage.

Keywords

• coffea arabica
• coffea canephora
• seed
• emergence
• rhizobacteria