Assessing the interaction between acid-tolerant strains of rhizobia and faba bean – Tamworth 2022.

Abstract

Key points • Several high-performing (acid-tolerant) rhizobia strains have been recently tested for their ability to nodulate pulse crops. Most tests have been conducted in acidic soils, with a small number in alkaline soils. • The nodulation ability of 2 high-performing strains (SRDI969 and WSM4643) on faba bean was tested at Tamworth in 2022. These strains were compared with the current Australian commercial inoculant group E/F strain, WSM1455 • Where rhizobia were applied to seed not treated with fungicide (common practice for faba bean), roots inoculated with SRDI969 and WSM4643 had nodule numbers equal to or higher than seed inoculated with the commercial strain. Where seed was inoculated with SRDI969, root nodule numbers were significantly higher than the commercial strain. • No yield increases were recorded for seed inoculated with SRDI969 and WSM4643, compared with WSM1455 inoculation. • The National Rhizobium Steering Committee (NRSC) has endorsed a strain change from WSM1455 to SRDI969 for faba bean inoculation. The new strain is available to growers for the 2024 season.