Screening and field evaluation of white clover rhizobia for New Zealand pastures

Context Biological nitrogen (N) fixation through the rhizobia–legume symbiosis is a sustainable and cost-effective source of N for agriculture. In New Zealand (NZ), white clover (Trifolium repens) key component pastures rhizobial inoculation widely used. The current commercial inoculant clover, TA1, was isolated in Australia 1950s may not be best partner modern cultivars.Aims To identify Rhizobium leguminosarum bv. trifolii (Rlt) isolates suitable use NZ pastures.Methods symbiotic potential >230 collected from throughout evaluated plant bioassays. Selected were further pot field trials.Key results Approximately 40% supported better growth than TA1 under N-limited conditions vitro. Of 24 Rlt glasshouse trial, five produced significantly higher biomass TA1. Three (S11N9, S20N7, S4N6) nine two trials 2018–2019 increased (12–38%) compared with paired uninoculated at several harvests, whereas did improve yield. third trial 2020, S11N9 S20N7 control three harvests; S4N6 performed one harvest. When tested four cultivars, had TA1.Conclusions Inoculating would beneficial if improved available.Implications We recommend some could developed into inoculants to performance NZ.