Nodule occupancy by Rhizobium leguminosarum strain WSM1325 following inoculation of four annual Trifolium species in Canterbury, New Zealand

Abstract

The genotype of nodule occupants in four annual clovers – balansa (Trifolium michelianum), Persian (Trifolium resupinatum), gland (Trifolium glanduliferum) and arrowleaf (Trifolium vesiculosum) – was investigated. The clovers were inoculated with the ALOSCA® group C granule preparation of strain WSM1325. A total of 224 strains were recovered from root nodules with between 55 and 58 strains for each clover species. Genotyping showed that no strains had fingerprints identical to strain WSM1325. The nodule occupants were diverse with 26, 35, 31 and 32 genotypes identified on arrowleaf, balansa, gland and Persian clovers, respectively. Arrowleaf clover had some specificity for genotype A with 43% of nodules occupied by this strain. The most dominant strain for the other three clovers ranged between 13%–18% occupancy. This work demonstrates a high diversity of naturalized rhizobia strains in New Zealand soils that had the ability to nodulate these top flowering annual clover species.