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Symbiotic performance of Mediterranean Trifolium spp. with naturalised soil rhizobia

Citation

Drew, EA and Charman, N and Dingemanse, R and Hall, E and Ballard, RA, Symbiotic performance of Mediterranean Trifolium spp. with naturalised soil rhizobia, Crop & Pasture Science, 62, (10) pp. 903-913. ISSN 1836-0947 (2011) [Refereed Article]


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Copyright Statement

Copyright 2011 CSIRO

DOI: doi:10.1071/CP11047

Abstract

Naturalised soil rhizobia that nodulate clover occur in high number and are known to vary in their symbiotic performance (SP) with subterranean clover (Trifolium subterraneum L.). However, the extent of suboptimal fixation across a range of other clover species is not well understood. T. subterraneum and nine other annual clover species of Mediterranean origin were evaluated for their SP in combination with the naturalised clover rhizobia in 71 Australian soils and five strains of Rhizobium leguminosarum bv. trifolii that have been used in the inoculants produced for clovers. The most probable number method, using subterranean clover as the trap plant was used to estimate the number of clover rhizobia in the soils. Ninety-two percent of soils tested contained more than 1000 rhizobia/g. An extract of each soil, or strain of rhizobia was used to inoculate plants growing in N-deficient media in the greenhouse. Plants were grown for 4 weeks after inoculation and shoot dry matter determined and expressed as a percentage of the ‘best’ soil rhizobia treatment, to provide a proportional measure of SP for each clover species. SP (mean of clover species) ranged from 96% with the current inoculant strain for annual clovers (WSM1325) down to 48% with former inoculant strain WU95. When inoculated with soils predominantly from mainland Australia, SP (mean of soil treatments) of the different Trifolium spp. was 55% (resupinatum), 53–47% (subterraneum), 50% (nigrescens), 49% (michelianum), 48% (isthmocarpum), 38% (hirtum), 35% (purpureum), 32% (vesiculosum), 25% (spumosum) and 21% (glanduliferum). Within each of the clover species, SP resulting from individual soil treatments ranged from 100% (by definition for the best soil treatment) down to close to zero. Trifolium glanduliferum formed nodules readily with the inoculant strains but nodulation was erratic with the rhizobia in many soils. It is therefore proposed that the naturalised rhizobia in many soils are unlikely to be inoculant strains. This research demonstrates symbiotic efficiency across annual clover species is compromised where diverse populations of clover rhizobia have naturalised in soils.

Item Details

Item Type:Refereed Article
Keywords:annual clover, nitrogen fixation, nodulation, Rhizobium leguminosarum bv. trifolii
Research Division:Agricultural and Veterinary Sciences
Research Group:Other Agricultural and Veterinary Sciences
Research Field:Agricultural and Veterinary Sciences not elsewhere classified
Objective Division:Environment
Objective Group:Climate and Climate Change
Objective Field:Social Impacts of Climate Change and Variability
Author:Dingemanse, R (Mr Rohan Dingemanse)
Author:Hall, E (Mr Eric Hall)
ID Code:77812
Year Published:2011
Web of Science® Times Cited:10
Deposited By:Tasmanian Institute of Agriculture
Deposited On:2012-05-30
Last Modified:2014-12-12
Downloads:1 View Download Statistics

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