New Zealand Journal of Agricultural Research abstracts
An inoculant Rhizobium strain for improved establishment and growth of
hexaploid Caucasian clover (Trifolium ambiguum)
HEATHER N. PRYOR*
W. L. LOWTHER
AgResearch
Invermay Agricultural Centre
Private Bag 50034
Mosgiel, New Zealand
H. J. MCINTYRE
C. W. RONSON
Department of Microbiology
University of Otago
P. O. Box 56
Dunedin, New Zealand
Abstract Strains of Rhizobium leguminosarum bv.
trifolii present in New Zealand soils are ineffective on Caucasian
clover (Trifolium ambiguum) and inoculation with an effective strain of
rhizobia is essential for nodulation. However, problems have been encountered
with nodulation of oversown Caucasian clover and this study was conducted to
determine whether nodulation could be improved by the use of an improved strain
of rhizobia. Five strains of rhizobia were compared with a re-isolate (ICC105)
of the recommended New Zealand commercial inoculant strain (ICMP4073b) for
their effect on the establishment of oversown hexaploid Caucasian clover in
Canterbury and Otago, South Island, New Zealand. When strains were incorporated
in peat inoculant and used to inoculate seed in a commercial pelleting process,
one strain (ICC148) increased the percentage of seedlings nodulated over that
obtained with ICC105, from 23% to 49%. In a further evaluation of these two
strains, seed was inoculated and lime-coated in the laboratory and stored for
either 1 or 20 days before oversowing on 7 tussock grassland sites. Inoculation
with ICC148 resulted in a 1.3-fold increase in the percentage of seedlings
nodulated over that obtained with ICC105. In addition, dry matter (DM) weights
of individual seedlings were increased with strain ICC148. The dry weights of
individual Caucasian clover plants after 6 and 13 months increased 1.5 and
3.0-fold, respectively, when inoculated with strain ICC148. Inter-tussock
Caucasian clover DM after 17 months was 1870 kg ha-1 for plants
inoculated with ICC105 and 3480 kg ha-1 for plants inoculated with
ICC148. Foliage N contents in spring were increased from 2.6% to 3.1%, when
seed was inoculated with ICC148. These results strongly support a change in the
Rhizobium strain recommended in New Zealand for hexaploid Caucasian
clover to strain ICC148.
Keywords Caucasian clover; inoculation; nodulation; rhizobia;
Rhizobium leguminosarum bv. trifolii; Trifolium ambiguum
New Zealand Journal of Agricultural Research, 1998, Vol. 41: 179-189
0028-8233/98/4102-0179 $7.00/0 (c) The Royal Society of New Zealand
1998
PDF file of entire paper: medium quality (1258K); (scanned from paper original: notes about this process)
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