New Zealand Journal of Agricultural Research abstracts
Allelopathic effects of endophyte-infected perennial ryegrass extracts on white
clover seedlings
B. L. SUTHERLAND
AgResearch
P.O. Box 60
Lincoln, New Zealand
D. E. HUME*
B. A. TAPPER
AgResearch
Grasslands Research Centre
Private Bag 11008
Palmerston North, New Zealand
Abstract Two glasshouse experiments were conducted to
evaluate possible allelopathic effects of perennial ryegrass/endophyte
(Lolium perenne/Neotyphodium lolii) associations on white clover
(Trifolium repens). The influence of between-species competition,
environmental stress, and soil fauna was eliminated by the use of a sterile
sand nutrient culture technique to sustain potted clover seedlings, to which
aqueous extracts from moisture-stressed perennial ryegrass pseudostem were
applied. In Experiment 1, extracts from two ryegrass cultivars (`Grasslands
Pacific' and `Grasslands Nui'), each hosting in separate seed lines two
endophyte strains (ES, WT), suppressed clover growth (mean suppression 22% at
100% concentration) relative to extracts from endophyte-free lines of the same
cultivars. The degree of suppression increased with increasing extract
concentration, differed between cultivars, but did not differ between endophyte
strains. In Experiment 2, extracts at 100% concentration from a third ryegrass
cultivar (`Grasslands Ruanui'), hosting in separate seed lines three endophyte
strains (AR4, ES, WT), suppressed clover growth by a mean of 27% relative to
extracts from an endophyte-free line of this cultivar (range 11 to 47%), with
significant differences between strains. The endophyte strains differed in
three known endophyte alkaloids, viz peramine, ergovaline, lolitrem B, but in
this study none of these alkaloids could solely account for the allelopathic
response. The suppression of clover by all ryegrass cultivar/endophyte strain
associations tested indicates that clover suppression is not confined to the
specific associations used in previous studies, and that further testing of new
associations is warranted as variation in the degree of allelopathy existed,
being dependant on endophyte strain and host ryegrass cultivar.
Keywords endophyte; ryegrass; white clover; allelopathy;
Trifolium repens; Neotyphodium lolii; Lolium perenne
New Zealand Journal of Agricultural Research, 1999, Vol. 42: 19-26
0028-8233/99/4201-0019 $7.00/0 (c) The Royal Society of New Zealand
1999
PDF file of entire paper: medium quality (649K); (scanned from paper original: notes about this process)
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