New Zealand Journal of Agricultural Research abstracts

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Cyanogenesis potential and iodine concentration in white clover (Trifolium repens L.) cultivars

J. R. CRUSH

AgResearch
Ruakura Agricultural Research Centre
Private Bag 3123
Hamilton, New Zealand

J. R. CARADUS

AgResearch
Grasslands Research Centre
Private Bag 11008
Palmerston North, New Zealand

Abstract  Hydrogen cyanide (HCN) and iodine (I) concentrations in the herbage were determined for 51 white clover (Trifolium repens L.) cultivars that had been grown under uniform conditions in a glasshouse. HCN contents ranged from 120 to 1110 ug HCN/g dry matter (DM). Cultivars that are agronomically successful in New Zealand, and cultivars of New Zealand origin, were mainly highly cyanogenic. There was evidence in `Grasslands Kopu' and `Aran' of a decline in cyanide content in plants raised from first generation seed, compared to plants from Breeders or Basic seed. This decline may result in part from contamination of seed crops by low HCN resident clovers. Iodine concentration in the white clovers ranged from 0.08 to 0.21 ug I/g DM with 77% of values being below 0.12 ug I/g DM. There was no correlation between I and HCN concentrations. It seems there is little potential to improve the I nutrition of stock by selecting for increased I content in white clover. The influence of cyanogenic clover on the metabolism of I, selenium (Se), and sulphur (S) in sheep is discussed. It is concluded that these factors, and safety margins against direct cyanide toxicity, warrant further study.

Keywords  cyanide; cyanogenesis; iodine; linamarin; lotaustralin; selenium; sulphur; Trifolium repens; white clover

New Zealand Journal of Agricultural Research, 1995, Vol. 38: 309-316

0028-8233/95/3803-0309 $2.50/0 (c) The Royal Society of New Zealand 1995

PDF file of entire paper: medium quality (590K); (scanned from paper original: notes about this process)

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