Wool science hits a snag

CHRISTCHURCH - Selective breeding to reduce yellowing in wools might not be as easy as it seems, say Lincoln University researchers.

Dr Peter Maher and Magda Benavides of the Animal and Food Sciences Division at Lincoln are working on the yellowing problem in fleece.

Using Corriedales, they are testing to find out how much of the wool is susceptible to yellow stain.

Dr Maher said sheep showed yellow stains in their wool only under moist and warm conditions. They might not show any yellow colour one year but develop it the next.

Colour is important because yellow wool does not take chemical dyes evenly, confining processors to the use of darker-coloured dyes and limiting options for end use.

Analysis of wool auction data over past years has indicated a gradual but important increase in relative economic value for brightness, and a discount for yellow discoloration of scoured wool.

"Farmers who decide to select sheep to improve the colour of their flocks will risk a reduction in their total wool clip," said Dr Maher.

The scientists were now looking for specific genetic markers to predict the colour of wool.

The Lincoln University work contradicts some aspects of a 1998 announcement by a Government scientist, Tumen Wuliji of Agresearch, that farmers could gradually improve the colour of wool by selecting breeding sheep that showed less yellow in their scoured fleece.

But he also warned that although wool colour could be inherited, the environment in which the wool was grown could have a stronger effect than genetics.

- NZPA