The evaluation of methods for assessing barley viability

Abstract

A bioluminescence technique has been used to measure ATP extracted from barley. The results indicate a linear relationship between ATP and grain viability in barley samples of similar moisture content.

More ATP is extracted from barleys of higher moisture content and this increase is not due to enhanced microbial activity. The increase in ATP levels obtained after immersion of live grain was not seen with laboratory-damaged grain. Warm water immersion enhanced the extraction of ATP from corns but final levels extracted from undried barleys appeared to reflect structural differences between varieties rather than viability.

The differences in ATP levels (multicorn samples) between viable and damaged grain were too small, however, to be of use at intake.

The relationship between malate dehydrogenase (MDH) activity and viability was also investigated. Large differences in activity were seen between homogenates of live and damaged corn but, as in the case of ATP measurement, the problem of detecting a 1-2% difference in viability still applied.

It is clear that predicting viability will not be successful using a homogenate from a large number of corns. Any measurement of barley viability must be conducted on a corn by corn basis.

MDH activity is insufficiently selective for use as an index of barley viability. However, the ATP content of individual corns can be used to detect damaged grain amongst viable grain.