A Gel Diffussion Assay for Diastatic Activity, and Its Use in Plant Breeding

A modification of Briggs' starch/agar α-amylase assay is described which enables total diastatic activity to be measured. This has been used to differentiate between a high diastase barley variety (Olli, green malt DP over 300° L) and a normal variety (Ymer, green malt DP approximately 120° L), although replication of measurements is shown to be necessary. The assay has been used in selection experiments, where a significant response to selection for increased “halo size” was obtained in one generation of selection. In addition, there were significant differences between the selected populations in ability to germinate, a character for which no conscious selection had been applied. The assay is of potential use in plant breeding as an aid to selection for diastatic power.