Quality test for the breeding of malting barley in relation to alpha-amylase activity.

Abstract

Two aspects concerning quality test in relation to AA (alpha-amylase activity) in malt were investigated for the breeding of malting barley using 11 to 36 cultivars and superior lines of barley as materials. In the first place, a new simplified method was tested for analysing AA of many small scale samples in practical breeding. The method was a modification of the BANASIK method (1971), and in the modified method, the procedure for heating-inactivation of beta-amylase in the sample solution was automated and the centrifugation of the sample solution after heating-inactivation of beta-amylase was omitted. As a result, the whole analysis could be performed with an Auto-Analyser. The data obtained with this method were closely correlated with those obtained with the standard ASBC method. Secondly, environmental conditions affecting AA in malt and interrelations between AA and the other malt quality characters were investigated. The years of harvest and the locations were selected as experimental factors representing the crop cultivation environment, and malting procedures (sample scale fcr malting) were selected as those relating to the malting conditions. The results of statistical analysis suggested that the quality tests in relation to AA might be used for selection in practical breeding but were somewhat difficult to evaluate as compared with DP (diastatic power) tests since AA was more liable to vary with environmental conditions. AA showed a high positive or negative correlation with soluble nitrogen content (SN), Kolbach index (KI), malt yield (MY) and wort colour (WC). Comparison between AA and DP led to the conclusion that the AA test should be performed independently of the DP test.