Environmental and varietal differences in diastatic power and four associated characteristics of spring barley

Abstract

Summary Results from two trials on spring barley varieties are presented. A factorial fertilizer trial estimated the effects of N, P and K at each of three levels on diastatic power, heat-stable alpha-amylase activity, grain nitrogen content, thousand corn weight and yield in a single variety. This revealed that the main effect of N was the most important source of variation. In a subsequent variety–nitrogen trial seven varieties were tested at each of three levels of N. In the variety–nitrogen trial, diastatic power was found to be positively correlated with both grain nitrogen content and alpha-amylase activity although these latter two variates were not themselves correlated. These observations were confirmed both within genotypes and within environments, and a hypothesis is advanced in explanation. The implications of the results for a breeding programme directed towards the production of high-yielding, high-diastase varieties are discussed.