The Effect of Cultivar and Environment on β-amylase Activity is Associated with the Change of Protein Content in Barley Grains

Eight malt barley cultivars were grown in seven locations with wide ecological differences in China for two successive years to study the cultivar and environmental variation of β‐amylase activity and its association with the change of protein content in grains. The results showed that the variation in β‐amylase activity was mainly attributable to the environment (location and year), although the effect of cultivar was also highly significant. The response of β‐amylase activity to the environment differed markedly among cultivars, reflected by large difference in coefficients of variation for the cultivars grown across diverse locations. The effect of cultivar and environment on protein content showed a pattern similar to that on β‐amylase, but the variations caused by cultivar and, in particular, environment were relatively smaller for protein content than for enzymatic activity. Regression analysis showed that there was a highly significant correlation between protein content and β‐amylase activity for all cultivars but ZAU 3. However, an obvious difference existed in the constants and regressive coefficients of the equation among cultivars, suggesting genetic differences in the effect of the changed protein content on β‐amylase activity.