Relationship between malt qualities and β-amylase activity and protein content as affected by timing of nitrogen fertilizer application*
Jin-xin Chen, Fei Dai, Kang Wei, and Guo-ping Zhang†‡
Department of Agronomy, Zhejiang University, Hangzhou 310029, China
The effects of different timing of N fertilizer application at the same rate on grain β-amylase activity, protein concentration, weight and malt quality of barley were studied. Grain β-amylase activity and protein concentration were significantly higher in treatments where all top-dressed N fertilizer was applied at booting stage only or equally applied at two-leaf stage and booting stage than in the treatment where all top-dressed N fertilizer was applied at two-leaf age stage only. On the other hand, grain weight and malt extract decreased with increased N application at booting stage. There were obvious differences between barley varieties and experimental years in the grain and malt quality response to the timing of N fertilizer application. It was found that grain protein concentration was significantly and positively correlated with β-amylase activity, but significantly and negatively correlated with malt extract and Kolbach index. The effect of grain protein concentration on malt quality was predominant over the effect of grain β-amylase activity.
Keywords: Barley, Nitrogen fertilizer, β-amylase, Malt quality
J Zhejiang Univ Sci B. 2006 January; 7(1): 79–84.