Geographical variation of β-amylase thermostability among varieties of barley (Hordeum vulgare) and β-amylase deficiency

Investigations onto the thermostability of β-amylase in 274 varieties of barley (Hordeum vulgare L.) indicated that all varieties except one were distributed into three types of high (type A), intermediate (type B), and low (type C) thermostability, respectively. One variety (TB29) from China showed no β-amylase activity. Geographical variation was observed in the thermostability of β-amylase. Type C varieties were not observed in East Asia (Japan, the Korean Peninsula, China and Nepal), although 36 out of 37 varieties in Ethiopia were type C. Most of the varieties were Type A in Japan, the Korean Peninsula and China, whereas the frequency of type A and type B were nearly equal in Nepal. Varieties in the other five areas (North America, North Africa, Southwest Asia, Turkey and Europe) consisted of types A, B and C. These results support the fact that East Asian cultivars are genetically different from those of the western regions, as previously reported.