Intron III-specific markers for screening of β-amylase alleles in barley cultivars

In modern malting barley breeding it is important to increase the level of beta-amylase activity level in barley. The aim of this study was to investigate if a PCR method for screening beta-amy1 alleles can be used as an indicator for beta-amylase activity level in barley. Activity was assayed from 24 cultivars, 7 lines, and a Hordeum spontaneum PI 296897 strain grown in the same field. The B-amyl alleles were identified by amplifying the intron III-specific region of the gene using PCR. No new alleles were detected in addition to the three alleles found earlier: cv Adorra-like, cv Haruna Nijo-like and PI 296897-like beta-amy1 allele. Samples were grouped according to the nature of their beta-amy1 locus and enzyme activities were compared between the groups. Cultivars carrying a cv Haruna Nijo-like beta-amy1 allele had 1.3 times and lines carrying a PI 296897-like beta-amy1 allele had 2.1 times higher beta-amylase activity than cultivars carrying a cv Adorra-like beta-amy1 allele. The mean activities are significantly different in the allele groups (Kruskal-Wallis: for protein H = 11.54, P < 0.01; for meal H = 12.74, Pc 0.01). PCR fragments can be used as allele specific markers to predict the level of beta-amylase activity in breeding when such variation of the intron III is concerned.