Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: July 14, 2010
Publication Date: July 25, 2010
Citation: Vinje, M.A., Filichkin, T., Duke, S.H., Hayes, P., Henson, C.A. 2010. Studies on the Utility of ß-amylase 1 IntronIII Sequences as Markers for ß-amylase Activity and Thermostability, Diastatic Power and Malt Quality [abstract]. Canadian Barley Symposium, July 25-28, 2010, Saskatoon, Saskatchewan, Canada. Poster 21. Technical Abstract: The third intron of barley (Hordeum vulgare L.) ß-amylase 1 (Bmy1) is extremely polymorphic. The use of specific insertion/deletions (indels) in the third intron as markers for cultivar development has been recommended based on associations with ß-amylase activity and thermostability. The third intron of Bmy1 was categorized into four alleles (Bmy1.a, Bmy1.b, Bmy1.c, and Bmy1.d) based on indels of 126-bp, 38-bp, 11-bp, and 21-bp. However, the Bmy1.d allele has only been found in one accession and was not analyzed in this study. ß-Amylase activity and thermostability were assayed in composite grain samples from 22 North American malting cultivars and 12 wild barley genotypes to determine if the third intron could be used as a predictor of activity and thermostability and thus be a reliable marker for marker assisted selection. North American malting cultivars were found to carry only the Bmy1.a (14 cultivars) and Bmy1.b (8 cultivars) alleles whereas the wild barleys had were found to have the Bmy1.a (3 genotypes), Bmy1.b (3 genotypes), and Bmy1.c (6 genotypes) alleles. Broad ranges of ß-amylase activity and thermostability were observed in both wild and cultivated genotypes. Significantly different activities were observed in cultivars carrying either Bmy1.a or the Bmy1.b allele when calculated on a fresh weight (FW) basis and the Bmy1.a allele when calculated on a protein basis. Significantly different thermostabilities were observed in cultivars carrying the Bmy1.a allele. Significantly different activities were found in wild barley genotypes with any of these three alleles when calculated on a FW basis yet only in those with the Bmy1.c allele when calculated on a protein basis. Significantly different thermostabilities in wild barley genotypes carrying either the Bmy1.b or Bmy1.c allele were observed. In another study, malting quality data were collected on malts from three barley (Hordeum vulgare L.) breeding program trials (165 lines) containing both winter/facultative and spring growth habits. Abundant malting quality variation, including ß-amylase activity, exists in the spring barley germplasm (114 lines) despite the parents all carrying the Bmy1.a allele. In the winter/facultative germplasm broad ranges were also observed for malting quality traits, ß-amylase activity, and thermostability despite 47 out of 51 lines carrying the Bmy1.a allele. In conclusion, broad ranges were observed for ß-amylase activity, thermostability, and other malting quality traits that indicate the Bmy1 intron III alleles are not reliable predictors of malting quality traits and thus would not be a useful as a selection tool for breeding elite malting cultivars in the germplasm studied here.