Identification of Reproducible PCR-RAPD Markers that Enable the Differentiation of Closely Related Six-Rowed Malting Barley (Hordeum vulgare L.) Cultivars (1). David L. Hoffman and Phil Bregitzer, U.S. Department of Agriculture, Agricultural Research Service, National Small Grains Germplasm Research Facility, Aberdeen, ID 83210. (1) Mention of a company or specific product is for informational purposes only and is not intended to imply endorsement by the USDA-ARS. J. Am. Soc. Brew. Chem. 54(3):172-176. Accepted February 14, 1996. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. American Society of Brewing Chemists, Inc., 1996.

Varietal purity of barley seed and malt lots is important to the malting and brewing industries. This study was conducted to see if a modified polymerase chain reaction (PCR) technique using random DNA primers (PCR-RAPD) could generate repeatable polymorphisms among the closely related six-rowed malting cultivars Morex, Robust, Stander, Excel, and elite breeding line M77. From a total of 80, 30 random 10-mer primers were selected based on their ability to generate reproducible polymorphisms between the cultivars Steptoe and Morex. Bulked DNA isolated from the leaves of 10-12 plants of each cultivar was amplified using the Stoffel fragment of recombinant Thermus aquaticus DNA polymerase and one primer per PCR. Nine of the 30 primers detected repeatable polymorphisms among the malting lines. Each cultivar or line could be distinguished from another with the exception of Stander and M77. The results of six primers were reproduced in a second laboratory. It was concluded that this PCR-RAPD technique could be useful for distinguishing the four six-rowed malting barley cultivars. A faster version of the technique may be required for practical cultivar identification by the barley processing industry. Keywords: Cultivar identification, Malting barley, PCR-RAPD, Reproducibility, Stoffel fragment.