Submitted to: Journal of the American Society of Brewing Chemists
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/14/1996
Publication Date: N/A
Interpretive Summary: Barley varieties have unique biochemical properties that can affect the flavor and quality of malt products. A mistaken variety or mixture of varieties can ruin a malt lot worth thousands of dollars. So, it is important to persons of barley processing industries to be able to monitor the varietal integrity of seed lots. At one time, barley varieties could be recognized by looking carefully at seed traits. However, some of the more modern varieties have nearly identical seed traits, but still have unique biochemical traits that affect malting and brewing. An identification procedure other than the visual means was needed. A few biochemical techniques have been used successfully for variety identification, but were not helpful in every case. We tried a modified biochemical procedure and it distinguished some important barley varieties. This was something that other biochemical procedures could not do. In addition, we found that results of our biochemical procedure were repeatable in another laboratory, an important finding for this particular procedure. Although we found a way to distinguish previously undistinguishable varieties, our technique needs DNA from growing plants to work properly. Further development is needed to adapt the procedure so that seeds can be used. This would provide even quicker answers to the barley processing industries' varietal identification questions.
Technical Abstract: 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 could generate repeatable polymorphisms among the closely-related six-rowed malting cultivars Morex, Robust, Stander, Excel, and elite breeding line M77. Thirty random 10-mers were selected based on their ability to generate polymorphisms between the cultivars Steptoe and Morex. DNA isolated from leaves of 10 to 12 plants of each cultivar was amplified using the Stoffel fragment of recombinant Taq DNA polymerase and one random 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 combined results of primers AB-05 and AB-06. The results of six primers were repeated in a second laboratory. It was concluded that this PCR-RAPD technique will be useful for six-rowed malting barley cultivar identification. A faster version of the technique may be needed to fulfill the needs of the barley processing industry.