Developing Low-GN and GN-zero Winter Malt Barley for the Eastern United States

dc.contributor.authorPerry, Alexis Danielleen
dc.contributor.committeechairSantantonio, Nicholasen
dc.contributor.committeememberBettenhausen, Harmonieen
dc.contributor.committeememberHaak, David C.en
dc.contributor.departmentCrop and Soil Environmental Sciencesen
dc.date.accessioned2025-06-07T08:02:57Zen
dc.date.available2025-06-07T08:02:57Zen
dc.date.issued2025-06-06en
dc.description.abstractGlycosidic nitriles (GN) are carcinogenic precursors produced by barley as a natural defense against insects. The most common GN in barley, epiheterodendrin (EPH), contains a cyanide group that, when combined with heat and copper during distillation, forms ethyl carbamate (EC), a known carcinogen. While GN-zero barley varieties have been developed in the European Union and the western United States, no known GN-zero or low-GN varieties are currently adapted to the Eastern U.S. climate. The Virginia Tech Small Grains Breeding and Genetics Program, in collaboration with the Center for Craft Food and Beverage at Hartwick College, is leading a multi-pronged effort to develop GN-zero winter malting barley adapted to the Eastern U.S. In 2023, grain from 220 elite malt breeding lines and two known GN-zero checks were grown in Blacksburg, VA and screened for GN content using a colorimetric assay. All VT lines tested positive for presence, and 93 were sampled for micromalting and GN quantification 2023. These lines, along with controls, were genotyped using genotyping-by-sequencing (GBS) and evaluated for genomic predictability and selection potential for GN reduction. Despite a low heritability estimate (h2 = 0.24), bi-directional genomic selection was effective (p = 0.003). Repeatability was confirmed through a second phenotyping round in fall 2024, where 48 lines showed strong GN correlation between years (r = 0.72), supporting the feasibility of breeding a GN-zero variety. In parallel, a winter speed breeding protocol was implemented to accelerate generation advancement and enable earlier GN screening in segregating populations. Of the 2,520 seeds planted from 12 GNzero crossed with adapted breeding lines F2:3 families, 103 heads were successfully harvested under extended photoperiod and controlled temperature conditions. These families will be advanced and evaluated under field conditions in Blacksburg, VA, laying the groundwork for future variety release. Together, these efforts demonstrate the viability of integrating phenotypic screening, genomic selection, and rapid generation cycling to breed low- and zero-GN barley adapted to the Eastern U.S.en
dc.description.abstractgeneralBarley naturally produces compounds called glycosidic nitriles (GN) to defend itself from insects. However, when one of these compounds, epiheterodendrin (EPH), is used in the whiskey-making process, it can lead to the formation of ethyl carbamate (EC), a substance classified as a potential cancer risk. While barley varieties that do not produce GN have been developed in Europe and the western U.S., no such varieties are currently adapted to the climate and growing conditions of the eastern U.S. To address this gap, the Virginia Tech Small Grains Breeding and Genetics Program, in partnership with the Center for Craft Food and Beverage at Hartwick College, is working to develop GN-zero winter malting barley for the eastern U.S. In 2023, 220 promising barley lines were grown in Virginia and screened for GN. Although none showed clear absence of GN using initial tests, 93 lines were selected for more detailed analysis in 2024. These lines were also genetically analyzed to explore whether GN levels can be predicted and reduced using modern DNA-based selection tools. Even though the genetic influence on GN was relatively low, the selection models worked well and consistently identified GN levels between years, an encouraging sign for future breeding. At the same time, a rapid growing technique called "speed breeding" was used to shorten the time it takes to develop new barley lines. From over 2,500 seeds planted from GN-zero crosses, more than 100 heads were successfully harvested under controlled conditions. These plants will be grown in the field to evaluate their potential for future use.en
dc.description.degreeMaster of Scienceen
dc.format.mediumETDen
dc.identifier.othervt_gsexam:43903en
dc.identifier.urihttps://hdl.handle.net/10919/135403en
dc.language.isoenen
dc.publisherVirginia Techen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectWinter malt barleyen
dc.subjectglycosidic nitrile (GN)en
dc.subjectgenomic selection (GS)en
dc.subjectdistillingen
dc.subjectrapid generation advancementen
dc.titleDeveloping Low-GN and GN-zero Winter Malt Barley for the Eastern United Statesen
dc.typeThesisen
thesis.degree.disciplineCrop and Soil Environmental Sciencesen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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