Brown Rice Variety Packs Antioxidant Punch STUTTGART, ARK.


sidelined its commercial prospects. Now, Agricul- tural Research Service (ARS) scientists' re-ex- amination of the trait and its link to increased antioxidant levels could give the rice variety a new commercial lease on life. GEDrew is the result of a mutagenesis


G rice


breeding program con- ducted more than a decade ago by rice ge- neticist Neil Rutger (re- tired) at the ARS Dale Bumpers National Rice Research Center


in


Stuttgart, Arkansas. The variety, a genetic mu- tant, didn't make the cut, however, and Rutger placed it in storage in the USDA-ARS World Rice Collection, a repository of more than 19,000 acces- sions and 12 species rep- resenting the genus Oryza. And there GEDrew


might have remained today, were it not for the follow-up investigations of ARS chemist Ming- Hsuan Chen and the center's current director, Anna McClung. In 2007, they began re-evaluating the collection's specialty rice accessions for traits that could contribute to improved grain yield or nutritional content. Such collections, popularly known as gene banks, serve as a critical source of diversity in the face of emerging pest and dis- ease threats, environ- mental change, market demands and other events. Their investigation of


GEDrew focused on a single gene mutation that results in kernels with enlarged, or "giant," embryos. In addition to a higher proportion of bran


EDrew is a brown rice with an odd kernel


trait that


to whole-kernel weight, the


researchers ob-


served, the giant embryo trait also correlated to a three-fold increase in alpha-tocopherol and a 20- and 29-percent in- crease in total cotrienols


to- and


gamma-oryzanol, respec- tively. Tocopherols and to-


cotrienols are forms of vi- tamin E with important biological activity in the human body. These may include helping prevent unstable


molecules


called free radicals from causing cellular damage and other associated harm, Chen


said.


Gamma-oryzanol, a mix- ture of antioxidant com- pounds in the bran's oil fraction, is thought to play role in reducing blood cholesterol levels, among other health-pro- moting benefits, she added. Grain yield evaluations


showed that GEDrew compared well to Drew and Cocodrie, two com- mercial varieties the re- searchers used for comparison in Texas and Arkansas trials. Even though GEDrew pro- duced slightly smaller grains, it was unmatched in terms of its yield of bran, lipids and the three antioxidants. All are high-value ingredients for specialty uses rang- ing from edible oil for cooking and salad dress- ings, to breakfast cere- als, nutrition bars, beverages and skin-care products, according to McClung. She credits the rice


mutation breeding efforts of Rutger, a 2009 ARS Hall of Fame inductee, with setting the stage for their finding that the giant embryo trait leads to whole grain with in- creased gamma-oryzanol levels and vitamin E—es-


pecially alpha-tocopherol (the only form listed on the nutrition facts of food packaging labels). At the time, "Rutger


was looking for any agro- nomically useful traits in his mutation breeding program,


like earlier flowering, male sterility,


elongated internode and apomixis but had the most success with semi- dwarfism," McClung noted. "The giant embryo


and a low phytic-acid mutant were examples of mutations that resulted in a change in grain


CONTINUED ON PAGE 16


New specialty uses could be in store for GEDrew, a variety of "giant embryo" brown rice whose bran is packed with antioxidants and vitamin E forms.


10• MidAmerica Farmer Grower www.mafg.net / February 7, 2020


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