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United States Department of Agriculture

Agricultural Research Service

Title: Determination of Silica in Rice Seeds Using Growth Stages

Authors
item Bryant, Rolfe
item Counce, Paul - UA RREC
item Rutger, J

Submitted to: American Association of Cereal Chemists Meetings
Publication Type: Abstract Only
Publication Acceptance Date: October 13, 2002
Publication Date: October 13, 2002
Citation: Bryant, R.J., Counce, P.A., Rutger, J.N. 2002. DETERMINATION OF SILICA IN RICE SEEDS USING GROWTH STAGES. American Association of Cereal Chemists Meetings. AACC Oct. 13-17, 2002 Abstract# 162.

Technical Abstract: The rice hull, which contains highly silicified cells, may protect developing grain from damage by insects, such as rice stink bugs. The bugs mainly attack the plant from flowering (R4) through soft dough stage (R6). Higher silica content during these stages may increase resistance. To date most silica analyses have been tied to planting or heading date which does not give the amount at different developmental stages. Our objective was to determine silica content in seed at different developmental stages of a brittle mutant of Wells and its normal parent. Seeds were obtained at three different growth stages; 1) R4 and early R5, 2) mid and late R5, and 3) R6. After determining moisture, dried seeds were acid digested, filtered, dried, charred, and ashed. After cooling, the ash was weighed and percent silica calculated. Moisture contents of normal Wells were 39.2, 50.1, 38.0 percent (%) for R4, R5, R6, respectively, and 31.9, 51.3, and 47.8%, respectively, for brittle Wells. Without separating into developmental stages, moisture content of normal Wells was 49.3% and brittle was 53.1%. Silica contents for normal Wells were 13.7, 7.9, 4.6 % for R4, R5, R6, respectively, and 17.5, 12.3, and 8.0%, respectively, for brittle. Without separating, silica content for normal was 9.1% and brittle was 11.4%. This procedure can be used to determine if there is a connection between silica content and stink bug resistance. It can also be used to show other correlations that may be growth dependent.

Last Modified: 11/23/2014
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