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Title: Survey of diverse wheat lines for forage tannins

item Mackown, Charles

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 10/31/2006
Publication Date: 11/12/2006
Citation: Mackown, C.T., Carver, B., Edwards, J. 2006. Survey of diverse wheat lines for forage tannins [abstract]. ASA-CSSA-SSSA Annual Meeting Abstracts, November 12-16, 12006, Indianapolis, IN. 2006 CD-ROM.

Interpretive Summary: ABSTRACT ONLY

Technical Abstract: High digestibility, soluble proteins, and intake of lush growing winter wheat (Triticum aestivum L.) pasture contribute to pasture bloat, leading to substantial economic loss. In the 1999-2000 grazing season 41% of OK producers reported pasture bloat with 40% of animal deaths attributed to bloat causing a $5 million loss. Forage tannins can reduce the incidence and severity of bloat, promote better use of forage protein, and provide a passive means to manage pasture bloat. We measured tannin content and variability in wheat cultivars and experimental lines to determine the feasibility of using traditional breeding methods to give producers a passive choice to reduce the incidence of bloat. Fall forage samples were collected from 218 diverse lines and four check cultivars of wheat distributed among 12 blocks in an augmented randomized complete block design. There were significant forage yield differences among the lines (range, 465-2820 kg/ha; mean, 1370 kg/ha not different from checks). Differences among the lines in extractable phenolic acids (tannic acid equivalents) were significant (range, 14.8-32.8 mg/g dry wt.; mean, 23.4 mg/g dry wt.), but condensed tannin (quebracho equivalents) differences were not significant (range 1.46-4.82 mg/g dry wt.; 2.67 mg/g dry wt.). While we observed marked differences in tannic substances among the lines, even the greatest amounts detected are unlikely sufficient for bloat-safe forage. Perhaps, lines with the most abundant tannin levels could be used in a traditional breeding program to increase the level of tannins in wheat forage, but to make substantial genetic changes in condensed tannin levels will probably require a molecular engineering approach.