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ARS Home » Midwest Area » Madison, Wisconsin » U.S. Dairy Forage Research Center » Research » Publications at this Location » Publication #219303
Title: Physical analysis of COMT and CCOMT downregulated alfalfa stems

Author
item Riday, Heathcliffe
item WHATLEN, DAVE - FORAGE GENETICS, INT.
item BOUTON, JOE - NOBLE FOUNDATION
item TEMPLE, STEPHEN - FORAGE GENETICS, INT.
item MCCASLIN, MARK - FORAGE GENETICS, INT.
item DIXON, RICHARD - NOBLE FOUNDATION

Submitted to: International Symposium of Molecular Breeding of Forage Turf
Publication Type: Abstract Only
Publication Acceptance Date: 7/1/2007
Publication Date: 7/1/2007
Citation: Riday, H., Whatlen, D., Bouton, J., Temple, S., Mccaslin, M., Dixon, R. 2007. Physical analysis of COMT and CCOMT downregulated alfalfa stems [abstract]. International Symposium of Molecular Breeding of Forage Turf. p. 60.

Interpretive Summary:

Technical Abstract: Caffeic Acid 3-O-Methyltransferase (COMT) and Caffeoyl CoA 3-O-Methyltransferase (CCOMT) downregulated alfalfas (Medicago sativa L.) have been created. This study examined stem characteristics of these lignin downregulated alfalfas grown in three environments. Twenty COMT and twenty CCOMT downregulation transformation events were crossed with two alfalfa plants (high quality plant and lodging tolerant plant). Null segregant progeny of these crosses were compared to downregulated progeny. Progeny plants were grown in space planted nurseries in three USA locations: Ardmore, OK; Prairie du Sac, WI; and West Salem, WI. Stem traits measured on space plants include: stem length, internode length, stems per crown, stem diameter, stem dry matter fraction of total plant dry matter fraction, and stem dry matter density. COMT downregulated alfalfas had: smaller stem diameters, shorter internodes, lower stem dry matter densities and lower stem dry matter yields compared to their null counterparts. CCOMT downregulated alfalfas had: shorter internodes and lower stem dry matter yields compared to their null counterparts. The reduced stem dry matter density of COMT downregulated alfalfas may have implications for in vivo ruminant feed passage rates and rumen function.