Selection and Evaluation of Smooth Bromegrass Clones with Divergent Lignin or Etherified Ferulic Acid Concentration
- Michael D. Casler *a and
- Hans-Joachim G. Jungb
Lignin and etherified ferulic acid (EthFA) are cell wall constituents believed to have important negative impacts on digestibility of forage cell walls. Our objective was to identify genotypes of smooth bromegrass (Bromus inermis Leyss) with unconfounded divergence in lignin and EthFA, such that their independent effects could be determined on in vitro fiber digestibility (IVFD). Eight clones were selected from each of four populations (‘Alpha’, WB19e, ‘Lincoln’, and WB88S). Selection was successful for EthFA in all populations except WB88S, creating repeatable divergence of 11.2 to 12.5%. Selection was unsuccessful for lignin concentration per se, most likely because of large genotype × environment interactions. Nevertheless, the resulting clones showed significant variation for both EthFA and lignin concentrations and these two variables were nearly independent among the selected clones. Both lignin and EthFA had significant negative effects on 96-h IVFD, regardless of the statistical estimation method used. Across estimation methods, there was not a clear difference in the magnitude of the lignin and EthFA effects on IVFD. Both the total amount of lignin in the cell wall and the amount of ferulic acid cross-linking lignin to polysaccharides via ether bonds appear to be under genetic control, and both components play a role in regulating the genetic potential for rumen degradation of cell walls in smooth bromegrass. These clones are a potential tool for conducting animal feeding trials using forages with relatively unconfounded differences in a single cell wall characteristic.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © 1999.