Author
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Jung, Hans Joachim |
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PHILLIPS, RONALD - University Of Minnesota |
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Submitted to: Crop Science
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 6/17/2009 Publication Date: 1/7/2010 Citation: Jung, H.G., Phillips, R.L. 2010. Putative Seedling Ferulate Ester (sfe) Maize Mutant: Morphology, Biomass Yield, and Stover Cell Wall Composition and Rumen Degradability. Crop Science. 50(1):403-418. Interpretive Summary: Corn silage is among the most important feeds used in dairy and beef production systems. Although the grain in corn silage has high feeding value, the stover portion of corn silage is of limited quality. The large amounts of fiber in stover and its poor digestibility account for the low feeding value of corn stover. It has been demonstrated that the chemical linkage of lignin, the major inhibitor of fiber digestion, to carbohydrates in fiber by ferulate molecules is critical in limiting fiber digestibility. We identified a mutant corn line that has reduced levels of ferulate molecules and evaluated the impact of this mutation on formation of links to lignin and effects on fiber digestibility. Reduced ferulates in the mutant corn line resulted in the formation of fewer linkages. The resulting corn silage stover had more digestible fiber. The mutation did not adversely impact corn growth or silage yield. Because the mutation was caused by a transposon (jumping gene), it should be possible to easily identify the gene that controls ferulate production. This corn mutant will be of value to geneticists who wish to develop corn hybrids with improved fiber digestibility for livestock feeding and to use corn stover for bioenergy production. Technical Abstract: Ferulate cross linking of lignin to arabinoxylan contributes to poor cell wall degradability of grass forages. We hypothesized that reduced ferulate ester deposition will result in formation of fewer ferulate ether cross links and improved degradability. Objectives were to determine if the putative seedling ferulate ester (sfe) maize (Zea mays L.) mutant, selected for reduced ferulate esters in seedling leaves, (i) exhibits reduced ferulate ethers; (ii) alters morphology, yield, and cell wall concentration and composition; and (iii) changes degradability. Four near-isogenic sfe lines and backcrosses to W23 were compared to the inbred W23. Maize lines were grown in replicated field trials. Leaf blade, sheath, and stem of immature (1-m plant height) and mature (silage) growth stages were analyzed for ferulate esters and ethers, cell wall concentration and composition, and in vitro rumen degradability. The sfe lines were taller and had greater internode cross-sectional area at silking than W23. Individual plant yield was greater at silage maturity for sfe lines, and backcross lines yielded more than sfe. Mature plant parts of sfe lines had lower ferulate ester concentrations than W23. At silage stage sfe lines had less ferulate ethers and small reductions in cell wall concentration and shifts in composition. Immature samples were inconsistent for cell wall traits, and backcross lines were generally intermediate, regardless of maturity. Cell wall degradability was higher for the sfe mutant as hypothesized. |
