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United States Department of Agriculture

Agricultural Research Service

Title: Stem Anatomy of Switchgrass Plants Developed by Divergent Breeding Cycles for Tiller Digestibility

Authors
item Sarath, Gautam
item Vogel, Kenneth
item Mitchell, Robert
item Baird, L - UNI OF SAN DIEGO

Submitted to: Grassland International Congress Proceedings
Publication Type: Proceedings
Publication Acceptance Date: November 15, 2004
Publication Date: June 26, 2005
Citation: Sarath, G., Vogel, K.P., Mitchell, R., Baird, L.M. 2005. Stem anatomy of switchgrass plants developed by divergent breeding cycles for tiller digestibility. p. 115. In F.P. O'Mara et al (ed.) Proc. XX Int. Grassland Congress, Dublin, Ireland 26 June-2 July 2005. Wageningen Academic Publishers, Wageningen, The Netherlands.

Interpretive Summary: Switchgrass is an important perennial forage and biomass crop that is native to the temperate prairies of the North America east of the Rocky Mountains. Breeding for improved forage in vitro dry matter digestibility (IVDMD) has been conducted using post-heading, whole plant IVDMD as the selection criterion. One breeding cycle for low IVDMD and three cycles for high IVDMD were completed in a switchgrass population adapted to the USA mid-latitudes. The multiple cycles of breeding for IVDMD produced plant populations that differ significantly in digestibility and lignin concentration of leaf, sheath and stem. In the stems of switchgrass, changes in lignin appear to involve two primary mechanisms: (1) the loss or decrease in cortical fibers and (2) changes in secondary cell wall deposition. These results indicate that plant anatomy can be significantly impacted by a simple selection tool and strongly suggest that genes that control these functions will be attractive targets for future manipulation to develop cultivars for use as forage or bioenergy.

Technical Abstract: Switchgrass (Panicum virgatum. L.) is an important perennial forage and biomass crop that is native to the temperate prairies of the North America east of the Rocky Mountains. Breeding for improved forage in vitro dry matter digestibility (IVDMD) has been conducted using post-heading, whole-tiller IVDMD as the selection criterion. One breeding cycle for low IVDMD and three cycles for high IVDMD were completed in a switchgrass population adapted to the USA mid-latitudes. The multiple cycles of breeding for IVDMD produced plant populations that differ significantly in digestibility and lignin concentration of leaf, sheath, and stem. In the stems of switchgrass, changes in lignin appear to involve two primary mechanisms: (1) the loss or decrease in cortical fibers and (2) changes in secondary cell wall deposition. These results indicate that plant anatomy can be significantly impacted by a simple selection tool and strongly suggest that genes that control these functions will be attractive targets for future manipulation to develop cultivars for use as forages or bioenergy.

Last Modified: 9/2/2014
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