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The Center for Native Grasslands Management

Title: The interrelationships of productivity, nutritive value, physiology, and lamina anatomy in switchgrass
Year: 2002
Author(s): Fisher, D. S., Burns, J. C., Timothy, D. H.
Source Title: Proceedings of the Third Eastern Native Grass Symposium
Source Type: Proceedings
pages: 218-222
Original Publication:  
Abstract: Switchgrass has shown promise as a native subtropical grass for both forage production and wildlife habitat in the eastern USA. A group of 6 types from a collection made in the humid east were selected to represent a range in estimated nutritive value and yield potential. In an effort to more fully evaluate this germplasm and test methods of identifying material of value in cultivar development, we examined the plant material for variation in photosynthetic rates, carbohydrate accumulation, leaf anatomy, and forage quality. We found that dry matter yield was correlated with lamina concentrations of starch. The strongest correlation with yield was found with starch measured near sundown (r =0.98) but the correlation was also strong with the estimated fluctuation in carbohydrates from evening to morning (r=0.83). This fluctuation occurs due to an accumulation of carbohydrate during the day while photosynthesis is in excess of carbohydrate export and the decline that occurs due to carbohydrate export without photosynthesis at night (0.83). Significant variation was found in lamina thickness, vascular bundle perimeter and area, and in the spacing of the vascular bundles. Vascular bundle spacing (r = -0.74) and lamina thickness (r = -0.76) were negatively correlated with estimates of dry matter in cell walls. An index of the percent vascular bundle in cross sectional area was negatively correlated with estimates of cell wall (r = 0.79), lignin (r =0.95), and hemicellulose (r =0.91). Variation in starch content from evening to morning may be useful in plant breeding programs for switchgrass improvement since it may provide selection for increased yield without selecting for higher cell wall components and consequently reduced nutritive value.
Publisher: The North Carolina Botanical Garden, Chapel Hill, NC, October 1-3, 2002. Omnipress, Madison, WI
Editor(s): J. Randall