Laboratory Evaluation of Quality in Subtropical Grasses: II. Genetic Variation Among Hemarthrias in In Vitro Digestion and Stem Morphology1
- S. C. Schank,
- M. A. Klock and
- J. E. Moore2
In vitro organic matter digestion (IVOMD) was studied in selfed progeny from four introductions of Hemarthria (limpograss) and in hybrids between two stoloniferous diploid lines. This grass genus occurs naturally in swampy areas of Africa, Asia, and South America, but introductions were not successfully introduced into the U.S. until 1964. Genetic improvement of the Hemarthrias was considered feasible because of their ability to persist under flooding, drought, and freezing temperatures. Information on the in vitro digestion of the limpograsses would also benefit long-range plant breeding objectives by indicating relative differences between lines. IVOMD was significantly higher in a coarse-stemmed tetraploid line from Africa than in any of the diploid lines studied. The stoloniferous diploid lines from Transvaal, Africa were intermediate in digestion but not significantly different from each other. F1 hybrid plants obtained from these two diploids were also intermediate in IVOMD. The least digestible Hemarthria studied was a bunch-type, diploid introduction from Argentina. IVOMD at 5 weeks regrowth ranged from 54.3% hi the Argentine diploid to 68.4% in the African tetraploid. In mature plants, IVOMD of the Argentine diploid averaged 38.5%; the African diploids, 56%; and the tetraploid, 66%. Studies of stem morphology revealed that the combined percentage area of vascular bundles for each cross section area was inversely related to IVOMD, indicating that structural differences can greatly reduce the digestibility of a grass.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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