Submitted to: Grass Breeders Work Planning Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 5/14/2002
Publication Date: 2/1/2004
Citation: Burson, B.L., Hussey, M.A. 2004. Plant exploration: The foundation for Paspalum improvement. Proceedings of the 37th Grass Breeders Work Planning Conference, May 14-16, 2002, Moscow, Idaho. p. 26-34. Interpretive Summary: Common dallisgrass is an important forage grass in the southern United States where it is widely recognized for producing high quality forage. However, the grass does not produce a lot of good seed and it also is infected by a fungus that causes a disease that is called ergot. Efforts have been made to improve the grass by breeding but little progress has been made because the grass propagates itself by a vegetative method of reproduction known as apomixis. Because of this, all dallisgrass plants in the US are identical and there is no variation in the grass for disease resistance. This manuscript discusses the importance of new dallisgrass plants that were collected in South America. The collections were made in South America because that is where the grass originated and more different types occur in that area. The different ways these new types were used in the breeding and improvement of dallisgrass also are discussed. The new dallisgrass types collected in South America have made it possible to learn more about common dallisgrass and how it originated. Because of these research activities, there are plans to release a new dallisgrass cultivar that is more productive than common dallisgrass.
Technical Abstract: Common dallisgrass, Paspalum dilatatum Poir., is an important forage grass throughout the humid, sub-tropical regions of the world. Because it is a meiotically irregular pentaploid (2n=5x=50) apomict, plant breeders have been unable to improve the species using conventional breeding methods. Three plant exploration trips were made to South America to collect additional Paspalum germplasm needed for the improvement of dallisgrass. This germplasm significantly increased the number of Paspalum accessions in the National Plant Germplasm System. The importance of this germplasm in identifying the progenitors of common dallisgrass and formulating a hypothesis of how the grass originated is discussed. Two other dallisgrass biotypes, a sexual tetraploid (2n=4x=40) yellow-anthered form and an apomictic hexaploid (2n=6x=60) form, appear to be the progenitors. Both of these biotypes also were used to develop a hybridization scheme to breed new improved forms of dallisgrass. The hexaploid biotype produced more forage than common and plans are underway to release it as a cultivar. The uniqueness and importance of other Paspalum species collected also were discussed.