Submitted to: American Society of Agronomy Branch Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 10/17/2001
Publication Date: 2/3/2002
Technical Abstract: Common dallisgrass (Paspalum dilatatum Poir.), introduced into the USA from South America, is an important forage grass in many of the warmer regions of the world. The term dallisgrass is synonymous with the common biotype which is distributed throughout the southeastern USA and is widely used for permanent pastures. However, there are other biotypes of this species, but little is known about their forage potential. This study was initiated to evaluate five dallisgrass biotypes(common, prostrate, Torres, Uruguaiana, and Uruguayan) for yield, nutritive value, and persistence of these biotypes in Louisiana and Texas and to identify superior germplasm. A secondary objective was to evaluate the response of these superior selections for grazing tolerance. Three years of clipping data were collected at Baton Rouge, LA and College Station, TX. Most of the Uruguayan accessions were equal or superior to common dallisgrass for yield and nutritive value and all had superior stand persistence. The Torres and Uruguaiana biotypes did not survive after the first harvest season. Six superior accessions of the Uruguayan biotype were selected and evaluated, along with common dallisgrass, for 3 years under grazing at Jeanerette, LA. After 2 yr. of rotational stocking, an average of 90% of the Uruguayan and 53% of the common stands survived. All of the Uruguayan accessions were superior to common with DM yield plant-1 averaging 156 g for common dallisgrass compared to a mean of 232 g for the Uruguayan genotypes. Overall yields were much less in 2000(140 g plant-1) than in 1999(300 g plant-1). This decline was due somewhat to reduced stands, but primarily because of reduced rainfall. Yields declined with each grazing period, but there was no grazing period x entry interaction. Following the third year, which was continuously stocked, an average of 75% of the Uruguayan and 33% of the common stands survived. Because the yield and persistence of the Uruguayan biotype was consistently superior to that of common, the Uruguayan should provide livestock producers with a viable alternative to common dallisgrass.