Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/18/1998
Publication Date: N/A
Interpretive Summary: In the southeast United States, white clover dramatically increases the quality of the diet and performance of grazing cattle. Many pastures in this region contain white clover plants that were not introduced by the farmer and have been growing in the pasture for many years despite adverse environmental conditions and relatively poor management practices. These long-lived plants may have characteristics that should be incorporated into breeding efforts to improve white clover productivity and longevity. We conducted this experiment to compare the growth of natural populations collected from pastures in Louisiana, Mississippi, Alabama, and Georgia with commercial varieties. Over a two-year period, the plants collected from pastures generally had superior growth and longevity than the commercial varieties, primarily because the pasture types produced more vegetative growing points and more roots to support growth of the plant, particularly during the summer. These plants thus represent a valuable source of traits that should be incorporated into breeding programs to improve white clover growth for the farmer who is producing cattle on pastures.
Technical Abstract: Ecotypes of white clover (Trifolium repens L.) are found in many southeast USA pastures, often persisting despite adverse environmental and cultural conditions. Our objective was to compare the growth, morphology, and vegetative persistence of white clover ecotypes with selected cultivars and improved germplasm. Seed or stolons of ecotypes were collected primarily from grazed pastures in spring, 1994 in Louisiana, Mississippi, Alabama, and Georgia, and increased by intercrossing. Plots of each of seven ecotype collections, `Osceola', `Regal', `Louisiana S-1', `Grasslands Huia', `Grasslands Prestige', Brown Loam Synthetic No. 2 germplasm, and Southern Regional Virus Resistant germplasm were established in October 1995 in each state. Plots were stocked continuously with cattle (5-cm stubble) from January 1996 to January 1998. Stolon length and axillary bud viability, and number of stolon apices, rooted nodes, and seedlings were measured every three months. Stolon length of the ecotypes usually exceeded that of the cultivars and germplasm at all locations, particularly in the winter and spring. By the end of the experiment, the ecotypes also exhibited greater stolon branching compared to the cultivars and germplasm (1580 vs 320 branches m-2). Superior vegetative growth of the ecotypes was attributed to a greater proportion of the stolon nodes being branched and rooted, particularly during the summer. The small to medium-leaf white clover ecotypes thus represent a worthwhile source of germplasm to incorporate into breeding programs or develop into more persistent cultivars.