Progress 05/01/04 to 12/31/10
Outputs
OUTPUTS: Presentations of results to cattle producers and extension workers have been made at experiment station field days and at meetings of local cattlemen's organizations. Selections from a collection of hexaploid dallisgrass germplasm regenerated from tissue culture represent another output from this project. Individual selections have been identified providing superior plant vigor, seed production, and plant population increases compared to the commercially available common dallisgrass. These selections will be increased for additional evaluation and potential release as improved cultivars. PARTICIPANTS: This project has been conducted as a cooperative effort between Bill Waltman, Research Associate, at the Red River Research Station and W. D. Pitman, Forage Agronomist, at the Hill Farm Research Station with field support from additional personnel at the Red River Research Station. TARGET AUDIENCES: The target audiences for this project have been cattle producers in north Louisiana and the surrounding area along with pasture advisory personnel of agencies supporting the area beef cattle industry. Interactions with these target audiences were intended to provide sufficient information regarding the research outcomes and outputs to allow potential users to assess the value of these developments to their operations. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Assessments of dallisgrass plant populations in grazed pastures revealed that individual plants were rather short-lived, especially when heavily grazed. Recruitment of new seedlings was required for sustained stands, and the commercially available common dallisgrass displayed inadequate seedling vigor for stand maintenance in years with adverse weather conditions. Identification of these characteristics help explain the lack of dependability of dallisgrass pastures on some Louisiana sites. Germplasm evaluation resulted in identification of superior genotypes with potential to improve both productivity and sustainability of dallisgrass pastures on appropriate sites in Louisiana.
Publications
- No publications reported this period
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Progress 01/01/09 to 12/31/09
Outputs
OUTPUTS: Results from this project were presented to livestock producers and extension personnel at the Red River Research Station field day in June 2009. Results were also shared with interested individual researchers through personal discussions during the year. PARTICIPANTS: W. D. Pitman, project leader, and Bill Waltman, research associate TARGET AUDIENCES: Louisiana livestock producers, area extension personnel, and the forage seed industry. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Differences in both vigor of individual plants as they age and colonization from natural seed dispersal combined with subsequent seedling recruitment were documented in field comparisons of 24 selected lines of dallisgrass. The identification of these superior lines will allow for the development of cultivars for more sustainable dallisgrass pastures, since current dallisgrass pastures persist through continuing recruitment of new seedlings to maintain plant populations because the rather short-lived individual plants die. Selected lines provide longer individual plant life, increased seed production, improved seed quality, and enhanced seedling recruitment under pasture conditions compared with common dallisgrass, which is the only dallisgrass variety currently available commercially.
Publications
- No publications reported this period
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Progress 01/01/08 to 12/31/08
Outputs
OUTPUTS: Results of this project were presented to cattlemens groups at the Red River Research Station on May 8, 2008, and in Jackson Parish on August 30, 2008. PARTICIPANTS: This project has been conducted as a cooperative effort between Bill Waltman, Research Associate, at the Red River Research Station and W. D. Pitman, Forage Agronomist, at the Hill Farm Research Station with field support from additional personnel at the Red River Research Station. TARGET AUDIENCES: The preliminary results of this project were targeted toward cattlemen in north Louisiana and the surrounding area. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Superior varieties of dallisgrass, which have traditionally been an important pasture plant on moist fertile sites in Louisiana, were identified in 2008. Vigor of individual plants in a replicated experiment was superior to that of the only commercially available dallisgrass (common dallisgrass) for five of the 24 entries evaluated. Two of these five plants also produced twice as many seedlings as common dallisgrass in an assessment of natural recruitment of additional seedlings to indicate potential for more-sustainable pasture stands. The use of dallisgrass pastures to extend the grazing period both early and late in the growing season, which can reduce winter feed costs for beef cow herds, can potentially be restored to the substantial traditional levels with a more sustainable and more readily established cultivar. As older stands of common dallisgrass have been lost, few new plantings have been made largely because of establishment limitations. The superior plants identified have potential to overcome existing establishment limitations and produce more-sustainable pasture stands.
Publications
- No publications reported this period
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Progress 01/01/07 to 12/31/07
Outputs
OUTPUTS: Results of this project were presented to producers and extension personnel at the Red River Research Station field day.
PARTICIPANTS: W.D. Pitman and W. Waltman conducted the research under this project during 2007.
TARGET AUDIENCES: Information generated during 2007 was particularly targeted to producers and extension personnel who may benefit from the application of approaches to improve success rates of dallisgrass establishment efforts.
PROJECT MODIFICATIONS: Due to recent difficulties in establishment of dallisgrass stands, treatments to assess plant establishment responses were added to this project which was initially developed to emphasize responses to grazing of dallisgrass pastures.
Impacts
Due to establishment failures with dallisgrass plantings in prior years of this project, responses to seeding rates were assessed in 2007. Essentially linear increases in stands with increased seeding rates were obtained over a wide range of seeding rates. Despite favorable responses to higher-than-recommended seeding rates, the partial stands at the recommended seeding rate indicate that past stand failures were associated with atypically low rainfall during the dallisgrass establishment period for the past two years. Both rather high seeding rates and periodic irrigation during the establishment period, especially during atypically dry periods, appear to be appropriate approaches for reliable establishment of dallisgrass pastures. Use of these suggested modifications to establishment recommendations for dallisgrass pastures will allow greater success rates with plantings of this generally difficult-to-establish grass and enhance profitability of livestock production
on heavy bottomland soils in the lower South.
Publications
- No publications reported this period
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Progress 01/01/06 to 12/31/06
Outputs
Two distinct objectives were included in this project. The first objective was to assess responses of young growing cattle and dallisgrass stands to different grazing pressures. The initial step in this process was to establish pastures with commercially available, pentaploid, common dallisgrass seed. Although seedbed preparation was thorough and weedy plant competition was not a problem, stands failed to establish for the second consecutive year. Insufficient rainfall appeared to be the primary factor in stand failure. Dallisgrass has been recognized as a difficult species to establish in pasture stands, and these results confirm the previous reports and observations. The few scattered dallisgrass plants in this pasture area will be augmented with additional seed, without soil disturbance, in an effort to develop stands. The second objective was to evaluate seed production potential of selected genotypes regenerated through tissue culture of hexaploid dallisgrass
germplasm. Individual plants of 24 regenerants and common dallisgrass previously transplanted to replicated, single-row plots were visually assessed for plant growth and vigor using a scale from 1 for lowest vigor to 9 for the most vigorous. Inflorescences of each entry were harvested with potential seed yield now being evaluated by determination of number of inflorescences per plant, number of branches per inflorescence, length of these branches, and number of spikelets per centimeter of branch. The number of inflorescences per plant differed substantially among individual plants. Average plant vigor ratings of the 24 regenerants differed and ranged from 5.1 to 8.4. Common dallisgrass plants had an average vigor rating of 6.9 and did not differ from any of the regenerants. Growth form was, however, distinct between common dallisgrass and the regenerants. Growth of common dallisgrass was somewhat decumbent, while all of the regenerants grew erectly. Field observations indicate that
opportunity may exist to identify a genotype within this group which possess superior establishment potential, primarily due to the upright growth, and improved seed production potential compared to common dallisgrass. Dallisgrass has long had a place in Louisiana forage systems on moist, fertile soils where it provides a longer season of forage productivity than do other warm-season grasses. Improvements in seed production and/or establishment potential could contribute to renewed planting of this important pasture plant and increased diversity of pastures in Louisiana.
Impacts
Limited seed availability and poor establishment have reduced the use of dallisgrass in Louisiana pastures in recent years. An improved variety could contribute to renewed use of dallisgrass, which provides benefits of a more diverse pasture base and an improved distribution of forage production on moist, fertile sites throughout Louisiana.
Publications
- No publications reported this period
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Progress 01/01/05 to 12/31/05
Outputs
During 2005, 25 of the 34 accessions which had previously been regenerated from tissue culture and planted into field plots for seed production were planted in the green house in early spring for transplanting into plots during the summer at the Red River Research Station. The 25 lines were randomly planted into four replications, to monitor plant vigor and to assess seed production and quality. Common dallisgrass was used as a check. The seedlings were planted August 3, 2005 and irrigated until the plants were established and growing. Plant vigor ratings were made on September 15, 2005 and several of the lines were much more vigorous in every plot than common dallisgrass. Seed was harvested from the lines in mid October and again in early November prior to the first frost. Seed quality and production data have not been completed at this time. Pastures of Common dallisgrass were planted three times in 2005 and extremely dry weather conditions have prevented a stand
from being esablished. Several isolated plants have come up and are being monitored to see if they exhibit any characteristics that are favorable for dry weather.
Impacts
This project is designed to improve management strategies to establish and maintain stands of dallisgrass and to identify superior lines of dallisgrass for seed production, seed quality and vigor.
Publications
- No publications reported this period
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Progress 01/01/04 to 12/31/04
Outputs
In 2004, 34 accessions which had previously been regenerated from tissue culture were established in the greenhouse from remnant seed and transplanted to field plots during mid-summer for seed increase. Seed was produced and hand harvested from 20 of these accessions prior to first frost. Individual plants of these 20 accessions were also dug and transported to College Station, Texas for DNA analysis to assess extent of detectable genetic modification in comparison to the plant sources of the original material subjected to the tissue culture process. The pastures for the grazing portion of the study were planted to common dallisgrass in November 2004. Grazing will be initiated when stands will support animal pressure, possibly in mid-summer 2005.
Impacts
To improve the reliability of and establish management strategies to graze dallisgrass.
Publications
- No publications reported this period
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