Full TGIF Record # 217256
Item 1 of 1
Web URL(s):http://archive.lib.msu.edu/tic/rpr/1987/11895, Texas A&M, Beard.PDF
    Last checked: 03/26/2013
    Requires: PDF Reader
Publication Type:
Material Type:Manuscript
Monographic Author(s):Beard, James B.
Author Affiliation:Turfgrass Physiologist, Texas A&M University
Monograph Title:Fourth Year Progress Report Concerning Physiological Investigations in Developing Water Conserving, Minimal Maintenance Turfgrasses and Cultural Systems: Volume IV, 1987.
Publishing Information:[College Station, Texas]: Texas A&M University
# of Pages:60
Collation:i, 47, [12] pp.
Abstract/Contents:"This report represents the status report for the fourth year of intensive research activity devoted to developing water conserving, minimal maintenance turfgrasses and cultural systems. Thus it seems appropriate at this time to present a definitive set of research milestones that have been accomplished to date. They are as follows: Scientific Contributions: 1. Based on the development of a sophisticated set of physical experiments proved that canopy resistance is the major factor controlling evapotranspiration rates from turfgrasses rather than stomatal resistance or other internal resistances within the plant.; 2. Shown that a high canopy resistance based on a high shoot density and more horizontal leaf orientation plus a low leaf area based on a slow leaf extension rate and narrow leaf width are the plant morphological factors that are most significant in controlling evapotranspiration from turfgrasses. This principal has served as the basis for the system used in developing plant markers in a breeding program for selecting low water use rate grasses and also for a diverse rate of modified cultural practices that ensure lower water use rates.; 3. Demonstrated that stomatal density and size had little influence on evapotranspiration rates; thus breeding programs should not place emphasis on this dimension.; 4. Developed the first comprehensive understanding of root hair morphology and viability among the major warm-season perennial turfgrass species. Based on this work it is evident that a lack of root hair number, length and/or viability can contribute significantly to reduce drought resistance.; 5. Have delineated the environmental factors inducing spring root decline and shown that carbohydrate partitioning away from the roots is strongly associated with the root dieback phenomenon.; 6. Identified the specific plant morphological and/or physiological characteristics most important in contributing to drought resistance of individual warn-season turfgrass species.; Breeding Contributions: 1. Have developed a rapid simple method for visually rating the evapotranspiration rates of warm-season turfgrasses in clonal nurseries via the high canopy resistance-low leaf area concept.; 2. From a breeding strategy standpoint have shown at both the interspecies and intraspecies levels that those species with the most deep, extensive root systems are characterized by a high verdure and shoot growth rate.; 3. Found a great range in diversity at the intraspecies level for the canopy resistance and leaf area components controlling evapotranspiration. This indicates that the genetic material is available to the breeder to develop low water use rate cultivars.; 4. Have delineated, among warm-season species, the key limiting factors affecting drought resistance. These vary greatly among the major warm-season turfgrasses including shallow rooting, high evapotranspiration rates, slow stomatal closure, minimal wax covering of the leaf/stomatal surface under water stress, and inferior internal tissue water stress tolerance.; Cultural Contributions: 1. For the first time, developed and published a comparison of the relative and potential evapotranspiration rates of the major warm-season and cool-season turf species which can be used as a guide in selecting grasses with low water use rates.; 2. For the first time, characterized and published the comparative rooting potentials of the major warm- and cool-season turfgrass species. Under mowing, the rooting depths range from 12 inches to 8 feet.; 3. Have investigated and published on the comparative drought resistance of the major warm-season turfgrass species and cultivars. For the first time this type of information is now available in selecting specific turfgrass species and cultivars for unirrigated turf areas.; 4. Based on the high canopy resistance, low leaf area concept, have shown specific cultural practices that can be used in lowering the evapotranspiration rate. For the most part these are based on a low leaf area and slow leaf extension rate. Included are a low cutting high, moderate to low nitrogen fertility level, judicious irrigation and the use of shoot growth inhibitors.; 5. Shown the lack of effectiveness of stomatal antitranspirants for use in reducing evapotranspiration from turfgrasses.; 6. Developed a set of cultural strategies that can be used in enhancing the rate of a root replacement following spring root decline. This system has resulted in a total change in the spring turfgrass cultural strategy compared to what has been used in the past."
See Also:See also related item, "Leaf blade stomatal characterizations and potential evapotranspiration rates of 12 cool-season, C-3 turfgrasses" Texas Turfgrass Research - 1986, May 1987, p. 8-9, R=14179. R=14179

See also related item, "Morphological and physiological plant parameters of bermudagrass cultivars with low nitrogen requirements" Texas Turfgrass Research - 1986, May 1987, p. 22, R=14186. R=14186

See also related item, "Criteria for visual prediction of low water use rates of bermudagrass cultivars" Texas Turfgrass Research - 1986, May 1987, p. 22-23, R=14188. R=14188

See also related item, "Comparative drought resistances among major warm-season turfgrass species and cultivars" Texas Turfgrass Research - 1986, May 1987, p. 28-30, R=14191. R=14191

See also related item, "An assessment of cutting height and nitrogen fertility requirements of seashore paspalum" Texas Turfgrass Research - 1986, May 1987, p. 43, R=14199. R=14199

See also related summary article, "Plant stress mechanisms", Annual Turfgrass Research Report [USGA/GCSSA], 1987, pp. 26-27, R=11895. R=11895
Note:"Jointly Sponsored By: United States Golf Association and Texas Agricultural Experiment Station"
Appendices include full copies of 11 other abstracts or items
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http://archive.lib.msu.edu/tic/rpr/1987/11895, Texas A&M, Beard.PDF
    Last checked: 03/26/2013
    Requires: PDF Reader
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