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| Web URL(s): | http://archive.lib.msu.edu/tic/rpr/2000/72139,%20Miss%20State, Goatley.PDF
Last checked: 02/08/2013
Requires: PDF Reader |
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| Publication Type:
| Report |
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| Material Type: | Manuscript |
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| Monographic Author(s): | Goatley, J. M.; Krans, J. V.; Davis, D. W. |
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| Author Affiliation: | Dept. of Plant & Soil Science, Mississippi State University, MS |
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| Monograph Title: | [Determining the Genetic Stability of Triploid Bermudagrass]: USGA 2000 Executive Summary, 2000. |
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| Publishing Information: | [Mississippi State, Mississippi]: Mississippi State University |
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| # of Pages: | 3 |
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| Collation: | 3 pp. |
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| Abstract/Contents: | "Application of dintroaniline class pre-emergent herbicides is an integral part of triploid bermudagrass sod production. The active ingredients in their formulation are known to cause chromosome lagging at mitosis, which can give rise to aneuploids. Aneuploids are plants with higher or lower chromosome numbers than expected. Aneuploidy can cause changes in leaf blade width and length; similar changes are often observed in naturally-occuring off-types. Another alternative which might explain off-types is that long-term, chronic dinitroaniline usage is mutagenic to DNA of perennially-grown bermudagrass; therefore dinitroaniline herbicides may be a causal agent in off-type formation. A third possibility is that herbicide usage may favor spontaneous (naturally-occuring) mutations which cause off-types. Mutation detection tests performed on mammals and bacteria have found that highly-purified oryzalin and pendimethalin are not mutagenic. While these tests supply yseful evidence about the safety of the active ingredient, they do not give us a "yes or no answer" about the potential mutagenicity (to plant tissues) of long-term chronic applications of the formulations as they are applied in the field. Our goal is to learn more about off-type formation using a 2 phased experiment. The first phase has been an "off-type induction" experiment. Six selected triploid bermudagrass varieties ('Champion', 'Floradwarf', 'MS-Supreme', 'Tifdwarf', 'Tifeagle', and 'Tifgreen') are subjected to acute (2X) doeses of oryzalin and pendimethallin, to determine if off-type plants can be produced. This has been performed in greenhouses using methyl bromide-sterilized growth medium, to eliminate contamination as a factor contributing to off-type recovery. A total of 6 cycles of induction will be completed at project's conclusion. The second phase of the experiment is an "off-type detection" experiment. We are using 3 separate routes to classify any off-types which might be induced by the off-type induction experiment. These are: morphological trait classification, AFLP profiling (a method of DNA fingerprinting), and chromosome number counting. Morphological traits (leaf blade length and width, internode length and diameter) showed no significant variation among cycles or among herbicide treatments, indicating that no morphological off-types were found by our random sampling. The only significant differences simply traced to pre-existing intervarietal variation. Our molecular results to date show that the majority of missing bands occured in the pendamethalin treatment. However, since missing AFLP bands occurred in the untreated control, we cannot make a firm conclusion regarding what caused their disappearance' analysis of further cycles will help form a clearer picture. All varieties have shown at least one band loss. Our cytology data has only been completed through Cycle 2. To date, no aneuploids were detected, with all samples showing the expected 27 chromosomes. Our chromosome counting technique requires fresh tissue (so we cannot use fixed specimens), which are unobtainable during dormancy, so this off-type detection method has lagged behind the other 2 methods. Additionally, we have conducted a small experiment to determine if bermudagrass contains active transposable elements (also known as "jumping genes") similar to those characterized in other grass species, such as rice and maize. These naturally-occurring elements are responsible for many of the spontaneous morphological mutations found in those species. To date, we have performed PCR-based experiments to determine if these elements are present in bermudagrass. We have found 4 elements from maize which are also in triploid bermudagrass DNA. These are named "Grande", "Huck-2", "Prem-1", and "Prem-2". Since there is some evidence that off-types may be a spontaneous occurrence, we hope to document the presence and activity of these elements as a possible explanation for bermudagrass off-types." |
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| Language: | English |
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| References: | 0 |
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| See Also: | See also related summary article, "Determining the genetic stability of triploid bermudagrass", 2000 Turfgrass and Environmental Research Summary [USGA], 2000, p. 37, R=72139. R=720139 |
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| Note: | Other title: USGA 2000 Executive Summary: Mississippi State University
Also appears as pp. 25-27 in the USGA Turfgrass Research Committee Reporting Binders for 2000
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Last checked: 02/08/2013
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