Progress 10/01/09 to 09/30/10
Outputs
Progress Report Objectives (from AD-416) The objective of this cooperative research project is to determine the nuclear DNA content of different grass species to provide a better understanding of their genome evolution, chromosome organization, and ploidy levels (polyploidy) as well as provide information beneficial for structural genomics. Approach (from AD-416) Germplasm representing a wide range of accessions of different grass species (Florida paspalum, dallisgrass, brown seeded paspalum, bahiagrass, buffelgrass, etc.) will be collected and analyzed. The DNA content of each accession within a selected species will be determined using flow cytometry. DNA content in the nuclei of the select plants will be measured by laser flow cytometry and ultra-violet flow cytometry using different fluorescent stains (propidium iodide [PI] and 4�, 6-diamidino-2- phenylindole [DAPI]). The DNA content of target species will be determined by comparing their mean fluorescences to that of established standards. The calculated values will be used to assess divergence within and among species involving both duplication of chromosomes (ploidy) and amplification or deletion of sequences within chromosomes. This information will provide insight into the evolutionary relationships of these species which is beneficial in selecting germplasm to use in the breeding of improved cultivars. DNA quantification is also of value in reconciling genetic vs. physical maps in genomic studies. The goal of this project is to determine the DNA content of different grass species to provide a better understanding of their overall genetic composition, how the plants evolved genetically, and how their genetic composition affects reproductive biology. Using modern analytical techniques, including flow cytometry, molecular markers, and classical cytology, a number of warm-season grasses were studied. The species emphasized during FY 2010 were bahiagrass, a valuable forage grass; and Florida paspalum, a native species that is a valuable food source for wildlife. Based on DNA content, it was determined that the naturalized bahiagrass populations in the southern United States (and that are slowly spreading in a northerly direction) are migrants of Pensacola bahiagrass, kown to exist in Florida for many years. Using molecular markers known as amplified fragment length polymorphisms, it was also determined that these naturalized populations are genetically diverse. Some diversity was expected because the grass is a sexual, cross-pollinated species, but the level of diversity observed exceeded expectations because of the narrow genetic base of the Pensacola germplasm of bahiagrass from which these populations originated. These findings demonstrate that grass breeders can use naturalized bahiagrass germplasm to make advances that should result in the development of improved bahiagrass cultivars to benefit the livestock industry in the southern U.S. Work with Florida paspalum established that this species reproduces both by sexual and non-sexual (apomictic) means, but that non-sexual reproduction predominates. The work on Florida paspalum is of importance to Natural Resource Conservation Service personnel and others interested in improving this species because it provides vital information as to the most effective breeding approaches to be employed. Work under this project, overall, has provided significant advances in understanding how important southern grass species can be improved for utilization as livestock forages and wildlife habitat, and also as possible feedstocks for production of biofuels. The ADODR of this project and the cooperator are located in close physical proximity and are in contact with each other on an ongoing basis. The ADODR and the cooperator (or key personnel working under the cooperator) meet and discuss the direction and progress of the work on a regular basis. This project expired in FY 2010 but was replaced by 6202- 21000-028-02S, which is continuing and expanding upon the work.
Impacts
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Progress 09/01/05 to 08/31/10
Outputs
Progress Report Objectives (from AD-416) The objective of this cooperative research project is to determine the nuclear DNA content of different grass species to provide a better understanding of their genome evolution, chromosome organization, and ploidy levels (polyploidy) as well as provide information beneficial for structural genomics. Approach (from AD-416) Germplasm representing a wide range of accessions of different grass species (Florida paspalum, dallisgrass, brown seeded paspalum, bahiagrass, buffelgrass, etc.) will be collected and analyzed. The DNA content of each accession within a selected species will be determined using flow cytometry. DNA content in the nuclei of the select plants will be measured by laser flow cytometry and ultra-violet flow cytometry using different fluorescent stains (propidium iodide [PI] and 4�, 6-diamidino-2- phenylindole [DAPI]). The DNA content of target species will be determined by comparing their mean fluorescences to that of established standards. The calculated values will be used to assess divergence within and among species involving both duplication of chromosomes (ploidy) and amplification or deletion of sequences within chromosomes. This information will provide insight into the evolutionary relationships of these species which is beneficial in selecting germplasm to use in the breeding of improved cultivars. DNA quantification is also of value in reconciling genetic vs. physical maps in genomic studies. This project expired in FY 2010; no project work was conducted during FY 2011.
Impacts
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Publications
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Progress 10/01/08 to 09/30/09
Outputs
Progress Report Objectives (from AD-416) The objective of this cooperative research project is to determine the nuclear DNA content of different grass species to provide a better understanding of their genome evolution, chromosome organization, and ploidy levels (polyploidy) as well as provide information beneficial for structural genomics. Approach (from AD-416) Germplasm representing a wide range of accessions of different grass species (Florida paspalum, dallisgrass, brown seeded paspalum, bahiagrass, buffelgrass, etc.) will be collected and analyzed. The DNA content of each accession within a selected species will be determined using flow cytometry. DNA content in the nuclei of the select plants will be measured by laser flow cytometry and ultra-violet flow cytometry using different fluorescent stains (propidium iodide [PI] and 4�, 6-diamidino-2- phenylindole [DAPI]). The DNA content of target species will be determined by comparing their mean fluorescences to that of established standards. The calculated values will be used to assess divergence within and among species involving both duplication of chromosomes (ploidy) and amplification or deletion of sequences within chromosomes. This information will provide insight into the evolutionary relationships of these species which is beneficial in selecting germplasm to use in the breeding of improved cultivars. DNA quantification is also of value in reconciling genetic vs. physical maps in genomic studies. Significant Activities that Support Special Target Populations The goal of this project is to determine the DNA content of different grasses to provide a better understanding of their genetic composition and organization, and their reproductive behavior. In FY 2009, the DNA content was determined for a number of Florida paspalum (Paspalum floridanum) genetic types (accessions), and the genetic diversity among these accessions was determined using the molecular biology approach known as molecular markers (single sequence repeats or SSRs). Fifty- three accessions from Texas, Louisiana, Arkansas, and Oklahoma were evaluated. The DNA content of the accessions varied significantly, indicating that the different accessions have different numbers of chromosomes. Appropriate techniques were used to establish the genetic similarity among the various accessions; the genetic diversity observed was in many cases significant enough to individually identify particular accessions. Work thus far under the project has provided good evidence that Florida paspalum reproduces by a process known as apomixis (seed development without fertilization) as well as by normal sexual means. Therefore, Florida paspalum appears to be what is known as a facultative apomict. The ADODR of this project and the cooperator are located in the same facility and are in contact with one another on a daily basis. Because of this close physical relationship, the ADODR and the cooperator discuss the direction and progress of the research on a regular basis.
Impacts
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Progress 10/01/07 to 09/30/08
Outputs
Progress Report Objectives (from AD-416) The objective of this cooperative research project is to determine the nuclear DNA content of different grass species to provide a better understanding of their genome evolution, chromosome organization, and ploidy levels (polyploidy) as well as provide information beneficial for structural genomics. Approach (from AD-416) Germplasm representing a wide range of accessions of different grass species (Florida paspalum, dallisgrass, brown seeded paspalum, bahiagrass, buffelgrass, etc.) will be collected and analyzed. The DNA content of each accession within a selected species will be determined using flow cytometry. DNA content in the nuclei of the select plants will be measured by laser flow cytometry and ultra-violet flow cytometry using different fluorescent stains (propidium iodide [PI] and 4�, 6-diamidino-2- phenylindole [DAPI]). The DNA content of target species will be determined by comparing their mean fluorescences to that of established standards. The calculated values will be used to assess divergence within and among species involving both duplication of chromosomes (ploidy) and amplification or deletion of sequences within chromosomes. This information will provide insight into the evolutionary relationships of these species which is beneficial in selecting germplasm to use in the breeding of improved cultivars. DNA quantification is also of value in reconciling genetic vs. physical maps in genomic studies. Significant Activities that Support Special Target Populations The goal of this project is to determine the DNA content of different grasses to provide a better understanding of their ploidy level, chromosome number and organization, and genome evolution. In FY 2008, the DNA content and genetic diversity were determined for 30 bahiagrass (Paspalum notatum) accessions that were collected near the species' northern range of adaptation. This is an extension of earlier work by this project that determined the DNA content and genetic diversity of bahiagrass accessions collected in northern Arkansas. As in the earlier work, the DNA content was measured using flow cytometry, and the genetic diversity across these accessions was determined using Amplified Fragment Length Polymorphisms (AFLPs). The DNA content of all accessions was similar to that of Pensacola bahiagrass, indicating that they are diploids, and suggesting that these accessions are volunteer plants from Pensacola bahiagrass. The average genetic similarity coefficient for these accessions was low (0.52), indicating the species to be highly diverse. This is expected because Pensacola bahiagrass is a highly cross- pollinated sexual species. These findings demonstrate that there is sufficient diversity within and among naturally occurring populations of bahiagrass in the southern U.S. such that genetic improvement can be made through breeding. This is important to grass breeders; the development of improved bahiagrass cultivars would greatly benefit livestock producers in the southern U.S. The ADODR of this project and the cooperator are located in the same facility and are in contact with one another on essentially a daily basis. Because of this close physical relationship, the ADODR and the cooperator discuss the direction and progress of the work on a regular basis.
Impacts
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Progress 10/01/06 to 09/30/07
Outputs
Progress Report Objectives (from AD-416) The objective of this cooperative research project is to determine the nuclear DNA content of different grass species to provide a better understanding of their genome evolution, chromosome organization, and ploidy levels (polyploidy) as well as provide information beneficial for structural genomics. Approach (from AD-416) Germplasm representing a wide range of accessions of different grass species (Florida paspalum, dallisgrass, brown seeded paspalum, bahiagrass, buffelgrass, etc.) will be collected and analyzed. The DNA content of each accession within a selected species will be determined using flow cytometry. DNA content in the nuclei of the select plants will be measured by laser flow cytometry and ultra-violet flow cytometry using different fluorescent stains (propidium iodide [PI] and 4�, 6-diamidino-2- phenylindole [DAPI]). The DNA content of target species will be determined by comparing their mean fluorescences to that of established standards. The calculated values will be used to assess divergence within and among species involving both duplication of chromosomes (ploidy) and amplification or deletion of sequences within chromosomes. This information will provide insight into the evolutionary relationships of these species which is beneficial in selecting germplasm to use in the breeding of improved cultivars. DNA quantification is also of value in reconciling genetic vs. physical maps in genomic studies. Significant Activities that Support Special Target Populations This report serves to document research conducted under a Specific Cooperative Agreement between ARS and Texas A&M University. Additional details of research can be found in the report for the parent project 6202-21000-020-00D, Genetic Enhancement of Warm-Season Perennial Forage and Range Grasses. The goal of this project is to determine the DNA content of different grass species to provide a better understanding of their ploidy level, chromosome number and organization, and genome evolution. In FY 2007, the DNA content and genetic diversity were determined for a number of Florida paspalum accessions collected in Arkansas, Louisiana, Oklahoma, and Texas. Researchers using traditional methods have not been able to determine how this species reproduces. Therefore, variation/uniformity in DNA content and genetic diversity of the accessions and their progeny was utilized to determine their reproductive behavior. DNA content was determined using flow cytometry and it ranged from 11.91 to 13.95 pg, with a mean of 12.16 pg. A total of 61 SSRs were used to determine the genetic diversity across these accessions and within the progeny of each accession. Following analysis with NTSYSpc, the average genetic similarity between individual accessions was 0.64. Diversity between plants was significant enough to individually identify each accession. Average pairwise genetic similarity across half-sib progeny families of selected accessions ranged from 0.66 to 0.87, with an overall average of 0.76. Project results thus far indicate that the accessions analyzed may reproduce by facultative apomixis. As the work progresses, more definitive genetic information will be gained on reproductive behavior of Florida paspalum and other important grasses; these findings will be of critical importance to plant breeders interested in improving the targeted grasses because it will focus efforts on the most effective breeding approaches to be employed. The ADODR of this project and the cooperator are located in the same facility and are in contact with one another almost daily. The ADODR and the cooperator meet and discuss the direction and progress of the project on a regular basis.
Impacts
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Progress 10/01/05 to 09/30/06
Outputs
Progress Report 4d Progress report. This report serves to document research conducted under a Specific Cooperative Agreement between ARS and Texas A&M University. Additional details of research can be found in the report for the parent CRIS 6202- 21000-020-00D Genetic Enhancement of Warm-Season Perennial Forage and Range Grasses. The goal of this project is to determine the DNA content of different grass species to provide a better understanding of their ploidy level, chromosome number and organization, and genome evolution. In FY 2006, the DNA content was determined for a number of winter-hardy bahiagrass plants that were collected at higher elevations in northern Arkansas, and the genetic diversity across these plants was also determined using AFLPs. All accessions were diploids which indicates they originated from the cultivar Pensacola bahiagrass. Genetically, they were highly diverse as illustrated by a low average genetic similarity coefficient of 0.57 across
all accessions and cultivars, including Pensacola. These findings demonstrate that there is considerable genetic diversity within plants in naturalized bahiagrass populations in the southern U.S. Bahiagrass breeders can use this naturalized germplasm in breeding programs to make advances that will ultimately result in the development of improved bahiagrass cultivars which will benefit livestock producers in the southern U.S.
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