2009 Annual Report
1a.Objectives (from AD-416)
Objective 1: Develop and evaluate improved grass germplasm for the southern U.S. that is more productive, biologically diverse, tolerant of biotic and abiotic stresses, improved in quality, and easier to establish and maintain in pastures and rural landscapes.
Sub-objective 1.A: Develop and evaluate kleingrass (Panicum coloratum) germplasm with improved forage yield, seedling vigor, and persistence.
Sub-objective 1.B: Produce intraspecific Paspalum hybrids between different dallisgrass biotypes to develop improved forage types.
Sub-objective 1.C: Identify superior Texas bluegrass (Poa arachnifera) genotypes that are rust resistant and adapted to the humid southeastern U.S. to develop a synthetic population from these genotypes.
Objective 2: Use genomic techniques to develop and identify molecular markers associated with traits of interest in forage and turf grasses.
Sub-objective 2.A: Identify molecular markers to further saturate the genomic region controlling apomixis and survey candidate genes for seed sterility in buffelgrass (Pennisetum ciliare).
Sub-objective 2.B: Develop a genetic map of dallisgrass (Paspalum dilatatum) to identify markers linked to apomixis, disease and insect resistance, and other traits of interest.
Objective 3: Develop improved breeding methodologies by determining the cytology, reproductive biology, and genetic diversity of native and introduced germplasm for the production of improved forage and turf grasses.
Sub-objective 3.A: Determine the method of pollination, chromosome number, ploidy level, and mode of reproduction of species in the genera Panicum, Paspalum, Pennisetum, Sorghum, Chloris, Setaria, Stenotaphrum, Tripsacum, and others to facilitate their genetic improvement.
Sub-objective 3.B: Determine the genetic diversity and phylogeny of Paspalum and Pennisetum species using DNA fingerprinting techniques.
1b.Approach (from AD-416)
The long-term objectives of this project are to obtain a better understanding of the cytology, reproductive biology, and genetic diversity of selected forage grasses, and to use this fundamental information in the breeding and development of superior germplasm that will be released as improved cultivars.
In FY 2009, work under this project continued to make advances in selecting superior germplasm that will be used to develop a new kleingrass (Panicum coloratum) cultivar. Seed was harvested from 12 elite kleingrass selections growing in a replicated polycross nursery. Equal quantities of seed from each maternal parent was bulked and will be used to establish forage evaluation tests at multiple locations to determine if this germplasm is superior to existing kleingrass cultivars. A replicated seed production block consisting of the 24 different plant types (genotypes) that make up the switchgrass (Panicum virgatum) germplasm line 'TEM-LoDorm' was established to provide seed of this unique germplasm line for other switchgrass breeders to use in their programs. A Texas bluegrass (Poa arachnifera) evaluation nursery was established at Rosepine, LA. These plants are progeny from plants that survived intense grazing pressure; the superior genotypes will be selected to expand the base population that will be used to breed a more productive, rust-resistant synthetic population that is adapted to the humid southeast. In cooperative research with Texas A&M University scientists, back-cross plants were derived by crossing Sorghum bicolor/S. macrospermum hybrids with S. bicolor. These plants were studied at the cellular level to establish the amount of genetic mixing (introgression) between the chromosomes of the two species.
New Dallisgrass Cultivar: Cattle producers in the southeastern U.S. have long needed a more productive dallisgrass. In collaboration with Texas AgriLife Research, and Louisiana State University AgCenter scientists, a new dallisgrass cultivar was developed and released under the name "Sabine." This new cultivar is morphologically different from common dallisgrass in significant ways, it produces significantly more forage, and it tolerates heavy grazing pressure better than common dallisgrass. Since the Sabine cultivar was released, many forage researchers and producers have requested seed; Sabine will also be made available to producers by one or more commercial seed companies. The release of Sabine dallisgrass is important because it provides livestock producers in the southeastern U.S. with a productive, nutritious, and hardy forage grass that will improve livestock production efficiency.
Burson, B.L., Tischler, C.R., Ocumpaugh, W.R. 2009. Breeding for reduced post-harvest seed dormancy in switchgrass: Registration of TEM-LoDorm switchgrass germplasm. Journal of Plant Registrations. 3:99-103.
Burson, B.L., Venuto, B.C., Hussey, M.A. 2009. Registration of 'Sabine' Dallisgrass. Journal of Plant Registrations. 3:132-137.