Location: Crop Germplasm Research
Project Number: 3091-21000-033-00-D
Project Type: In-House Appropriated
Start Date: Feb 26, 2013
End Date: Feb 25, 2018
The long-term objectives of this project are to investigate the reproductive biology, cytology, breeding behavior, and genetic diversity of selected grasses for the purpose of integrating this fundamental information into developing breeding and genetic improvement strategies targeting the creation of elite germplasm that will ultimately be released as improved cultivars. Specifically, during the next five years we will focus on the following objectives. Objective 1: Develop and evaluate improved germplasm of kleingrass and Texas bluegrass 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. Subobjective 1A: Develop and evaluate kleingrass (Panicum coloratum) germplasm with improved forage yield, forage quality, seedling vigor, seed retention, and persistence. Subobjective 1B: Develop and evaluate Texas bluegrass (Poa arachnifera) germplasm with increased forage yield, rust resistance, and adaptation for the humid southeastern U.S. Objective 2: Develop and evaluate novel perennial biofuel sorghum as feedstocks for cellulosic ethanol and biopower. Subobjective 2A: Produce interspecific and intergeneric hybrids between sorghum (Sorghum bicolor) and (1) other Sorghum species and (2) diverse species of other Poaceae genera. Subobjective 2B: Evaluate all interspecific and intergeneric Sorghum hybrids produced for winter-hardiness, perenniality, seed fertility, biomass production, and weediness mitigation. Objective 3: Determine the cytology, reproductive behavior, and genetic diversity of native and introduced species to develop more efficient breeding methodologies for the production of improved forage and bioenergy grasses. Subobjective 3A: Determine the method of pollination, chromosome number, ploidy level, and method of reproduction of species of Panicum, Pennisetum, Sorghum, Tripsacum, and other genera that will be utilized in the wide hybridization program to facilitate hybridization and the genetic improvement of the resulting wide hybrids. Subobjective 3B: Utilize molecular markers to identify and assess parental contribution of interspecific and intergeneric hybrids via species-specific markers and characterize the genetic diversity within targeted germplasm.
Improved perennial germplasm of warm- and cool-season grasses will be developed, evaluated, and released as cultivars or germplasm lines to be used as forage and/or bioenergy feedstocks in the southern Great Plains and the southeastern U.S. Because kleingrass and Texas bluegrass are cross-pollinated and sexually reproducing species, recurrent selection using replicated nurseries will be used to develop germplasm with improved forage potential. Wide hybridization will be used to produce perennial sorghum germplasm that potentially can be grown as a dual-purpose crop for bioenergy feedstocks and forage. Interspecific crosses will be made between Sorghum bicolor and different perennial Sorghum species, and intergeneric crosses will be made between different Sorghum species and a number of winter-hardy, robust, apomictic grasses that belong to other genera. Apomictic species will be used to provide a means whereby seed sterility in the intergeneric hybrids produced can be circumvented. Cytogenetic approaches will be used to identify pollen-pistil incompatibilities between different species crossed to produce the wide hybrids, and this information will be used to develop strategies to circumvent incompatibilities and allow the species to hybridize. The cytology and reproductive behavior of the hybrids produced will be studied using cytological approaches to learn more about the relationships of the parental species and fertility-sterility issues in the hybrids. Molecular approaches will also be used to identify hybrids, determine the genetic diversity within the germplasm used, and identify molecular markers associated with traits of interest.