Location: Crop Germplasm Research
2021 Annual Report
Objectives
Objective 1: Develop and evaluate improved germplasm of perennial forage sorghum genotypes, napiergrass, pearl millet x napiergrass hybrids, and kleingrass that are more productive, biologically diverse, tolerant of biotic and abiotic stresses, improved in quality, and easier to establish and maintain in sustainable agroecosystems.
Subobjective 1A: Produce intra- and interspecific and intergeneric perennial forage Sorghum hybrids and evaluate them for winter-hardiness, perenniality, biomass production, forage quality, disease/insect resistance, seed fertility, and weediness mitigation.
Subobjective 1B: Develop improved napiergrass (Pennisetum purpureum) genotypes and pearl millet (Pennisetum glaucum) x napiergrass hybrids and evaluate them for improved winter-hardiness, higher forage yield and quality, drought tolerance, seed fertility, and weediness mitigation.
Subobjective 1C: Develop and evaluate kleingrass (Panicum coloratum) synthetic varieties with improved forage yield and quality, seed weight, seedling vigor, and persistence.
Objective 2: Determine the reproductive biology, cytology, crossability, and genetic diversity of all new germplasm of different Sorghum species, napiergrass and other Pennisetum species, and their interspecific hybrids to support development of more efficient forage and bioenergy grass breeding strategies.
Subobjective 2A: Determine the method of pollination, chromosome number, ploidy level, and reproductive behavior of species of Sorghum, Pennisetum, and other genera used in the wide hybridization program to facilitate hybridization and the genetic improvement of recovered wide hybrids.
Subobjective 2B: 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.
Approach
Better adapted and more productive forage grasses are needed to improve livestock production and the ecological stewardship of the southern U.S. Species that produce large quantities of biomass also have potential as bioenergy crops and value-added bioproducts. This is an ongoing, long-term, 1-Scientific Year project that collaborates closely and effectively with Texas A&M University (TAMU) scientists. Many warm-season perennial grasses are complex polyploids, which makes improvement utilizing conventional breeding methods a difficult undertaking. Apomixis, a vegetative form of reproduction, is prevalent within many of these species, and this further complicates improvement. Interspecific hybridization and induced polyploidization are often required to create germplasm and this complicates improvement. The first objective addresses the breeding and genetic enhancement of perennial forage sorghum, napiergrass including napiergrass x pearl millet hybrids, and kleingrass. Elite germplasm from these breeding efforts will be evaluated in anticipation of selecting and releasing better adapted and more productive cultivars to be used as forage for livestock. Perennial forage sorghum and napiergrass germplasm also will be evaluated sustainable bioenergy feedstocks and as sources for value-added bioproducts. The second objective investigates the reproductive biology, cytology, pollination/incompatibility mechanisms, and genetic and genomic relationships of all new germplasm of different Sorghum species, napiergrass accessions, and other Pennisetum species introduced into and used in the breeding programs. Similar information will be determined for all interspecific hybrids recovered from crosses between napiergrass and other Pennisetum species and between perennial forage sorghums and wild Sorghum species. This basic information is needed to establish more efficient breeding strategies for the production and selection of improved forage and bioenergy grasses.
Progress Report
Research under Objective 1 continued to make advances in the development, selection, and evaluation of superior sorghum germplasm for the purpose of developing improved perennial sorghum cultivars to be used for forage and bioenergy purposes. In collaboration with Texas A&M University scientists, work continued on the characterization of advanced generations of an induced tetraploid Sorghum bicolor x S. propinquum hybrid. Selections were made to establish a recurrent selection program to develop synthetic cultivars. During Fiscal Year 2021, research associated with this project under Objective 2 made significant advances in determining the cytological relationship between S. bicolor and S. propinquum. Controlled crosses were made between S. propinquum and S. halepense to produce hybrids to investigate their cytological relationships. Hybrids recovered will provide important information on the genetics of perennialism in Sorghum. Work involving a Texas A&M University collaborator screened 320 molecular tools known as SSR markers using diploid S. bicolor x S. propinquum F4 hybrids to identify genotypes with higher rhizome and root biomass. Twenty-three candidate markers were identified for increased below ground biomass accumulation. These findings are important in identifying sorghum genotypes with the potential for higher carbon sequestration, and provide a valuable tool for carbon sequestration studies in response to global climate change concerns.
Accomplishments
