Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 3, 1997
Publication Date: N/A
Interpretive Summary: Eastern gamagrass is a native warm season species which can be utilized as a nutritious and palatable forage grass for grazing livestock. Very little information regarding the reproductive and potential breeding characteristics of this species are known. The purpose of this research was to identify the classic and novel reproductive characters represented in both sexual and apomictic eastern gamagrass. Results of the study concluded that triploid and hexaploid lines can be used to introgress desirable genes across reproductive barriers. The results provide a clear outline or breeding strategy for developing superior cultivars of eastern gamagrass. The results will be useful to forage breeders and geneticists.
Technical Abstract: Eastern gamagrass (Tripsacum dactyloides), a native, warm-season species, is a nutritious and palatable forage for grazing livestock. The grass has potential for rangeland and pasture improvement. This field study was conducted over 14 years at one location to determine the reproductive characteristics of the various cytotypes of Tripsacum and identify methods for breeding agronomically superior cultivars. Intra- and interspecific crosses were made and evaluated between several Tripsacum cytotypes. Cytological and polymerase chain reaction-random amplified polymorphic DNA (PCR-RAPD) techniques were used to identify methods of reproduction and types of individuals generated. Results of the study identified two methods for facilitating horizontal gene flow among sexual and apomictic cytotypes. Materials with triploid and hexaploid constitutions were essential in the movement of sexual germplasm into apomictic tetraploids and of tetraploid germplasm into sexual diploids, respectively. Triploids and hexaploids were useful materials to introgress and transfer desirable alleles across species. In addition, the generation of triploid and hexaploid genotypes will continue to exert major influences on Tripsacum evolution and speciation. This study identified additional methods and systems for improving Tripsacum germplasm by utilizing its distant relative maize (Zea mays L.) in a breeding or genetic evaluation program.