Submitted to: Genetica
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/12/1996
Publication Date: N/A
Citation: Interpretive Summary: Apomictic reproduction does not occur in maize but potential exists for the transfer of this characteristic from Tripsacum, a distant relative of maize. The development of an apomictic form of maize could provide a genetically stable hybrid which would maintain its original level of hybrid vigor, yield and disease resistance capabilities for an infinite number of generations. Presently, an apomictic mode of reproduction has been identified in a series of maize-Tripsacum hybrids. A comparison of the apomictic reproductive behaviors observed in these materials is compared to that exhibited in apomictic Tripsacum dactyloides (eastern gamagrass). Chromosome counts, followed by biochemical and molecular studies indicate good expression of the Tripsacum apomictic gene(s) in a partial maize background. This study indicates that the Tripsacum gene(s) controlling apomictic reproduction will be fully functional in a maize background. Continued efforts to complete the transfer are also indicated from this study. This research is of particular interest to maize geneticists as well as public and private maize breeding programs.
Technical Abstract: The expression of gene(s) governing apomictic reproduction in Tripsacum provides the best foundation for comparing the effectiveness of apomictic reproduction in a series of maize-Tripsacum hybrids. Several 38- chromosome, apomictic maize-Tripsacum hybrids are available which possess gene(s) conferring apomictic reproduction from Tripsacum. Without a base line for comparison, studies directed toward discerning the successful transfer or effectiveness of the gene(s) expression in a maize background are hampered. The objectives of this study are to review and compare the reproductive features found in apomictic Tripsacum with those in the apomictic maize-Tripsacum hybrids. In addition, this study determined the feasibility of utilizing these maize- Tripsacum hybrid materials to continue an attempt to transfer these genes into a pure maize background. The frequency and occurrence of five unique reproductive features found in apomictic accessions of Tripsacum dactyloides were compared to the reproductive behaviors exhibited in the maize-Tripsacum hybrids. Based upon these comparisons, it was concluded that that the genes controlling apomictic reproduction in tetraploid Tripsacum are fully functional in both a diploid and triploid maize background. This favorable conclusion indicates that the concept of developing an apomictic maize may merit further investigation.