ASSIGNMENT OF A GENE(S) CONFERRING APOMIXIS IN TRIPSACUM TO A CHROMOSOME ARM - CYTOLOGICAL AND MOLECULAR EVIDENCE

Attempts are underway to locate and transfer genes conferring diplospo rous apomixis from Tripsacum to maize. The objective of this study was to evaluate several apomictic and sexual maize-Tripsacum hybrids for the presence or absence of Tripsacum chromosomes, PCR-RAPD generated m arkers, and RFLP markers that would have an association with apomictic development. Cytological and molecular analysis resulted in the ident ification of the Tripsacum chromosome arm carrying the gene(s) conferr ing diplosporous apomixis. Evaluations made on apomictic sexually deri ved maize + Tripsacum addition lines and an apomictic line possessing a Mz6L-Tr16L translocation were used to establish the location of the gene(s). Results of the study indicate that the successful transfer of a single Tripsacum chromosome is all that is necessary to maintain ap omictic reproduction in a maize background. Additional use of this mat erial may facilitate the development of an apomictic maize prototype a nd the eventual isolation of the gene(s).