A COMPARISON OF APOMICTIC REPRODUCTION IN EASTERN GAMAGRASS (TRIPSACUM DACTYLOIDES (L) L) AND MAIZE-TRIPSACUM HYBRIDS

The expression of gene(s) governing apomictic reproduction in Tripsacu m provides the best foundation for comparing the effectiveness of apom ictic reproduction in a series of maize-Tripsacum hybrids. Several 38- chromosome, apomictic maize-Tripsacum hybrids are available which poss ess the gene(s) conferring apomictic reproduction from Tripsacum. With out a base line for comparison, studies directed towards discerning th e successful transfer or effectiveness of gene expression in a maize b ackground are hampered. The objectives of this study are to compare th e reproductive features found in apomictic Tripsacum with those in apo mictic maize-Tripsacum hybrids. In addition, this study determined the feasibility of utilizing these maize-Tripsacum hybrid materials to co ntinue an attempt to transfer the genes into a pure maize background. The frequency and occurrence of five unique reproductive features foun d in apomictic accessions of Tripsacum dactyloides were compared to th e reproductive behaviours exhibited in the maize-Tripsacum hybrids. Re sults indicate the genes controlling apomixis in tetraploid Tripsacum are fully functional in maize-Tripsacum hybrids with diploid and tripl oid maize constitutions. The ability of the Tripsacum apomictic genes to retain full expression provides evidence to continue their transfer to a diploid or tetraploid maize background.