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Title: SECTIONAL DELINEATION OF SEXUAL TRIPSACUM DACTYLOIDES-T. MAIZAR ALLOTRIPLOIDS

Author
item Li, Yong
item Dewald, Chester
item SOKOLOV, VICTOR - INST. CYTOLOGY, RUSSIA

Submitted to: Annals of Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/23/2000
Publication Date: 11/20/2000
Citation: N/A

Interpretive Summary: In recent studies it was determined that certain interspecific hybrids produced from intermating of sexual Eastern gamagrass plants (Tripsacum dactyloides, 2n = 2x = 36, section Tripsacum) and another non-sexual gamagrass species (T. maizar, 2n = 4x = 72, section Fasciculata) reproduce sexually. Offsprings developed from these hybrids backcrossed with one of its parents can be clearly classified to either section Tripsacum or section Fasciculata due to their distinctively different morphology. More importantly, sectional differences of the progeny shifted in the direction of pollinator, the male parent, through genome substitution. We did not expect to find this result following just one generation of backcrossing in a normal breeding program. Our main objective was to investigate genetic differences between the chromosomes from section Tripsacum and section Fasciculata. Our results indicate that there were significant genetic differences between these two sections.

Technical Abstract: In recent studies it was determined that certain allotriploids produced from crosses of sexual diploid Tripsacum dactyloides (2n = 2x = 36), section Tripsacum and apomictic tetraploid T. maizar (2n = 4x = 72), section Fasciculata reproduce sexually. Backcrossing progenies can be clearly classified to either sect. Tripsacum or sect. Fasciculata due to their distinctively different inflorescence phenotype. More importantly, sectional delineation of the progeny shifted in the direction of pollinator through genome substitution, which is not to be expected following just one generation of backcrossing in a normal breeding program. Our main objective was to investigate whether there were potential genetic differences between the genomes from sect. Tripsacum and sect. Fasciculata at the molecular level that supports the differentiation of sections in Tripsacum.