CHROMOSOME DOUBLING AND MODE OF REPRODUCTION OF INDUCED TETRAPLOIDS OF EASTERN GAMAGRASS (TRIPSACUM DACTYLOIDES L.)

Eastern gamagrass, (Tripsacum dactyloides L.) is a perennial, warm-sea son grass that is being developed as a forage plant. Shoots were deriv ed from callus initiated from immature embryos and immature infloresce nces of diploid (2n=2x=36) gynomonoecious eastern gamagrass. These sho ots were induced to microtiller in the presence of 3 mg/l benzyladenin e. Amiprophosmethyl (10, 15, or 20 mu M) was applied to 27 microtiller s for 3-5 days to induce chromosome doubling. All 14 surviving plants were tetraploid, (2n=4x=72), as determined by flow cytometry or chromo some counts. These plants were morphologically normal and produced see d. Test crosses were made with a known diploid. Flow cytometry and chr omosome counts showed that the progeny were triploid, proving that the induced tetraploids reproduce sexually.