Submitted to: International Turfgrass Society Research Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/25/2013
Publication Date: 7/26/2013
Citation: Schwartz, B.M., Harris-Shultz, K.R., Contreras, R.N., Hans, C.S., Hanna, W.W., Milla-Lewis, S.R. 2013. Creation of artificial triploid and tetraploid centipedegrass using colchicine and breeding. International Turfgrass Society Research Journal. 12:327-334. Interpretive Summary: Centipedegrass is a low maintenance turfgrass that is grown in the southern United States. Genetic and morphological variability within accessions exists in centipedegrass but it is far lower than most warm-season turfgrass species. A study was conducted to induce polyploidy in centipedegrass to increase morphological variation. Colchicine was used to induce polyploidization and seedlings were obtained that are tetraploids. Evaluation of the turfgrass performance of these induced polyploids is underway.
Technical Abstract: Centipedegrass (Eremochloa ophiuroides) is a low maintenance, diploid (2n = 2x = 18) turfgrass species that is well adapted to sandy, acidic soils in the southern United States. Morphological variation and differential responses to distinct environmental conditions can be seen on an individual plant basis in this species, but phenotypic and genotypic variation is relatively small at the population level. Therefore, an effort was initiated in to induce polyploidy in ‘TifBlair’ centipedegrass using six colchicine seed treatments. Seedlings that germinated after exposure to these treatments were screened using flow cytometry for genome size changes. One putative tetraploid (63-9) and one cytochimera (63-8) were identified, both from the water/0.1% colchicine treatment. Stomata length of the colchicine induced putative tetraploid was 12% larger than that of TifBlair, but there was not a significant change in leaf stomata length in the cytochimera. The pollen diameter of the cytochimera was significantly larger than that of the putative tetraploid and TifBlair. Ploidy instability was discovered in the majority of 63-9 plant materials sampled in early 2011. Additionally, only five of the 580 seedlings derived from open-pollination of 63-9 in 2010 were triploid or tetraploid, further supporting that the L-II histogenic layer (germ line) of 63-9 was not stable at the time of fertilization. Results of flow cytometry analysis through 2011 of 63-8 have indicated that the chimeric state of this plant have remained constant, but all 19 seedlings derived from it have a 2C nuclear DNA content similar to that of a tetraploid. This information supports that DNA content of the L-II histogenic layer was doubled in 63-8, but that the L-I histogenic layer (epidermis) was still diploid. Evaluation of the turfgrass performance of these induced polyploids should be carried out to determine the value of this breeding procedure for improvement of centipedegrass.