Submitted to: Journal of New Seeds
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/15/2003
Publication Date: 5/28/2004
Citation: Kindiger, B.K. 2004. Interspecific hybrids of Poa arachnifera x Poa secunda. Journal of New Seeds. 6:1-26. Interpretive Summary: Texas bluegrass (Poa arachnifera) is a vigorous, sod-forming perennial bluegrass species which is native to the Southern Plains region of the U.S. Few attempts have been made to hybridize Texas bluegrass with other species in the bluegrass genus. In this study, fifty-five hybrids were obtained by crossing Texas bluegrass with another native bluegrass species, Sandberg bluegrass (P. secunda).Barriers to hybridization were not limiting, and plump, viable seed were readily obtained from the Texas bluegrass maternal parent. Hybrid plants were generally robust and their pollen fertility ranged from 0% to 90%. Viable seed were obtained from two of thirty-five examined hybrids. The method of reproduction identified in two hybrid plants which produced fertile seed appeared to be apomictic, which is a characteristic of the Sandberg bluestem parent. All the hybrids had a sod-forming root system with rhizomes, which is characteristic of Texas bluegrass, rather than the non-rhizomatous root system typical of Sandberg bluestem. Texas bluegrass seed have cobwebby hairs, but the hairs were reduced or absent on seeds produced by the hybrids. The hybrids exhibited chromosome numbers which were equivalent to or exceeded the chromosome number of each parent. Preliminary forage quality evaluations indicate that the hybrids are comparable to other perennial cool-season grass forages. The hybrids appear promising for the development of new forms of native bluegrasses with high value as forage and turf and a wide range of adaptation to both the southern and western U.S.
Technical Abstract: Interspecific hybrids of Texas bluegrass (Poa arachnifera) and other Poa species have rarely been generated. In order to determine the value of Texas bluegrass in such interspecific hybridizations, crosses were made between a locally collected P. arachnifera and a P. secunda cultivar. Barriers in hybridization were limited and the hybrids exhibited characteristics representative of both parents. As seedlings, the hybrids were robust and pollen fertility among the hybrids ranged from 0% to 90%. Viable seed was obtained from two of thirty-five examined hybrids and evaluated by the PCR-RAPD method to identify their parents mode of reproduction. All F1 hybrids exhibited a rhizomatous root system, which is characteristic of the P. arachnifera parent. The floral structure of the hybrid infloresence was monoecious and more closely resembled the P. secunda parent. The hybrids exhibited somatic chromosome numbers ranging from 54 to 72. Seed production in a single seed fertile hybrid was tentatively identified as apomictic. Forage quality estimates indicated that the F1 hybrids possess quality forage characteristics comparable to Lolium ssp., Bromus inermis and Dactylis glomerata. The generation of fertile interspecific hybrids of P. arachnifera x P. pratensis appears to be a promising new source of Poa germplasm for the future development and introduction of a native, cool-season perennial forage having adaption to both the Southern and Central plains regions of the United States.