Pennisetum alopecuroides (L.) Spreng. is a perennial warm-season grass native to Asia and Australia that is used mainly as an ornamental in the United States. This species is frequently referred to as “fountain grass,” which can be misleading because a number of Pennisetum species use this common name designation. The Missouri Botanical Gardens (2020) website ‘Pennisetum alopecuroides’ reports that cultivars usually range in height from 0.75 to 1.5 m.
Reduced seed production in vegetatively propagated ornamentals and turfgrass is a desirable trait because it helps maintain the purity of a commercial cultivar. Seed-sterile turfgrasses have been developed by creating triploid interspecific hybrids and by using gamma radiation (Baxter and Schwartz, 2018). Seed set in Miscanthus sinensis Andersson (1855) has been reduced by ploidy manipulation (Ranney and Touchell, 2016) and gamma radiation (Hanna and Schwartz, 2019).
‘Desert Plains’ (Trucks, 2010) and ‘Ginger Love’ (Horvath, 2016) are P. alopecuroides cultivars developed from seedling selections. ‘JS Jommenik’ (Spruyt, 2016) was selected as a shoot mutation. All are vegetatively propagated P. alopecuroides patented cultivars, but none mentions seed production for these cultivars in the patents. Blackman (2011) developed ‘Burgundy Bunny’ from a natural mutation and mentions no seed observed, but this cultivar was not compared to a seed-producing genotype. Hanna and Schwartz (2020) significantly reduced seed production in ‘PralineTM’ (‘Tift H18’) and ‘Hush PuppyTM’ (‘Tift PA5’) with cobalt 60 gamma radiation. Our objective was to use cobalt 60 gamma radiation to reduce seed production in P. alopecuroides genotypes with desirable ornamental characteristics.
‘Tift PA17’ (PP31,062), ‘Tift PA18’ (PP31,097), and ‘Tift PA19’ (PP31,176) are perennial P. alopecuroides selections with desirable ornamental characteristics and significantly reduced seed production. They were approved for release by the University of Georgia College of Agricultural and Environmental Sciences in 2016 after evaluation in Tifton, GA (elevation, 107.9 m; lat. 31.4505°N, long. 83.5085°W) and Blairsville, GA (elevation, 573.9 m; lat. 34.8762°N, long. 83.9582°W). They were compared with Tift PA24, a seed-fertile P. alopecuroides genotype with desirable ornamental characteristics, at both locations. Cultivars were tested on a Tifton loamy sand and a Transylvania clay loam in Tifton and Blairsville, respectively. Their active growing seasons are April through November in Tifton and May through October in Blairsville. The 20-year average monthly rainfall values for the growing season were 114 mm (range, 94–121 mm) and 90 mm (range 68 to 118 mm) in Blairsville and Tifton, respectively. The 20-year average monthly high temperatures for the growing season are 26 °C (range, 21 to 29 °C) and 28 °C (range, 21 to 33 °C), whereas the average monthly low temperatures are 13 °C (range, 6 to 17 °C) and 16 °C (range, 8 to 21 °C) in Blairsville and Tifton, respectively. There were no droughts or floods and no extreme deviations in average temperatures during the testing years.
Genotypes were evaluated for inflorescence and leaf height, canopy diameter, inflorescence length and number per plant, leaf length and width, and seed set. Data for each variable were subjected to an analysis of variance. Fisher’s least significance differences at P ≤ 0.05 were used for mean separation.
Blackman, L. 2011 Pennisetum plant named ‘Burgundy Bunny’. US PP21917 P2
Horvath, B. 2016 Pennisetum alopecuroides plant named ‘Ginger Love’. US PP26442 P2
Missouri Botanical Gardens Pennisetum alopecuroides. (n.d.) 10 Apr. 2020 <https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=285289&isprofile=1&basic=Pennisetum%20alopecuroides>
Ranney, T.G. & Touchell, D.H. 2016 Miscanthus sinensis grass named ‘NCMS1’. US PP26387 P3
Royal Horticultural Society 2007 RHS colour chart. 5th ed. Royal Horticultural Society, London
Spruyt, J. 2016 Pennisetum plant named ‘JS Jommenik’. US PP27435 P2
Trucks, G.M. 2010 Pennisetum plant named ‘Desert Plains’. US PP20,751 P2