Pennisetum alopecuroides (L.) Spreng. is a perennial warm-season grass native to Asia and Australia. It is sometimes referred to “fountain grass”; however, be aware that a number of Pennisetum species are referred to as “fountain grass.” It is mainly used as an ornamental in the United States and it performs well in sunny locations. Cultivars usually range in height from 0.75 to 1.5 m (Missouri Botanical Gardens ‘Pennisetum alopecuroides’, n.d.).
Reduced seed production in vegetatively propagated ornamental plants is a desirable trait because it helps maintain the purity of the commercial cultivar. Seed set in Miscanthus sinensis has been reduced through ploidy manipulation (Ranney and Touchell, 2016) and gamma radiation (Hanna and Schwartz, 2019). ‘Desert Plans’ (Trucks, 2010) and ‘Ginger Love’ (Horvath, 2016) were cultivars developed from seedling selections, and ‘JS Jommenik’ (Spruyt, 2016) developed from a shoot mutation are among vegetatively propagated P. alopecuroides patented cultivars, but none report seed production for these cultivars in the patents. Blackman (2011) developed ‘Burgundy Bunny’ from a natural mutation and reported that no seed were observed, but did not report the comparison of this cultivar to a seed producing-genotype. Our objective was to use Cobalt 60 gamma radiation to reduce seed production in P. alopecuroides genotypes with desirable ornamental characteristics.
‘Tift H18’ (PP30724 P2) and ‘Tift PA5’ (PP31027 P2) are perennial P. alopecuroides grasses with desirable ornamental characteristics and significantly reduced seed production. Both were approved for release by the University of Georgia College of Agricultural and Environmental Sciences in 2016. We evaluated ‘Tift H18’ and ‘Tift PA5’ at Tifton, GA (lat. 31.4505°N, long. 83.5085°W; elevation, 107.9 m) and Blairsville, GA (lat. 34.8762°N, long. 83.9582°W; elevation, 573.9 m) in comparison with Tift PA24, a seed-fertile P. alopecuroides with desirable ornamental characteristics. Cultivars were tested on soil types Tifton loamy sand and Transylvania clay loam at Tifton and Blairsville, respectively. The active growing seasons are April through November at Tifton and May through October at Blairsville. Average monthly rainfall for the growing season was 114 mm and 90 mm at Blairsville and Tifton, respectively. Average monthly high temperatures for the growing season are 26 and 28 °C, whereas average monthly low temperatures are 13 and 16 °C for Blairsville and Tifton, respectively. 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 analysis of variance, and Fisher’s least significance difference at P ≤ 0.05 was 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 Pains’. US PP20751 P2