‘Tift H18’ and ‘Tift PA5’ Ornamental Pennisetum alopecuroides

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  • 1 Department of Crop and Soil Sciences, University of Georgia, Tifton Campus, 2360 Rainwater Road, Tifton, GA 31793

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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.

Origin

Vegetative plants of P. alopecuroides var. Hameln were obtained from Emerald Coast Growers in Spring 2008. We harvested open-pollinated (OP) seed from the plants in 2008 and transplanted 400 plants from the OP seed into a field nursery in 2009. Seeds were harvested from 50 plants with the most desirable ornamental morphological characteristics, and these seeds were irradiated in 2010 with 10 and 15 Kr Cobalt 60 gamma radiation. One hundred sixty-nine and 154 plants from the 10-Kr and 15-Kr treatments, respectively, were established in the field in 2010. Three plants from the 10-Kr treatment and three plants from the 15-Kr treatment with one or no seed per inflorescence (many sectors) were selected. These six plants had desirable ornamental morphological characteristics and were numbered 1 through 6. These six plants were propagated vegetatively by sections of the plants, with 3 o’clock being “a” and, moving counterclockwise around the plant, “b” being 12 o’clock, “c” being 9 o’clock, and “d” being 6 o’clock. The plants were transplanted to the field in 2011. As many propagules as possible were obtained from each section. Inflorescences from six plants from section 4b (15-Kr treatment) set various amounts of seed, but one plant (field entry 133) produced no seed and became ‘Tift H18’.

Seeds of the plant collection Tift PS989 (mixed genotypes of P. alopecuroides sent to the United States from Korea in 1989) were irradiated on 11 Nov. 2010 with 10 Kr Cobalt 60 gamma radiation, and 256 plants were planted into the field on 29 Mar. 2011. In 2011, six of the 256 plants grown from the 10-Kr-treated seeds were evaluated and selected based on morphological desirability and reduced seed set. OP pollinated seeds (a second generation of seeds) from these six selected plants were harvested and irradiated with 10 Kr Cobalt 60 on 10 Jan. 2012. Sixty-four plants were established in the field in 2012 from only one of the six plants selected in 2011. Plants grown from irradiated seeds usually have chimeras or sectors for the traits of interest. Therefore, each of the 64 plants was divided into four quadrants (as described earlier for ‘Tift H18’), and five or more inflorescences from each quadrant were examined for seed set. A highly seed-sterile sector “a” from plant no. 60 was selected and propagated asexually to produce ‘Tift PA5’.

‘Tift H18’ (Supplemental Figs. 1 and 2) and ‘Tift PA5’ (Supplemental Figs. 3 and 4) were tested at Tifton and Blairsville from 2012 through 2015. Evaluation tests consisted of five and four single-plant replications arranged in a randomized complete block experiment at Tifton and Blairsville, GA, respectively. Propagules were rooted and established in the greenhouse 6 weeks before being transplanted to the field on 160-cm centers. Weeds were controlled by both chemical and mechanical methods. Plots were irrigated only at planting to ensure uniform establishment. Other experimental entries were included in each test. Tift PA24 was selected from Tift PS1122 and served as the seed-fertile control with desirable ornamental characteristics (Supplemental Fig. 5).

Description and Performance

‘Tift H18’ and ‘Tift PA5’ were significantly shorter from ground level to top of inflorescences (Table 1) and to top of leaf canopy (Table 2), and had a smaller canopy diameter (Table 3) compared Tift PA24. However, in the 2014 Tifton test, ‘Tift PA5’ had similar inflorescence and leaf height as Tift PA24. Inflorescence and leaf height of ‘Tift H18’ were significantly shorter than those of ‘Tift PA5’ in all tests where these two cultivars were compared. Canopy diameter was significantly less for ‘Tift H18’ compared with ‘Tift PA5’ in the 2015 Blairsville test, but significantly larger in the 2012 Tifton test, whereas canopy diameter was similar in the 2015 Tifton test. Inflorescence number was significantly less for ‘Tift H18’ and ‘Tift PA5’ or similar to Tift PA24 except in the 2015 Blairsville test, in which ‘Tift PA5’ produced significantly more inflorescences than ‘Tift H18’ and Tift PA24 (Table 4). Inflorescence length was generally significantly shorter or equal to Tift PA24. In the 2012 Blairsville test, ‘Tift H18’ inflorescences were significantly longer than those of either ‘Tift PA5’ or Tift PA24 (Table 5). Leaf length and width were significantly narrower in all tests for ‘Tift H18’ and in four of six tests for ‘Tift PA5’ compared with Tift PA24 (Table 6). Gamma radiation of seeds successfully reduced seed set in these selections (Table 7). ‘Tift H18’ produced significantly less seed per inflorescence than Tift PA24 in all tests. Germination tests were conducted on seeds produced by ‘Tift H18’ and Tift PA24. Seed were stored in manila envelopes for six months at room temperature in the threshing shed and then allowed to germinate for 45 d at 27 °C in steam-sterilized soil in the greenhouse. Germination of the few seeds produced by ‘Tift H18’ was 48% compared with 93% for Tift PA24, further reducing the seed-producing potential of ‘Tift H18’. ‘Tift PA5’ did not produce any seed in any of the tests and appears to be seed sterile. Although we have not determined the cause of seed sterility in these cultivars, research with mutagens in our laboratory (unpublished) has shown that Cobalt 60 gamma radiation can break chromosomes, thereby resulting in irregular segregation at microsporogenesis and megasporogenesis, and pollen and egg cell abortion.

Table 1.

Height of inflorescence of three Pennisetum alopecuroides grasses (Tift PA24 is the seed-fertile control) planted at two locations in Georgia.

Table 1.
Table 2.

Height of leaves of three ornamental Pennisetum alopecuroides grasses (Tift PA24 is the seed-fertile control) planted at two locations in Georgia.

Table 2.
Table 3.

Canopy diameter of three ornamental Pennisetum alopecuroides grasses (Tift PA24 is the seed-fertile control) planted at two locations in Georgia.

Table 3.
Table 4.

Number of inflorescences per plant of three ornamental Pennisetum alopecuroides grasses (Tift PA24 is the seed-fertile control) planted at two locations in Georgia.

Table 4.
Table 5.

Inflorescence length of three ornamental Pennisetum alopecuroides grasses (Tift PA24 is the seed-fertile control) planted at two locations in Georgia.

Table 5.
Table 6.

Leaf characteristics of individual plants of three ornamental Pennisetum alopecuroides grasses (PA24 is the seed-fertile control) planted at two locations in Georgia.

Table 6.
Table 7.

Seed set per inflorescence of three ornamental Pennisetum alopecuroides grasses (Tift PA24 is the seed-fertile control) planted at two locations in Georgia.

Table 7.

‘Tift H18’ compares favorably with ‘Tift PA5’ at Tifton, but overall this selection did not perform as well in the replicated tests at Blairsville. We have no replicated data, but it appears that ‘Tift H18’ is sensitive to atrazine on heavier clay soils. However, we observed that ‘Tift H18’ performed well in isolated plantings where no herbicides were used. Mature plant color for ‘Tift PA5’ and ‘Tift H18’ was Green-141B and -139B, respectively, according to the Royal Horticultural Society (2007), whereas inflorescence colors were Greyed Orange-165B for both ‘Tift PA5’ and ‘Tift H18’.

‘Tift PA5’ and ‘Tift H18’ have desirable ornamental characteristics and will be cultivars with significantly reduced seed production. ‘Tift PA5’ and ‘Tift H18’ are finer and more petite cultivars best suited for pot arrangements and isolated plantings. Although we have tested these cultivars in only U.S. Department of Agriculture hardiness zones 7 and 8, this species is reported to grow in zones 5 to 9, but this species may not be a reliable winter-hardy perennial in zone 5 (Missouri Botanical Garden website: “Pennisetum alopecuroides).

Availability

‘Tift H18’ and ‘Tift PA5’ are patented cultivars by the University of Georgia. A field planting of breeder material for ‘Tift H18’ and ‘Tift PA5’ is maintained at the University of Georgia, Tifton Campus. As protected cultivars, ‘Tift H18’ and ‘Tift PA5’ can only be produced by nurseries licensed by the Georgia Research Foundation. ‘Tift H18’ will be marketed as PralineTM and ‘Tift PA5’ will be marketed as HushpuppyTM.

Literature Cited

  • Blackman, L. 2011 Pennisetum plant named ‘Burgundy Bunny’. US PP21917 P2

  • Hanna, W.W. & Schwartz, B.M. 2019 ‘M77’ ornamental Miscanthus sinensis HortScience 54 1 3

  • Horvath, B. 2016 Pennisetum alopecuroides plant named ‘Ginger Love’. US PP26442 P2

  • 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

Supplemental Fig. 1.
Supplemental Fig. 1.

‘Tift H18’ at anthesis in maintenance plots (year of establishment) in Tifton, GA.

Citation: HortScience horts 55, 6; 10.21273/HORTSCI15002-20

Supplemental Fig. 2.
Supplemental Fig. 2.

‘Tift H18’ at anthesis in yard (year of establishment) in Blairsville, GA.

Citation: HortScience horts 55, 6; 10.21273/HORTSCI15002-20

Supplemental Fig. 3.
Supplemental Fig. 3.

‘Tift PA5’ in research plots (year of establishment) in Blairsville, GA.

Citation: HortScience horts 55, 6; 10.21273/HORTSCI15002-20

Supplemental Fig. 4.
Supplemental Fig. 4.

‘Tift PA5’ in maintenance plots (year of establishment) at Tifton, GA.

Citation: HortScience horts 55, 6; 10.21273/HORTSCI15002-20

Supplemental Fig. 5.
Supplemental Fig. 5.

Tift PA24 in maintenance plots at Blairsville, GA (1-year-old plants).

Citation: HortScience horts 55, 6; 10.21273/HORTSCI15002-20

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Contributor Notes

We thank the University of Georgia Research Foundation and Georgia Seed Development for financial support. We also appreciate the cooperation and/or assistance of Ray Covington, Larry Baldree, Leanna Leach, Amanda Webb, and Jacob Kalina.

W.W.H. is the corresponding author. E-mail: whanna@uga.edu.

  • View in gallery

    ‘Tift H18’ at anthesis in maintenance plots (year of establishment) in Tifton, GA.

  • View in gallery

    ‘Tift H18’ at anthesis in yard (year of establishment) in Blairsville, GA.

  • View in gallery

    ‘Tift PA5’ in research plots (year of establishment) in Blairsville, GA.

  • View in gallery

    ‘Tift PA5’ in maintenance plots (year of establishment) at Tifton, GA.

  • View in gallery

    Tift PA24 in maintenance plots at Blairsville, GA (1-year-old plants).

  • Blackman, L. 2011 Pennisetum plant named ‘Burgundy Bunny’. US PP21917 P2

  • Hanna, W.W. & Schwartz, B.M. 2019 ‘M77’ ornamental Miscanthus sinensis HortScience 54 1 3

  • 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

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