Turf bermudagrass ‘JSC 2-21-18’

#‘JSC 2-21-18’ turf bermudagrass is disclosed as a new clonal cultivar. ‘JSC 2-21-18’ is an interspecific F1 hybrid originating from a cross of Cynodon dactylon var. dactylon (L.) Pers. x Cynodon transvaalensis Burtt-Davy parent plants.

#FIG. 1 is a photo of ‘JSC 2-21-18’ turf bermudagrass growing in a 30 cm diameter pot in the greenhouse.

#FIG. 2 shows a vegetative shoot of ‘JSC 2-21-18’ in comparison to vegetative shoots of other turf bermudagrass cultivars.

#FIG. 3 shows a stolon internode of ‘JSC 2-21-18’ in comparison to stolon internodes of other turf bermudagrass cultivars.

#‘JSC 2-21-18’ turf bermudagrass is a clonally propagated interspecific F1 hybrid plant resulting from a cross of respective parent plants of Cynodon dactylon var. dactylon (L.) Pers. and Cynodon transvaalensis (Burtt-Davy). Natural crossing between plants of Cynodon dactylon var. dactylon and Cynodon transvaalensis is known to occur at relatively high frequency. Accordingly, interspecific crossing was achieved by growing a selected plant of C. dactylon (‘Cda 35-5’) in proximity to a selected plant of C. transvaalensis (‘Ctr 4-10’) in a small field plot (ca 9 m2) isolated from other bermudagrass. The plot was located on a Johnston Seed Company (JSC) farm near Enid, Okla. The ‘Cda 35-5’ and ‘Ctr 4-10’ plants were selected from JSC bermudagrass breeding nurseries on the bases of good adaptation, turf quality, and fertility. Seeds harvested from the small crossing block in summer 2007 were used to start individual plants in the greenhouse in late winter 2008. These plants were transplanted to a field screening nursery as spaced plants (8′ centers, 2′ alleys) in May 2008. The screening nursery was located on a JSC farm in Major County Okla. (36° 22′ 23.99″, −98° 21′ 25.28″) approximately 25 miles west of Enid, Okla. ‘JSC 2-21-18’ was selected in late 2009 for more comprehensive evaluation. It was identified at time of selection by its nursery plot ID, 2-21-18. It and other JSC experimental turf bermudagrasses were established in a replicated small plot test in May 2010 at the JSC research center at Enid, Okla. 36° 26′ 13.79″, −97° 48′ 51.35″). This test was managed using the typical protocol used for golf course bermudagrass fairways. Entries in the test were evaluated for visual turf quality and other characteristics influencing overall performance. In January, 2013, 540 clonal plants of ‘JSC 2-21-18’ were started in the JSC greenhouse, Enid, Okla., in plastic trays (18 cells/tray) and subsequently shipped to the National Turfgrass Evaluation Program (NTEP) which then distributed required amounts of planting material to each of the 19 sites participating in the NTEP 2013 turf bermudagrass evaluation test. In winter 2015, clonal plants of ‘JSC 2-21-18’ were started in the JSC greenhouse, Enid, Okla., and subsequently used to plant a 1.24 acre scale-up nursery in summer 2015 at the JSC research center, Enid, Okla., Garfiled county (36° 26′ 13.79″, −97° 48′ 51.35″). In July 2017, springs were taken from the 1.24 acre ‘JSC 2-21-18’ scale up plot and used to plant a 6.71-acre sod production field on a JSC farm near Enid, Okla. in Garfield county (36° 28′ 52.97″, −97° 59′ 4.11″).

#Putative chromosome numbers of ‘Cda 35-5’, ‘Ctr 4-10’ and ‘JSC 2-21-18’ are respectively 2n=4x=36, 2n=2x=18, and 2n=3x=27. Accordingly, ‘JSC 2-21-18’ received 18 chromosomes (two genomes) from the ‘Cda 35-5’ parent and 9 chromosomes (one gnome) from the ‘Ctr 4-10’ parent. ‘JSC 2-21-18’ is highly sexually sterile, setting only an occasional seed when grown in the presence of one or more fertile plants of the C. dactylon and/or C. transvaalensis taxa that serve as pollinators. High sterility is typical for triploid plants with an unbalanced number of genomes. The high sexual sterility of ‘JSC 2-21-18’ is presumed to result from the nine chromosomes (one genome) received from the ‘Ctr 4-10’ parent having no fully homologous chromosomal pairing partners during meiosis. Both parents of ‘JSC 2-21-18’ are highly sexually fertile. The morphology and sexual sterility of ‘JSC 2-21-18’ are consistent with expectations for interspecific hybrids of C. dactylon and C. transvaalensis. The fidelity of ‘JSC 2-21-18’ has been maintained through many clonal generations of propagation since it's selection in 2008 indicating it to be genetically stable.

#‘JSC 2-21-18’ is a stoloniferous sward-forming perennial with slender underground rhizomes. ‘JSC 2-21-18’ has morphological features with mean values generally between those of the parents. A plant of ‘JSC 2-21-18’ growing in a greenhouse pot is shown in FIG. 1. A vegetative shoot of ‘JSC 2-21-18’ is shown in FIG. 2 in comparison to shoots of other clonal turf bermudagrass cultivars. Shoots of ‘JSC 2-21-18’ are slender attaining a maximum height of approximately 25 cm on un-mowed swards. Leaf size (length and width) and stem size diameter) of JSC ‘2-21-18’ are smaller than ‘Cda 35-5’ and slightly larger than ‘Ctr 4-10’. Shoot density of ‘JSC 2-21-18’ is high resulting in a dense sward. The sod density (conditioned by shoot density) of ‘JSC 2-21-18’ is substantially greater than that of ‘Cda 35-5’ and slightly less than that of ‘Ctr 4-10’. ‘JSC 2-21-18’ leaves are slightly convex, sparsely hirsute on the abaxial and adaxial surfaces, and smooth on the edges. Hairs on the leaves attain a maximum length of approximately 1 mm. Leaves emanating from the last visible node below the apex of shoots vary in width at their base from 2 to 4 mm and attain a length from about 25 to 38 mm. The ligule is a membranous rim about 0.2 mm long with short hairs on the edge except at the outer edges that have much longer hairs. Leaf sheaths are glabrous.