Registration of `Exacta' Perennial Ryegrass.
Exacta is an advanced generation synthetic cultivar selected from the maternal half-sib progenies of 51 clones, each containing a fungal endophyte [Neotyphodium lolii (Latch, Christensen, and Samuels) Glenn, Bacon, Price, and Hanlin]. Half-sib progenies of seven endophyte-free clones served as additional pollen parents. Twenty-four propagules of each of 26 clones selected from large spaced-plant nurseries at the Rutgers Plant Science Research and Extension Farm at Adelphia, NJ, were established in an isolated, replicated, spaced-plant nursery at Adelphia, NJ, during the late summer of 1995. These clonal propagules were interplanted with 1536 plants selected from 32 turf plots, each of which had been seeded to a half-sib progeny selected from spaced-plant nurseries at Adelphia in 1994. A total of 1638 plants were removed from this nursery prior to anthesis in the spring of 1996 to improve uniformity and select for more attractive, disease-free plants. Breeder seed was subsequently harvested from 264 plants showing good floret fertility. This seed was sent to Lebanon Seaboard for the establishment of a Foundation seed increase field in Oregon in 1996.
The parental clones of Exacta were selected from germplasm composites developed through a germplasm collection and population improvement program initiated in 1962 to develop turf-type perennial ryegrasses with greater disease resistance, better heat and drought tolerance, improved mowing quality, attractive appearance, and a lower growth profile. Over 90% of the parental germplasm used in Exacta traces to plants selected near the sheep meadow in Central Park in New York City, NY (3); southeast Pennsylvania; Baltimore and College Park, MD; Warinaco Park in Elizabeth, NJ; and the Colonia and Atlantic City golf courses in New Jersey from 1962 through 1978. Selected plants exceeded 1.0 m in diam. and appeared to be at least 30 yr old at the time of collection. Additional germplasm used traces to `Manhattan II' (6), `Loretta,' and plant introductions from Greece (PI 131587) and Finland (PI 197270).
A rigorous level of selection intensity was practiced during all stages of the germplasm selection and population improvement programs. Normally, [is less than] 5% of the plants were selected in numerous disease screening trials, spaced-plant nurseries, and single-plant progeny trials maintained as turf. Selection was directed to leafy, low-growing plants with good vigor, abundant tillering, a bright, darker green color, winter survival, tolerance of summer stress and close mowing, good establishment vigor, improved wear tolerance, presence of a Neotyphodium endophyte, and improved resistance to common diseases. These included Rhizoctonia brown patch (caused by Rhizoctonia solani Kuhn), red thread [caused by Laetisaria fuciformis (Mc Alpine) Burdsall], crown rust (caused by Puccinia coronata Corda var. coronata), and brown blight [caused by Drechslera dictyoides (Drechs.) Shoemaker].
Exacta is a leafy, persistent, turf-type cultivar capable of producing a dense, fine-textured, medium-low-growing turf with a bright, dark-green color. It has performed well in turf trials in New Jersey (7).
Exacta is recommended for use on sports fields, lawns, parks, school grounds, and golf course cart paths, tees, and fairways in regions where turf-type perennial ryegrasses are well adapted. It should blend well with darker, lower-growing Kentucky bluegrasses (Poa pratensis L.). Exacta also should perform well for winter overseeding of dormant warm-season turfs in the southern USA and similar regions.
Freshly harvested seed of Exacta perennial ryegrass contains a fungal endophyte, (Neotyphodium lolii). Perennial ryegrasses containing selected strains of Neotyphodium endophytes have shown enhanced resistance to many, but not all, harmful insects as well as increased persistence and improved performance under some conditions (1,4,5). Perennial ryegrass cultivars that contain a Neotyphodium endophyte can be very useful for turf and conservation plantings; however, they may adversely affect the health and performance of animals consuming large amounts of endophyte-infected forage under some conditions (2).
Breeder seed of Exacta is maintained by Lebanon Seaboard with the cooperation of the New Jersey Agricultural Experiment Station. Seed propagation is restricted to three generations of increase from Breeder seed; one generation each of Foundation, Registered, and Certified. U.S. Plant Variety Protection of Exacta has been applied for (PVP Certificate no. 9900392).
References and Notes
(1.) Ahmad, S., J.M. Johnson-Cicalese, W.K. Dickson, and C.R. Funk. 1986. Endophyte-enhanced resistance in perennial ryegrass to the bluegrass billbug. Sphenophorus parvulus. Entomol. Exp. Appl. 41:3-10.
(2.) Fletcher, L.R. 1982. Observations of ryegrass staggers in weaned lambs grazing different ryegrass pastures. N.Z.J. Exp. Agric. 10:203-207.
(3.) Funk, C.R., R.E. Engel, and P.M. Halisky. 1969. Registration of Manhattan perennial ryegrass. Crop Sci. 9:679-680.
(4.) Funk, C.R., P.M. Halisky, S. Ahmad, and R.H. Hurley. 1985. How endophytes modify turfgrass performance and response to insect pests in turfgrass breeding and evaluation trials, p. 127-145. In F. Lemaire (ed.) Proc. 5th Int. Turfgrass Res. Conf., Avignon, France. 1-5 July 1985. INRA Publ., Versailles.
(5.) Funk, C.R., P.M. Halisky, M.C. Johnson, M.R. Siegel, A.V. Stewart, S. Ahmad, R.H. Hurley and I.C. Harvey. 1983. An endophytic fungus and resistance to sod webworms: Association in Lolium perenne L. Bio/Technology 1:189-191.
(6.) Funk, C.R., W.A. Meyer, and B.L. Rose. 1984. Registration of Manhattan II perennial ryegrass. Crop Sci. 24:823-824.
(7.) Mohr, Melissa M., W.A. Meyer, J.A. Murphy, W.K. Dickson, M.E. Secks, and R.F. Bara. 1998. Performance of perennial ryegrass cultivars and selections in New Jersey turf trials. Rutgers Turfgrass Proc. 29:83-105.
(8.) T.M. Ford, Lebanon Seaboard Corporation, P.O. Box 10, Huntsville, UT 84317-0010; and W.A. Meyer, and C.R. Funk, Plant Science Department, NJAES, Cook College, Rutgers Univ., P.O. Box 231, New Brunswick, NJ 08901. Publication no. D-12155-1000. Some of this work was conducted as part of NJAES Project no. 12155, supported by NJ NJAES funds, other grants, and gifts. Additional support was received from the U.S. Golf Association-Golf Course Superintendents Association of America Research Fund, and from the New Jersey Turfgrass Association. Registration by CSSA. Accepted 30 Sept. 2000. (*) Corresponding author (firstname.lastname@example.org).
We appreciate the many contributions of Dirk A. Smith, Ronald F. Bara, Melissa Mohr, Barbara Smith, George Ziemienski, and Michael Reynolds.
Published in Crop Sci. 41:591-592 (2001).
TIMOTHY M. FORD,(*) W.A. MEYER, AND C.R. FUNK (8)