Kentucky bluegrass

Abstract

A variety of Kentucky bluegrass having a good level of disease resistance and in particular to the leaf spot diseases. The variety provides a desirable dark blue green color throughout the growing season, a color which is accented during cool periods of the year as found in spring and fall months. The variety produces a thick dense turf and persists throughout the growing season under a wide range of environmental conditions.

Description

SUMMARY OF THE VARIETY

The present invention relates to a new and distinct variety of Poa pratensis which has been designated Ba 62-55-M and is now named Merit Kentucky bluegrass. Merit plant material was one of several biotypes selected out of an old established turf area in southern California. Turf performance evaluations of these types were made which resulted in selecting the best turf type. This final selection resulted in one plant type which is now called Merit. Seed of Merit was produced first at Marysville, Ohio, then Salem and Gervais, Oreg. This seed was used to plant turf trials for evaluation of turf performance. Variety evaluation trials were established at Marysville, Ohio; Accokeek, Md.; Long Beach and Somis, Calif.; Gervais, Oreg.; St. Louis, Mo.; Bolton, Mass. and the province of Ontario, Canada.

Merit Kentucky bluegrass reproduces asexually both by propagules (tillers and rhizomes) and disseminules (modified coryopses produced by agomospermy) and has consistently produced progeny plants indistinguishable from the mother plant.

Merit has a number of highly desirable characteristics including a good level of resistance to Helminthosporium spp and Sclerotinia homoeocarpa, has a decumbent growth habit and will tolerate low heights of cut. It has a pleasing dark blue green color and produces a good dense turf that persists over a wide range of environmental conditions.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a photograph of Merit Kentucky bluegrass maintained under turf management conditions;

FIG. 2 is a Merit Kentucky bluegrass clone in early spring at Gervais, Oreg.;

FIG. 3 is a Merit Kentucky bluegrass clone after anthesis at Gervais, Oregon; and

FIG. 4 is a Merit Kentucky bluegrass panicle.

DETAILED DESCRIPTION OF THE VARIETY

The morphological characteristics of Merit and other commercially available bluegrass varieties are compared in Table 1. As shown by Table 1, the morphological characteristics of Merit afford a basis for distinguishing it from other bluegrass varieties.

TABLE 1 ______________________________________ MORPHOLOGICAL COMPARISON OF MERIT AND OTHER KENTUCKY BLUEGRASS VARIETIES No. of No. of No. of No. of Nodes Panicle Panicle Branches Spikelets Per Length Branch Per Whorl Per Whorl Plant Variety in cm. Whorls Lowest 3rd Lowest 3rd Stem ______________________________________ Merit 9.0 8.4 5.4 4.2 52.6 29.6 1.8 Merion 10.3 7.2 3.4 3.4 42.2 27.6 2.6 Newport 10.9 9.4 3.8 3.6 33.6 18.8 2.4 Bristol 11.7 8.4 3.4 2.6 38.0 23.2 4.0 Leaf Blade Width* Length of No. of Measured 2 cm. Top Internode Florets From end of Boat Variety in cm. Per Spikelet Tip Leaf ______________________________________ Merit 22.2 4.98 2.50 mn Merion 33.6 3.98 2.07 mn Newport 38.6 3.02 2.39 mn Bristol 34.9 5.42 2.52 mn ______________________________________ *Leaf blade width of plants maintained under mowed turf conditions (3.8 c to 6.4 cm)

Mowed plots have been evaluated under turf conditions in many different tests and at numerous locations. Turfgrass performance information presented indicates the distinctiveness of Merit compared to other bluegrass varieties and its desirable characteristics and persistence.

Seed germination rate and seedling establishment are important factors in a new seedling. Kentucky bluegrasses are recognized for their slowness to germinate and establish compared to other turfgrass species. Differences do occur in germination rates between Kentucky bluegrass varieties. The variety Merion has been rated as slow to germinate whereas the variety Park is normally considered as a faster germinating bluegrass variety. In controlled laboratory tests and field evaluations Merit was rated above Merion and equal to Park in controlled conditions and below Park in actual field conditions. See Tables 2, 3 and 4.

TABLE 2. ______________________________________ AVERAGE GERMINATION PERCENTAGES OF VARI- OUS KENTUCKY BLUEGRASS VARIETIES UNDER CONTROLLED CONDITIONS USING LABORATORY GERMINATING CABINET. Days After Seeding Variety 7 10 15 21 ______________________________________ Merit 55% 77% 81% 85% Victa 54% 71% 83% 88% Park 50% 65% 81% 85% Merion 14% 24% 60% 72% ______________________________________ Rating Scale: Number indicates percent of seeds that germinated. Germinating Conditions: Temperature 15.degree. C. for 16 hours - dark 25.degree. C. for 8 hours - light 100 seeds per replication - 3 replications

TABLE 3. ______________________________________ AVERGE GERMINATION PERCENTAGES OF VARI- OUS KENTUCKY BLUEGRASS VARIETIES SEEDED IN -MID SUMMER UNDER FIELD CONDITIONS. Days After Seeding Variety 6 8 15 ______________________________________ Merit 0% 25% 78% Victa 0% 42% 78% Park 0% 43% 84% Merion 0% 19% 65% ______________________________________ Rating Scale: Number indicates percent germination made by visual estimates of three replications.

TABLE 4. ______________________________________ AVERAGE GERMINATION PERCENTAGES OF VARIOUS KENTUCKY BLUEGRASS VARIETIES SEEDED IN LATE FALL UNDER FIELD CONDITIONS. Days After Seeding Variety 8 21 32 ______________________________________ Merit 0% 59% 78% Victa 0% 80% 90% Park 0% 70% 83% Merion 0% 37% 64% ______________________________________ Rating Scale: Number indicates percent germination by visual estimates of three replications.

Leafspot (Helminthosporium spp) diseases cause severe plant damage and thinning of bluegrass turf in most locations in the Northern United States and Canada during the months of April, May and June of each year. Table 5 provides leaf spot information in the spring on two year old turf grown at Marysville, Ohio. Merion and Fylking are recognized as having an acceptable and a good level of resistance to leaf spot diseases. The common types of Kentucky bluegrass varieties such as Kenblue are quite susceptible to leaf spot disease. In Table 5 Merit is seen to be equal to or slightly lower in resistance than Merion or Fylking but significantly more resistant than Kenblue.

TABLE 5. ______________________________________ LEAF SPOT (Helminthosporium spp) INCIDENCE OF TWO YEAR OLD TURF OF VARIOUS KENTUCKY BLUEGRASS VARIETIES. Percent Leaf Spot Variety April May June ______________________________________ Merit 15% 23% 25% Kenblue 50% 60% 50% Merion 15% 20% 15% Fylking 20% 20% 20% ______________________________________ Rating Scale: Number indicates percent of leaves infected with leaf spot.

Rating leaf spot diseases for the entire growing season in two consecutive years Merit again demonstrates that it has good resistance compared to other known varieties. See Tables 6 and 7.

TABLE 6. ______________________________________ AVERAGE LEAF SPOT (Helminthosporium spp) INCIDENCE OF ONE YEAR OLD TURF OF VARIOUS KENTUCKY BLUEGRASS VARIETIES. Avg. Percent Leaf Spot Incidence Variety for Entire Year ______________________________________ Merit 22% Kenblue 48% Merion 30% Pennstar 25% ______________________________________ Rating Scale: Number indicates percent of leaves infected with leaf spot.

TABLE 7. ______________________________________ AVERAGE LEAF SPOT (Helminthosporium spp) INCIDENCE OF TWO YEAR OLD TURF OF VARIOUS KENTUCKY BLUEGRASS VARIETY. Avg. Percent Leaf Spot Incidence Variety for Entire Year ______________________________________ Merit 31% Kenblue 63% Merion 28% Pennstar 30% ______________________________________ Rating Scale: Number indicates percent of leaves infected with leaf spot.

Good leaf spot resistance was also noted in 3 year old turf plots at Accokeek, Maryland. (Table 8).

TABLE 8. ______________________________________ LEAFSPOT (Helminthosporium spp) INCIDENCE OF THREE YEAR OLD TURF OF VARIOUS BLUEGRASS VARIETIES AT ACCOKEEK, MARYLAND. Variety Percent Leaf Spot ______________________________________ Merit 13% Kenblue 60% Merion 8% Victa 10% ______________________________________ Rating Scale: Number indicates percent of leaves infected with leaf spot.

Further demonstrating that Merit has a good level of leaf spot resistance over a wide range of environmental conditions seedings were installed in various locations in Ontario, Canada. Table 9 provides leaf spot resistance data of one year old turf in Ontario, Canada, again indicating that the level of resistance is comparable to known resistant varieties.

TABLE 9. ______________________________________ LEAF SPOT (Helminthosporium spp) INCIDENCE IN EARLY SUMMER OF ONE YEAR OLD TURF IN ONTARIO, CANADA, OF VARIOUS KENTUCKY BLUEGRASS VARIETIES Variety Percent Leaf Spot ______________________________________ Merit 10% Kenblue 44% Merion 10% Flyking 4% ______________________________________ Rating Scale: Number indicates percent of leaves infected with leaf spot.

Dollar spot (Sclerotinia homoeocarpa) is unsightly and can cause damage if infestation is severe. Dollar spot normally occurs in mid to late summer on Kentucky bluegrass and progresses from very small initial spots of dead turf to circular, straw colored areas 2 to 3 inches in diameter. Affected leaves at first show yellow-green blotches, which become water-soaked and finally bleach to a strain colored tan. Merit has shown good resistance to dollar spot with minimum amount of infestation during peak times of the year. Tables 10 and 11 show a good level of dollar spot resistance of Merit compared to other varieties. Fylking and Nugget are normally considered as being susceptible varieties and the common types such as Kenblue being resistant.

TABLE 10. ______________________________________ DOLLARSPOT (Sclerotinia homoeocarpa) INCIDENCE OF TWO YEAR OLD TURF OF VARIOUS KENTUCKY BLUEGRASS VARITIES Variety Percent Dollar Spot ______________________________________ Merit 4% Kenblue 0% Nugget 20% ______________________________________ Rating Scale: Number indicates percent of leaves infected with dollar spot.

TABLE 11. ______________________________________ DOLLAR SPOT (Sclerotinia homoeocarpa) INCIDENCE OF VARIOUS KENTUCKY BLUEGRASS VARIETIES AT ACCOKEEK, MARYLAND Variety Percent Dollar Spot ______________________________________ Merit 16% Kenblue 7% Fylking 42% Nugget 23% Merion 11% Bristol 5% ______________________________________ Rating Scale: Number indicates percent of leaves infected with dollar spot.

Merit can be characterized as moderately slow to green up in early spring (Tables 12 and 13).

TABLE 12. ______________________________________ EARLY SPRING GREEN UP OF VARIOUS KENTUCKY BLUEGRASS VARIETIES Variety Early Spring Color ______________________________________ Merit 4.1 Kenblue 6.4 Vantage 6.4 Victa 4.1 Nugget 1.8 ______________________________________ Rating Scale: 1 = straw colored 10 = dark green.

TABLE 13. ______________________________________ EARLY SPRING GREEN UP OF VARIOUS KENTUCKY BLUEGRASS VARIETIES AT ACCOKEEK, MARYLAND Variety Early Spring Color ______________________________________ Merit 3.0 Vantage 4.0 Kenblue 4.3 Merion 2.8 ______________________________________ Rating Scale: 1 = straw colored 10 = dark green.

Kenblue and Vantage are known to be one of the first to break winter dormancy and turn green with Merion being late and Nugget very late. When greening is complete Merit has a very dark distinctive blue-green color in the spring compared to other varieties. The depth of its color is shown in Table 14.

TABLE 14. ______________________________________ SPRING COLOR OF VARIOUS BLUEGRASS VARIETIES AFTER COMPLETE WINTER DORMANCY HAS BEEN BROKEN AT ACCOKEEK, MARYLAND Variety Spring Color ______________________________________ Merit 9.5 Vantage 8.0 Kenblue 7.5 Merion 9.3 ______________________________________ Rating Scale: 1 = straw colored 10 = dark green.

Merit has a moderate to low vertical growth habit which makes its use as a turfgrass quite acceptable. Clippings are not excessive when maintained at a turf cutting height and mowed at normal frequent intervals such as 7 to 10 days during active growth. This moderate vertical growth habit can be demonstrated from seedling stage to turf use conditions to mature plant height when seed heads are produced (Tables 15, 16 and 17).

TABLE 15. ______________________________________ SEEDLING GROWTH HABIT SIX WEEKS AFTER SEEDING Variety Growth Habit ______________________________________ Merit 1.8 Kenblue 3.4 Vantage 2.5 Bristol 1.8 ______________________________________ Rating Scale: 1 = low growing 4 = tall.

TABLE 16. ______________________________________ PLANT HEIGHT REGROWTH OF VARIOUS BLUEGRASS VARIETIES ONE WEEK AFTER MOVING AT 38 mm IN AUGUST Variety Plant Height in mm ______________________________________ Merit 86 Kenblue 96 Merion 77 Bristol 69 Newport 92 ______________________________________ Rating Scale: Number indicates length of leaf from ground level to end of leaf.

TABLE 17 ______________________________________ MATURE PLANT HEIGHT INCLUDING PANICLE OF VARIOUS KENTUCKY BLUEGRASS VARIETIES GROWN AT MARYSVILLE, OHIO Variety Mature Plant Height in Centimeters ______________________________________ Merit 42 cm. Bristol 47 cm. Park 67 cm. Kenblue 64 cm. Merion 44 cm. Bonnieblue 36 cm. ______________________________________ Rating Scale: Number indicates length of plant from ground to top of panicle.

Turf quality, a rating taking all turfgrass performance characteristics together and assigning it a value, was measured at Ontario, Canada; Accokeek, Md. and Marysville, Ohio. A rating scale of 1 to 4 was used with 4 being the best turf. Merit is rated as moderate to good performance in all locations, outperforming the common type varieties and slightly below the recognized improved types (Tables 18, 19 and 20).

TABLE 18. ______________________________________ AVERAGE TURF QUALITY RATING FOR ENTIRE GROWING SEASON OF ONE YEAR OLD TURF IN ONTARIO, Canada Avg. Turf Quality Ratings for Variety Entire Growing Season ______________________________________ Merit 2.1 Kenblue 1.8 Merion 2.2 Fylking 2.3 ______________________________________ Rating: 1 - Poor 4 - Excellent.

TABLE 19. ______________________________________ TURF QUALITY OF TWO YEAR OLD TURF OF VARIOUS KENTUCKY BLUEGRASS VARIETIES IN MAY AT MARYSVILLE, OHIO. Variety Turf Quality ______________________________________ Merit 2.0 Bristol 2.5 Kenblue 1.5 Newport 1.9 Fylking 2.0 ______________________________________ Rating Scale: 1 - Poor 4 - Excellent.

TABLE 20. ______________________________________ AVERAGE TURF QUALITY FOR ENTIRE GROWING SEASON OF TWO YEAR OLD TURF AT ACCOKEEK, MARYLAND Variety Turf Quality ______________________________________ Merit 2.6 Merion 2.8 Victa 2.9 Kenblue 2.0 ______________________________________ Rating scale: 1 - Poor 4 - Excellent.

Ten randomly selected seeds of various varieties were laid end to end to obtain total length of the 10 seeds. Merit was shortest in length (27.5 mm) compared to five other varieties. In measuring these same ten seeds as to width by placing them side by side Merit was second widest (7.5 mm) of the group (Table 21), therefore indicating that Merit seed may be distinguished as being a short wide seed. Merit is further distinguished in that it exhibits high seed-set and high seed yield.

TABLE 21. ______________________________________ SEED LENGTH AND WIDTH OF TEN RANDOMLY SELECTED SEEDS LAYED END TO END AND SIDE BY SIDE RESPECTIVELY OF VARIOUS KENTUCKY BLUEGRASS VARIETIES Variety Length in mm Width in mm ______________________________________ Merit 27.5 mm 7.5 mm Fylking 29.8 mm 7.2 mm Park 29.3 mm 6.5 mm Kenblue 29.0 mm 6.7 mm Bristol 28.7 mm 8.5 mm ______________________________________

In seed yield trials under same growing conditions at Gervais, Oreg., differences were noted between varieties in respect to time in heading and anthesis compared to other varieties evaluated (Tables 22 and 23).

TABLE 22. ______________________________________ PERCENT HEADING AT DIFFERENT DATES OF VARIOUS KENTUCKY BLUEGRASS VARIETIES AT GERVAIS, OREGON Variety April 29 May 3 May 7 May 10 May 17 May 19 ______________________________________ Merit 2 25 75 95 Vantage 40 90 95 95 100 100 Victa 2 10 45 95 Bristol 5 10 25 90 95 100 Windsor 10 50 90 95 100 ______________________________________ Rating Scale: Number indicates percent of plants that are heading out.

TABLE 23. ______________________________________ PERCENT ANTHESIS AT DIFFERENT DATES OF VARIOUS KENTUCKY BLUEGRASS VARIETIES AT GERVAIS, OREGON Variety May 21 May 25 May 27 May 30 June 2 June 4 ______________________________________ Merit 1 25 25 50 100 Vantage 25 40 60 100 Victa 1 30 30 100 Bristol 40 80 90 100 Windsor 5 30 50 100 ______________________________________ Rating Scale: Number indicates percent of plants that are flowering.

Claims

1. A variety of bluegrass plant, substantially as shown and described, characterized particularly by a high level of resistance to disease and especially leaf spot disease, a desirable dark blue-green color throughout the growing season but particularly during cool periods of the year, a thick dense turf and persistance under a wide variety of environmental conditions.