St. Augustine grass

Abstract

A perennial St. Augustine grass having outstanding dark green color, rapid lateral spread, a semi-dwarf growth habit, and a medium level of flowering shoot production. This variety has good gray leafspot resistance throughout the year and is cold tolerant.

Description

SUMMARY OF THE VARIETY

This invention relates to a new and distinct perennial St. Augustine grass selected from the progeny of an open pollinated purple stigma diploid parent Ea611081. This purple stigma genotype was labeled 615866 and propagated vegetatively by stolons to provide planting stock for studying performance and making comparisons to present commercial varieties.

Genotype 615866 has a wide leaf blade, a short leaf length, and an outstanding dark green color. These characteristics along with the rapid spread, its medium level of flowering shoot production, its good gray leafspot (Piricularia grisea) resistance, and its cold tolerance can be used to distinguish 615866 from other St. Augustine grasses.

BRIEF DESCRIPTION OF THE ILLUSTRATIONS

FIG. 1 is a photograph of 615866 St. Augustine turf showing generally the characteristics of this new grass;

FIG. 2 shows the leaves and stem of a 615866 St. Augustine grass plant;

FIG. 3 shows a spike of a 615866 St. Augustine grass plant; and

FIG. 4 shows florets of a 615866 St. Augustine grass plant.

DETAILED DESCRIPTION OF THE VARIETY

Genotype 615866 possesses a Munsell color designation 7.5 GY 4/4 .sup.1/ and is characterized by compressed and branched culms. The leaf blades are relatively short, averaging 44.8 mm. long, but are very coarse, averaging 7.66 mm. wide. These characteristics can be used to distinguish 615866 from both the dwarf and non-dwarf St. Augustine grasses. The average internode length is 35.0 mm., thus allowing this semi-dwarf to have a vigorous lateral spread. Genotype 615866 has a purple stigma color and an unreduced chromosome number of 18.

Total soluble salts measured in micromhos/cm. specific conductance using a Beckmann Solu-Bridge will allow differentiation between 615866 and other St. Augustine grasses. The average reading for 615866 was 146.1 micromhos/cm. The chromosome numbers, stigma colors, morphological measurements of 615866 and other St. Augustine grasses are compared in Tables 1, 2 and 3.

Table 1 ______________________________________ Chromosome Numbers and Stigma Colors of 615866 and other St. Augustine grasses ______________________________________ Chromosome Number Stigma Selection/Variety (Unreduced).sup.2 Color ______________________________________ 615866 18 Purple 45176 18 " 73176 18 " Ea611081 18 " Floratine 27 " Bitter Blue 27 " Texas Common 18 White ______________________________________ .sup.1 The Munsell designated color is of plant material grown in the greenhouse. The color is subject to variation depending upon the environmental conditions under which the grass is grown. .sup.2 Chromosome Number determinations made on pollen mother cells.

Table 2 ______________________________________ Comparative Leaf Blade Length, Width and Internode Length for 615866 and Other St. Augustine grasses ______________________________________ Leaf Blade Leaf Blade Internode Selection/ Length Width Length Variety (mm.).sup.1 (mm.).sup.2 (mm.).sup.3 ______________________________________ 615866 44.8 .+-. 11.6 7.66 .+-. 0.72 35.0 .+-. 7.7 45176 44.2 .+-. 11.8 6.04 .+-. 0.89 22.8 .+-. 3.8 73176 33.4 .+-. 7.3 5.86 .+-. 1.09 10.8 .+-. 2.2 Ea611081 78.4 .+-. 33.3 7.12 .+-. 1.38 36.0 .+-. 7.4 Floratine 82.8 .+-. 25.9 7.81 .+-. 2.46 36.3 .+-. 7.3 Bitter Blue 105.2 .+-. 31.8 8.55 .+-. 1.25 38.3 .+-. 8.7 Texas Common 45.0 .+-. 16.8 6.48 .+-. 0.85 34.0 .+-. 4.2 LSD 5% 12.1 .71 4.0 ______________________________________ .sup.1 All plant material grown unclipped in greenhouse. .sup.2 Measurements recorded 15 millimeters above leaf collar. .sup.3 Measurements recorded between third and fourth internodes.

Table 3 ______________________________________ Specific Conductance Measurements of 615866 and Other St. Augustine grasses ______________________________________ Specific Conductance Selection/Variety (micromhos/cm.).sup.1 ______________________________________ 615866 146.1 45176 104.1 73176 107.3 Ea611081 132.3 Bitter Blue 190.2 Texas Common 122.8 ______________________________________ .sup.1 Measurements were made on a six centimeter stem section.

The characteristic growth habit can be used to distinguish 615866 from the dwarf St. Augustine grasses 73176 and 45176, and the more upright growing types Bitter Blue and Texas Common. In addition, fresh weight clipping yields can be used to distinguish 615866 from the two dwarf selections and Ea611081. This information is illustrated in Tables 4 and 5. In Table 6 it can be seen that the leaf texture of 615866 is similar to that of the coarser types Bitter Blue and Texas Common thus differentiation in these cases must be based on the lower growth habit of 615866.

Table 4 ______________________________________ Comparative Growth Habit Averages for 615866 and Other St. Augustine grasses at Apopka, Florida, and Katy, Texas ______________________________________ Growth Habit.sup.1 Selection/ Florida Texas Florida Variety 1971 1971 1972 ______________________________________ 615886 3.4 4.1 3.0 45176 2.6 2.5 2.1 73176 2.4 2.5 1.6 Ea611081 3.4 4.0 3.2 Bitter Blue 4.4 4.5 3.7 Texas Common -- -- -- -- -- .2 ______________________________________ .sup.1 Rating 1 - low growing, 5- upright growing

Table 5 ______________________________________ Fresh weights of Clippings Removed From Plots of 615866 and Other St. Augustine grasses ______________________________________ Fresh Weights Selection/ (gms/.48m .times. 1.52 m plot) Variety July August September ______________________________________ 615866 24.7 .+-. 9.1 40.0 .+-. 15.1 38.3 .+-. 8.7 45176 6.3 .+-. 2.1 19.7 .+-. 10.0 13.7 .+-. 6.4 73176 3.0 .+-. 1.7 6.0 .+-. 3.6 7.7 .+-. 2.9 Ea611081 36.7 .+-. 12.9 74.0 .+-. 12.5 45.0 .+-. 8.2 Bitter Blue 22.3 .+-. 9.9 43.7 .+-. 15.3 29.7 .+-. 4.9 LSD 5% 16.6 21.8 11.0 ______________________________________

Table 6 ______________________________________ Comparative Texture Averages for 615866 and Other St. Augustine grasses at Apopka, Florida, and Katy, Texas ______________________________________ Texture.sup.1 Selection/ Florida Texas Florida Variety 1971 1971 1972 ______________________________________ 615866 1.9 1.7 2.3 45176 2.7 2.1 3.0 73176 2.9 2.5 3.1 Ea611081 1.7 2.0 2.3 Bitter Blue 1.4 1.5 2.0 Texas Common -- 1.1 -- LSD 5% -- -- .2 ______________________________________

Genotype 615866 has an outstanding dark green color and a medium level of flowering shoot production. Field observations have shown that 615866 has the fastest rate of cover of any St. Augustine grass tested including Ea611081. The observations of color and rate of cover used in combination can allow distinction of 615866 from Ea611081. This information is illustrated in Tables 7, 8 and 9.

Table 7 ______________________________________ Comparative Color Averages for 615866 and Other St. Augustine grasses at Apopka, Florida, and Katy, Texas ______________________________________ Color.sup.1 Selection/ Florida Texas Florida Variety 1971 1971 1972 ______________________________________ 615866 9.4 8.9 8.0 45176 8.7 9.3 7.9 73176 8.9 9.3 8.1 Ea611081 8.7 8.7 7.8 Bitter Blue 9.1 8.7 7.8 Texas Common -- 8.8 -- LSD 5% -- -- .2 ______________________________________ .sup.1 Rating 1 - lightest green, 10 - darkest green

Table 8 ______________________________________ Comparative Ratings of Average Flowering Shoot Production of 615866 and Other St. Augustine grasses at Apopka, Florida, and Katy, Texas ______________________________________ Average Flowering Shoot Production.sup.1 Selection Texas Florida Variety 9/17/71 6/15/72 ______________________________________ 615966 1 2.3 45176 3 2.3 73176 0 .7 Ea611081 0 2.0 Bitter Blue 0 1.3 -Texas Common 3 -- LSD 10% -- 1.0 ______________________________________ .sup.1 Rating 0 - no flowering shoot production, 5 - heavy flowering shoo production.

Table 9 ______________________________________ Relative Comparison of Percent Turf Cover of 615866 and Other St. Augustine grasses at Apcpka, Florida ______________________________________ Selection/ Average Percent Area Covered.sup.1 Variety 2/15/72 4/3/72 5/1/72 ______________________________________ 615866 53 60 97 100 45176 37 47 60 93 73176 40 47 67 93 Ea611081 57 60 87 97 Bitter Blue 47 53 70 97 LSD 5% 8 10 15 N.S. ______________________________________ .sup.1 Initial planting made 12/1/71

Genotype 615866 has a lower percent gray leafspot (Piricularia grisea) infestation throughout the whole year than any selection other than the very leafspot resistant dwarf 73176. This observation can be used to distinguish 615866 from other less resistant selections such as Bitter Blue and Texas Common. This information is given in Table 10.

Table 10 __________________________________________________________________________ Comparative Gray Leafspot (Piricularia Grisea) Resistance of 7615866 and Other St. Augustine grasses at Apopka, Florida and Katy, Texas. __________________________________________________________________________ Percent Gray Leafspot Selection/ Florida Texas Variety 6/28/71 4/31/71 6/29/71 7/31/71 9/2/71 9/17/71 __________________________________________________________________________ 615866 20 10 10 10 10 0 45176 20 20 30 10 20 30 73176 20 10 20 10 5 0 Ea611081 20 10 30 20 10 30 Bitter Blue 40 90 10 10 10 20 Texas Common -- 10 60 20 30 20 __________________________________________________________________________

The cold tolerance of 615866 and other St. Augustine grasses is shown in Table 11. The cold tolerance of this genotype allows differentiation from other less tolerant St. Augustine grasses under sub-zero (centigrade) stress.

Table 11 ______________________________________ Comparative Cold Damage from Below Zero (centigrade) Temperature of 615866 and Other St. Augustine grasses in Apopka, Florida and Katy, Texas ______________________________________ Percent Cold Damage.sup.1 Selection/ Texas Florida 1973 Variety 1972 Test - A.sup.2 Test - B.sup.3 ______________________________________ 615866 0 5 27.5 45176 95 60 47.5 73176 99 40 35.0 Ea611081 99 15 50.0 Bitter Blue 20 5 52.5 Texas Common 0 -- -- ______________________________________ .sup.1 Cold damage as measured by percent stolons killed. .sup.2 Test - A, Two year old sod. .sup.3 Test - B, One year old sod.

Claims

1. A St. Augustine grass, substantially as herein illustrated and described.