Strawberry plant called "Carlsbad"

Abstract

`Carlsbad` is a short-day (June-bearing) cultivar similar to `Chandler` (U.S. Plant Pat. No. 5,262) but with larger total productivity, substantially larger early productivity, larger fruit, firmer fruit, and is a more vigorous plant.

Description

DESCRIPTION

This invention relates to a new and distinctive short-day type cultivar designated as `Carlsbad`, which resulted from a cross performed in 1988 between the cultivar `Irvine` (U.S. Plant Pat. No. 7,172) and advanced selection Cal 85.218-605.

`Carlsbad` was first fruited at the University of California South Coast Research and Extension Center, near Irvine, Calif. in 1989, where it was selected, originally designated Cal 88.70-613, and propagated asexually by runners. Asexual propagules from this original source have been tested at the South Coast Research and Extension Center, the Watsonville Strawberry Research Facility, and to a limited extent in grower fields starting in 1990.

FIG. 1 shows the general flowering and fruiting characteristics of the plant;

FIG. 2 shows a typical mature leaf during late spring; and

FIG. 3 shows representative mid-season fruit.

`Carlsbad` is typical of short-day types and products fruit over an extended period when treated appropriately in arid, subtropical climates. `Carlsbad` differs from `Irvine` in that `Irvine` is a day-neutral type with essentially no photoperiodic flowering response and as compared with `Carlsbad` is more difficult to grow. The production pattern for `Carlsbad` is similar to that for `Chandler`, although it produces substantially greater quantities of early-season fruit. `Carlsbad` will be of special interest for winter plantings, where `Chandler` has been successful, and in summer plantings where `Pajaro` has been successful.

Plants and foliage: Fruiting plants of `Carlsbad` are larger, more erect, and more vigorous than plants of `Chandler` (U.S. Plant Pat. No. 5,262), and are generally similar in form to plants of `Oso Grande` (U.S. Plant Pat. No. 6,578). `Carlsbad` forms branch crowns in greater quantity than `Chandler` with similar branching to `Oso Grande`. When propagated in the nursery, `Carlsbad` has similar or greater runner production capacity compared with `Chandler`. Comparative statistics for foliar characters, including leaf color, near mid-season are given for the three cultivars in Table 1 with visual comparisons of leaf color according to the Munsell color scale (Nickerson Color Fan) given in Table 5. Leaf color is distinctly lighter on the underside for `Carlsbad`; the differential is larger than for `Chandler` and similar to that for `Oso Grande`. Individual leaflets for `Carlsbad` are larger and somewhat more elongated than `Chandler`, and are less rounded than for `Oso Grande`. Leaves (including petioles) are longer and much broader than for `Chandler`. Petioles are thicker and stiffer than those of `Chandler` and are similar to those of `Oso Grande`. Paired stipules, borne in a median position on the petiole, appear as small, stalked, ovate to heart-shaped structures on most leaves for `Carlsbad` and the comparison cultivars. Stipule size varies greatly both within and among individual plants for `Carlsbad`, and one or both stipules may be absent or may be abscise as the leaf matures. Leaf and petiole pubescence characters for `Carlsbad` are similar to those for `Oso Grande`, except that tomentum on leaves are less dense. Also, leaves for `Carlsbad` are darker than leaves of `Chandler` and similar in color but slightly darker than those of `Oso Grande`. Visual comparisons of fruit color according to the Munsel color scale (Nickerson Color Fan) are given in Table 5. `Carlsbad` has flat (occasionally concave) leaves, which are easily distinguished from ` Chandler`, and are similar in convexity to `Oso Grande`.

Isozymes in leaf extracts: `Carlsbad` has been classified for three isozyme systems using starch gel electrophoresis (Table 2): Phosophoglucoisomerase (PGI), Leucine Aminopeptidase (LAP), and Phosphoglucomutase (PGM). It is distinguishable from all other short-day cultivars released to date. For electrophoretic procedures see: J. Amer. Soc. Hort. Sci. 106:684-687.

Disease and pest reaction: `Carlsbad` is moderately resistant to common leaf spot (Ramularia tulasnei) and powdery mildew (Sphaerotheca macularis). When treated properly, it has equal or greater tolerance to two-spotted spidermites (Tetranychus urticae) than `Chandler`. `Carlsbad` is tolerant to strawberry viruses encountered in California.

TABLE 1______________________________________Foliar characteristics for`Carlsbad`, `Chandler`, and `Oso Grande`. CultivarFoliar Character `Carlsbad` `Chandler` `Oso Grande`______________________________________Mid-tier leafletLength (mm)mean 90.4 82.4 77.2range 85-97 78-94 75-80Width (mm)mean 75.8 71.4 67.6range 65-82 63-88 62-71Mid-tier leafLength (mm)mean 261.0 244.2 191.6range 257-269 218-262 170-200Width (mm)mean 162.4 148.0 137.2range 148-175 132-158 130-149Leaf color(CIELAB)*L*mean 30.0 31.4 31.9range 27.7-31.8 27.1-33.3 29.9-33.0a*mean -6.7 -8.0 -5.3range -3.8--8.8 -5.2--8.2 -4.2--8.3b*mean 14.2 16.0 15.5range 10.0-17.5 12.9-21.4 12.5-20.6# leaflets/leaf 3 3 3Leaf convexity flat/slight concave concave concaveSerrationsnumber few many moderateshape semi-round semi-pointed semi-roundLeaf pubescence moderate moderate/ moderate/ sparse heavyPetiole pubescencedensity heavy heavy heavydirection perpendicular acropetal perpendicular______________________________________ *CIELAB is the abbreviation of the international color system known as "Commission Internationale De L'Eclairage" 1978. Recommendations on uniform color spaces -- color difference equations, psychometric color terms, Supplement No. 2 to CIE Publication No. 15. PARIS. 2 TABLE 2______________________________________Isozyme phenotypes for `Carlsbad`, `Chandler`, and `Oso Grande`.CultivarLocus `Carlsbad` `Chandler` `Oso Grande`______________________________________PGI A2 A1 A2LAP B3 B3 B3PGM C1 C1 C2______________________________________

Flowering, fruiting, fruit, and production characteristics: Comparative statistics for flower and fruit characters, including fruit color, near mid-season are given for `Carlsbad`, `Chandler` and `Oso Grande` in Table 3. The primary flowers for `Carlsbad` are slightly larger than those of `Chandler` and `Oso Grande`, whereas the sepals are substantially larger than for the comparison cultivars. Each primary flower has 5-7 petals. The calyx for `Carlsbad` is usually even with the shoulder of the fruit, but is occasionally slightly indented and ocassionally necked. The primary fruit shape for `Carlsbad` is a very flat conic, with secondary fruit usually a blocky conic. External fruit color for `Carlsbad`, is lighter than `Chandler`, and `Oso Grande`. and the fruit somewhat less glossy than `Chandler`; internal color is lighter than `Chandler` and darker than for `Oso Grande`. Achenes vary from yellow to dark red, and are even with the fruit surface or slightly extruded.

`Carlsbad` has been tested under a variety of cultural regimes, and optimal performance is obtained when nursery treatments, pre-plant chilling regimes, plant densities, and nutritional programs similar to those that optimize performance for `Chandler` are used. In general, `Carlsbad` is more adapted to early-season planting with less supplemental chilling than `Chandler`.

When treated with appropriate planting regimes, `Carlsbad` has larger fruit and produces greater yields than `Chandler` or `Oso Grande` (Table 4). `Carlsbad` is similar to `Chandler` and `Oso Grande` in its production pattern, although it produces substantially more early-season fruit than either cultivar (with conventional winter planting). Commercial appearance ratings have been comparable to or better than those for `Chandler`. Fruit of `Carlsbad` is firmer than that for `Chandler`; `Carlsbad` is about as firm as `Oso Grande`. Subjectively, `Carlsbad` has very good flavor, somewhat less aromatic than `Chandler`, but with better acid balance and more aromatic components than `Oso Grande`. The fruit will be outstanding for both fresh market and processing, due to its firm flesh and relatively dark internal color, and will be useful for home garden purposes.

TABLE 3______________________________________Flower and fruit characters for`Carlsbad`, `Chandler`, and `Oso Grande`. CultivarCharacter `Carlsbad` `Chandler` `Oso Grande`______________________________________# petalsmean 6.2 6.6 5.0range 5-7 6-8 5-5Flower position exposed even/ exposed(relative to foliage) exposedCalyx diam. (mm)mean 63.8 47.7 34.1range 56-70 45-53 27-38Corolla diam. (mm)mean 40.7 39.3 32.2range 37-44 36-46 27-41Fruit shapelength/width 1.02 1.33 1.06ratiosubjective flat/conic flat conic blocky/conicCalyx position even/slight even/slight even/slight indent neck indentSeed position slight even/slight even extrude indentFruit color (CIELAB)externalL* 25.4 23.6 22.4a* 29.9 38.5 31.2b* 16.3 14.8 17.2internalL* 47.8 46.2 54.1a* 37.9 39.1 30.4b* 28.9 29.4 22.7______________________________________ TABLE 4______________________________________Performance for selection `Carlsbad` compared with `Oso Grande`and `Chandler` at the South Coast Research and Extension Centerin 1991. All plants were dug from the South Coast nursery onOctober 1 and planted October 2 (68"/4-row beds, 23,061plants/A, 100 g/plant = 425 Crates/A). Yield Total Appear- To 4/1 Yield Size ance Firm- (g/plant) (g/plant) (g/fruit) Score ness______________________________________`Carlsbad` 510 2,308 27.2 4.2 4.7`Chandler` 463 1,738 23.3 3.9 4.0`Oso Grande` 530 1,675 25.0 3.8 4.9______________________________________ TABLE 5______________________________________Munsell color classification for leaf and fruit characters.Munsell MunsellLeaf Color Classes Fruit Color Classes Upper LowerItem (Adaxial) (Abaxial) External Internal______________________________________Chandler 5GY 4/3 5GY 5/6 5R 5/13 7R 5/13 5GY 5/6 5R 4/12Oso 5GY 4/3 5GY 5/6 5R 5/13 7.5R 7/9 5GY 3/2 7.5GY 6/8 7.5R 5/13 7.5R 6/12Carlsbad 7.5GY 4/4 7.5GY 5/8 7.5R 5/13 7.5R 6/12 5GY 4/3 7.5GY 4/7 7.5R 4/11 7.5R 5/13______________________________________

Claims

1. The new and distinct variety of strawberry plant illustrated and described and having the characteristics above enumerated.