Strawberry Plant Named 'UCD Valiant'

Abstract

UCD Valiant is a day-neutral strawberry cultivar of garden strawberry that provides high yields and produces large, firm fruit. The variety has performed particularly well in low-input and organic production systems.

Claims

1. A new and distinct cultivar of strawberry plant having the characteristics substantially as described and illustrated herein.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The colors in the photograph are depicted as nearly true as is reasonably possible to obtain in color reproductions of this type.

[0011] FIG. 1 shows fruit of UCD Valiant in cross-section.

[0012] FIG. 2 illustrates color of the fruit.

[0013] FIG. 3 depicts general flowering and fruiting characteristics of UCD Valiant.

[0014] FIG. 4 shows representative fruit trusses of the plant.

[0015] FIG. 5 shows representative flowers of the plant.

[0016] FIG. 6 shows representative leaves of the plant.

[0017] FIG. 7 depicts plant habit.

DETAILED DESCRIPTION OF THE INVENTION

Fruit Production

[0018] UCD Valiant and comparison cultivars were asexually propagated in high-elevation nurseries in Dorris and Mcdoel, Calif. for field testing in 2015-2016, 2016-2017, and 2017-2018. Clones were harvested according to commercial planting schedules, which were calibrated by the number of chill hours required for optimum production in Santa Maria and Prunedale, Calif.

[0019] Cultivar testing in small-plot yield trials was performed as follows. Test day-neutral cultivars and comparison cultivars were field tested in Oso Flaco (Santa Maria, Calif.) and Prunedale, Calif. in 2015-2016. Fruit was harvested once or twice per week over the spring and summer growing season: March 16 to Aug. 18, 2016 in Santa Maria (31 harvests) and April 2 to Aug. 27, 2016 in Prunedale (30 harvests). UCD Valiant was selected on the basis of fruit appearance, size, shelf-life, and cumulative marketable fruit yield for a second year (2016-17) of replicated testing in Santa Maria and Prunedale (Tables 1-2). Fruit was harvested once or twice per week over the growing season: March 13 to Aug. 21, 2017 in Santa Maria (25 harvests) and April 3 to Sep. 1, 2017 in Prunedale (44 harvests in Prunedale). To highlight differences among cultivars, the yield data were displayed in three ways: (a) per plant yields for individual harvests for each location x year combination for UCD Valiant, Monterey, San Andreas, and Cabrillo; (b) per plant cumulative marketable yields for UCD Valiant, Monterey, San Andreas, and Cabrillo; and (c) per plant cumulative marketable yields tested in both years and locations. Entry ranks were highly consistent and the best and worst performing cultivars were virtually identical over locations and years.

[0020] Table 1 shows marketable yield (g/plant) for UCD Valiant compared to that for Monterey, San Andreas (U.S. Plant Pat. No. 19,975), and Cabrillo tested in small-plot yield trials in Santa Maria, Calif. and Prunedale, Calif. in 2015-16 and 2016-17.

[0021] Table 2 shows the range in increase in yield compared to Monterey, San Andreas, and Cabrillo for the small-plot yield trials.

TABLE-US-00001 TABLE 1 Least-square means for cumulative marketable yield tested in small-plot yield trials in Santa Maria, CA and Prunedale, CA in 2015-2016 and 2016-2017 Yield across Locations and Santa Maria Prunedale Years Cultivar 2015-16 2016-17 2015-16 2016-17 (g/Plant) UCD Valiant 1,984 2,380 1,460 2,482 2,078 Cabrillo 1,617 2,073 1,362 2,299 1,838 Monterey 1,115 1,324 1,077 1,722 1,310 San Andreas 1,229 1,096 1,048 1,569 1,236

TABLE-US-00002 TABLE 2 Least-square means for cumulative marketable yield (g/plant) across years and locations in the small-plot yield trials. Yield Yield Yield Percent Increase Increase Increase Market- Range Range Range Yield able Over San Over Over Cultivar (g/plant) Fruit Andreas Monterey Cabrillo UCD Valiant 2,078 84-86 39-117% 35-80% 7-22% Cabrillo 1,838 86-87 Monterey 1,310 79-82 San Andreas 1,236 76-84 The ranges for yield increases over comparison cultivars were estimated from least square means for individual environments (see, Table 1). (Percent Marketable Fruit = (Cumulative Marketable Fruit Yield)/(Cumulative Total Fruit Yield)

[0022] The cumulative marketable fruit yields of UCD Valiant were significantly greater than Monterey (p<0.0001), San Andreas (p<0.0001) and Cabrillo (p<0.055) across years and locations (Table 1). The per plant yields of UCD Valiant were 7 to 117% greater than Cabrillo, Monterey, and San Andreas (Table 2). The mean fruit size for UCD Valiant (35.3 g/fruit) was significantly different from Cabrillo (30.0 g/fruit; p<0.0001), Monterey (28.4 g/fruit p<0.0001), and San Andreas (26.7 g/fruit; p<0.0001).

[0023] The marketable fruit percentages for UCD Valiant and Cabrillo were comparable (84-87%) and superior to Monterey and San Andreas (76 to 84%) (Table 2).

[0024] UCD Valiant was selected, with other test varieties, for advanced testing in large-plot yield trials (150 plants/plot) with five commercial growers in 2017-18. The selection criteria were: high cumulative marketable yields, high marketable fruit percentages, resistance to bruising and deterioration with harvest, handling, and storage, fruit appearance, and reduced runner production in coastal production environments. The production systems for large-plot yield trials were diverse and included: low-input organic (Santa Maria, Calif.), low-input fumigated (Salinas, Calif.), and high-input fumigated (Oso Flaco, Calif., Prunedale, Calif. and Moss Landing, Calif.). Fruit was harvested from February 2 to October 5 in Oso Flaco (52 harvests), April 3 to October 4 in Santa Maria (53 harvests), April 12 to October 6 in Prunedale (48 harvests), May 7 to October 8 in Moss Landing (45 harvests), and March 9 to October 12 in Salinas (36 harvests). The residual for statistical analyses was the entry x location interaction mean square.

TABLE-US-00003 TABLE 3 Least square means for cumulative marketable fruit yield (cartons/acre) for UCD Valiant, Monterey, and Cabrillo grown in unreplicated large-plot (150 plant) yield trials in five locations in 2017-18, where a carton = eight clamshells and eight clamshells/carton one pound/ clamshell = eight pounds/carton. Santa Oso Mossing Across Cultivar Salinas Maria Flaco Prunedale Landing Locations UCD Valiant 11,241 11,490 16,155 16,135 8,878 12,780 Cabrillo 5,201 6,892 17,569 14,057 9,465 10,637 Monterey NA 7,891 14,731 11,940 10,257 10,274

TABLE-US-00004 TABLE 4 Least square means for fruit weight (g/fruit) for UCD Valiant, Monterey, and Cabrillo grown in unreplicated large-plot (150 plant) yield trials in in five locations in 2017-18,where fruit weight = (weight of fruit per clamshell)/(number of fruit per clamshell). Santa Oso Mossing Across Cultivar Salinas Maria Flaco Prunedale Landing Locations UCD Valiant 31.2 24.3 32.1 31.2 38.7 31.5 Cabrillo 26.1 21.9 28.0 27.5 34.0 27.5 Monterey NA 21.6 29.4 27.9 33.8 27.8

TABLE-US-00005 TABLE 5 Statistical significance (Pr > F) of differences between least square means for cumulative fruit yield (cartons/acres) and fruit weight (g/fruit) for UCD Valiant, Monterey, and Cabrillo tested in unreplicated large-plot (150 plant) yield trials in five locations in 2017-18. Fruit Weight Yield (g/fruit) Difference Difference Comparison (carton/acre) Pr > F (g/fruit) Pr > F UCD Valiant- 2,506 0.0203 3.68 <0.0001 Monterey UCD Valiant- Cabrillo 2,143 0.0307 4.01 <0.0001

[0025] The mean cumulative marketable yield of UCD Valiant was 12,780 cartons/acre=102,240 pounds/acre across production systems and locations (Table 3). The cumulative marketable fruit yields of UCD Valiant were significantly greater than Monterey (p =0.02) and Cabrillo (p=0.03) across production systems and environments. UCD Valiant produced 2,506 cartons/acre more than Monterey (p=0.008) and 2,143 cartons/acre more than Cabrillo (Tables 3 & 5). UCD Valiant provided high yields in both of the low-input production systems tested (Santa Maria and Salinas). UCD Valiant fruit weights were significantly larger than Monterey (p<0.0001) and Cabrillo (p<0.0001) (Tables 4 & 5).

[0026] To assess the quality of freshly harvested fruit, firmness (grams force), total soluble solids (SS) concentration, and titratable acid (TA) concentrations were measured from samples of fruit harvested on three dates from each location in 2017-18 (Tables 6-7). Harvest dates were one month apart with one replication per harvest date, 10 sub-samples per replication for firmness, and three subsamples per replication for SS and TA. Firmness was quantified with a hand-held penetrometer measuring the grams of force needed to puncture the fruit. SS and TA concentrations were quantified with benchtop instruments. The SS to TA ratio provides a relative measure of sweetness. To assess shelf-life, fruit weight (g/clamshell), SS, brightness (ordinal scale with 1=excellent to 5=unmarketable), liquid leakage (g/clamshell), and mold incidence (%) were quantified from samples of fruit harvested on two dates from each location with fruit stored under standard 4 C. conditions for 0, 7, 14, and 21 days (Table 8). Harvest dates were one month apart with one replication per harvest date.

TABLE-US-00006 TABLE 6 Least-square means (LSMs) for firmness, soluble solids concentration (SS), and titratable acid concentration (TA) for UCD Valiant, Monterey, and Cabrillo grown in five locations in 2017-18. LSMs were estimated from three harvest dates per location, one biological replication per harvest date, 10 sub-samples per harvest date for firmness, and three sub-samples per harvest date for SS and TA. Titrable Firmness Acids Cultivar (g force) SS (%) (g/100 ml) SS/TA UCD Valiant 377.44 7.62 0.83 9.19 Cabrillo 359.61 8.05 0.77 10.50 Monterey 294.55 8.71 0.77 11.48

TABLE-US-00007 TABLE 7 Statistical significance (Pr > F) of differences between least square means for SS, TA, and SS/TA for UCD Valiant, Monterey, and Cabrillo tested in unreplicated large-plot yield trials in five locations in 2017-18. Soluble Solids Titratable Acids SS/TA Concentration (SS) Concentration (TA) Least Least Square Least Square Square Mean Difference Mean Difference Mean Comparison (%) Pr > F (g/ 100 ml) Pr > F Difference Pr > F UCD 1.09 0.0041 0.07 0.0147 2.29 <0.0001 Valiant- Monterey UCD 0.43 0.2624 0.06 0.0354 1.31 0.0028 Valiant- Cabrillo

TABLE-US-00008 TABLE 8 Least-square means (LSMs) for fruit weight (g/clamshell), soluble solids concentration and (SS), fruit brightness, liquid leakage, and mold formation for UCD Valiant, Monterey, and Cabrillo grown in four locations in 2017-18 and stored for zero to 21 days postharvest. LSMs were estimated from two harvest dates per location Days Post- Soluble Liquid Harvest Weight Solids Leakage Mold Cultivar Storage (g/clamshell) (%) Brightness (g) (%) UCD Valiant 0 576.4 7.1 1.4 0.0 0.0 Cabrillo 0 555.4 7.5 1.3 0.0 0.0 Monterey 0 572.0 9.2 1.2 0.0 0.0 UCD Valiant 7 561.1 6.7 2.6 0.0 0.0 Cabrillo 7 538.7 7.4 2.0 0.2 0.0 Monterey 7 556.3 9.1 1.8 0.0 0.0 UCD Valiant 14 546.4 7.0 3.8 0.8 1.3 Cabrillo 14 522.9 7.3 3.3 0.8 1.2 Monterey 14 542.3 9.5 3.0 0.0 0.5 UCD Valiant 21 527.5 6.8 4.8 24.2 31.7 Cabrillo 21 504.4 7.3 4.3 35.8 36.7 Monterey 21 526.4 8.7 3.8 0.2 11.8

[0027] UCD Valiant produced fruit meeting or exceeding industry standards for mass-production cultivars (Tables 6-8). The fruit was firm, withstood the rigors of harvest, packing, and storage, and maintained acceptable fruit quality and appearance for over two weeks of storage. UCD Valiant produced significantly firmer fruit than Monterey (p<0.0001), but not significantly different from Cabrillo (p=0.11). UCD Valiant additionally had significantly lower SS concentration than Monterey (p<0.004), but was not significantly different from that of Cabrillo (p =0.26). The SS/TA ration for UCD Valiant was significantly lower than Monterey (p<0.0001) and Cabrillo (p=0.0028).

[0028] UCD Valiant maintained adequate marketability and visual appeal over 14 days of post-harvest storage, the industry standard (Table 8), as did Cabrillo and Monterey. The marketability of fruit stored for 21 days post-harvest was inadequate for all three cultivars. Fruit weight and brightness significantly decreased as post-harvest storage time increased (Table 8). The fruit weight decreases were not significantly different among cultivars. Cultivar x post-harvest storage time interactions were only statistically significant for liquid leakage and mold formation, with Cabrillo deteriorating more than UCD Valiant and Monterey (Table 8).

Disease Resistance Evaluation

[0029] UCD Valiant and additional cultivars were screened for resistance to Fusarium wilt, Verticillium wilt, Macrophomina, and Phytophthora crown rot in Davis, Calif. field experiments between 2015 and 2018. These included 2015-16 and 2016-17 Fusarium wilt screening experiments with 480 to 960 entries, a 2015-16 Macrophomina experiment with 960 entries, 2016-17 and 2017-18 Verticillium wilt experiments with 480 to 960 entries, and a 2017-18 Phytophthora crown rot experiment with 480 entries. Entries were arranged in randomized complete blocks experiment designs with four single-plant replications per entry. The 2015-16 experiments were planted in virgin soil in Davis, Calif. The 2016-17 and 2017-18 experiments were planted in fumigated soils in Davis, Calif. For each experiment, plants were artificially inoculated with the respective pathogen and phenotyped for disease symptoms on an ordinal scale, where 1=highly resistant (symptomless), 2=resistant, 3=intermediate, 4=susceptible, and 5=highly susceptible (dead). Within each experiment, plants were phenotyped at six different time points to study changes in the phenotypic distributions and quantify the progression of disease symptoms over time.

[0030] UCD Valiant was susceptible to Fusarium wilt (4.5 on scale), moderately susceptible to Verticillium wilt (3.3 on scale), moderately susceptible to Phytophthora crown rot (3.0 on scale), and susceptible to Macrophomina (5.0 on scale).

Botanical Description

[0031] The following botanical descriptors are characteristic of UCD Valiant. The descriptors were collected from two different sites in May 2017 in Santa Maria, Calif. The characteristics of UCD Valiant may vary in detail, depending upon environmental factors and culture conditions. [0032] Growth habitat: Semi-upright. [0033] Density of foliage: Medium. [0034] Vigor: Strong. [0035] Position of inflorescence in relation to foliage: Above. [0036] Number of stolons: Few. [0037] Stolon, anthocyanin coloration: Medium. [0038] Stolon, density of pubescence: Sparse. [0039] Leaf size: Medium. [0040] Leaf, color of upper side: Medium green. [0041] Leaf blistering: Medium. [0042] Leaf glossiness: Medium glossy. [0043] Leaf variegation: Absent. [0044] Terminal leaflet, length in relation to width: Moderately longer in length compared to width. [0045] Terminal leaflet, shape of base: Obtuse. [0046] Terminal leaflet, margin: Serrate to crenate. [0047] Terminal leaflet, shape in cross section: Concave. [0048] Petiole, length: Long. [0049] Petiole, Attitude of hairs: Upwards. [0050] Stipule, anthocyanin coloration: Absent or very weak. [0051] Inflorescence, number of flowers: Many. [0052] Pedicel, attitude of hairs: Upwards. [0053] Flower diameter: Medium. [0054] Flower, arrangement of petals: Free. [0055] Flower, size of calyx in relation to corolla: Smaller. [0056] Flower stamen: Present. [0057] Petal, length in relation to width: Equal. [0058] Petal, color of upper side: White. [0059] Fruit, length in relation to width: Moderately longer. [0060] Fruit size: Large. [0061] Fruit shape: Conical. [0062] Fruit, difference in shape of terminal and other fruits: Slight. [0063] Fruit color: Medium red. [0064] Fruit, evenness of color: Even or very slightly uneven. [0065] Fruit glossiness: Strong. [0066] Fruit, evenness of surface: Even or very slightly uneven. [0067] Fruit, width of band without achenes: Absent or very narrow. [0068] Fruit, positions of achenes: Below surface. [0069] Fruit, position of calyx attachment: Inserted. [0070] Fruit, attitude of sepals: Upwards. [0071] Fruit, diameter of calyx in relation to fruit diameter: Slightly smaller. [0072] Fruit, adherence of calyx: Weak. [0073] Fruit firmness: Firm. [0074] Fruit, color of flesh (excluding core): Light red. [0075] Fruit, color of core: Light red. [0076] Fruit cavity: Medium. [0077] Time of beginning of flowering: Early. [0078] Time of beginning of fruit ripening: Early. [0079] Type of bearing: Day neutral.