Resource Information

Vegetable Cultivar Trials in Hawaii  

By: Hector Valenzuela, Joe DeFrank, Steven Fukuda, Randy Hamasaki, Ronald Mau, and Dwight Sato

HITAHR, University of Hawaii at Manoa

This summary lists results from experiments on different vegetable cultivars

TSWV Resistant Tomato Lines
Eggplant Cultivar Trials
Pepper Cultivar Trials
Cabbage Cultivar Trials
High Elevation Chinese

By: Hector Valenzuela, HITAHR, Univ. Hawaii at Manoa

A tomato trial was conducted at UH Waimanalo Station in late Spring '93 to evaluate horticultural traits of several Peto Seed tomato lines resistant to TSWV as compared to 'Celebrity', the industry standard but susceptible to this important viral disease. Also tested were 'Healani' and old UH cultivar popular locally because of its flavor as well as two large fruited cultivars from the continental U.S.

Seeds were sown on 12 February 1993 in the Magoon Greenhouse and seedlings transplanted in the field on 11 March. Spacing was 6 feet between rows and 4 ft between plants (density of about 1,815 plants per acre). Cultivar plots were 30 feet long and were replicated 4 times arranged in the field in a completely randomized design. The crop was drip irrigated as needed and received two split applications of 750 lbs/Acre of 10-20-20. Soil analysis conducted before planting determined a soil pH of 6.2, and electric conductivity of EC=0.089 mmo/cm, organic matter content= 0.18% and nutrient levels of P=424, K=865, Ca=5060 and Mg=1520 ppm. Three weekly harvests were conducted on 19 May, 26 May, and on 3 June. Fruit was picked at the pink-turning stage and graded as follows: 1) Grade A; 2) Grade B plus off-grade; and 3) Unmarketable. To obtain an estimate on foliage growth plant height and canopy diameter were determined about 35 days after transplanting (Table 2). To obtain an estimate of postharvest shelf-life a representative sample of 3 Grade A fruits were kept per cultivar at room temperature for 7 days for determination of fruit diameter, percent sugar contents, and firmness (Table 2). All cultivars tested were determinate or semi-determinate.

Table 1. Yields and fruit number per plant for tomato cultivars in Waimanalo Station, Spring 1993.

Cultivar Name Fruit No.Gr. A Fruit Wt. Gr. A (lbs) Fruit No. Gr. B& Off Fruit Wt. Gr. B& Off (lbs) Fruit Wt. (Total) (lbs) % Grade A (by wt.)
P-55789 25.7 9.8 7.8 2.2 13.2 67.1
P-55689 24.2 9.8 10.8 3.0 14.5 58.2
P-55389 23.59 9.5 8.9 2.6 13.6 60.8
P-56289 17.81 8.1 4.25 1.92 11.0 69.9
P-55289 20.9 9.2 6.9 2.1 13.1 63.7
Pik-Rite 18.6 9.2 3.5 1.2 13.3 66.4
Celebrity 22.3 9.1 5.7 1.7 13.2 56.7
Flavor #500 25.9 11.1 5.0 1.7 14.4 66.2
Healani 0.75 0.03 67.1 12.5 13.3 0.02
Significance ** ** ** ** NS **

Seed Sources: P-lines= PetoSeed; Pik-Rite= Harris-Moran; Celebrity= PetoSeed; Sumer Flavor= Abbott; Healani= Univ. Hawaii. All variables were significant at the 0.05 level except total weight (no significance detected on total fruit weight, marketable plus unmarketable, on cultivars tested).

Table 2. Plant height, plant width, estimated canopy "volume", fruit diameter, fruit % sugar content and fruit firmness of tomatoes grown in Waimanalo, Spring '93.

Cultivar Plant Height (cm) Plant width (cm) Plant canopy volume (cm3) Fruit diameter (inch) Sugar Content (%) Fruit Firmness (kg/cm2)
P-55789 47.6 58.79 129,293 3.2 3.7 4.4
P-55689 45.7 66.5 158,487 2.9 3.7 7.8
P-55389 47.0 61.4 138,881 3.1 3.6 4.7
P-56289 44.2 52 93,880      
P-55289 44.5 60.5 128,200 3.5 3.1 4.1
Pik-Rite 44.2 61.0 129,300 3.6 3.8 2.7
Celebrity 50.2 57.2 129,144 3.5 2.4 2.7
Flavor #500 46.6 61.5 138,445 3 4.0 2.4
Healani 43.6 58.7 117,579 2.5 3.8 1.9

Note: All variables significant at the 0.05 level. Plant dimensions (height and width) determined 35 days after transplanting. Plant canopy "volume" estimated using the volume formula for a cylinder based on height and width determinations. For fruit determinations (sugar content and firmness) plants were left at room temperature for 7 days after picking before measurements were taken to get an estimate of shelf-life. Firmness was determined with a penetrometer. Fruit diameter is based on diameter of a standard Grade A fruit within the cultivar tested.

All PetoSeed TSWV lines yielded similarly to the TSWV-susceptible industry standard 'Celebrity' under the low-elevation conditions found in Waimanalo. The other mainland cultivars 'Pik-Rite' and 'Spring-Flavor #500' also yielded similarly or better but showed TSWV susceptibility even though the field suffered little disease pressure from spotted wilt. Both of these cultivars produced large fruit (see table 1) of about 0.5 lbs each for Grade A and diameter > 3 inches (Table 2). 'Healani' was very prolific, producing mostly Grade B sized fruits which would make more of an ideal crop for home-garden use. Top growth also was similar between the cultivars tested. The calculated index of canopy 'volume' (Table 2) was found to be linearly correlated to total fruit fresh weight (Y= 16,028.78X - 83,759.27; R2= 0.84, P<0.001). Sugar content was higher for the newer PetoSeed lines than for Celebrity but the sample numbers were small so this data should be treated with caution. Firmness, an indication of how well the fruit will sustain shipping and increased shelf life was also greater for the newer PetoSeed lines as compared to Celebrity. Healani matured very quickly which was observed by rapid ripening under room temperature and by the rapid decline in fruit firmness after harvest (Table 2), once again indicating that it would be a better crop for home-gardeners. Problems in the field included tomato pinworm early in the season and leafminers and sweetpotato whitefly later in the season. Early leafminer populations were especially high on plants of 'Peto-55689', 'Celebrity', and 'Healani'. Radial cracking was only a problem initially but decreased after irrigation frequency was increased. On-farm trials conducted by Randy Hamasaki in 1992 and 1993 in Oahu have corroborated the comparable or greater productivity of the newer PetoSeed lines to yields obtained with other standard cultivars under low elevations in Hawaii.

Crop Value
Retail prices at time of these harvests (late May to early June) were about $2/lb for Grade A tomatoes and about $1.50/lb for off-grade tomatoes. Retail sales per plant for the 3 harvests in late May and early June would thus have been >$20 per plant (about $40,000 per acre retail value from 3 picks). Honolulu wholesale values for tomatoes on 2 June 1993 were about $1 for Hilo greenhouse tomatoes and a range of $1-1.40/lb for extra-large fruit from California ($0.90-1.20 for medium-sized fruit).


By: Hector Valenzuela, Randy Hamasaki, and Joe DeFrank
HITAHR, University of Hawaii at Manoa

Introduction and Methods
An eggplant cultivar trial was conducted at UH Waimanalo Station in late Spring '93 to evaluate horticultural characteristics of several long-type of pickle-type eggplants to UH-lines grown locally. Seeds were sown in the Magoon Greenhouse on 12 February and transplanted at the UH Waimanalo Research Station on 24 March. Spacing was 5 ft between rows and 4 ft between plants for an estimated population of 2,178 plants per acre. A 3 ft 'weed-mat' was placed in the rows prior to transplanting. A 7 gr slow-release fertilizer pellet (14-3-3 with micronutrients) was placed by the root systems at planting time. Cultivar plots were 25 ft long and replicated four times in the field arranged in a completely randomized design. The crop was drip irrigated as needed and received two split applications of 750 lbs/Acre of 10-20-20. Soil analysis conducted before planting determined a soil pH of 6.2, and electric conductivity of EC=0.089 mmo/cm, organic matter content= 0.18% and nutrient levels of P=424, K=865, Ca=5060 and Mg=1520 ppm. Three weekly harvests were conducted on 19 May, 25 May, and on 2 June. Picked fruit was divided as 1) Grade A; 2) Grade B plus off-grade; and 3) Un-marketable, numbered and fresh weight was determined.

Table 3. Yields and fruit number per plant for eggplant cultivars in Waimanalo Station, Spring 1993.

Cultivar Name Fruit No.Gr. A Fruit Wt. Gr. A (lbs) Fruit No. Gr. B& Off Fruit Wt. Gr. B& Off (lbs) Fruit Wt. (Total) (lbs) % Grade A (by wt.)
Long (Japanese) Type            
Green type 6.8 3.1 4.3 1.6 5.4 49.7
Nitta X            
Waimanalo 7.1 2.7 1.9 0.76 3.8 68.5
Farmers Long 9.3 1.9 7.3 1.4 3.7 45.2
Nitta 5.7 2.3 1.4 0.95 3.5 58.6
Oval/Pickling Type            
Millionaire 10.2 4.0 4.5 1.4 6.8 53.7
Sanshi Long 8.2 3.2 4.5 1.4 6.2 50.7
Nun-0679 10.1 4.5 1.9 .63 5.2 84.1
Black Shine 9.5 3.6 7.0 2.1 7.1 51.5
Suzukuro 9.3 3.6 6.4 1.7 6.9 48.6
Significance NS NS ** NS ** **

Seed Sources: Sanshi Long= Johnny's; Farmers Long= Know-you; Suzukuro= Kyowa; Black Shine and Millionaire= Takii; Nunhems-0679= Nunhems; Nitta x Waimanala and Nitta= UH and Green Type= UH. Significance at 0.05 level detected for Grade B fruit No., Total fruit weight (marketable plus unmarketable) and for Percent No. .

Table 4. Plant height, plant width, estimated canopy "volume", fruit diameter, fruit length and fruit firmness of tomatoes grown in Waimanalo, Spring '93.

Cultivar Plant Height (cm) Plant width (cm) Plant canopy volume (cm3) Fruit diameter (inch) Fruit Length (inch) Fruit Firmness (kg/cm2)
Long (Japanese) Type            
Green Type 24.3 49.85 48,389 2.2 14.2 1.8
Nitta X            
Waimanalo 21.0 43.0 30,572 2.1 12.5 2.2
Farmers Long 16.2 44 24,635 1.2 10.9 1.9
Nitta 22.6 53.0 50,007 2.0 10.7 2.2
Oval/Pickling Type            
Millionaire 31.8 42.6 45,387 2.1 9.0 2.7
Sanshi Long 29.8 40.85 39,042 2.3 8.1 2.6
Nun-0679 27.9 48.67 51,928 2.7 7.4 2.4
Black Shine 34.2 47.6 60,938 2.2 8.0 2.9
Suzukuro 32.9 47.2 57,706 2.3 6.7 2.8
Significance ** ** NA NA NA **

Note: Plant dimensions (height and width) determined 30 days after transplanting. Plant canopy "volume" estimated using the volume formula for a cylinder based on height and width determinations. For fruit determinations (firmness) 3 to 4 fruits per cultivar were left at room temperature for 5 days after picking before measurements were taken to get an estimate of shelf-life. Firmness was determined with a penetrometer, 3 determinations per fruit for a total of 9 to 12 total determinations per cultivar. Fruit dimensions are based on means of 3-4 representative Grade A fruits for the cultivar tested.

In Hawaii consumers prefer long eggplants > 10 inches. Of the cultivars tested none were superior to the Nitta line of eggplants in terms of fruit size. The green type has not yet been accepted in the market, because of the color, but its total fruit yields were greater than the Nitta line eggplants. Both the Green eggplant and Farmer longs had a high percentage of either Grade B or Unmarketable compared to the Nitta line eggplants. The Green type eggplant was susceptible to an unidentified fruit rot. Farmers Long, however, fruited earlier than the other long eggplants, was quite prolific and the fruits were skinny, long (>10 in) and an attractive bright purple which may be of use to chefs or to decorate salad bars. The oval/pickling type eggplants were quite early (Suzukuro, Black Shine, Millionaire), were more productive than the long-type eggplants in terms of fruit number (average number of Grade A of 9.4 vs 7.2 for long-type eggplant) and weight (average weight per plant of 3.7 lbs vs 2.5 lbs/plant for long-type eggplant). The oval types will be the eggplants of choice for those looking for a "meaty" type of eggplant in their cooking such as in breakfast, baked or in some barbecued dishes. The oval type of eggplants, however, were more susceptible to leafminer, tomato pinworm, and thrips attack than either the Green type of Nitta line eggplants. As a result with the exception of Nun-0679 the average percent of Grade A fruits for the oval type eggplants was 51.1% compared to 63.5% for the Nitta line of eggplants. Nun-0679 was especially prolific and the fruits were large (0.4 lbs/fruit, with a surprising 84% of fruits being recorded as Grade A, see Table 4), meaty, and had a dark shiny black skin. One of the four Nun-0679 plots, however, resulted in complete plant death, perhaps due to Bacterial Wilt. Cultivars which showed an incidence for fruit scars included 'Suzukuro', 'Millionaire' and 'Sanshi Long.' Eggplant fruits deteriorated a lot faster than the tomato fruits when harvested in concurrent experiments and left at room temperature after harvest. Overall the oval/pickling type eggplants tended to have a greater fruit firmness than the long-type eggplants (a mean value of 2.0 kg/cm2 for long-types compared to 2.7 kg/cm2 for the oval types). Like with the tomato trials a similar but less significant linear correlation was found between canopy "volume" (table 4) and total fruit fresh weight (table 3) (Y= 4.46-7.65x10-6X, R2=0.40, P<0.10). The cultivars with the highest canopy 'volume' (Black Shine and Suzukuro) also had the greatest fruit fresh weights, while the ones with the smallest volume (Farmer's long) also had within the smallest yield-range. Would canopy 'volume' be an efficient index to identify high yielding improving Solanaceous lines for breeders?

Crop Value
Retail prices at time of these harvests (late May to early June) were about $3.40/lb for Grade A eggplants and about $1/lb for off-grade eggplants (sold in 1.5 lb plastic bags). Retail sales per plant for the 3 harvests in late Spring would thus have ranged from $9-$10 for the Nitta line, and from $12-$15 per plant for the oval-type eggplants (overall range of $19,000 to $33,000 retail value per acre). Honolulu wholesale values for eggplants on 2 June 1993 were $1.15-1.25/ lb for Hilo- and Kauai-grown long types (with steady to heavy supply including from Oahu) and $0.75-1.10 for Maui-grown round-type eggplants (with lower to moderate supplies).

By: Steven Fukuda and Hector Valenzuela
HITAHR, University of Hawaii

Introduction and Methods
A bell pepper cultivar trial was conducted by Steve Fukuda during 1992 to identify productive cultivars for Oahu vegetable growers. Three week-old seedlings were transplanted to the field on 4 December 1991. Planting distance was 5 ft between rows and 1.5 ft between plants (for a population of 5,808 plants per acre). Plots consisted of 20 plants per cultivar replicated 3 times. The plants were side-dressed every 3 weeks with a complete 16-16-16 fertilizer. The plots were harvested 28 times for 5 months beginning 27 January until 25 June. Number of harvests per month were Jan.= 1; Feb.= 8; Mar.= 6; Apr. = 5; May= 4; and Jun.= 4.

Results and Discussion
Cultivars which outperformed others included those which produced > 11 Grade A fruits per plant, > 3 lbs of Grade A fruit per plant; and > 4.6 lbs of marketable fruit per plant. These indices amount to >63,000 fruit Grade A/Acre, and > 23,000 lbs/Acre of marketable fruit. The most outstanding cultivars in this trials were Orobelle, Verdel, Zohar, Bell Tower and Zerto (Table 5). In addition Galaxy had excellent fruit quality. Out of this trials in Poamoho, Ted Hori, County Extension agent for Maui selected several cultivars for trial in Kula, Maui during late Spring and Summer 1993 to test for resistance to tomato spotted wilt virus. Even though little TSWV resistance was experienced in Kula, all varieties were shown to be susceptible to TSWV under controlled greenhouse conditions. In the field Bell Tower, Cal Wonder, and Galaxy showed no symptoms to TSWV even after the 7th week of harvest. However pepper weevil damage was the main pest of the peppers in Kula. The most productive cultivars in Kula were Whopper Improved (2.5 fruits per plant produced and 1.02 lbs of fruit/plant), Zohar (3.5 fruits per plant and 0.74 lbs/plant), and Carlos (2.5 fruits/plant and 0.97 lbs/plant). The largest fruits in Kula were produced by Whooper Improved (0.41 lbs/fruit), Carlos (0.38 lbs/fruit) and by Galaxy and Verdel (0.35 lbs/fruit). A pepper trial was also run by Steve Fukuda at the UH Waimanalo Research Station but crop failure resulted primarily due to Phytophtora infestation in the soil.

Table 5. Fruit Number and Yields per plant for bell pepper cultivars in University of Hawaii Poamoho Experiment Station (The Seed Source follows the Cultivar Name).

Cultivar Name Fruit No. Gr. A Fruit No. Gr. B Fruit No. Off-Gr. Total No. Marketable
Fruit Wt. Gr. A (lbs/plt) Fruit Wt. Gr. B (lbs/plt) Fruit Wt. Off-Gr. (lbs/plt) Total Wt. Marketable (lbs/plt) Wt./Fruit Gr. A (lbs/fruit)
Orobel (4,3) 12.88 11.48 3.08 27.44 4.20 2.94 0.60 7.74 0.33
Verdel (1) 13.02 7.42 2.94 23.38 3.92 1.68 0.49 6.09 0.30
14.14 11.20 4.20 29.54 2.94 1.68 0.38 5.00 0.21
Bell Tower 1,4 12.88 7.14 3.78 23.80 3.64 1.40 0.52 5.56 0.28
12.18 5.18 1.96 19.32 3.64 1.23 0.43 5.31 0.30
10.22 7.14 4.06 21.42 2.80 1.40 0.64 4.84 0.27
Bomby (1) 10.50 6.30 2.80 19.60 3.08 1.40 0.50 4.98 0.29
Carlos (6) 11.48 4.20 2.10 17.78 3.36 0.87 0.45 4.68 0.29
Galaxy (1,4) 13.30 4.62 1.68 19.60 4.20 1.15 0.36 5.71 0.32
Maor (9), OP 12.60 5.60 2.38 20.58 3.36 1.15 0.32 4.83 0.27
P1288 11.06 4.48 1.68 17.22 3.64 1.16 0.29 5.10 0.33
P3187 13.86 5.32 1.68 20.86 4.20 1.08 0.32 5.60 0.30
7.00 5.88 5.32 18.20 2.10 1.23 0.80 4.13 0.30
Tenno 10.64 4.76 2.24 17.64 3.22 1.05 0.45 4.72 0.30
Cadice 5.46 2.24 0.98 8.68 1.40 0.45 1.40 3.25 0.26
3.64 2.24 0.85 6.73 0.97 0.45 0.14 1.55 0.27
Elisa (4) 10.08 3.78 1.68 15.54 3.22 0.94 0.34 4.49 0.32
Florida VR2,5 9.24 6.16 3.64 19.04 2.52 1.36 0.57 4.45 0.27
N8510 9.94 4.06 1.54 15.54 2.94 0.97 0.27 4.17 0.30
4.20 1.82 0.70 6.72 1.34 0.41 0.14 1.89 0.32
Superset 4.20 1.82 1.16 7.18 1.11 0.29 0.17 1.57 0.26
Super Sw (1) 8.68 6.30 2.10 17.08 2.66 1.40 0.38 4.44 0.31
Valley Giant 2.66 2.94 1.82 7.42 0.83 0.70 0.29 1.82 0.31
Vidi (3,7) 9.80 3.78 2.10 15.68 3.36 0.83 0.41 4.59 0.34
Whopp Imp. 4 4.34 1.82 0.55 6.71 1.54 0.39 0.14 2.07 0.35

Seed Sources: 1. Abbott; 2. Asgrow; 3; Green Barn; 4. Rogers NK; 5. SunSeed; 6. Nunhems; 7. Vilmorin;
8. Siegers; 9. Hazera

Hybrid Bell Pepper Cultivar Descriptions.
_ Orobelle (Rogers NK, Green Barn) is a strong, vigorous plant with excellent coverage with maturity at 70-74 days. It is a high yielding, early yellow variety. Fruit has four lobes and has 4.5 by 4.25 inch dimensions.
_ Jupiter (Rogers NK, Harris) was not tested in this trials but is an OP variety which is grown from the Carolinas, to Florida to the Imperial Valley in California, and it does well in Molokai as well. It has high yields and produces large, blocky fruit of 4.5 by 4.25 inch, with maturity of 74-78 days.
_ Verdel (Abbott) produces consistent high yields of 4-lobed dark green blocky fruits sized 4 by 3.5 inches, maturing in about 78 days. Produces a vigorous foliage.
_ Zohar (Hazera) produces a yellowish-green turning light green fruit. It has excellent fruit setting even under hot conditions, adapted to long harvesting seasons. The conical shaped 3-lobed fruit has a thin fruit wall and has PVY resistance. Matures in 60-65 days. Fruit dimensions are 4.25 by 2.25 inches.
_ Bell Tower (Rogers NK, Abbott) produces large, deep-blocky fruit sized 3.75 by 4 inches with maturity of 74-76 days. It is high yielding and has a wide adaptability. Adapted to cool-growing conditions.
_ Zerto (Nunhems) is adapted to both greenhouse and field growing conditions. It is an early variety which turns red on ripening. Produces short blocky fruits and the plant has a vigorous growth.
_ Zico (Nunhems) is adapted to both greenhouse and field growing conditions, the fruits turn red on ripening, and it has higher than average adaptability to growing conditions. Resistant to PVY.
_ Galaxy (Rogers, Abbott) is a vigorous plant which yields large 4.75 by 4 inch thick-walled, deep green fruit early and throughout the growing cycle. Matures in 74-78 days and is adapted to cool growing conditions.

Industry Contributors:

Seed Sources

Abbott & Cobb, Inc.
POB F307
Feasterville, PA 19053-0307

Champion Seed (includes PetoSeed and Rogers NK)
529 Mercury Lane
Brea, CA 92621

Green Barn Seed Co. Inc.
18855 Park Ave.
Wayzata, MN 55391

Johnny's Selected Seeds
Foss Hill Rd.
Albion Maine 04910

Known-you seed Co., Ltd.
26, Chung Cheng 2nd Road

Kyowa Seed Co., Ltd
15-13 Nanpeidai
Tokyo, Japan

Nunhems Seeds Corp.
P. O. Box 18
Lewisville, Idaho 83431

Harris Moran Seed Co.
POB 3091
Modesto CA 95353

Hazera Seed Limited
POB 1565
Haifa, Israel

Nunhems Seeds Corp.
P. O. Box 18
Lewisville, Idaho 83431

Rogers NK (Northrup & King)
POB 4188
Boise, ID 83711

Siegers Seed Co.
8265 Felch St.
Zeeland, MI 49464

Sunseeds Genetics, Inc.
P. O. Box 1480
2320 Technology Parkway
Hollister, CA 95024-1480

American Takii, Inc.
301 Natividad Rd
Salinas, CA 93906

Vilmorin, Inc.
6104 Yorkshire Ter.
Bethedesa, Maryland 20814

By: Hector Valenzuela and Ron Mau
HITAHR, University of Hawaii

Based on initial discussions with commercial cabbage growers four standard head cabbage cultivars were selected to evaluate their tolerance to diamondback moth attack. These were Tastie (Rogers NK), Harvester Queen (Sakata), Pacifica (Sakata), and Scorpio (Sakata). The experiment was conducted in the Kula Agricultural Park plots managed by technicians from the University of Hawaii Kula Experiment Station. One-month old seedlings provided by commercial growers were transplanted on 2 July 1993. Plot size per cultivar was 40 feet by 6 feet (4 rows spaced 2 ft each). Each plot (replication) per cultivar was replicated four times. Cultural practices were followed as recommended for commercial head cabbage production. Insect counts were conducted on 16 and 27 July and on 12 August, 1993. Procedure for insect number determinations was destructive harvest of 6 randomly selected plants per plot (border rows) and determination of: damage index assessment; egg number; larvae instar 1-4 number; pupae number; incidence of thrips, spiders, and imported cabbage worm; and parasitized pupae number. The damage index assessment consisted of 0= no damage; 1= very light, not very noticeable; 2= moderate; 3= heavy; and 4= severe, only veins on many of the leaves. On 8 August leaf samples were also collected for Nitrogen content determinations. The plants were harvested on 27th August and fresh weight of top growth as well as head fresh weight were determined at that time. A field day was conducted on 27 August to have the commercial growers evaluate for themselves the experimental results. Individual growers also visited the research plot throughout the experimental period.

Results and Discussion
As indicated in Table 6 and Figure 1, a tolerance range to the diamondback moth was detected among the 4 cultivars tested. The cultivar 'Harvester Queen' had the overall highest larvae number, foliage damage index, and incidence of imported cabbage worm. At the lowest spectrum the cultivar Scorpio had the lowest mean larvae number, lowest damage index, and the highest harvest index among all the cultivars tested. The cultivar 'Tastie' which is preferred by growers and wholesalers alike had a higher caterpillar number than 'Scorpio' but a lower number than 'Harvester Queen (Table 6, Figure 1).' It would therefore not be recommended that 'Harvester Queen' be grown in areas with high diamondback moth pressure. During the summer months were DBM pressure is highest in Kula it is recommended that growers grow cultivars such as 'Scorpio' with a higher tolerance than the other cultivars. During the winter and spring months when DBM pressure may not be as high, growers may be able to grow 'Tastie', the cultivar mostly preferred by growers and in the marketplace. Nitrogen tissue content between cultivars does not appear to have been a determining factor for DBM attack in this experiment. Nitrogen tissue content for Scorpio was 5.2% and for Tastie it was 5.3%. This experiment shows that diamondback moth populations in Hawaii show feeding preference under field situations among plants of the cabbage family.

Farmer Participation
Growers representing >80% of the cabbage acreage in the Kula area participated in the planning stages of this trial as well as in the evaluation stages during the field day on the final day of the trial. This trial also formed part of a diamondback moth workshop held in Kula by Dr. Ron Mau in which growers also learned about other important management tools for control of this important pest. For the 1993 Summer season many cabbage growers were already planting the more tolerant cultivar 'Scorpio' taking in consideration the high population levels of DBM expected at that time of the year.

Table 6. Effect of four head cabbage cultivars on mean incidence of diamondback moth numbers and damage index assessment in Kula in late Summer 1992.

Cultivar DBM Larvae
Damage(0-5) ICW (%) Yield of Head
Head Weight (lbs) Harvest Index
Tastie 4.1 2.2 38 63913c 4.4 74
Pacifica 4.37 2.3 23 53791ab 3.7 68
Queen 5.68 2.93 62 58273bc 4 60
Scorpio 3.33 1.77 23 48296.4a 3.3 61
Significance ** ** ** ** ** **

Damage Index, 0= no damage, and 5= maximum damage
ICW= imported cabbage worm, percent of plants which had ICW.
Yield of both marketable and unmarketable heads.
Significance-- ** = significant at 0.05 level


By: Hector Valenzuela and Dwight Sato

Summer 1993 Trials
A Chinese cabbage cultivar trial was conducted at the UH Volcano Station in the Summer 1993. The station is located at 4000 ft elevation, has volcanic ash soils, 150 in median annual rainfall, and 50-60F temperature range. The soil is classified as an immature Hydrol Humic Latosol. The surface consists of relatively recent ash deposits (1886). Soil analysis prior to starting the experiment showed a soil pH of 5.9, organic carbon content of 5.14%, and soil solution with EC of 0.049 mmho/cm, P= 87 ppm, K= 67 ppm, Ca= 1160 ppm, and Mg= 276 pm. One month old seedlings were transplanted on 21 May, 1993. An earlier crop had to be replanted due to cutworm damage. Of the 20 varieties evaluated harvest data was collected only for the ones which developed heads. Five varieties, typically grown in temperate areas, bolted earlier and were not included in the analysis. Each replication consisted of two 9 foot rows replicated 4 times. Planting distance was 2 ft between rows and 1.5 ft in the row.

A SAS multiple comparisons statistical evaluation determined that the low yielding varieties (1.1-1.24 lbs/head) were China Express, WR-60, and WR Crusader. Mid yielding varieties (1.36-1.65 lbs/head) were WR-55, Tempest, Takatoh, Chorus, SCC-9206, China Flash, China Pride, Mini 1000, and Tango. The high yielding ones (1.76-1.92 lbs/head) were Blues, Shunkei, and Kasumi.

Local farmers in the Volcano area visited the experimental site on several occasions and identified the following varieties as having adequate growth and head shape: Takatoh, Chorus, WR-60, China Pride, SCC 9206, Shunkei, Blues, Kasumi, WR-55, China Flash, and Tango. A follow-up trial was thus established in late Dec. 1993 to evaluate the varieties preferred by local growers and to evaluate their growth during the winter (rainy) season.

Winter 1993 Trials
Six Chinese cabbage varieties were selected, based on preliminary Spring trials and on grower acceptance. These were Chorus, China Pride, SCC-9206, Takatoh, Tango, and WR-60. The crops were seeded on 3 Dec. transplanted on 28 Dec. 1993, and harvested on 8 Mar. 1994. Each plot consisted of two 20 ft. rows. Spacing was 2 ft between rows and 2 ft between plants. Each treatment was replicated three times. Fertilization, and pest control practices were followed as recommended for commercial production. Results are presented below.

Cultivar Yield (lbs/head)
Spring '93
Yield (lbs/head)
Winter '93
% Marketable
Tango 3.6a 4.7a 73
WR-60 2.5d 4.5ab 77
Chorus 3.1ab 4.3bc 77
China Pride 3.3ab 4.2bc 75
Takatoh 3.1abc 4.1bc 60
SCC-9206 3.2ab 4.1c 47

Means within a column with the same letter are not significantly different (P<0.05).

Tango had the greatest yields in both Summer and Winter trials (62,726 plants/Acre in Summer based on 17,424 plants per Acre, and 37,363 lbs/Acre in Winter based on 10,890 plant/Acre and 27% culls due to rotting in Winter). WR-60 was as productive as Tango in the Winter but was the least productive, among these varieties, in Summer trials. All varieties produced adequate yields in the Summer with the exception of WR-60, which had smaller heads. Both Takatoh and SCC-9206 had high rotting incidence in the Winter resulting in yields of 26,789 and 20,985 lbs/Acre, respectively, which indicates lower adaptability during the rainy/cooler months. Head weight was about 25% greater in the winter due to the cooler weather and the wider plant spacing (2 x 2 instead of 2 x 1.5 ft spacing). This trials indicate the potential for Chinese Cabbage production in the Volcano Area. Important production factors will be incidence of diamondback moth during the warmer summer months, and the greater incidence of foliar and root diseases in the winter months. Cultural practices such as plant spacing, fertilization, rotation, sanitation, and cultivar selection can be adapted to minimize potential crop losses due to pests and diseases for the production of cole crops in Volcano.

Industry Cooperators:
Thank-you to Sakata, Mikado, Kyowa, Stokes, Takii, and Know-You Seed Companies for providing seed samples.
Chemicals: United Horticultural Supplies, and HGP Inc. in Hilo.
We thank Mr. Gaillane Maehira and Volcano Station Staff for data collection and field plot maintenance.