The purpose of these experiments was to determine the effect of a commercial cytokinin preparation on yield and quality of several Willamette Valley horticultural crops. Atlantic and Pacific Research, Inc. manufactures a marine algae extract, containing 100 ppm kinetin, which has increased fruit and vegetable yields in several areas of the country and is registered for use on tomatoes. This product, Cytex, is stable and can be applied with standard spray equipment.
Methods
Five crops were involved in these trials which took place in 1979: 'Hood' strawberry, 'Russet Burbank' potato, 'Nantes' carrot, 'Summer Pascal' celery and 'Early Girl' tomato. All plots were laid out in randomized block design with three to six replications per treatment. All plots were on Willamette sandy loam, pH 5.6, three percent organic matter. Details for each crop are as follows:
Strawberry: A two-year-old planting of strawberries with three-foot x 1.25-foot spacing was used. Each plot consisted of a single 20-foot row and treatments were replicated six times. Treatments consisted of a control, one spray at 10 percent bloom (April 26) and a 10 percent bloom spray plus a second spray two weeks later. All sprays were at a rate of two quarts Cytex/ acre in 25 gallons/acre of solution. Data collected included total yield, marketable yield, and berry size from harvests on June 7 and June 18.
Potato: The crop was planted on May 8. Plot size was 20 row feet with four replicates per treatment. In-row spacing was 1.5 feet and 100 percent stand was obtained. The four treatments included a control, one spray at early bloom, one spray at the first sign of foliar dehiscence, and a combination of both sprays. All sprays were at two quarts/acre. Data collected included gross yield, number of tubers, and percentage by grade. All plots were harvested on September 27.
Carrots: The crop was planted on May 11. Plot size was three 10-foot rows with five replicates per treatment. Between-row spacing was 20 inches. The three treatments included a control, application of a single spray at first sign of fleshy taproot formation, and a single spray three weeks later. All sprays were at two quarts/acre. Data obtained included total yield and yield by grade.
Celery: The crop was seeded in flats in a glasshouse on March 19 and transplanted to the field on May 16. Plot size was 10 row feet, in-row spacing was six inches and there were five replicates per treatment. The three treatments were a control, single pre-transplant application at the four leaf stage, and a post-transplant application on May 21. Sprays were with 2.0 percent Cytex solution applied to runoff, approx. two quarts/acre. Data obtained included yield/plot and stalk length.
Tomato: The crop was seeded in a greenhouse on April 25 and transplanted on May 25. Plots consisted of two plants with three replications per treatment. Plants were grown on black plastic mulch with drip irrigation. Treatments were a control and a single spray of two quarts/acre at full bloom of the first cluster. Data obtained included gross yield, mean fruit size, percent blossom-end rot and percent misshapen fruit.
All crops were fertilized at a rate of 100 pounds/acre of total N at planting. The celery received an additional 100 pounds/acre N on July 7. The herbicide linuron at a rate of one pound/acre was used on potatoes and carrots. The other crops were hand weeded. All sprays were at total volume of 25 gallons/acre and applied with handheld equipment.
Results
Table 11. Effect of Cytex on Yield of Strawberry Total marketableZ Percent rotted Mean berry Treatment weight, tons/acre fruit size, grams/fruit Check 9.6 6.0 9.2 Single Applic. Cytex 8.6 5.7 9.0 Two Applic. Cytex 9.1 6.8 8.3 ZYield June 7 and 18 combined. Table 12. Effect of Cytex on Yield of Potato Treatment Gross yield Tubers per Tubers over (tons/acre) plot 5 inches, % Check 33.0 101 41 Early Bloom Spray 35.1 109 38 Late Spray 37.0 111 37 Both Sprays 33.0 115 35 Table 13. Effect of Cytex on Yield of Carrot Treatment Yield Mean root weight Grade No. 1Z (tons/acre) grams % Check 13.3 65 47 Early Spray 10.6 60 43 Late Spray 11.9 61 43 ZOver six inches length and without defects. Table 14. Effect of Cytex on Yield of Celery Treatment Yield Stalk length Yield (lb/plant) (inches/plant) (tons/acre) Check 0.65 16.3 13.5 Pre-Transplant Spray 0.67 16.5 13.8 Post-Transplant Spray 0.69 15.6 14.1 Table 15. Effect of Cytex on Yield of Tomato Gross yield Mean fruit Blossom-end Misshapen Treatment tons/acre size, pounds rot, % fruit, % Check 21.5 a 0.31 a 10 a 8 a Single Applic. 27.6 b 0.33 a 11 a 7 a
Out of five crops tested, Cytex significantly increased yield only for tomatoes. Lack of positive results for potato were expected as this confirms the lack of response of Russet Burbank potatoes in trials at other sites in North America. Positive results for carrots, strawberry, and celery have been reported by other researchers. Failure of Cytex to increase strawberry yields may be attributable to heavy rains within 24 hours of application. The major effect of Cytex on tomato was on number of fruit produced rather than on fruit size.