Containerized Strawberry Transplants as a Replacement for Methyl Bromide Soil Fumigation in California Strawberry Nurseries

Transcription

1 Containeried Strawberry Transplants as a Replacement for Methyl Bromide Soil Fumigation in California Strawberry Nurseries Final Report - September 2002 Principal Investigator: Kirk D. Larson Associate Pomologist and Associate CE Specialist, UC Davis Dept. of Pomology Siskiyou Resource Conservation District University of California South Coast R.E.C Irvine Blvd. Irvine, CA Phone: (949) Fax: (949) kdlarson@ucdavis.edu Co-Principal Investigator: Eliabeth E. Ponce Lassen Canyon Nursery, Inc Salmon Creek Rd. Redding, CA Phone: (530) Fax: (530) lcnci@snowcrest.net Cooperators: Douglas V. Shaw Department of Pomology, University of California, Davis Phone: (530) Fax: (530) Project Locations ( ): Lassen Canyon Nursery, 1300 Salmon Creek Rd, Redding, Shasta County, CA Lassen Canyon Nursery, Macdoel Ranch, Macdoel, Siskiyou County, California UC South Coast REC, 7601 Irvine Blvd., Irvine, Orange County, California UC Davis Pomology Department Wolfskill Experimental Orchards, Solano County, California UC Davis (Pomology Department) Watsonville Strawberry Research Facility, Santa Cru County, California. Commodity: Strawberry Funding: UC SAREP FUNDS MATCHING FUNDS $17,080 Calif. Strawberry Comm. $16,200 1

2 $35,089 Calif. Strawberry Comm. $28, $38,667 Calif. Strawberry Comm. $32,000 Total $90,836 Table of Contents: Objectives Summary Specific Results Potential Benefits/Impacts on Agriculture Dissemination of Findings Tables Objectives Annual plantings of pathogen-free strawberry transplants are the basis for high productivity and successful strawberry IPM programs in California, and the state produces more than 900 million strawberry transplants annually. In California, propagation of strawberry transplants for fruit production entails at least three field propagation cycles, with the final propagation phase conducted in high elevation (HE) nurseries in northeastern California. In this HE region, exposure to chilling temperatures (< 7 C) and short days in late summer and early fall results in transplants that produce greater yields, and larger fruit with better appearance scores compared to low elevation (non-conditioned) plants. To ensure production of pathogen- and nematode-free transplants, strawberry nurseries fumigate the soil prior to each propagation cycle with mixtures of methyl bromide (MB) and chloropicrin (CP). The impending ban on MB requires development of alternative technologies for strawberry transplant production. Compared to MBCP, alternative fumigants are more difficult to use and less effective in controlling soilborne pathogens, and crop rotations provide ineffective control of serious pests and pathogens in strawberry nurseries. The use of containeried transplants ("tray plants", "plug plants", or "plugs") produced in disease-free, soilless media has been suggested as an alternative to MB nursery soil fumigation, but information on plug propagation methods for California's unique production system is unavailable. In addition, because plugs are not widely used in California, information on plug productivity and fruit quality is also lacking. Research is needed to determine: 1) cost-effective methods for strawberry plug propagation, 2) appropriate methods for conditioning strawberry plugs to maximie fruit quality and yield, and 3) plug performance (yield, fruit quality) in the state's major strawberry production regions. Summary Containeried strawberry plants ("plugs") are readily produced without soil fumigation, but little information is available for optimiing plug plant production and performance under California 2

3 conditions. Although strawberry plug plants can be established with less irrigation water and enter into fruit production sooner than bare-root plants, plugs have relatively high production and transportation costs, and plug plants in California often produce a high proportion of off-grade (small and misshapen) fruit late in the season. This inferior quality fruit has low market value and high harvest labor costs. Our research has focused on developing protocols for producing high-quality strawberry plugs that have performance characteristics similar to, or better than, conventional (field-grown) nursery planting stock. By propagating runner tips at about two week intervals from mid-july to mid-august and using different container (cell) sies, we have been able to compare the effects of plug plant sie and plug physiological maturity on plug plant yield performance. To compare the effect of conditioning environment on yield performance, we propagated plug plants at a low elevation (LE) nursery site in Redding, Calif. in 1999 and 2000, and then conditioned a subset of these plugs at a high elevation (HE) nursery site (Macdoel, Calif.) for 3-4 weeks prior to transplanting. In the third year of trials, we propagated and conditioned plug plants at both HE and LE, thereby lengthening the HE conditioning period. Yield performance for all plant material then was assessed under commercial strawberry management systems typical of the farming practices in those regions. In our trials, the effects of cell sie and nursery environment on plug yield performance varied somewhat from year to year, but results demonstrated significant effects of rooting date, plug cell sie and nursery environment on early season (December-March) yield performance, and early and total season fruit quality (fruit sie and shape) in most years. Early rooting date (July), use of a large plug cell sie, and HE conditioning generally maximied early season yields compared to later rooting dates, smaller cell sie and LE conditioning. Compared to LE conditioning of plugs, HE conditioning also resulted in increased fruit sie and fruit appearance scores. Compared to conventional bare-root transplants, HE plugs generally produced greater early-season yields but had reduced fruit quality (i.e., reduced sie and appearance scores). However, in the third year of our investigations, propagation and conditioning of plugs at HE resulted in fruit quality equal to that of conventional transplants and yields that were superior to either conventional transplants or LE conditioned plugs. There was little or no difference in total yield (December-June) among bare-root plants and plugs in most years. Also during two years ( ), yield performance of plug plants vs. bare-root transplants was assessed in the Central Valley at the U.C. Davis Pomology Department's Wolfskill Experimental Orchards (WEO), in Winters. In both years, plug plants yielded less than conventional plants, and had significantly reduced fruit sie and fruit appearance scores. In additional trials conducted over a two-year period ( ), yield performances of plug and bareroot transplants were evaluated in fumigated and nonfumigated soil in Irvine. In the production season, plants established in fumigated soil outyielded plants in nonfumigated soil, and there was no effect of plant type (plug vs. bare root) on yield, and no interaction between soil treatment and plant type. In the production season, an identical trial was established on a site that had been cropped only in barley during the previous 20 years. For this trial, both plug plant and bare-root plant yields were identical, and there was no effect of soil fumigation. Specific Results There are three objectives to the research conducted: 1) develop suitable methods for propagating strawberry plug plants under California conditions; 2) determine suitable methods for conditioning (temperature and photoperiod conditioning) plug plants prior to transplanting in fruit production fields; 3) determine plug plant yield performance (early season and total season yield, early and total marketable yields, fruit sie, and fruit appearance scores) in various production environments in 3

4 California. Objectives # 1 and #3: Develop suitable methods and protocols for strawberry plug plant propagation in California; specifically, determine the effect of rooting date and propagation cell sie on subsequent yield performance. Propagation of containeried strawberry plants ("plugs") entails removing runner "tips" from the "mother" plant and rooting them under intermittent misting. In our trials, runner tips were rooted in a peat-vermiculite based potting media (Scott's-Sierra Premium Professional Potting Mix, Scott, Inc., Marysville, Ohio). Runner tip rooting date. Previous research demonstrated that strawberry runner plant rooting date affects subsequent yield after transplant to fruiting fields (K.D. Larson, unpublished data, 1993). For this reason, we considered it necessary to examine the effects of plug plant rooting date on yield performance. We did this by harvesting runner tips from mother plants and propagating plugs at about 14-day intervals from early August to mid-august in 1999 and We observed significant effects of rooting date on plug performance in both years. In , plugs rooted on August had greater early season (December - March) yield and early season marketable yield than plugs rooted two weeks later (Tables 1-3). In , rooting date affected fruit sie, with plugs rooted on August 2 having larger fruit than plugs rooted on August 16 (Tables 4, 5). However, we observed no effect of rooting date on yield in the second year. Due to the difficulty in obtaining sufficient numbers of strawberry runner tips before mid-august, and due to the variable effect of runner tip rooting date across the two years of our study, we concluded that additional studies on the effect of runner tip rooting date not a priority, and we therefore terminated this line of research in Plug plant cell sie. Previous research demonstrated that strawberry runner plant sie affects fruit yield (K.D. Larson, unpublished data, 1993). Based on these previous observations, we wanted to examine the effects of plug plant sie on yield performance. We created plug plants of various sies by propagating runner tips in trays molded into different plug cell sies. We use two different cell sies in all three trial years: a standard strawberry plug tray (Cooks Garden, Hodges, SC 29653) containing 50 round-conic cells, with individual cells measuring 5 cm wide x 6 cm deep (referred to as "#1 plugs"), and larger, round-conic cells measuring 5.5 cm wide x 11 cm deep with 36 cells per tray ("#2 plugs"). In addition to these two cell sies, we used large square cells (8 cm wide x 8 cm deep) (#3 plugs) to propagate plugs in There were significant effects of cell sie on early season yields in both and production seasons, with plants produced in larger cells outperforming plugs produced in smaller cells (Tables 6-8). In addition, in , large plugs had greater total yield than smaller plugs, and in 2002, large plugs had greater total season marketable yield than smaller plugs (Table 9). However, propagation of large plugs requires considerably more resources (propagation space, potting media) than smaller plugs. Perhaps more importantly, the cost of transporting and planting large plugs, which may be four times larger and weigh 4-6 times more than the smaller plugs, could be prohibitive. Despite the benefits that consistently accrued from use of large plug plants, we consider that use of large plugs is probably not cost-effective. Objectives #2 and #3. Based on yield performance in fruiting fields, determine suitable methods for conditioning (temperature and photoperiod conditioning) plug plants prior to transplanting in fruit 4

5 production fields. For all of our plug trials, runner tips were cut from mother plants, then planted immediately in trays in potting media. Trays were placed in a screenhouse immediately after planting and subjected to intermittent, overhead misting during a 3-week period. Regardless of cell sie or planting date, all plugs had well-developed root systems within two weeks after runner tip planting. Three weeks after tip cutting, rooted plugs were transferred to different environments where they were exposed to natural or artificial temperature and daylength conditioning treatments during a 3-6 week period. Plug plant conditioning and yield performance. In 1999, newly-rooted, 3-week old plugs were transferred to three conditioning environments on September 7: 1) outdoor (ambient temperature and light) conditioning at low elevation in Redding California; 2) ambient daytime conditions as in environment #1, but with a 15-hour night period at 5 C achieved by placing the plugs in a walk-in cooler each day at 4:00 p.m.; 3) exposure to ambient conditions at a high-elevation nursery site in Macdoel, California (41.8 N, elevation 1,200 m). Plugs were maintained in these environments until September 28, when they were transported to Irvine and established in fruit production trials. Plugs conditioned at high elevation had greater early season yields and fruit appearance scores than plugs conditioned at LE, whereas artificially conditioned plugs had an intermediate yield and appearance response (Table 10). The impracticality of moving plugs from an ambient to an artificial environment on a daily basis during a 3-week period precluded continued examination of artificial conditioning methods for plug plants, and this treatment was discontinued after Also, the significant enhancements in yield and fruit quality obtained by conditioning plugs in a natural HE environment prompted us to focus our efforts on the use of a high elevation nursery site for conditioning plugs rather than artificial methods. In 2000, newly-rooted plugs were transferred to the HE nursery site in Macdoel, California or were maintained in Redding, California to undergo conditioning under ambient conditions. After about one month of conditioning, plugs were transplanted into yield performance trials in Irvine. High-elevation conditioning resulted in greater early-season and total season yields, and early-season and total season fruit sie compared to plugs conditioned at LE (Table 11). Recogniing that transport of newly-rooted plugs to HE conditioning site would be impractical on a commercial scale, we resolved to propagate plugs at both HE and LE sites. For propagating runner tips under mist, we established a small metal-framed structure and covered it with clear polyethylene; later, after plugs were completely rooted, this same structure was left open at both and served as the HE conditioning site. After six weeks of propagation and conditioning, plugs from both HE and LE sites were transported to Irvine and established in yield performance trials. Compared to LE conditioned plugs, HE conditioning resulted in greater early-season yields, and larger fruit with better appearance scores (Table 12). Compared to LE conditioning, HE propagation and conditioning also resulted in greater total yields, and larger fruit with better appearance scores (Table 13). Performance of plug plants compared to bare-root transplants, The information presented above was derived from comparative studies that examined the effects of plug rooting date, cell sie and nursery conditioning environment on plug plant performance. Our trials demonstrated significant differences between HE and LE plugs; differences among plugs due to cell sie and tip rooting date were also observed. While these studies are useful for developing protocols and methodology for propagating high-quality plug plants, ultimately, plug performance must be compared with that of bare-root transplants, which is the present day standard planting material. Yield performance comparisons of plugs and bare-root transplants were made in each of the three years of investigations. Plug plants, and in particular, plug plants conditioned and/or propagated at high 5

6 elevation, usually produced greater early season yield than bare-root transplants (Tables 14, 16, 18), but often had inferior fruit appearance scores. However, for the trial, HE plugs had the highest early season appearance scores, LE plugs had the lowest scores, and bare-root transplants had intermediate scores (Table 18). For the and trials, there was little difference in total yield between plugs and bare-root transplants (Tables 15, 17), but bare-root plants generally had the highest fruit appearance scores; only a few of the HE plug treatments had fruit appearance scores similar to those of the bare-root plants. In the trial, plugs had greater total season yields than bare-root plants, but only the small HE plugs had greater total marketable yields than bare-root plants (Table 19). Also, for this trial, there was no difference between bare-root plants and HE plugs in regard to fruit sie and fruit appearance scores, but LE plugs had reduced sie and appearance scores compared to bare-root plants (Table 19). Early season yield is an important consideration for fruit growers in southern California, since early season (December-March) fruit commands relatively high prices in the marketplace: market prices are high because fruit production is limited. It is important to recognie that the use of plug plants by a large portion of the industry will result in increased early season production and lower early season fruit prices; the point at which market saturation occurs and prices drop is unclear, but the early season market is limited. The previous sections summarie the performance trials conducted in Irvine to assess the effects of propagation methodology and plug plant conditioning environment. Additional trials were conducted to assess plug plant performance in the Central Valley (Winters) and the Central Coast (Watsonville) regions. Results of trials in these regions are presented below. Central Valley Fruiting Field Performance Trials, Trials were conducted in and in to compare performance of strawberry plugs with that of bare-root transplants in the Central Valley region of California. For both trials, plantings were established using plug plants that had not been exposed to any artificial temperature or photoperiod conditioning. For the trial, 80 #1 plugs were established at the Department of Pomology Wolfskill Experimental Orchard (WEO) near Winters, California on August 13. On September 7, 2000, 80 #1 plugs were transported to the U.C. Davis Department of Pomology Wolfskill Experimental Orchard (WEO) near Winters, California and planted on 2-row raised beds in four replicate plots of 20 plants each. Plug plots were established adjacent to plots of Camarosa plants that had been planted on August 11 using cold-stored, bare-root plants, and following U.C. recommendations for commercial strawberry production in the Central Valley. Visual observation indicated that plug vegetative growth was greater (i.e., more crown development) than that of conventional (bare-root) plants, and that plug plants over-wintered well. Fruit were harvested weekly from April 13 to May 31, Compared to conventional plant material, plugs produced 87% of the yield and had significantly reduced fruit sie and appearance scores (data not shown). We considered that the greater crown development observed in plug plants in the trial may have resulted in a greater number of branch crowns that produced more flowers but smaller fruit and consequently reduced yield. In a second trial conducted at WEO in , and in an effort to reduce the excessive crown development, plugs were established on September 7, 2000, more than three weeks later than in The delayed planting date resulted in a plant that was equal in sie and vigor to the bare-root controls, but yield performance was similar to the previous year's results: compared to control plants, plugs produced less fruit and with reduced fruit sie (data not shown). Watsonville Fruiting Field Performance Trials, This trial was conducted to ascertain the feasibility of using plug culture to generate properlyconditioned plug plants of 'Diamante', the leading day-neutral strawberry cultivar used in California. 6

7 Like all other day-neutral cultivars, 'Diamante' benefits from rather extensive exposure to chilling temperatures in the nursery prior to digging in mid-october, as well as a brief period of supplemental chilling (about two weeks) in a cooler after digging the plants. Here our concern was that Diamante plug plants left at HE until mid-october to accumulate chilling could be subjected to damaging low temperatures in the nursery prior to "digging" the plants. Diamante plugs were propagated at HE using the tunnel structure described previously. Runner tips were rooted in mid-august, and were left at HE until mid-october, Despite minimum temperatures of -8 C (18 F) during the second week of October, plug plants maintained at HE did not suffer freee damage. Plugs were lifted from the nursery on October 15, then transplanted into fruit yield performance trials in Watsonville either on October 23, or on November 6, after two weeks of cold storage at 1 C (33 F). Plugs developed well during fall and winter, but suffered significant plant die-out in spring due to infection with Phytophthora cactorum. As a result, meaningful data was not obtained from this study. Performance of conventional transplants and plug plants in fumigated and nonfumigated soil. Trials were conducted in and to compare the performance of plugs and bare-root (conventional) transplants established in fumigated (methyl bromide + chloropicrin) and non-fumigated soil. In both years, results of ANOVA indicated that conventional transplants and plug plants responded similarly to soil fumigation treatment. In , we observed significant yield reductions due to non-fumigation for both types of plants, and with no fumigation x plant material interactions (Tables 20, 21). In , on "new" ground (ground cropped only to winter barley for 20 years) we observed no yield differences between fumigated and nonfumigated soil environments, and no differences in yield performance between conventional and plug plants (Table 22). Potential Benefits/Impacts on Agriculture Grower experience with plug plants in California has been highly variable. Some growers are pleased with the relatively high early-season yields that are possible with plugs, while other growers have experienced significant fruit quality (poor appearance and small fruit sie) in mid- and late-season. Although use of strawberry plug plants appears to be increasing, particularly in southern California where early fruit obtains a premium price, plug plants still account for considerably less than one percent of the strawberry transplants used in California. Currently, all commercial strawberry plug plants are produced in mild climate areas of southern California in Santa Barbara and San Luis Obispo Counties. These areas are close to the major southern California strawberry growing districts, an important factor in reducing the high cost of plug plant transport. However, the mild climate in these areas is an obstacle to plant conditioning by means of exposure to low temperature and short daylength in late summer and early fall. For decades the California strawberry transplant industry has recognied the importance of a high- elevation environment for producing quality transplants that produce high quality fruit, and the industry has sacrificed productivity while incurring greater production costs at high elevation to do so. The results of our research demonstrate consistently significant benefits of high-elevation plug propagation and conditioning in regard to early and total season yields, fruit sie and fruit appearance scores. Not surprisingly, the best quality strawberry plug plant is one that is produced in a high-elevation environment. However, although high-elevation plugs consistently outperformed low-elevation plugs, high-elevation plugs generally had lower fruit appearance scores than bare-root transplants, as well as smaller fruit sie. Only in the third year of our studies, when plugs were propagated and conditioned at high-elevation, did HE plugs have fruit quality similar to that of bare-root transplants. The importance of fruit quality for California strawberry growers cannot be ignored, as the market recognies and pays a 7

8 premium for quality fruit: California strawberries typically obtain market prices that are at least 50% greater than that paid for fruit from other US production regions. A major constraint to producing strawberry plugs at high-elevation is the distance from market and the associated high transportation cost. Our attempts to artificially condition plugs in walk-in coolers resulted in plants that were inferior to those conditioned at high elevation, and artificial conditioning of plugs by use of coolers and darkrooms is probably impractical on a commercial scale. Strawberry plug plants require considerably less irrigation during the initial planting and establishment phase, and savings that accrue from using less irrigation will offset the higher cost of plugs. Water cost, quality and availability are expected to become increasingly important issues in the near future, particularly in southern California. Additional, large-scale research research needs to eb conducted to determine the costs and benefits of producing high-elevation and low-elevation plug plants, as well as the economics of plug transport and fruit production. The main limitation to conducting this research is that no commercial high-elevation strawberry nursery currently appears interested in plug plant production. Most commercial nurseries view plug plants as a niche market, rather than as a viable system for producing about one billion runner transplants per year. Dissemination of Findings Presentations of the project's research objectives and results have been made at numerous UCCE/CSCsponsored strawberry grower meetings in Irvine, Watsonville and Santa Maria, with an estimated total attendance of over 1,400 people. Additional presentations were made to 400 fruit and nursery growers in Zamora, Mexico (December 2000), and in Huelva, Spain (February 2001). There is a definite need for additional educational efforts in the California strawberry plug and fruit industries regarding improved plug plant propagation methods and high elevation conditioning to enhance early yield, total yield and fruit quality. With the project successfully completed, we intend to further highlight our research findings at nursery and fruit grower meetings statewide and worldwide. 8

9 Table 1. Rooting dates, cell sies, nursery environments, and numbers of plots and plants per plot for plug physiology trials established in Irvine on October 1, Trt. no. Plant Material No. reps (plots) Plants/plot Rooting date Cell sie Nursery enveronment y 1 plug 4 6 Aug LE 2 plug 4 6 Aug Cooler 3 plug 4 6 Aug HE 4 plug 4 6 Aug LE 5 plug 4 6 Aug Cooler 6 plug 4 6 Aug HE 7 plug 4 6 Aug LE 8 plug 4 6 Aug Cooler 9 plug 4 6 Aug HE 10 plug 4 6 Aug. 4 1 HE 11 plug 4 6 Aug. 4 1 Cooler 12 plug 4 6 Aug. 4 1 HE 13 plug 4 6 July 21 1 HE 14 plug 4 6 July 21 3 HE 15 bare root HE 1 = 5 cm wide X 6 cm deep, 2 = 6 cm wide X 11 cm deep, 3 = 8 wide X 8 cm deep y Enverionmental conditions Sept. 7-28, 1999; LE = exposure to ambient light and temp. conditions at Redding, Calif. (41.3 N, elev 150 m); Cooler = exposure to 5 C for 15-hr night periods in a walk-in cooler with ambient daytime conditions at Redding, Calif.; HE = exposure to ambient conditions at Macdoel, Calif. (41.8 N, elev 1,200 m) Table 2. Trt. no. No. reps (plots) plants/plot Plant material Rooting date Cell sie Nursery enveronment y bare root plug 21-Jul 1 LE Rooting date, cell sie, nursery environment and numbers of plants and replicate plots for Central Valley plug performance trials established in Winters on August 13, = 5 cm wide X 6 cm deep, 2 = 6 cm wide X 11 cm deep, 3 = 8 wide X 8 cm deep y LE = exposure to ambient light and temp. conditions at Redding, Calif. (41.3 N, elev 150 m) from Sept. 7-28, Table 3. Rooting date, cell sie, nursery environment and number of plants and replicate plots for plug performance trials in fumigated and nonfumigated soil established in Irvine on October 4, Trt. no. Fumigation trt Plant material No. Reps (plots) Plants/plot Rooting date Nursery enveronment y Cell sie x 1 Fume bare root HE - 2 Fume plug 3 10 Aug. 18 HE 1 3 Non fume bare root HE - 4 Non fume plug 3 10 Aug. 18 HE 1 9

10 Fume = preplant soil fumigation with 350 lbs/acre of a 2:1 (wt:wt) mixture of methyl bromide:chloropicrin; y HE = exposure to ambient conditions at Macdoel, Calif. (41.8 N, elev 1,200 m) from Sept. 7-28, x 1 = 5 cm wide X 6 cm deep Table 4. Performance of Camarosa plugs and bare-root transplants in fumigated and non-fumigated soil in Irvine, California, Fumigation trt. Plant material N Total yield (g/plant) Fruit sie (g) Fume bare root a 27.0 a plug a 25.3 a Non fume bare root b 21.3 b plug b 22.3 b preplant fumigation with a 2:1 mixture of methyl bromide:chloropicrin, applied at a rate of 350 lbs/acre. y Mean separation withing columns by Tukey's mean separation, P <= 0.05 Table 5. Results for analysis of variance for early season fruit yield for 14 strawberry plug plant treatments and a bare-root control in Irvine, California, Between subjects R (rep) T (trt) Error Table 6. Results for analysis of variance for early season marketable fruit yield for 14 strawberry plug plant treatments and a bare-root control in Irvine, California, Between subjects R (rep) T (trt) Error Table 7. Results for analysis of variance for early season fruit sie for 14 strawberry plug plant treatments and a bareroot control in Irvine, California, Between subjects R (rep) T (trt) Error

11 Table 8. Results for analysis of variance for early season fruit appearance scores for 14 strawberry plug plant treatments and a bare-root control in Irvine, California, Between subjects R (rep) T (trt) Error Table 9. Results for analysis of variance for total season fruit yield for 14 strawberry plug plant treatments and a bare-root control in Irvine, California, Between subjects R (rep) T (trt) Error Table 10. Results for analysis of variance for total season marketable fruit yield for 14 strawberry plug plant treatments and a bare-root control in Irvine, California, Between subjects R (rep) T (trt) Error Table 11. Results for analysis of variance for total season fruit sie for 14 strawberry plug plant treatments and a bare-root control in Irvine, California, Between subjects R (rep) T (trt) Error Table 12. Results for analysis of variance for total season fruit appearance scores for 14 strawberry plug plant treatments and a bare-root control in Irvine, California, Between subjects R (rep) T (trt)

12 Error Table 13. Early season performance of 'Camarosa' strawberry plug plants produced with various rooting dates, container sies and nursery locations compared with conventional, bare-root nursery transplants in Irvine, California, Trt. no. N Plant material Tip rooting date Plug cell sie y Nursery environement x Total Yield (g/plant) Marketable yield (g/plant) Fruit sie (g) App. v (1-5) 1 4 plug Aug LE cd w de 26.6 abcd 2.59 bc 2 4 plug Aug Cooler d e 27.7 abc 2.71 bc 3 4 plug Aug HE bcd bcde 27.8 abc 2.79 bc 4 4 plug Aug LE bcd abcde 24.4 bcd 2.60 bc 5 4 plug Aug Cooler cd e 22.8 d 2.76 bc 6 4 plug Aug HE ab abc 27.9 abc 2.73 bc 7 4 plug Aug LE ab abcd 26.5 abcd 2.69 bc 8 4 plug Aug Cooler abc abcde 23.6 cd 2.69 bc 9 4 plug Aug HE abc abcde 23.9 bcd 2.75 bc 10 4 plug Aug. 4 1 LE bcd cde 27.8 abc 2.66bc 11 4 plug Aug. 4 1 Cooler abcd abcde 28.2 ab 2.71 bc 12 4 plug Aug. 4 1 HE ab abcd 27.7 abc 2.86 ab 13 4 plug July 21 1 HE ab ab 29.7 a 2.84 ab 14 4 plug July 21 3 HE a a 25.5 abcd 2.49 c 15 4 bare root - - HE cd de 29.4 a 3.10 a for all treatments, plants were lifted from the nursery on September 28 and established in Irvine on October 1, y 1 = 5 cm wide X 6 cm deep, 2 = 6 cm wide X 11 cm deep, 3 = 8 cm wide X 8 cm deep x Environmental conditions Sept. 7-28, 1999; LE = exposure to ambient light and temp. conditions at Redding, Calif. (lat N, elev 150 m); w Mean separation withing columns by Tukey's mean separation, P <0.05 w App. = subjective appearance score with 5 = best Table 14. Performance of 'Camarosa' strawberry plug plants produced with various rooting dates, container sies and nursery locations compared with conventional, bare-root nursery transplants in Irvine, California, Trt. no. N Plant material Tip rooting date Plug cell sie y Nursery environement x Total Yield (g/plant) Marketable yield (g/plant) Fruit sie (g) App. v (1-5) 1 4 plug Aug LE 1918 bc w 1466 ab 26.6 abcd 2.79 bc 2 4 plug Aug Cooler 1927 bc 1436 ab 27.7 abc 2.83 bc 3 4 plug Aug HE 2272 ab 1685 a 27.8 abc 2.88 ab 4 4 plug Aug LE 1963 bc 1451 ab 24.4 bcd 2.79 bc 5 4 plug Aug Cooler 1611 c 1163 b 22.8 d 2.88 ab 6 4 plug Aug HE 2348 ab 1722 a 27.9 abc 2.83 bc 7 4 plug Aug LE 2234 ab 1681 a 26.5 abcd 2.82 bc 8 4 plug Aug Cooler 2096 ab 1567 a 23.6 cd 2.82 bc 9 4 plug Aug HE 2222 ab 1649 a 23.9 bcd 2.88 ab 12

13 10 4 plug Aug. 4 1 LE 2087 ab 1568 a 27.8 abc 2.80 bc 11 4 plug Aug. 4 1 Cooler 2103 ab 1602 a 28.2 ab 2.85 bc 12 4 plug Aug. 4 1 HE 2186 ab 1658 a 27.7 abc 2.92 ab 13 4 plug July 21 1 HE 2136 ab 1654 a 29.7 a 2.85 ab 14 4 plug July 21 3 HE 2459 a 1753 a 25.5 abcd 2.68 c 15 4 bare root - - HE 1975 ab 1412 ab 29.4 a 3.03 a for all treatments, plants were lifted from the nursery on September 28 and established in Irvine on October 1, y 1 = 5 cm wide X 6 cm deep, 2 = 6 cm wide X 11 cm deep, 3 = 8 cm wide X 8 cm deep x Environmental conditions Sept. 7-28, 1999; LE = exposure to ambient light and temp. conditions at Redding, Calif. (lat N, elev 150 m); w Mean separation withing columns by Tukey's mean separation, P <0.05 w App. = subjective appearance score with 5 = best Table 15. Results for analysis of variance for early season fruit yield for strawberry plug plants rooted on two dates with 3 different nursery conditioning environments. Between subjects R (rep) D (date) N (nurs) DN Error Table 16. Mean early season yield for strawberry plug plants rooted on two dates and planted in Irvine, California. Rooting date N yield (g/plant) 4-Aug a 18-Aug b Table 17. Mean early season yield for strawberry plug plants conditioned in 3 nursery environments and planted in Irvine California on October 2, Nursery N yield (g/plant) LE b Cooler ab HE a Environmental conditions Sept. 7-28, 1999: LE = exposure to ambient light and temp. conditions at Redding, Calif. (41.3 N, elev 150 m); Cooler = 5 C for 15-hr night periods in a cooler with ambient daytime conditions at Redding; HE = exposure to ambient conditions at Macdoel, Calif. (41.8 N, elev 1,200 m) 13

14 Table 18. Results for analysis of variance for early season marketable fruit yield for strawberry plug plants rooted on two dates and conditioned in 3 nursery environments and planted in Irvine, California on October 2, Between subjects R (rep) D (date) N (nurs) DN Error Table 19. Mean early season marketable yield for strawberry plug plants rooted on two dates, and planted in Irvine, California on October 2, Rooting date N yield (g/plant) 4-Aug a 18-Aug b Table 20. Mean early season marketable yield for strawberry plug plants conditioned in 3 nursery environments and planted in Irvine, California on October 2, Nursery N yield (g/plant) LE b Cooler ab HE a Environmental conditions Sept. 7-28, 1999: LE = exposure to ambient light and temp. conditions at Redding, Calif. (41.3 N, elev 150 m); Cooler = 5 C for 15-hr night periods in a cooler with ambient daytime conditions at Redding; HE = exposure to ambient conditions at Macdoel, Calif. (41.8 N, elev 1,200 m) Table 21. Results for analysis of variance for mean early season marketable yield in Irvine for strawberry plugs rooted on August 18 using three container sies and three nursery locations. Between subjects R (rep) S (sie) N (nurs) SN Error Table 22. Mean early season marketable yield in Irvine for strawberry plug plants propagated using three container sies on August 18,

15 Container cell sie N Mean b ab a 1 = 5 cm wide X 6 cm deep, 2 6 cm wide X 11 cm deep, 3 = 8 cm wide X 8 cm deep Table 23. Mean early season marketable yield in Irvine for strawberry plug plants propagated on August 18, 1999 and conditioned in three different nursery environments. Nursery N Mean Redding ab Redding-Cooer b Macdoel a Table 24. Results for analysis of variance for total marketable yield for high elevation plugs and bare-root transplants grown in fumigated and non-fumigated soils in Irvine, Between subjects F (fume) P (plant) FP Error