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Open access

Joseph W. Braun and Jeannie K. L. Garth

Abstract

Butanedioic acid mono-(2,2-dimethylhydrazide) (daminozide) (2000 and 4000 ppm) was applied to ‘Heritage’ primocane fruiting red raspberry (Rubus idaeus L.) primocanes at combinations of several dates, when the canes averaged 19, 42, 65, and 79 or 91 cm in height. Daminozide-treated plots achieved 50% of the eventual final yield an average of 8 days earlier (averaged for 5 treatments involving daminozide application at 42 cm) than controls. This advance of the production curve resulted in an average yield increase of 51% during the first 28 days of production. However, while early yields were increased, total yields were unaffected. Increasing the concentration of daminozide from 2000 to 4000 ppm did not increase the effects. Double application of daminozide (2000 ppm) at 65 and 79 cm and single application at 91 cm reduced yield during the 14 to 28 day harvest period compared to that of the single 65 cm application. This reflects, in part, the reduced berry size during the early harvest period resulting from the later (79 or 91 cm) applications of daminozide. Daminozide reduced the number of nodes formed and advanced the date of anthesis. Application of (2-chloroethyl)phosphonic acid (ethephon) (300 ppm at 19 and 42 cm) increased the number of nodes formed, delayed anthesis by about 13 days, delayed fruiting, and reduced total production.

Open access

P. C. Crandall, J. D. Chamberlain, and J. K. L. Garth

Abstract

Primocanes were sprayed after they reached about 18 cm in height with 4, 6-dinitro-o-sec-butylphenol (dinoseb) plus superior spray oil to kill the tops down to ground level. Additional treatments involved spraying after the second flush of growth reached 18 cm in height. Primocane suppression by this means increased yields by up to 70% over unsprayed plots. Plots of vigorous ‘Williamette’ raspberries (Rubus idaeus L.) were re-sprayed each year for 4 years and maintained the yield increase. A less vigorous ‘Sumner’ planting subjected to similar treatments did not develop adequate cane height and number after 2 or 3 sprays and yields the following year were greatly reduced. Berry size was sometimes increased. Most of the increased yields were due to greater numbers of berries. Primocane suppression had no effect on the number of berries on the upper laterals but greatly increased the numbers on laterals that developed from the middle and lower portions of the canes. The amount of carbohydrates per bud in dormant canes was reduced by dinoseb sprays applied the previous growing season.

Free access

Fumiomi Takeda, D. Michael Glenn, and Thomas Tworkoski

Three experiments were performed to determine the effect of amending the soil surface layer and mulching with hydrophobic kaolin particle on weeds and blackberry (Rubus subgenus Rubus Watson) plants. In the first study a processed kaolin material (product M-96-018, Engelhard Corporation, Iselin, N.J.), was incorporated in August into the top 3 cm of freshly roto-tilled field that had been in pasture the previous 5 years. The following spring, dry weight of weed vegetation in the control treatment was 219 g·m–2 and was significantly higher (P = 0.05) than the 24 g·m–2 harvested from the treated soil. In two other studies, planting holes for blackberry transplants were either 1) pre- or postplant mulched with a 2- or 4-cm layer of 5% or 10% hydrophobic kaolin in field soil (w/w), or 2) postplant treated with a) napropamide, b) corn gluten meal, c) a product comprised of hydrous kaolin, cotton seed oil, and calcium chloride in water (KOL), d) hand weeded, or e) left untreated. Although untreated plots had 100% weed cover by the end of July, herbicide treatments, 4-cm deposition of hydrophobic kaolin particle/soil mulch, and KOL all suppressed weeds the entire establishment year. Preplant application of hydrophobic kaolin mulch and postplant application of KOL reduced blackberry growth and killed transplants, respectively. In year 2, blackberry plants produced more primocanes that were on average 10-cm taller in weed-free plots (herbicide, 4-cm kaolin soil mulch, and mechanical weeding) than in weedy plots (control and 2-cm kaolin soil mulch). In year 3, yield was significantly lower in control plots (1.5 kg/plant) than in plots that were treated with napropamide and 2- and 4-cm hydrophobic kaolin mulch, or hand weeded during the establishment year (4 kg/plant). The results showed that 4-cm hydrophobic kaolin mulch applied after planting can suppress weeds without affecting blackberry productivity. These kaolin products are excellent additions to the arsenal of tools for managing weeds in horticultural crops.

Free access

Stenhen F. Klauer, J. Scott Cameron, and Paul W. Foote

Results from previous cultural and physiological studies of red raspberry suggest that primocanes compete with floricanes for light, nutrients and/or photoassimilates. This study was undertaken to determine whether this competition might be reflected in the actual translocation of photoassimilates between the two types of canes. In 1993, pairs of greenhouse grown, potted red raspberry (Rubus idaeus L.) plants contaming one or two floricanes and numerous primocanes were labeled with 14CO2 on four dates corresponding with early anthesis, green fruit, red fruit and post fruit maturity stages of the growing season. For each experiment, either a floricane or a primocane was exposed to 92.5μCi 14CO2 within a sealed bag. After 24 hours, the bag was removed and the presence of label was monitored for up to 11 days. Activity was determined using liquid scintillation. At all developmental stages 14C moved from the labeled floricane to primocanes that were from 2.5 cm to 1.5 m tall and to the roots. Movement was quickest and relatively greatest at early anthesis, dccreascd during fruiting, and was still occuring at 2 months after fruit maturity. Small amounts of label were detected in roots of labeled primocanes at all stages, but trace amounts were present in fruit and other primocanes only at post fruit maturity.

Free access

J.A. Sullivan, B.A. Hale, and D.P. Ormrod

Factorial experiments in two growing seasons in open-top field chambers with two or three O3 concentrations and two primocane-fruiting raspberry (Rubus idaeus L.) cultivars were used to obtain dose-response relationships describing the effects of seasonal O3 exposure on raspberry plant vegetative and reproductive growth. At the lower concentration (0.12 μl·liter-1), the response to O3 was nonsignificant. However, at 0.24 μl·liter-1, `Heritage' showed a significant decline relative to the control in cane height, node count, cane diameter, and dry weight. These changes were accompanied by a 52% decrease in yield, caused mainly by a reduction in fruit count. In contrast, vegetative and yield characters of the `Redwing' were not affected by O3.

Free access

T. Kostman, J. S. Cameron, C. Chen, and S. F. Klauer

The red raspberry industry of the Pacific Northwest depends upon chemical primocane suppression to temporarily reduce competing vegetation during fruit development. This practice increases yield and harvest efficiency, but can reduce cane vigor, number and diameter over time. Few chemicals are available for this purpose and thus the potential of nonchemical alternatives is being explored. The purpose of this project was to evaluate the potential of blown air as a thigmic stress to temporarily suppress primocane growth.

Blown air treatments were applied once (12 PM) or twice (12\4pm) per day, five days per week using a portable leaf blower generating winds of 273 km per hr. Treatments also included several rates of three experimental herbicides and an untreated control. All treatments were applied when primocanes were 10-15 cm in length and blown air treatments continued through fruit development. Primocane development was monitored over the course of the season.

Blown air reduced primocane length by 15-30% prior to harvest giving control equivalent to current chemical methods. Blown air increased cane diameter but reduced yield by reducing fruit numbers. Reductions in fruit numbers are likely due to flowering\fruiting points removed by blown air.

Free access

Neil C. Bell, Bernadine C. Strik, and Lloyd Marti

Primocanes were cut at ground level at one-month intervals from late April to late July 1991 and 1992. An uncut control was included. Four canes per plant were trained either in August or the following February, the others being removed and measured. Yield data were collected and yield components measured in 1992 and 1993. Cane diameter, main cane length and branch cane length per plant generally declined with later suppression date. Consequently, yield per meter of cane declined with later suppression date. However, cane number and total plant main cane length were greater for all suppression treatments and percent budbreak increased with later suppression date. As a result, April- and May-suppressed plants had increased-yields compared to control plants in both 1992 and 1993, as did June-suppressed plants in 1993. August-trained plants had significantly higher yields than February-trained in both years, primarily because of increased budbreak. The basal section of canes was the most productive, because of increased budbreak and branch cane production.

Free access

David C. Percival, J.T.A. Proctor, and J.A. Sullivan

Field experiments including supplementary trickle irrigation (IR), IRT-76 plastic film (PF), and straw mulch (STR) treatments were conducted during 1993 and 1994 to determine the influence of root-zone temperature and soil moisture status on carbon assimilation and dry mass distribution, and soil and plant nutrient content, during the establishment of Rubus idaeus L. `Heritage' primocane-fruiting raspberries. The IR, PF, and STR treatments were reapplied after the 1993 establishment year to examine their effects on an established, hedgerow planting. Physical environment, vegetative and reproductive data were collected. PF increased root and shoot mass, total flower number, and total berries harvested. Maximum leaf net photosynthetic (Pn) rates were observed under cool air temperatures and root-zone temperature of 25 °C. Field Pn measurements indicated that there was no seasonal decline in Pn. Mulch treatments however, were not beneficial to the established (i.e., 2-year-old) hedgerow planting. The root system of the 2-year-old planting was largely confined to an area within the foliage wall and also at a greater depth from the mulch treatments. Therefore, beneficial effects of mulch management on the growth and development of raspberries may be limited to the establishment year.

Free access

Joseph A. Fiola, Robert Lengyen, and Harry J. Swartz

A major objective of the MD/NJ/VA/WI Cooperative Raspberry Breeding Program is to develop new primocane-fruiting raspberry cultivars that are early, with large fruit size, and good fresh flavor, relative to the `Heritage' standard. Step I seedling selections were made and tissue culture-propagated. The Step III advanced selection trial, planted in 1993, consisted of two advanced selections, JCR-F1 [Geo-1 (Autumn Bliss × Glen Moy) × Heritage–red], and JEF-B1 (Amity × Glen Eagles–golden), with a `Heritage' check. The planting was a RCB (four replications), with 3-m plots, 60-cm plant spacing, on raised beds with black plastic mulch (establishment year), and trickle irrigation. The 1994 season started dry, and mid-summer was warm and wet, inducing an early harvest overall. JCR-F1 was >2 weeks earlier, 40% higher yielding, with 18% larger fruit size than `Heritage'. JCR-F1 fruit was tall conic, cohesive, and had good flavor; plant vigor was very good. JEF-B1 was 10 days earlier than `Heritage', had 40% larger fruit size, but was 25% lower yielding; plant vigor was also good. The flavor was described as banana and apricot. The planting will be fruited for multiple seasons for continued comparison.

Free access

Pedro B. Oliveira, Cristina M. Oliveira, and António A. Monteiro

The aim of this study was to determine the effects of date of summer pruning and cane densities on growth and fruiting characteristics of the raspberry (Rubus idaeus) plant. Three summer-pruning dates (early, middle, and late July) and four cane densities (8, 16, 24, and 32 canes/m row) were imposed to the greenhouse-grown primocane-fruiting raspberry `Autumn Bliss' in 2 consecutive years (1994 and 1995). A higher light microclimate and CO2 assimilation rate were measured within the canopy at the lowest density. Some compensation in CO2 assimilation rates were observed in the upper leaves of the high-density treatments, probably in response to low light. Delayed pruning decreased yield per cane and per row. The highest yields per cane were always observed at the lowest cane density. Densities of 16 and 24 canes/m produced the highest fruit yield. Light conditions appeared to be the most important environmental factor affecting plant productivity. Fruit were a weaker sink than roots; therefore, the role of carbohydrate reserves should be investigated.