Fumiomi Takeda and Michael Newell
Flowering occurred over a 5-week period in semi-erect, tetraploid thornless blackberries (Rubus spp.) (cvs. Black Satin, Hull Thornless, and Dirksen Thornless). The harvest durations were slightly longer. The terminal flower bud of the primary axis (A1) of the inflorescence was first to open, followed by the terminal flower bud on one of basal secondary axes (A2). Remaining terminal flower buds on A2 axes opened sequentially in acropetal direction at a constant rate (two flowers/day). However, bloom pattern of flower buds located laterally on A2 axes was less definite. Within a floricane, the bloom on the primary fruiting laterals began at the distal end and progressed basipetally to the cane base. Ripening sequence of berries in a cluster followed that of the bloom. The time difference in anthesis between fruiting laterals and among flower buds within inflorescences was a major factor affecting the range of fruit maturity.
Fumiomi Takeda and Donald L. Peterson
There is increased interest in growing blackberries in the United States for the fresh fruit market. For fresh market blackberry production, >350 h/acre (900 h·ha-1) of work is required to hand pick blackberries over a season that lasts 5 weeks with harvest every 2 days. Existing bramble mechanical harvesters can detach fruit from plants trained on a vertically oriented I trellis and harvest more cheaply than when harvested by hand, but the harvested fruit does not have fresh-market quality. We developed a cane training and trellis system for semierect blackberries to orient canes horizontally with the fruit positioned below the canes. Also, we developed an over-the-row mechanical harvester that uses vibrating nylon rods on a drum to shake fruit from horizontally trained canes onto a moving fruit-catching surface directly under the canopy to minimize impact damage to fruit. A new trellis design, new cane training practices, and new harvesting technologies have allowed fruit to be removed efficiently and be acceptable for fresh-market sales. This production system has been evaluated economically and appears to be profitable. It could overcome the high cost of handpicking, which has limited the expansion of fresh-market blackberries.
Fumiomi Takeda and Ann K. Hummell
A new trellis system called the “rotatable cross-arm” (RCA) trellis was developed to ease mechanical fruit harvesting of eastern thornless blackberries. The rotation of the cross-arm following bloom 1) positions all the fruit to one side of the trellis in a plane underneath the cross-arm and 2) permits primocanes to be trained to side without the fruit. To maintain productivity, the number of lateral shoots that arise from primocanes must be maximized. In this study, we examined the growth and development of individual primocanes within plants and the number of lateral canes that developed on them to decide which canes should be retained during the growing season. In `Chester Thornless' blackberry, primocanes trained early in the season produced more laterals per cane, had higher percentage of buds forming laterals, and were much larger in diameter than primocanes trained later in the season. Field observations suggested high sink strength and less light competition probably contributed to the increased productivity of early canes. These results indicated that the canes that become trainable early in the season must be retained for the success of the RCA trellis. Conversely, the primocanes that become trainable later in the season do not develop sufficiently and should be removed.
Fumiomi Takeda and Penelope Perkins-Veazie
Julian C. Crane and Fumiomi Takeda
‘Kerman’ pistachio trees produced incompletely developed leaflets and leaves with a reduced number of leaflets following the mildest winter in 48 years in California. Nuts were produced both laterally and terminally on current season’s shoots in addition to their normal production laterally on 1-year-old wood.
Michele Warmund, Milon George, and Fumiomi Takeda
Differential thermal analyses (DTA) and freeze viability tests were conducted to investigate the biophysics of freezing in floral buds of `Danka' black (Ribes nigrutn L.) and `Red Lake' red currants [Ribe.s sativum (Rchb.) Syrne] sampled from Nov. 1989 through Mar. 1990. Scanning electron microscopy was also used to determine the relationship between floral morphology and the freezing characteristics of the buds. Floral buds had multiple abrupt low-temperature exotherms (LTEs) and one or two broad LTEs in DTA tests. Abrupt LTEs from DTA were associated with apparent injury to the inflorescence in viability tests. The number of LTEs did not correspond to the number of racemes or flowers per bud, indicating that several flowers froze simultaneously. DTA experiments conducted in Dec. 1990 revealed that the broad exotherm detected between - 14 and - 20C in `Danka' samples resulted from freezing of supercooled water in the outer nonliving region of the periderm of cane tissue attached to the bud.
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.
Fred B. Abeles and Fumiomi Takeda
The two enzymes frequently associated with fruit softening and cell wall degradation during ripening are polygalacturonase (EC 184.108.40.206) and cellulase (EC 220.127.116.11) (Huber, 1983). The work reported here provides evidence that, using a viscometric assay, cellulase, but not polygalacturonase, activity increased during the ripening of blackberries.
Fumiomi Takeda and Donald L. Peterson
Separation pull force of thornless blackberries (Rubus spp.) decreased at a rate insufficient to allow adequate mechanical harvest differentiation between the black ripe and red fruit. When a force sufficient to remove 80% of black ripe fruit was applied to floricanes, green and red fruit comprised as much as 50% of detached fruit. Ethephon, applied at 500 and 1000 ppm 4 days prior to harvest, reduced fruit size and total soluble solids, but increased the ripe/unripe harvest ratio more than two-fold. Two shaker models tested were effective in removing black ripe fruit. Of the two, the unit with higher frequency (40 vs. 25 Hz), but with shorter stroke (1.7 vs. 5.0 cm), was more efficient, as it removed fewer unripe fruit. Chemical name used: (2-chloroethyl) phosphonic acid (ethephon).