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  • Author or Editor: Fumiomi Takeda Takeda x
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Using the rotating cross-arm (RCA) trellis and cane training system, lateral canes of trailing ‘Siskiyou’ blackberry (genus Rubus subgenus Rubus) were kept vertically or rotated down to horizontal so that plant canopy was close to the ground. In winter, the plots were either covered with a non-woven rowcover (RC) or left uncovered. Cane injury was least in plants with lateral canes oriented horizontally and covered. Cane injury was high in plants with lateral canes oriented vertically in winter, whether covered or not, and among plants with lateral canes laid close to the ground but not covered. Among ‘Siskiyou’ plants that had lateral canes oriented horizontally, 280 flower clusters and 6.0 kg fruit/plant were produced on plants that had a RC in the winter compared with only 72 flower clusters and 1.7 kg fruit/plant for plants that were not covered in winter, in 2009. Fewer flower clusters developed and the yield was ≤2 kg/plant on plants with lateral canes oriented vertically. Yield differences between the most and least productive treatments were low in 2010 because of milder winter conditions and snowfall during the coldest periods that fully or partially covered the lateral canes oriented horizontally and close to the ground. The RC treatment had no effect on cane injury or yield when lateral canes were oriented vertically. The findings suggested that ‘Siskiyou’ blackberry can be grown in the eastern United States, where winter injury has frequently caused a crop failure, by positioning the lateral canes close to the ground and covering plants with a RC.

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The objective of this study was to evaluate primocane cane training and propagation techniques for the production of long-cane blackberry (Rubus spp.) plants. Seventeen to 29 6-ft-long canes were produced from each semierect ‘Triple Crown’ and trailing ‘Siskiyou’ blackberry plant grown on the rotating cross-arm (RCA) trellis and cane training system. By early August, the lateral canes had grown beyond the top wire ≈6 ft above the ground and continued growing downward to the ground. The tips of the lateral canes reached the soil level from mid-August to mid-September at which time they were placed in 1/2-gal pots containing peat-based media. In early Oct. 2009, the tip-rooted lateral canes were cut from the stock plant at the uppermost trellis wire. Among the long-cane plants produced in 2009, 76% of buds in ‘Siskiyou’ broke, but less than 30% of buds in ‘Triple Crown’ broke in a heated greenhouse. Flowering occurred in 15% of the shoots that developed on rooted ‘Siskiyou’ long canes, but the shoots on the long-cane plants of ‘Triple Crown' were morphologically vegetative and flowering did not occur. In 2010–11, the long-cane plants were detached from the stock plants in December, January, and March. The numbers of nodes with a flowering shoot improved to 41% and 16% and the number of flowers per shoot increased to two and five flowers on long-cane plants of ‘Siskiyou’ and ‘Triple Crown’ blackberry, respectively.

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Postharvest decay represents major losses in the horticultural industry. Synthetic fungicides are an effective tool in controlling postharvest diseases. However, the need for new methods to control postharvest diseases is emphasized because of resistance to certain fungicides, increased incidence of iatrogenic diseases, health risk concerns, and regulatory constraints on pesticide usage.

The use of biologically derived bioactive substances is an alternative approach for the control of postharvest diseases. For example, pyrrolnitrin, a compound produced by Pseudomonas cepacia, has high antifungal activity toward several pathogenic fungi. Chitosan, obtained from deacetylation of chitin, activates the natural defense mechanism in the host tissue. Some volatile compounds from plants and fruits have fungitoxic properties. Hinokitiol, an extract from Japanese cypress trees, is highly effective in extending the shelflife of peaches. The usefulness and limitations of a number of natural bioactive substances will be discussed.

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Abstract

‘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.

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Abstract

The two enzymes frequently associated with fruit softening and cell wall degradation during ripening are polygalacturonase (EC 3.2.1.15) and cellulase (EC 3.2.1.4) (Huber, 1983). The work reported here provides evidence that, using a viscometric assay, cellulase, but not polygalacturonase, activity increased during the ripening of blackberries.

Open Access

Abstract

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).

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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.

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Abstract

Neither abscisic acid (ABA) levels in developing kernels nor in the developing inflorescence buds themselves were found to be related to abscission of inflorescence buds and consequent alternate bearing in pistachio (Pistacia vera L.).

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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.

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