Search Results

You are looking at 31 - 40 of 51 items for

  • Author or Editor: Fumiomi Takeda Takeda x
Clear All Modify Search

Mature 'Chester Thornless' blackberry plants were trained to the rotatable cross-arm (RCA) trellis to determine the effect of retaining two, four, or six primocanes on plant productivity. Retention of only the two oldest primocanes and generally the most vigorous primocanes per plant yielded 14.1 kg of fruit compared to 17.1 kg per plant in which as many as six primocanes were retained. Increasing the number of canes did not result in significant yield increase (P = 0.09) because the primocanes trained in late-June and July produced only a few, and, in some cases, no lateral branches. Thus, retaining only those canes that become trainable early in the season decreased labor inputs and allowed primocane training to be completed prior to the onset of harvest. As a result, the effort to train and retain only those primocanes that reach the trainable height before mid-June may be advantageous to minimize labor costs, but will not effect plant productivity.

Free access

Fresh strawberries (Fragaria ×ananassa Duch) are readily available throughout the year with several new cultivars being successfully grown in diverse environmental conditions (e.g., field and greenhouse). Consumption of strawberries with higher nutritive values and antioxidant activity may contribute to improved human wellness. Phytonutrient contents and antioxidant activity was measured as oxygen radical absorbance capacity (ORAC) were assayed in berries (`Camarosa', `Diamante', and `Gaviota') sampled in January, February to March, and April to May from fields in Plant City, Fla., and Oxnard, Calif., and from a greenhouse in Kearneysville, WV. Strawberry cultivars varied in skin color, soluble solids, total phenolics, and anthocyanins, ascorbic acid, folic acid, and ORAC activity. Response to environment was cultivar dependent. All phytonutrient constituents were lower in `Diamante' berries compared to `Camarosa' and `Gaviota'. For all cultivars, berry ORAC activity declined as TSS increased, and ORAC activity was coincident with phenolic content. ORAC activity in berries fruit harvested from plants grown in a temperature-controlled greenhouse did not change during the January to May sampling period. For `Gaviota', ORAC activity in greenhouse-produced berries was the same as that of field-produced berries. Whereas greenhouse vs. field-gown `Camarosa' and `Diamante' berries ORAC was higher and lower respectively. These findings demonstrate that the environmental conditions in greenhouses in Kearneysville, W.Va., from winter to spring are adequate for `Camarosa' and `Gaviota' color development, but not for `Diamante' strawberries. Of the three cultivars, only `Camarosa' was highly productive (1.2 kg berries per plant), even in the greenhouse. Berries were high in ascorbic acid, folic acid, phenolic acid, anthocyanins, and ORAC activity.

Free access

‘Navaho’ and ‘Apache’ blackberry plants were maintained at 10, 15, 20, 25, 30, or 35 °C in growth chambers to determine optimum temperature for budbreak and flowering (fewest days to flowering). In a separate experiment, bloom dates were observed for a collection of 117 Rubus genotypes over four seasons. Using these phenological data, predictive linear and curvilinear models were tested using a range of cardinal temperatures. The growth chamber experiment indicated optimum temperatures for bloom were 25.6 °C for ‘Apache’ and 29.2 °C for ‘Navaho’. For the field observations, time to bloom was best defined by a linear model with base and optimum temperatures of 6 and 25 °C and a curvilinear model defined by base and optimum temperatures of 4 and 27 °C, respectively. Based on the linear growing degree hour (GDH) model, heat units to bloom varied among cultivars in the collection from 9,200 GDH for ‘Chickasaw’ to 18,900 GDH for ‘Merton Thornless’.

Free access

July-plugged transplants of short-day cv. Strawberry Festival (Fragaria ×ananassa) flowered in October and November although they were grown under long photoperiods and warm temperatures (greater than 21 °C) in July and August. These unexpected results were attributed to a high plant density (320 transplants/m2) that provided continuous and heavy leaf cover, which eliminated red light (less than 700 nm) from reaching the crowns. This hypothesis was tested by illuminating crowns of transplants growing in 50-cell packs for 16 h·d−1 with red light-emitting diode lamps (maximum wavelength at 639 nm and 80% of output between 617 and 655 nm). Red light treatment caused a significant reduction in fall flowering. It is proposed that a high ratio of far-red light to visible light reaching the crown will play a role in floral bud induction, possibly as early as mid-August. Transplants of some short-day cultivars started as plug plants in early July have the capacity to flower and fruit in the fall and the next spring, enabling growers in the mid-Atlantic coast region to obtain two harvests within 1 year from a single planting.

Free access

Strawberry (`Chandler') plants were grown in a greenhouse hydroponic culture system from 28 Apr. to 20 July to produce runners (stolons) with several daughter plants. By mid-July, each `Chandler' plant had developed about 30 daughter plants on 12 runners with 1 to 6 daughter plants on each runner. Daughter plants varied in weight from <0.9 to >10 g. Daughter plant weight and position on the runner affected new root development on plug plants during the first 7 days under mist irrigation. At 3 weeks, 87% of daughter plants that weighed <0.9 g and at least 96% of daughter plants that weighed >1.0 g were rated acceptable for field transplanting, respectively. The percentage of daughter plants from second to tenth node position that were rated acceptable for field planting ranged from 98% to 88%, respectively. Runner production in the fall was not affected by either position on the runner or weight at the time of daughter plant harvest. But, larger daughter plants produced more branch crowns than did smaller daughter plants in the fall. Transplant survival in the field was 100%. In the spring, `Chandler' plants produced a 10% greater yield from daughter plants that weighed 9.9 g compared to those that weighed only 0.9 g.

Free access

One- or two-node hardwood cuttings were taken from 9-year-old ‘Triple Crown’ and ‘Siskiyou’ blackberry (Rubus) plants on 5 Nov. 2009, 3 Dec. 2009, and 21 Jan. 2010. The response of cuttings with and without partially excised axillary buds to an application of cytokinin was compared with control cuttings with intact axillary buds and no cytokinin. Differences in root development were evident in the two cultivars tested. The cuttings of ‘Siskiyou’ and ‘Triple Crown’ callused on cut ends, but many of the adventitious roots developed from the base of the axillary buds. Shoots emerged from the bud in ≈90% of ‘Siskiyou’ cuttings stuck in November, December, and January. Rooting occurred in more than 90% of cuttings stuck in November and December but declined in cuttings stuck in January. In ‘Siskiyou’, bud excision had no effect on shoot and root emergence, but cytokinin treatment suppressed rooting in cuttings collected in November and January. Shoot emergence and rooting were poorer in ‘Triple Crown’ cuttings than in ‘Siskiyou’. In ‘Triple Crown’ cuttings, partial excision of buds reduced shoot emergence only in January but had no effect on rooting at three sticking dates. Cytokinin treatment improved shoot emergence in November and December but reduced rooting in January. The enclosed system is a viable method for propagating ‘Siskiyou’ blackberry by non-leafy floricane cuttings.

Full access

Northern highbush (NH) blueberry (Vaccinium corymbosum) and southern highbush (SH) blueberry (V. corymbosum hybrids) have fruit that vary in firmness. The SH fruit is mostly hand harvested for the fresh market. Hand harvesting is labor-intensive requiring more than 500 hours/acre. Rabbiteye blueberry (V. virgatum) tends to have firmer fruit skin than that of NH blueberry and has been mostly machine harvested for the processing industry. Sparkleberry (V. arboreum) has very firm fruit. With the challenges of labor availability, efforts are under way to produce more marketable fruit using machine harvesting. This could require changing the design of harvesting machine and plant architecture, and the development of cultivars with fruit that will bruise less after impact with hard surfaces of machines. The objectives of this study were to determine the fruit quality of machine-harvested SH blueberry, analyze the effect of drop height and padding the contact surface on fruit quality, investigate the effect of crown restriction on ground loss, and determine the effect of plant size on machine harvestability. The fruit of ‘Farthing’, ‘Scintilla’, ‘Sweetcrisp’, and several selections were either hand harvested or machine harvested and assessed during postharvest storage for bruise damage and softening. Machine harvesting contributed to bruise damage in the fruit and softening in storage. The fruit of firm-textured SH blueberry (‘Farthing’, ‘Sweetcrisp’, and selection FL 05-528) was firmer than that of ‘Scintilla’ after 1 week in cold storage. Fruit drop tests from a height of 20 and 40 inches on a plastic surface showed that ‘Scintilla’ was more susceptible to bruising than that of firm-textured ‘Farthing’ and ‘Sweetcrisp’. When the contact surface was cushioned with a foam sheet, bruise incidence was significantly reduced in all SH blueberry used in the study. Also, the fruit dropped 40 inches developed more bruise damage than those dropped 20 inches. Ground loss during machine harvesting was reduced from 24% to 17% by modifying the rabbiteye blueberry plant architecture. Further modifications to harvesting machines and plant architecture are necessary to improve the quality of machine-harvested SH and rabbiteye blueberry fruit and the overall efficiency of blueberry (Vaccinium species and hybrids) harvesting machines.

Full access

Flower bud development was studied in `Cherokee', `Boysen', and `Marion' blackberries (Rubus subgenus Rubus Watson). In `Cherokee' (erect type), the transition to reproductive development in buds on the branch canes occurred during September in Arkansas and Oregon. Transitions of buds in the axils of the most basal nodes (proximal to the main cane) and the most distal nodes lagged behind buds in the midsection (about nodes 6 to 10). Along the midsection of branch canes, the buds developed uniformly. In buds of `Boysen' and `Marion' (trailing type), the transition to reproductive development occurred in October and sepal primordia were observed in most buds examined by November. Progression of floral bud development continued into January, but at a slower rate than in autumn. Buds on the main canes (>3 m long) of `Boysen' and `Marion' remained at a more advanced stage of flower bud differentiation than buds on the basal branch canes. In both cultivars, buds from the middle one-third section, and sometimes buds from the bottom one-third section, tended to be more advanced than those buds in the top one-third section during much of the sampling period. The results suggest that rate and patterns of flower bud development vary among cultivars grown in different locations. However, the pattern of flower bud development was not in a basipetal fashion on main or branch canes.

Free access

Transition to reproductive development and subsequent development of floral primordia (e.g., sepals, petals, stamens, and pistils) were determined in several blackberry (Rubus subgenus Rubus Watson) cultivars (Boysen, Cherokee, Chester Thornless, Marion, and Thornless Evergreen) growing in one or more locations (Clarksville, Ark., Aurora and Hillsboro, Ore., and Kearneysville, W. Va.). Also, daily maximum, mean, and minimum temperatures were recorded at three sites (Clarksville, Aurora, and Kearneysville) for the September to April sampling period. In buds of `Boysen' and `Marion' from Oregon, sepal primordia were first observed in November and December, respectively. Further floral bud development continued into January. Sepal development in `Cherokee' buds occurred in October in Oregon and in December in Arkansas. At all three sites, the buds of `Chester Thornless' blackberry remained undifferentiated until spring. The average mean temperatures in Oregon were generally well above 5 °C during the bud sampling period, but were near 0 °C on most days from mid-December to January in Arkansas and from December to late-February in West Virginia. The phenology of flower bud differentiation varied among the cultivars and was strongly influenced by prevailing winter temperatures. The results suggest that the shortening day lengths of late summer trigger flower bud development in blackberry. Floral bud development in blackberry, once initiated, was continuous; however, periods of low temperature (<2 °C) can arrest development.

Free access