scholarly journals Development and Evaluation of a Portable, Handheld Mechanical Shaker to Study Fruit Detachment in Blueberry

HortScience ◽  
2013 ◽  
Vol 48 (3) ◽  
pp. 394-397 ◽  
Author(s):  
Anish Malladi ◽  
Tripti Vashisth ◽  
Scott NeSmith

A portable, handheld, mechanical shaking device was developed and its effects on fruit detachment in rabbiteye bluebbery (Vaccinium ashei Reade) and southern highbush blueberry (hybrids of mostly Vaccinium corymbosum L. and Vaccinium darrowi Camp.) were evaluated. The instrument facilitated effective detachment of fruit within a branch, especially in rabbiteye blueberry (greater than 75%). Approximately 3 to 4 seconds of shaking was sufficient to detach the majority of the fruit. Differences in the extent of fruit detachment were observed across the genotypes, especially among southern highbush blueberry genotypes. The majority of fruit detachment in rabbiteye blueberry and most of the southern highbush blueberry genotypes occurred at the point of attachment of the pedicel to the berry, although a significant portion detached with the stem intact, resulting in stemmy fruit. Although only a small proportion of the detached fruit was immature in the rabbiteye blueberry genotypes, up to 23% of the detached fruit was immature in the southern highbush blueberry genotypes. Application of the abscission agents methyl jasmonate (MeJa; 20 mm) and ethephon (1000 mg·L−1) reduced the time required for fruit detachment on mechanical shaking by up to 5-fold. Together, these data indicate that the mechanical shaking device developed here is an effective tool for studying fruit detachment in blueberry. This instrument has potential applications in blueberry research programs evaluating fruit production. It can be used in breeding programs to aid in the selection of genotypes with fruit detachment characteristics that are potentially better suited for mechanical harvesting, and also in programs involving the screening and evaluation of abscission agents in blueberry.

HortScience ◽  
2012 ◽  
Vol 47 (12) ◽  
pp. 1745-1749 ◽  
Author(s):  
Anish Malladi ◽  
Tripti Vashisth ◽  
Lisa Klima Johnson

Two abscission agents, ethephon and methyl jasmonate, were investigated in five studies to determine their potential for increasing fruit detachment during harvest in rabbiteye (Vaccinium ashei Reade) and southern highbush (hybrids based largely on Vaccinium corymbosum L. and Vaccinium darrowi Camp.) blueberry. In the first study with a rabbiteye blueberry genotype, T-451, ethephon applications up to 1000 mg·L−1 did not affect fruit drop but reduced fruit detachment force (FDF) by up to 21%. In the second study with two southern highbush blueberry genotypes, ethephon (up to 1500 mg·L−1) and methyl jasmonate (MeJa; up to 10 mm) applications resulted in significant fruit drop in ‘Star’ but neither of the growth regulators affected the fruit detachment characteristics of ‘Farthing’. In a third study with rabbiteye blueberry genotypes, MeJa applications of 10, 20, and 30 mm displayed an increasing linear trend in fruit drop in ‘Climax’ and linear and quadratic trends in fruit drop in ‘Powderblue’. In a fourth study with ‘Powderblue’, MeJa (20 mm) and ethephon (1000 mg·L−1) applications resulted in rapid and significant fruit drop. The fruit drop induced by MeJa in this study was attenuated by the coapplication of aminoethoxyvinylglycine (AVG), an ethylene biosynthesis inhibitor, suggesting that MeJa induced fruit detachment partly through its effects on ethylene biosynthesis. In another study with the southern highbush blueberry genotype, O’Neal, MeJa applications (20 mm) induced significant fruit drop but ethephon (1000 mg·L−1) applications did not affect fruit detachment. Overall, MeJa applications (20 mm or greater) generally induced rapid and extensive fruit abscission, often within 1 day after treatment. Applications of MeJa resulted in leaf yellowing and necrosis of leaf tips and margins, especially at high rates of application (20 mm or greater). Ethephon applications resulted in the abscission of mature and immature berries. Both ethephon and MeJa applications resulted in the detachment of the pedicel along with the fruit. Together, these data suggest that although ethephon and MeJa have the potential to be used as harvest aids in blueberry, the rates of application require further optimization to minimize potential phytotoxicity. Additionally, effective de-stemming of the berries may be essential if these compounds are to be used as harvest aids.


2002 ◽  
Vol 12 (2) ◽  
pp. 271-274 ◽  
Author(s):  
P. Manjula Carter ◽  
John R. Clark ◽  
R. Keith Striegler

Southern highbush blueberry, a hybrid of northern highbush (Vaccinium corymbosum) and southern-adapted Vaccinium species, has the potential to meet the need for an early-ripening blueberry in the southern U.S. southern highbush cultivars can ripen up to one month earlier than the earliest rabbiteye (Vaccinium ashei) cultivars currently grown in the southern U.S. However, chilling requirement and cold-hardiness are cultivar-dependent for southern highbush and cultivar testing has been necessary to determine the cultivars best adapted to specific hardiness zones. In a 4-year study at Hope, Ark. (hardiness zone 7b), several southern highbush cultivars were evaluated for productivity, fruit quality and reliability of cropping. Yields were based on 1089 plants/acre (2690 plants/ha) for southern highbush cultivars and 605 plants/acre (1494 plants/ha) for rabbiteye cultivars. `Ozarkblue' and `Legacy' showed the most adaptability at this location, yielding on average 11,013 lb/acre (12,309 kg·ha-1) and 10,328 lb/acre (11,543 kg·ha-1) respectively, compared to 4882 lb/acre (5456 kg·ha-1) for `Premier' (rabbiteye) over 4 years. `Ozarkblue' and `Legacy' also rated well for plant vigor and fruit quality. We would recommend `Ozarkblue' and `Legacy' for commercial planting in southwest Arkansas and believe these cultivars have production potential for other areas of the southern U.S. that have similar hardiness zones and soil type to southwest Arkansas.


2015 ◽  
Vol 140 (1) ◽  
pp. 38-44 ◽  
Author(s):  
Alisson P. Kovaleski ◽  
Jeffrey G. Williamson ◽  
James W. Olmstead ◽  
Rebecca L. Darnell

Blueberry (Vaccinium spp.) production is increasing worldwide, particularly in subtropical growing regions, but information on timing and extent of inflorescence bud development during summer and fall and effects on bloom the next season are limited. The objectives of this study were to determine time of inflorescence bud initiation, describe internal inflorescence bud development, and determine the relationship between internal inflorescence bud development and bloom period the next spring in two southern highbush blueberry [SHB (Vaccinium corymbosum interspecific hybrids)] cultivars. ‘Emerald’ and ‘Jewel’ SHB buds were collected beginning in late summer until shoot growth cessation in late fall for dissection and identification of organ development. Inflorescence bud frequency and number, vegetative and inflorescence bud length and width throughout development, and bloom were also assessed. Inflorescence bud initiation occurred earlier in ‘Emerald’ compared with ‘Jewel’. Five stages of internal inflorescence bud development were defined throughout fall in both cultivars, ranging from a vegetative meristem to early expansion of the inflorescence bud in late fall. ‘Emerald’ inflorescence buds were larger and bloomed earlier, reflecting the earlier inflorescence bud initiation and development. Although inflorescence bud initiation occurred earlier in ‘Emerald’ compared with ‘Jewel’, the pattern of development was not different. Timing of inflorescence bud initiation influenced timing of bloom with earlier initiation resulting in earlier bloom.


2018 ◽  
Vol 16 (3) ◽  
pp. e07SC01
Author(s):  
Márcia Carvalho ◽  
Manuela Matos ◽  
Valdemar Carnide

Vaccinium crops offer a variety of benefits for human health due their high levels of antioxidants. Genetic diversity between two Vaccinium species (sixteen cultivars of Vaccinium corymbosum and three wild populations of Vaccinium myrtillus) were evaluated using Inter Simple Sequence Repeat (ISSR) markers. In V. corymbosum 74 polymorphic markers corresponding to 83.2% of polymorphism were obtained while in V. myrtillus only four polymorphic markers corresponding to 83.2% and 10.6% of polymorphism were observed. The dendrogram obtained showed a clear division into two distinct groups corresponding to the two analyzed species. V. corymbosum group is divided in different sub-clusters based on cultivars pedigree relationships. Twenty-eight specific bands were detected in total; 6 for V. corymbosum and 22 for V. myrtillus. Results allowed the selection of five primers due it potential to detect specific bands in the two species. These markers could be useful for identifying species and cultivars and consequently help in the management of germplasm collections and in breeding programs.


HortScience ◽  
1994 ◽  
Vol 29 (4) ◽  
pp. 324-326 ◽  
Author(s):  
Creighton L. Gupton ◽  
James M. Spiers

To determine the effects of pollen source on blueberry production, we made a partial diallel set of crosses involving seven rabbiteye (Vaccinium ashei Reade) and seven southern highbush (SH; V. corymbosum L.) parents. Pollination of rabbiteye blueberry flowers with SH pollen reduced fruit set, seeds per berry, and berry weight and increased fruit development period (FDP) compared to pollination with rabbiteye pollen. Pollination of SH flowers with rabbiteye pollen resulted in about the same fruit set and FDP but fewer seeds per berry and slightly lower berry weight compared to intraspecific pollination. Self-pollination significantly decreased the number of seeds per berry and berry weight and increased FDP in SH. Pollination of rabbiteye and SH flowers with mixed pollen produced the same results as intraspecific pollination. Using `Tifblue' and `Baldwin' (rabbiteye) as the pollen parent significantly increased FDP in rabbiteye blueberry. Using `Georgiagem' and `Cape Fear' as pollen parents produced the longest FDP, and using `O'Neal' and `Gulfcoast' produced the shortest FDP in SH blueberry. The heaviest berries were produced by using `Blue Ridge', `O'Neal', and `Gulfcoast' (SH) as pollen parents on SH females. These results suggest that xenia possibly could be used to increase yield and reduce FDP in blueberry.


HortScience ◽  
2013 ◽  
Vol 48 (7) ◽  
pp. 835-843 ◽  
Author(s):  
Jessica L. Gilbert ◽  
Michael L. Schwieterman ◽  
Thomas A. Colquhoun ◽  
David G. Clark ◽  
James W. Olmstead

Previously, when selecting for flavor in the University of Florida southern highbush blueberry (SHB, Vaccinium corymbosum L. hybrids) breeding program, sugar/acid ratios and breeder preference were the only factors considered. A more precise method of evaluating flavor would include volatile compounds that may also contribute to the flavor experience. Therefore, volatile profiles of five SHB cultivars (Farthing, FL01-173, Scintilla, Star, and Sweetcrisp) were compared using gas chromatography–mass spectrometry. All cultivars were harvested on four separate dates within the harvest season, and fruit from each cultivar were also harvested at four developmental stages on the first harvest date. Among the cultivars, soluble solids content and volatile production tended to increase with fruit maturity, whereas titratable acidity decreased. All volatile components were more variable than measures of sugars and acids during the harvest season. Many of the volatiles present varied significantly between harvest dates, resulting in significant genotype × environment interactions during the harvest season. A closer examination of linalool, trans-2-hexenol, trans-2-hexenal, hexanal, and 1-penten-3-ol, five volatile compounds commonly associated with blueberry flavor, showed cultivar, developmental stage, and harvest date differences for each volatile. ‘Star’ experienced the least variation through the harvest period.


2015 ◽  
Vol 25 (2) ◽  
pp. 185-191 ◽  
Author(s):  
Jeffrey G. Williamson ◽  
Luis Mejia ◽  
Bradley Ferguson ◽  
Paul Miller ◽  
Dorota Z. Haman

Nonweighing drainage lysimeters were used to measure seasonal water use of mature ‘Emerald’ southern highbush blueberry (SHB; Vaccinium corymbosum interspecific hybrid) plants grown in pine bark beds and in pine bark amended soil in north central Florida. In the absence of rain, irrigation was applied daily with microsprinklers at ≈120% to 175% of reference evapotranspiration as either single or split applications. Leachate was collected and its volume determined from each lysimeter at 6- to 10-day intervals throughout the study. Water use, expressed as L/plant, was calculated as the difference between the amount of irrigation/rain added to lysimeters and the amount of leachate collected from lysimeters during each measurement period. Average daily water use was calculated for monthly intervals beginning in Apr. 2010 and ending in Sept. 2012. Water use increased rapidly during spring through the final stages of fruit ripening and harvest (May) with peak water use occurring during mid to late summer (July, August, and September). Plants grown in pine bark beds used more water than plants in pine bark amended soil during Apr., May, and Dec. 2010, Feb. 2011, and Mar. 2012, but there were no differences during the periods of highest water use. No differences in water use were observed between single or split-application irrigation treatments. Monthly averages for daily water use during the 30-month period ranged from ≈1.75 L/plant in January to ≈8.0 L/plant in mid to late summer. Mean monthly crop coefficient values during the 30-month period ranged from 0.44 in February to 0.86 in September. Canopy volume, yield, and mean berry weight were unaffected by soil or irrigation treatments.


HortScience ◽  
1999 ◽  
Vol 34 (4) ◽  
pp. 607-610 ◽  
Author(s):  
B.E. Maust ◽  
J.G. Williamson ◽  
R.L. Darnell

Floral budbreak and fruit set in many southern highbush blueberry (SHB) cultivars (hybrids of Vaccinium corymbosum L. with other species of Vaccinium) begin prior to vegetative budbreak. Experiments were conducted with two SHB cultivars, `Misty' and `Sharpblue', to test the hypothesis that initial flower bud density (flower buds/m cane length) affects vegetative budbreak and shoot development, which in turn affect fruit development. Flower bud density of field-grown plants was adjusted in two nonconsecutive years by removing none, one-third, or two-thirds of the flower buds during dormancy. Vegetative budbreak, new shoot dry weight, leaf area, and leaf area: fruit ratios decreased with increasing flower bud density in both cultivars. Average fruit fresh weight and fruit soluble solids decreased in both cultivars, and fruit ripening was delayed in `Misty' as leaf area: fruit ratios decreased. This study indicates that because of the inverse relationship between flower bud density and canopy establishment, decreasing the density of flower buds in SHB will increase fruit size and quality and hasten ripening.


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