Vegetative and Reproductive Traits of Two Southern Highbush Blueberry Cultivars Grafted onto Vaccinium arboreum Rootstocks

Vaccinium arboreum Marsh is a wild species adapted to high pH (above 6.0) and low organic matter soils (below 2.0%). The use of V. arboreum rootstocks may be a viable option to increase soil adaptation of southern highbush blueberry (SHB) (Vaccinium corymbosum interspecific hybrid) under marginal soil conditions. The objective of this research was to evaluate the vegetative and reproductive traits of ‘Farthing’ and ‘Meadowlark’ SHB own-rooted or grafted onto V. arboreum and grown in pine bark–amended or nonamended soil. The study was conducted from 2012 through 2014 at a research center in Citra, FL, and a grower’s farm in Archer, FL. Vaccinium arboreum rootstock generally induced the same effects in both cultivars. Grafted plants in both soil treatments had reduced canopy growth in the first year after field planting compared with own-rooted plants in amended soil. However, canopy volume of grafted plants was greater than own-rooted plants in nonamended soil and similar to own-rooted plants in amended soil 2 years after field planting for ‘Meadowlark’ and 3 years after planting for ‘Farthing’. Fruit yield was lower in grafted plants compared with own-rooted plants in the first fruiting year (2 years after field planting). By the second fruiting year, yields of grafted plants were similar to or greater than yields of own-rooted plants when grown in nonamended soil, whereas in amended soil, yields of grafted plants were similar to yields of own-rooted plants. Grafted plants had greater mean berry weight, but lower berry firmness; however, the firmness values were still considered acceptable (greater than 160 g⋅mm−1). Internal fruit quality [total soluble solids (TSS) and total titratable acidity (TTA)] was not consistently affected by the rootstock or soil treatments. These results suggest that grafting SHB onto V. arboreum does not increase yield in the establishment years compared with own-rooted SHB when grown in amended soils, but may have the ability to increase yield with no negative effects on fruit quality when grown in nonamended soils.

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Impacts of Vaccinium arboreum Rootstocks on Vegetative Growth and Yield in Two Southern Highbush Blueberry Cultivars

HortScience ◽

10.21273/hortsci14585-19 ◽

2020 ◽

Vol 55 (1) ◽

pp. 40-45

Author(s):

Rebecca L. Darnell ◽

Jeffrey G. Williamson ◽

Deanna C. Bayo ◽

Philip F. Harmon

Keyword(s):

Pine Bark ◽

Soluble Solids ◽

Growth And Yield ◽

Soil Conditions ◽

Highbush Blueberry ◽

Leaf Scorch ◽

Canopy Volume ◽

Southern Highbush ◽

Vaccinium Arboreum ◽

Bacterial Leaf Scorch

Vaccinium arboreum Marsh is a small tree adapted to low-organic matter soils and is one of the few ericaceous species that tolerates soil pH greater than 6.0. It has a deep root system and is more drought tolerant than cultivated blueberry. The use of V. arboreum as a rootstock for commercial blueberry production has been studied previously in young blueberry plantings. The objective of the current study was to expand on earlier work and evaluate growth, productivity, and tolerance to bacterial leaf scorch (Xylella fastidiosa) in established plantings of own-rooted vs. grafted southern highbush blueberry (SHB). Two field plantings of grafted and own-rooted ‘Meadowlark’ and ‘Farthing’ SHB were established in May 2011: one at the University of Florida–Institute of Food and Agricultural Sciences (UF-IFAS) Plant Science Research and Education Unit in Citra, FL, and the other at a commercial blueberry farm in Archer, FL. At both sites, four rootstock–scion combinations were grown in either pine bark-amended or nonamended soil. Canopy volume was greater in grafted compared with own-rooted ‘Meadowlark’ at both locations throughout the 4 years of the study (2015–18), whereas canopy volume in ‘Farthing’ was not consistently different. For both cultivars and both locations, canopy volume was greater on amended compared with nonamended soil. Although canopy growth was not consistently increased in the grafted compared with own-rooted plants, yield was greater in grafted plants of both cultivars at both locations. Cumulative yield over the 4 years was similar between grafted plants grown on both amended and nonamended soil, and was significantly greater than yield of own-rooted plants on nonamended soil, suggesting the use of this rootstock may decrease the requirement for pine bark amendment. In general, grafted plants produced larger berries, with no negative impacts on fruit soluble solids, titratable acidity, or firmness. ‘Meadowlark’—an SHB cultivar that exhibits high sensitivity to bacterial leaf scorch—displayed decreased development of bacterial leaf scorch symptoms when grafted onto V. arboreum compared with own-rooted plants. These results indicate the potential benefits of grafting SHB onto V. arboreum rootstock, particularly under marginal soil conditions. However, a complete economic analysis that also takes into account any differences in longevity between the two systems must be done to determine whether the benefits of using grafting are feasible financially for the grower.

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Effects of Machine-Harvest Interval on Fruit Quality of Fresh Market Northern Highbush Blueberry

Horticulturae ◽

10.3390/horticulturae7080245 ◽

2021 ◽

Vol 7 (8) ◽

pp. 245

Author(s):

Yixin Cai ◽

Fumiomi Takeda ◽

Brian Foote ◽

Lisa Wasko DeVetter

Keyword(s):

Fruit Quality ◽

Titratable Acidity ◽

Vaccinium Corymbosum ◽

Soluble Solids ◽

Highbush Blueberry ◽

Labor Costs ◽

Fresh Market ◽

Harvest Intervals ◽

Northern Highbush Blueberry

Machine harvesting blueberry (Vaccinium sp.) alleviates labor costs and shortages but can reduce fruit quality. Installation of softer catching surfaces inside modified over-the-row harvesters (modified OTR) and adjusting harvest intervals may improve fruit quality and packout. The objective of this study was to determine the effect of harvest interval on fruit quality of fresh market northern highbush blueberry (Vaccinium corymbosum L.) harvested using a modified OTR. ‘Liberty’ blueberry bushes were harvested by hand or using a modified OTR at 3-, 10-, and 14-day intervals in 2019 and at 7-, 11-, and 14-day intervals in 2020. Hand-harvested ‘Liberty’ had greater packout and firmness than machine-harvested fruit. Machine harvesting at the 3-day interval in 2019, and the 14-day interval in 2020 reduced packout from 70–80% to 60% and 54%, respectively. In 2019, machine harvesting at a 3-day interval overall resulted in fruit with greater firmness, higher titratable acidity (TA), and lower total soluble solids (TSS) and SS/TA, compared to other harvest intervals. In 2020, the 7-day machine-harvest interval had a greater TA and lower TSS/TA, compared to the 11- and 14-day intervals. Overall, modified OTR machine-harvest intervals can be extended to 10–11 days for fresh market northern highbush cultivars such as ‘Liberty’ grown in northwest Washington.

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Potential for Increasing Southern Highbush Blueberry Flavor Acceptance by Breeding for Major Volatile Components

HortScience ◽

10.21273/hortsci.48.7.835 ◽

2013 ◽

Vol 48 (7) ◽

pp. 835-843 ◽

Cited By ~ 12

Author(s):

Jessica L. Gilbert ◽

Michael L. Schwieterman ◽

Thomas A. Colquhoun ◽

David G. Clark ◽

James W. Olmstead

Keyword(s):

Volatile Compounds ◽

Developmental Stages ◽

Titratable Acidity ◽

Vaccinium Corymbosum ◽

Harvest Date ◽

Soluble Solids ◽

Gas Chromatography Mass Spectrometry ◽

Volatile Components ◽

Highbush Blueberry ◽

Southern Highbush

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.

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Seasonal Water Use of Southern Highbush Blueberry Plants in a Subtropical Climate

HortTechnology ◽

10.21273/horttech.25.2.185 ◽

2015 ◽

Vol 25 (2) ◽

pp. 185-191 ◽

Cited By ~ 4

Author(s):

Jeffrey G. Williamson ◽

Luis Mejia ◽

Bradley Ferguson ◽

Paul Miller ◽

Dorota Z. Haman

Keyword(s):

Water Use ◽

Late Summer ◽

Vaccinium Corymbosum ◽

Pine Bark ◽

Highbush Blueberry ◽

Daily Water ◽

Irrigation Treatments ◽

Southern Highbush ◽

Seasonal Water Use ◽

Amended Soil

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.

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Flower Bud Density Affects Vegetative and Fruit Development in Field-grown Southern Highbush Blueberry

HortScience ◽

10.21273/hortsci.34.4.607 ◽

1999 ◽

Vol 34 (4) ◽

pp. 607-610 ◽

Cited By ~ 17

Author(s):

B.E. Maust ◽

J.G. Williamson ◽

R.L. Darnell

Keyword(s):

Leaf Area ◽

Fruit Development ◽

Fruit Size ◽

Dry Weight ◽

Vaccinium Corymbosum ◽

Soluble Solids ◽

Highbush Blueberry ◽

Flower Buds ◽

Flower Bud ◽

Southern Highbush

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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Comparing the Efficacy of Postharvest Cooling Methods to Enhance Fruit Quality and Reduce Salmonella in Artificially Inoculated Southern Highbush Blueberry

HortTechnology ◽

10.21273/horttech04238-19 ◽

2019 ◽

Vol 29 (3) ◽

pp. 314-319 ◽

Cited By ~ 1

Author(s):

Jaysankar De ◽

Aswathy Sreedharan ◽

You Li ◽

Alan Gutierrez ◽

Jeffrey K. Brecht ◽

...

Keyword(s):

Shelf Life ◽

Fruit Quality ◽

Microbiological Quality ◽

Vaccinium Corymbosum ◽

Temperature Management ◽

Air Cooling ◽

Highbush Blueberry ◽

Fresh Market ◽

Southern Highbush

Cooling procedures used by blueberry (Vaccinium sp.) growers often may include delays up to 24 hours that can damage the fruit through rough handling and adverse temperatures, thereby potentially compromising quality and, subsequently, safety. The objectives of this experiment were to compare forced-air cooling (FAC) compared to hydrocooling without sanitizer (HW) and hydrocooling with sanitizer (HS) regarding the quality and shelf life of southern highbush blueberry [SHB (Vaccinium corymbosum)] and to determine the efficacy of these treatments for reducing Salmonella in SHB. Freshly harvested SHB that were inoculated with a five-serovar cocktail of rifampin-resistant Salmonella were rapidly chilled by FAC or hydrocooling (HW and HS) using a laboratory model system. FAC did not show any significant reduction (P > 0.05) in Salmonella or in the effects on the microbiological quality of blueberries. HW and HS reduced Salmonella by ≈2 and >4 log cfu/g SHB, respectively, on day 0. These postharvest treatments were also evaluated for their ability to help maintain fruit quality throughout a storage period of 21 days at 1 °C. Hydrocooling (both HS and HW) provided more rapid cooling than FAC. Hydrocooled blueberries showed significant weight gain (P < 0.05), whereas FAC resulted in a slight, but insignificant (P > 0.05), reduction in final weight. The results of hydrocooling, both HS and HW, shown in this study could help to extend the shelf life while maintaining or increasing the microbiological quality of fresh market blueberries. Information obtained by this study can be used for developing the best temperature management practices to maintain the postharvest safety and quality of blueberries.

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Optimizing Nitrogen Fertigation Rates for Young Southern Highbush Blueberry

Agronomy ◽

10.3390/agronomy10030389 ◽

2020 ◽

Vol 10 (3) ◽

pp. 389

Author(s):

Yang Fang ◽

Jeffrey Williamson ◽

Rebecca Darnell ◽

Yuncong Li ◽

Guodong Liu

Keyword(s):

Fruit Quality ◽

Ground Cover ◽

Vaccinium Corymbosum ◽

Fruit Yield ◽

Growth And Yield ◽

Nutrient Concentrations ◽

Highbush Blueberry ◽

Soil Nitrate ◽

Southern Highbush ◽

N Rates

The commercial blueberry industry in Florida has expanded significantly in both acreage and value in the past several years. The southern highbush blueberry (SHB, Vaccinium corymbosum L. interspecific hybrid) is the major blueberry type grown in Florida. The nitrogen (N) demand of young SHB differs from the northern highbush blueberry (NHB, V. corymbosum L.) and from mature blueberry plants. The objective of this study was to optimize fertigated N rates for the growth and yield of young SHB plants. One-year-old ‘Emerald’ and ‘Farthing’ plants were fertilized with 32N-0P-0K through drip irrigation at annual rates of 0, 42, 84, 168, and 336 kg N ha−1. Soil nitrate levels at multiple depths were measured along with leaf nutrient concentration, percent canopy ground cover, fruit yield and fruit quality. The results indicated that N rates had no significant effect on leaf nutrient concentrations. Greater N rates advanced bloom and harvest, increased percentage of ground cover (an indicator of canopy size), fruit yield and berry numbers per plant, but decreased mean berry diameter and weight. The soil nitrate results from both ‘Emerald’ and ‘Farthing’ revealed that the 336 kg N ha−1 treatment had a significantly greater risk for nitrate leaching than the lower N treatments in spring. The effect of N rates on fruit quality varied with cultivar and harvest season. The linear plateau regression of fruit yield and N rates indicated that the maximum yield reached at the annual N fertigation rate of 222 kg ha−1 for ‘Emerald’ and 206 kg ha−1 for ‘Farthing’.

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Potential of Deficit Irrigation, Irrigation Cutoffs, and Crop Thinning to Maintain Yield and Fruit Quality with Less Water in Northern Highbush Blueberry

HortScience ◽

10.21273/hortsci11533-16 ◽

2017 ◽

Vol 52 (4) ◽

pp. 625-633 ◽

Cited By ~ 3

Author(s):

Khalid F. Almutairi ◽

David R. Bryla ◽

Bernadine C. Strik

Keyword(s):

Water Use ◽

Fruit Quality ◽

Deficit Irrigation ◽

Vaccinium Corymbosum ◽

Soluble Solids ◽

Highbush Blueberry ◽

Stem Water Potential ◽

Full Irrigation ◽

Northern Highbush Blueberry ◽

Stem Water

Drought and mandatory water restrictions are limiting the availability of irrigation water in many important blueberry growing regions, such as Oregon, Washington, and California. New strategies are needed to maintain yield and fruit quality with less water. To address the issue, three potential options for reducing water use, including deficit irrigation, irrigation cutoffs, and crop thinning, were evaluated for 2 years in a mature planting of northern highbush blueberry (Vaccinium corymbosum L. ‘Elliott’). Treatments consisted of no thinning and 50% crop removal in combination with either full irrigation at 100% of estimated crop evapotranspiration (ETc), deficit irrigation at 50% ETc (applied for the entire growing season), or full irrigation with irrigation cutoff for 4–6 weeks during early (early- to late-green fruit) or late (fruit coloring to harvest) stages of fruit development. Stem water potential was similar with full and deficit irrigation but, regardless of crop thinning, declined by 0.5–0.6 MPa when irrigation was cutoff early and by >2.0 MPa when irrigation was cutoff late. In one or both years, the fruiting season was advanced with either deficit irrigation or late cutoff, whereas cutting off irrigation early delayed the season. Yield was unaffected by deficit irrigation in plants with a full crop load but was reduced by an average of 35% when irrigation was cutoff late each year. Cutting off irrigation early likewise reduced yield, but only in the 2nd year when the plants were not thinned; however, early cutoff also reduced fruit soluble solids and berry weight by 7% to 24% compared with full irrigation. Cutting off irrigation late produced the smallest and firmest fruit with the highest soluble solids and total acidity among the treatments, as well as the slowest rate of fruit loss in cold storage. Deficit irrigation had the least effect on fruit quality and, based on these results, appears to be the most viable option for maintaining yield with less water in northern highbush blueberry. Relative to full irrigation, the practice reduced water use by 2.5 ML·ha−1 per season.

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New Foliar-applied Biofilm Had No Impact on Splitting or Fruit Quality in ‘Elliott’ and ‘Legacy’ Blueberry in Oregon

HortTechnology ◽

10.21273/horttech04196-18 ◽

2018 ◽

Vol 28 (6) ◽

pp. 836-842

Author(s):

Amanda J. Vance ◽

Bernadine C. Strik

Keyword(s):

Fruit Quality ◽

Color Change ◽

Vaccinium Corymbosum ◽

Sprinkler System ◽

Soluble Solids ◽

Highbush Blueberry ◽

Fresh Market ◽

Visual Rating ◽

Berry Size ◽

Current Product

Fresh market blueberry (Vaccinium sp.) sales require high-quality, firm fruit with no significant defects. A new phospholipid biofilm product was developed to reduce splitting and increase firmness when applied directly to blueberry fruit. Two trials were undertaken to test the effects of the biofilm using various application timings and methods. In highbush blueberry cultivar Elliott (Vaccinium corymbosum), four treatments included: 1) rate and timing on the current product label (5- to 10-mm berry size, 10% to 20% color change, and between the first and second harvests), 2) addition of a preharvest timing (5- to 10-mm berry size, 10% to 20% color change, and 7 to 10 days preharvest); 3) starting applications later (10% to 20% color change, 7 to 10 days preharvest, and between the first and second harvests), and 4) a water-sprayed control. Biofilm was applied at a rate of 2 qt/acre for all applications. In highbush blueberry cultivar Legacy (Vaccinium corymbosum × Vaccinium sp.), the same volume of biofilm was applied via an airblast sprayer or through an overhead sprinkler system typically used for chemigation and compared with a water-sprayed control. Data collected included yield (in ‘Elliott’), berry weight, firmness, skin toughness, total soluble solids (TSS), weight loss during storage, percent splitting (in ‘Legacy’), and a visual rating, evaluated on the day of harvest and about 14 and 28 days postharvest. There were no visual defects caused by application of biofilm. Compared with the controls in either study, biofilm had no consistent impact on fruit quality, firmness, shelf life, yield in ‘Elliott’, or splitting in ‘Legacy’.

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Mechanical Harvesting and Postharvest Storage of Two Southern Highbush Blueberry Cultivars Grafted onto Vaccinium arboreum Rootstocks

HortScience ◽

10.21273/hortsci11323-16 ◽

2016 ◽

Vol 51 (12) ◽

pp. 1503-1510 ◽

Cited By ~ 7

Author(s):

Bruno Casamali ◽

Jeffrey G. Williamson ◽

Alisson P. Kovaleski ◽

Steven A. Sargent ◽

Rebecca L. Darnell

Keyword(s):

Soil Amendments ◽

Soil Treatment ◽

Highbush Blueberry ◽

Fresh Market ◽

Postharvest Storage ◽

Berry Quality ◽

Harvesting Efficiency ◽

Southern Highbush ◽

Vaccinium Arboreum ◽

Amended Soil

The profitability of the fresh market blueberry industry in many areas is constrained by the extensive use and cost of soil amendments, high labor requirements for hand harvesting, and the inefficiencies of mechanical harvesters. Vaccinium arboreum Marsh is a wild species that has wide soil adaptation and monopodial growth habit. It has the potential to be used as a blueberry rootstock, expanding blueberry production to marginal soil and improving the mechanical harvesting efficiency of cultivated blueberry. The objectives of this research were to compare yield, berry quality, and postharvest fruit storage of own-rooted vs. grafted southern highbush blueberry (SHB) cultivars (Farthing and Meadowlark) grown on amended vs. nonamended soil and either hand or mechanical harvested. Yields of hand-harvested SHB during the first two fruiting years were generally greater in own-rooted plants grown on amended soil compared with own-rooted plants on nonamended soil or grafted plants on either soil treatment. However, by the second fruiting year, hand-harvest yields of grafted SHB were ≈80% greater than own-rooted plants when grown in nonamended soil. Yields of mechanical-harvested SHB grafted on V. arboreum and grown in either soil treatment were similar to yields of mechanical-harvested own-rooted plants in amended soil the second fruiting year, and greater than yields of own-rooted plants in non-amended soil. In general, mechanical harvesting reduced marketable yield ≈40% compared with hand harvesting. However, grafted plants reduced ground losses during harvest by ≈35% compared with own-rooted plants for both cultivars. Mechanical-harvested berries had a greater total soluble solids:total titratable acidity ratio (TSS:TTA) than hand-harvested berries, and berries harvested toward the end of the harvest season had a greater TSS:TTA than those from early-season harvests. As postharvest storage time increased, berry appearance ratings decreased and berry softness and shriveling increased, particularly in mechanical-harvested compared with hand-harvested berries. Firmness of mechanical-harvested berries decreased during storage, whereas firmness of hand-harvested berries remained relatively stable. However, fruit quality at harvest and during postharvest storage was unaffected by V. arboreum rootstocks or lack of pine bark amendment. This study suggests that using V. arboreum as a rootstock in an alternative blueberry production system has the potential to decrease the use of soil amendments and increase mechanical harvesting efficiency.

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