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

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

HortScience ◽

10.21273/hortsci.51.7.880 ◽

2016 ◽

Vol 51 (7) ◽

pp. 880-886 ◽

Cited By ~ 3

Author(s):

Bruno Casamali ◽

Rebecca L. Darnell ◽

Alisson P. Kovaleski ◽

James W. Olmstead ◽

Jeffrey G. Williamson

Keyword(s):

Fruit Quality ◽

Reproductive Traits ◽

Vaccinium Corymbosum ◽

Soluble Solids ◽

Soil Conditions ◽

Highbush Blueberry ◽

Canopy Volume ◽

Southern Highbush ◽

Vaccinium Arboreum ◽

Amended Soil

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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Effects of Fertilizer Rate and Form on Vegetative Growth and Yield of Southern Highbush Blueberry in Pine Bark Culture

HortTechnology ◽

10.21273/hortsci.19.1.152 ◽

2009 ◽

Vol 19 (1) ◽

pp. 152-157 ◽

Cited By ~ 10

Author(s):

J.G. Williamson ◽

E.P. Miller

Keyword(s):

Root Systems ◽

Fruit Yield ◽

Pine Bark ◽

Growth And Yield ◽

Highbush Blueberry ◽

Fertilizer Rate ◽

Liquid Fertilizer ◽

Berry Weight ◽

Canopy Volume ◽

Southern Highbush

Growth and yield of ‘Misty’ and ‘Star’ southern highbush blueberry (Vaccinium corymbosum hybrid) plants that were grown in pine bark culture were evaluated under several rates of granular or liquid fertilizers. Granular fertilizer resulted in larger canopy volumes and slightly greater annual fruit yield than liquid fertilizer. In 2003 and 2004, canopy growth increased linearly as fertilizer rate increased up to the highest rate tested [81 g nitrogen (N), 11.8 g phosphorus (P), and 44.6 g potassium (K) per plant per year]. Similarly, a positive relationship was found for fruit yield and fertilizer rate during all 3 years. Berry yield was positively correlated with canopy size, and there was no relationship between fertilizer rate and berry yield per canopy volume, indicating that yield and canopy volume increased proportionally with increased fertilizer rate. Mean ‘Star’ berry weight was greater for granular fertilizer treatments than for liquid fertilizer treatments, but mean berry weight of ‘Misty’ was unaffected by fertilizer form. At the end of the experiment, visual examination of eight plants excavated by hand indicated that root systems of blueberry plants were primarily located in the pine bark layer with very few roots penetrating into the underlying soil. Limited water and nutrient holding capacities of pine bark, coupled with frequent irrigations to the shallow root systems in pine bark culture, probably resulted in considerable nutrient leaching and a high fertilizer requirement.

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Effects of Fertilizer Rate on Growth and Fruiting of Containerized Southern Highbush Blueberry

HortScience ◽

10.21273/hortsci.43.1.143 ◽

2008 ◽

Vol 43 (1) ◽

pp. 143-145 ◽

Cited By ~ 7

Author(s):

Wendy L. Wilber ◽

Jeffrey G. Williamson

Keyword(s):

Plant Growth ◽

Pine Bark ◽

Growth And Yield ◽

Highbush Blueberry ◽

Flower Bud ◽

Soil Culture ◽

Fertilizer Rate ◽

Stem Blight ◽

Southern Highbush ◽

Fertilizer Rates

The effects of fertilizer rate and composition on growth and fruiting of ‘Misty’ and ‘Star’ southern highbush blueberry were evaluated in a containerized production system using pine bark medium. Two fertilizer analyses (12N–1.8P–46.6K and 12N–5.2P–9.9K) and three fertilizer rates were used. Plant growth and fruiting were unaffected by fertilizer analysis. Growth and fruit yield of ‘Star’ increased linearly with increasing fertilizer rate. For ‘Misty’, plant growth and yield were reduced at the highest fertilizer rate as a result of a high incidence of blueberry stem blight associated with that treatment. Flower bud density was highest for the ‘Misty’ plants receiving the high fertilizer rate and this may have resulted in excessive fruit set leading to stress-induced blueberry stem blight. Optimum fertilizer rates for young southern highbush blueberry plants grown in containerized pine bark systems appear to be cultivar-specific and similar to fertilizer requirements in soil culture.

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First Report of Bacterial Leaf Scorch Caused by Xylella fastidiosa on Southern Highbush Blueberry in Florida

Plant Disease ◽

10.1094/pdis-93-11-1220a ◽

2009 ◽

Vol 93 (11) ◽

pp. 1220-1220 ◽

Cited By ~ 5

Author(s):

P. F. Harmon ◽

D. L. Hopkins

Keyword(s):

Xylella Fastidiosa ◽

Vaccinium Corymbosum ◽

Pathogen Transmission ◽

Highbush Blueberry ◽

Disease Symptoms ◽

Leaf Scorch ◽

Three Samples ◽

Southern Highbush ◽

Das Elisa ◽

Bacterial Leaf Scorch

In May of 2008, samples of southern highbush blueberry (interspecific Vaccinium corymbosum hybrids) exhibiting marginal leaf necrosis were collected at a farm in Interlachen, FL. The cv. Star showed severe leaf scorch, partial defoliation, and a generally unthrifty growth structure of many thin twigs as has been observed in Georgia (1). The block of Star plants was approximately 10 years old and incidence of the disease was 100%. The grower reported the planting had become increasingly unproductive in the most recent 4 to 5 years. Plants of the cv. Windsor also showed scorch symptoms and yellow-to-red discoloration of leaves. Proportionally fewer Windsor plants showed disease symptoms than Star plants and the disease was not as severe on this cultivar on the basis of visual estimates at the time. Each sample consisted of 5 to 10 cuttings of spring wood with attached leaves showing marginal necrosis taken from a single plant. Three samples, two from Star plants and one from a Windsor plant, were divided into two subsamples each. One subsample was submitted to Agdia for Xylella fastidiosa double-antibody sandwich (DAS)-ELISA assay (TSE XF; Agdia Inc., Elkhart IN). All three samples were reported as positive for X. fastidiosa by DAS-ELISA. A number of asymptomatic plants from this farm and other additional farms were tested in the same manner and results were negative. The other subsample was used for isolation of the causal bacterium. Petioles and main veins from symptomatic leaves were surface disinfested in 1% sodium hypochlorite, cut into segments (0.5 cm), and squeezed with forceps or pliers. Sap that exuded from the segment was blotted directly onto periwinkle wilt medium (2). Bacterial colonies consistent in morphology with X. fastidiosa that were DAS-ELISA positive were obtained from all three samples. One isolate from each sample was inoculated into four Star plants each with the pin-pricking method (3). Leaf scorch symptoms were first observed 8 weeks after inoculation. By 12 weeks after inoculation, all plants inoculated with the three isolates had developed symptoms, including defoliation. Plants inoculated without bacteria showed no symptoms. X. fastidiosa was reisolated from symptomatic plants. Bacterial leaf scorch is an important emerging disease that threatens the southern highbush blueberry industry in the south. On certain cultivars like Star, the potential to reduce yield appears to be great. Differences between cultivars are likely, but have not yet been explored. Additional research is needed into the epidemiology of the disease and potential vectors of pathogen transmission. References: (1) C. Chang et al. HortScience 44:413, 2009. (2) M. Davis et al. Curr. Microbiol. 6:309, 1981. (3) D. L. Hopkins et al. Phytopathology 75:713, 1985.

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Nutrient Assimilation in Southern Highbush Blueberry and Implications for the Field

HortTechnology ◽

10.21273/horttech.25.4.460 ◽

2015 ◽

Vol 25 (4) ◽

pp. 460-463 ◽

Cited By ~ 5

Author(s):

Rebecca L. Darnell ◽

Bruno Casamali ◽

Jeffrey G. Williamson

Keyword(s):

Organic Matter ◽

Soil Ph ◽

Nutrient Availability ◽

Vaccinium Corymbosum ◽

Growth And Yield ◽

Soil Conditions ◽

Highbush Blueberry ◽

High Organic Matter ◽

Mineral Soils ◽

Southern Highbush

Successful blueberry (Vaccinium sp.) cultivation typically requires soils with low pH, high organic matter, readily available iron, and nitrogen (N) in the ammonium form. Growth of blueberry on typical mineral soils (higher pH, low organic matter) is reduced. Although soil pH effects on nutrient availability and uptake are known, it is unclear if the requirement for low soil pH in blueberry production is due to effects on nutrient availability/uptake or is a more direct effect of rhizosphere pH on root function. In addition, it is unclear if the requirement for high organic matter (soil amendments) is related directly to nutrient availability/uptake. Several studies have examined the use of rootstocks to increase soil adaptation of blueberry and some of these rootstocks have been found to increase plant vigor and yield. In particular, we have investigated whether sparkleberry (Vaccinium arboreum)—a wild blueberry species that is adapted to high pH and low organic matter soils—could be used as a rootstock for commercial production of blueberry on mineral soils. Our work indicates that both nitrate (NO3−) and iron (Fe) uptake and assimilation are greater in sparkleberry compared with southern highbush blueberry [SHB (Vaccinium corymbosum interspecific hybrid)]. This is correlated with increased activity of nitrate reductase (NR) and iron chelate reductase, the rate limiting enzymes for NO3− and Fe acquisition, respectively. Field studies comparing growth and yield of own-rooted vs. grafted ‘Meadowlark’ and ‘Farthing’ SHB in amended vs. nonamended soils are ongoing. In general, own-rooted plants on amended soils exhibit greater growth than own-rooted on nonamended soils, while grafted plants in either soil system exhibit intermediate growth. Yields generally followed this pattern. Our preliminary results suggest that tolerance of SHB to mineral soils is greater when plants are grafted onto sparkleberry than when grown on their own roots. However, growth and yield of grafted plants grown under mineral soil conditions may not equal or exceed that of own-rooted plants grown under optimum soil conditions, at least in the first years after field planting. Longer term studies are necessary to fully evaluate the potential of using sparkleberry and other blueberry species as rootstocks for SHB and northern highbush blueberry (V. corymbosum).

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Effects of Pecan Bacterial Leaf Scorch on Growth and Yield Components of Cultivar Cape Fear

Plant Disease ◽

10.1094/pdis.2003.87.3.259 ◽

2003 ◽

Vol 87 (3) ◽

pp. 259-262 ◽

Cited By ~ 9

Author(s):

R. S. Sanderlin ◽

K. I. Heyderich-Alger

Keyword(s):

Yield Components ◽

Growth And Yield ◽

Yield Reduction ◽

Phosphorus Concentration ◽

Potential Yield ◽

Leaf Scorch ◽

Significant Yield ◽

Number Of Leaves ◽

Cape Fear ◽

Bacterial Leaf Scorch

Pecan bacterial leaf scorch (PBLS) recently was recognized to be caused by the bacterium Xylella fastidiosa. The objective of this work was to compare certain tree growth and yield components of trees with and without PBLS. The evaluations were made for 3 years (1999 to 2001) on the disease-sensitive cv. Cape Fear. At nut maturity (October) each year, the number of leaves and leaflets and the leaflet weight were significantly smaller on terminals from trees with leaf scorch than on terminals from trees not infected with X. fastidiosa. Similar amounts of defoliation occurred on bearing and nonbearing terminals. The symptomatic terminals averaged 58% fewer leaflets at the end of the growing season. The weight of terminals from diseased trees was significantly lower in 2 of the 3 years for nonbearing terminals compared with similar terminals from uninfected trees. Terminals of infected trees generally were not significantly shorter than terminals of uninfected trees. The weight of the nuts from terminals with leaf scorch was lower than the weight from uninfected trees each year. The primary effect was on kernel development, which averaged 16% lower weight. Phosphorus concentration was slightly but significantly lower in infected leaflets during October in three of six comparisons. There were no other consistent differences in the concentration of nine other elements in leaflets between diseased and uninfected terminals. PBLS is capable of causing economically significant yield reductions. Because the disease is chronic, the potential yield reduction over the life of a tree is large on disease-sensitive trees.

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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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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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