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A growing number of metagenomics-based approaches have been used for the discovery of viruses in insects, cultivated plants, and water in agricultural production systems. In this study, sixteen blueberry root transcriptomes from eight clonally propagated blueberry plants of cultivar ‘Emerald’ (interspecific hybrid of Vaccinium corymbosum and V. darrowi) generated as part of a separate study on varietal tolerance to soil salinity were analyzed for plant viral sequences. The objective was to determine if the asymptomatic plants harbored the latent blueberry red ringspot virus (BRRV) in their roots. The only currently known mechanism of transmission of BRRV is through vegetative propagation; however, the virus can remain latent for years with some plants of ‘Emerald’ never developing red ringspot symptoms. Bioinformatic analyses of ‘Emerald’ transcriptomes using de novo assembly and reference-based mapping approaches yielded eight complete viral genomes of BRRV (genus Soymovirus, family Caulimoviridae). Validation in vitro by PCR confirmed the presence of BRRV in 100% of the ‘Emerald’ root samples. Sequence and phylogenetic analyses showed 94% to 97% nucleotide identity between BRRV genomes from Florida and sequences from Czech Republic, Japan, Poland, Slovenia, and the United States. Taken together, this study documented the first detection of a complete BRRV genome from roots of asymptomatic blueberry plants and in Florida through in silico analysis of plant transcriptomes.

Blueberry (Vaccinium spp.) plants are exposed to existing and emerging viruses as a result of expanding acreage of blueberry plantations across the world, primarily in North America. Since blueberry is cultivated in areas where there are wild Vaccinium spp., there is increasing risk of virus movement between wild and cultivated blueberries. This is theoretically possible because viruses can spread from commercial cultivars to native species and vice versa causing the spread of existing and new viruses. The occurrence of these viruses in blueberry can be devastating to the industry considering the cost for cultivation and production of this perennial crop. However, the advent of high-throughput sequencing and bioinformatic sequence analysis have allowed for rapid identification of known and novel viruses in any crop including blueberry, thus facilitating proper intervention in response to serious viral diseases. In this paper, we aim to focus on the current status of known and novel viruses emerging in blueberry worldwide, which may impact the blueberry industry.

To determine how the dormancy-breaking agent hydrogen cyanamide (HC) advances budbreak in peach (Prunus persica), this study compared the transcriptome of buds of low-chill ‘TropicBeauty’ peach trees treated with 1% (v/v) HC and that of nontreated trees at 3 and 7 days after treatment (DAT), respectively, using an RNA sequencing analysis. The peak of total budbreak occurred 6 weeks earlier in the HC-treated trees (at 32 DAT) than the nontreated trees (at 74 DAT). There were 1312 and 1095 differentially expressed genes (DEGs) at 3 and 7 DAT, respectively. At 3 DAT, DEGs related to oxidative stress, including the response to hypoxia, lipid oxidation, and reactive oxygen species (ROS) metabolic process, were upregulated in HC-treated buds. Additionally, DEGs encoding enzymes for ROS scavenging and the pentose phosphate pathway were upregulated at 3 DAT but they were not differently expressed at 7 DAT, indicating a temporary demand for defense mechanisms against HC-triggered oxidative stress. Upregulation of DEGs for cell division and development at 7 DAT, which were downregulated at 3 DAT, suggests that cell activity was initially suppressed but was enhanced within 7 DAT. At 7 DAT, DEGs related to cell wall degradation and modification were upregulated, which was possibly responsible for the burst of buds. The results of this study strongly suggest that HC induces transient oxidative stress shortly after application, leading to the release of bud dormancy and, subsequently, causing an increase in cell activity and cell wall loosening, thereby accelerating budbreak in peach.

Reproductive Growth and Development of Blueberry (HS976/HS220) This 7-page fact sheet discusses flower bud initiation and development, pollination and fruit set, fruit development and yield, and the use of plant growth regulators. Written by J. G. Williamson, J. W. Olmstead, and P. M. Lyrene, and published by the UF Department of Horticultural Sciences, February 2012. http://edis.ifas.ufl.edu/hs220

‘Flicker’ is a southern highbush blueberry (SHB, Vaccinium corymbosum) cultivar frequently selected by growers in Central and South Florida. In 2014, several growers in Central Florida experienced issues with anthracnose stem lesions and twig dieback on ‘Flicker’, resulting in a reduction in new plantings and the removal of many existing plantings. The objective of this study was to determine the level of anthracnose susceptibility of certain commercially available SHB cultivars, which information can be used to limit further use of susceptible cultivars in the University of Florida blueberry breeding program. The screening was performed using a spray inoculation of a virulent Colletotrichum gloeosporioides isolate onto whole V. corymbosum plants, followed by measurement of incidence and severity of disease over time. In repeated experiments, ‘Flicker’ and two other cultivars had a significantly higher mean number of lesions and area under the disease progress curve (AUDPC) than any other tested cultivar, and in both experiments, the observed lesions were similar in many respects to those previously reported on northern highbush blueberry (also V. corymbosum). Although the results of these experiments may ultimately indicate that Flicker has a unique genetic susceptibility to this form of anthracnose among SHB cultivars commercially grown in Florida, screening of additional cultivars must be performed for confirmation.

Blueberry (Vaccinium spp.) is a specialty crop with expanding production and consumption worldwide. Southern Highbush Blueberries (SHB) require few chilling hours and include early-ripening cultivars which can be harvested in an early market window making the crop more profitable for growers in sub-tropical regions. To expand the marketability of the crop, fruit breeders are seeking to meet the current demand for fruit quality. To this end, this study gathered sensory measurements (firmness, sweetness, sourness, blueberry flavor, green flavor and off-flavors), chemical (pH, titratable acidity and soluble solids concentration), and physical attributes (compression force) on six SHB cultivars, in order to understand how fruit quality traits are affected by environmental conditions such as storage duration, year and harvest date. Differences across environmental conditions for all attributes were observed. Indigocrisp and Keecrisp were the firmest cultivars and maintained firmness over time in storage. Additionally, Indigocrisp was the sweetest and had the most blueberry and green flavors among the cultivars. On the other hand, Arcadia was the softest, as measured by sensory and compression force, but varied with year and harvest. Arcadia and Emerald were the least sweet and most sour of the cultivars, and Endura and Patrecia were intermediate for all sensory attributes. In general, sensory descriptors were well explained by instrumental measurements. Variations across seasons and storage were inconsistent among cultivars, but Indigocrisp was the most stable cultivar for the quality traits evaluated. In the end, all fruit quality traits assayed in this study were influenced by environmental conditions throughout the season.

Freeze events during January and February can result in major crop and economic losses for growers of low-chill, early-ripening cultivars of blueberry (Vaccinium spp.) in Florida. Overhead irrigation for freeze protection is commonly used by growers to protect their crop from freeze events. Freezes are typically categorized as either radiative or advective, each with their own set of risk parameters. The objective of this research was to use historical weather data to provide growers with additional information for their selection of passive and active freeze protection strategies to mitigate risk. Three sites in Florida were chosen as representative of major blueberry growing regions and weather data from 2000-2015 were downloaded from the Florida Automated Weather Network (FAWN) and analyzed. Hourly temperature, wind speed, and relative humidity were used to determine the average of number of days per month with sub-zero temperatures, the average duration of freeze events, and to classify each event as a radiation, advective, or mixed freeze. Radiation freezes were the most common type of freeze event in Alachua County, Florida, whereas Polk County has fewer freeze events including some years without sub-zero temperatures, without a clear prevalent freeze event type. Ultimately, the frequency and severity of freeze events, based on historical data, can be used to further inform grower investments in freeze avoidance and protection.

Producing temperate-zone fruit crops in subtropical environments requires alterations in fertilizer application and rates. Nitrogen (N) is a critical mineral nutrient required in high amounts by the tree; however, it is often over- or under-applied for optimal fruit quality and can affect the phytochemical composition of fruits. The effects of different N fertilizer rates and harvest date on total phenolic content, total flavonoid content, total anthocyanins, total antioxidant capacity, total soluble solids, titratable acidity, and organic acids (citric and malic acid) of two subtropical peach (Prunus persica) cultivars, TropicBeauty and UFSharp, were investigated. N rate did not affect total soluble solids in ‘TropicBeauty’, although total soluble solids decreased as N rate increased in ‘UFSharp’. Titratable acidity and organic acid content was significantly higher in ‘UFSharp’ as compared with ‘TropicBeauty’, although there was no effect of N rate on titratable acidity. An overall increase in phenolic content, flavonoid content, anthocyanins, and antioxidant capacity were observed with decreasing N rates in both subtropical peach cultivars. A stronger genotype × N treatment interaction was observed for ‘TropicBeauty’ for phenolic content, flavonoid content, and antioxidant capacity than for ‘UFSharp’. In ‘TropicBeauty’, among the treatments with no N and highest N, an almost 100% increase in phenolic content, 200% increase in flavonoid content, 50% increase in anthocyanin content, and 80% increase in antioxidant activity was observed. A positive correlation among phenolic content, flavonoid content, and antioxidant capacity was observed in both ‘TropicBeauty’ and ‘UFSharp’. Late harvest date decreased phenolic content in ‘TropicBeauty’, ranging from 6% to 32% among different N treatments. Late harvest increased anthocyanin content as compared with fruit that were harvested on early dates. The results suggest that subtropical peach phytochemical composition can be affected by different cultivars and tree age, and can be manipulated with cultural practices like N fertilization and harvest time to produce fruit with altered or desired nutritional composition for consumers.

The average American child eats fewer fruits than recommended. Although taste is the primary motivator for food intake among children, little research has systematically measured children's liking of fruit and determined whether their preferences differ from adults. We phenotyped 49 children and their mothers to determine: (1) their liking of the taste of 3 blueberry cultivars (“Arcadia,” “Keecrisp,” and “Kestrel”) from 2 harvests for which total soluble solids were determined using a handheld Brix refractometer; (2) the association between liking and blueberry sugar content; and (3) the most preferred level of fructose, one of the primary sugars in blueberry fruit. Multiple methods, identical for all participants, assessed which cultivar they liked best. Dietary intake, determined via 24‐h dietary recall, revealed most children (73%) and adults (92%) did not meet dietary guidelines for fruit intake. We found that during the 1st harvest, Keecrisp was sweeter by 4° Brix than either Arcadia or Kestrel and was the cultivar most preferred by both children and adults. For the 2nd harvest, mothers liked each of the cultivars equally, but children preferred Arcadia, which was 2° Brix sweeter than the other 2 cultivars. Like other sugars, children's most preferred concentration of fructose was significantly higher than that of adults. In sum, children appear to be more sensitive to smaller variations in sweetness than are adults. Identifying drivers of fruit preference and assessing children's liking for whole fruits are important steps in developing strategies to increase fruit consumption among children. Although taste is the primary motivator for food intake among children, little research has systematically measured children's liking of fruit and determined whether their preferences differ from adults. In this farm‐to‐sensory‐lab study, we used multiple methods to assess liking for the taste of 3 blueberry cultivars picked during the beginning of the Florida blueberry season. We found that children prefer higher levels of fructose and appear to be more sensitive to small changes in the sugar content of blueberry fruit than did adults. These findings provide insight into the child consumer and highlights the potential for consumer‐driven breeding to produce fruit accepted by young children.

The rate-limiting step in the iron uptake mechanism of strategy-I plants is ferric chelate reductase (FCR)-mediated iron reduction. Southern highbush blueberry (SHB, Vaccinium corymbosum L. interspecific hybrids) is a specialty crop that commonly exhibits iron deficiency in agricultural soils due to its low FCR activity. Extracellular iron reduction has been reported in some fungi and peronosporomycetes (subsequently referred to as oomycetes), and this has the potential to increase iron reduction capacity in the rhizosphere and impact plant iron uptake. Here, we isolated and identified fungi and oomycetes from the roots and nutrient solution of hydroponically grown SHB. Then, we built a consortium of iron-reducing microorganisms and used this to study the iron nutrition of inoculated and non-inoculated SHB plants in vitro and ex vitro . We found isolates of nine fungal species and the oomycete Pythium irregulare complex, all of which exhibited detectable levels of extracellular iron reduction. Isolates of Alternaria alternata, Bjerkandera adusta , and Pythium irregulare exhibited extracellular iron reduction that was equal to or higher than that of SHB roots, and they were used to create a microbial consortium for the inoculation experiments. In vitro , inoculation with a consortium of iron-reducing microorganisms did not affect iron reduction capacity in the SHB rhizosphere under iron deficiency conditions, but it increased iron reduction capacity in the SHB rhizosphere under iron abundance conditions. Nevertheless, inoculation treatments generally decreased SHB iron uptake from the medium. Ex vitro , inoculation with a consortium of iron-reducing microorganisms did not affect iron reduction capacity in the SHB rhizosphere. In all experiments, the inoculation treatment did not increase leaf active iron concentration. Altogether, our results suggest that inoculation with iron-reducing microorganisms is not a viable alternative for enhancing SHB iron nutrition.

Root growth and root system architecture (RSA) are affected by edaphic and genetic factors and they can impact plant growth and farm profitability. Southern highbush blueberries [SHBs (Vaccinium corymbosum hybrids)] develop shallow, fibrous root systems, and exhibit a preference for acidic soils where water and ammonium are readily available. The amendments used to create these soil conditions negatively affect the profitability of SHB plantations. Hence, breeding for RSA traits has been suggested as an alternative to soil amendments. Vaccinium arboreum is a wild species that is used in SHB breeding. V. arboreum exhibits greater drought tolerance and broader soil pH adaptation than SHB, and—according to anecdotal evidence—it develops deep, taproot-like root systems. The present study constitutes the first in-depth study of the RSA of Vaccinium species with the intention of facilitating breeding for RSA traits. Root systems were studied in rhizotron-grown seedling families. In separate experiments, we tested the effect that growth substrate and family pedigree can have on root growth and RSA. Subsequently, a genotyping by sequence approach was used to develop single nucleotide polymorphism (SNP) markers that could be used along with the phenotyping method to investigate the heritability of RSA traits and look for marker-trait associations. We found that RSA is affected by growth substrate and family pedigree. In addition, we found that V. arboreum exhibited greater maximum root depth and a lower percentage of roots in the top 8 cm of soil than SHB, and interspecific hybrids generally exhibited intermediate phenotypes. Also, we found that RSA traits exhibit moderate to low heritability and genetic correlations among them. Finally, we found 59 marker-trait associations. Among these markers, 37 were found to be located in exons, and 16 of them were annotated based on protein homology with entries in National Center for Biotechnology Information (NCBI) GenBank. Altogether, the present study provides tools that can be used to breed for root architecture traits in SHB.

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.

Cross-pollination has been associated with improved fruit set, weight, and shortened time to ripening in southern highbush blueberry [SHB (Vaccinium corymbosum interspecific hybrids)]. Because of this, growers commonly plant two or more cultivars in small blocks to facilitate cross-pollination. However, many SHB cultivars may vary in the degree of improvement in each parameter after cross-pollination. Understanding the impacts of cross-pollination on a particular cultivar is crucial to forming planting recommendations, particularly as growers begin to transition to fields designed for machine harvest where large solid blocks would increase the harvest efficiency. The objective of this study was to examine the effects of cross- and self-pollination among 13 commonly planted or newly released SHB cultivars. Cross-pollination typically improved fruit set, fruit weight, and seed number while decreasing the average days to harvest. Cross-pollinated fruit always weighed more than self-pollinated fruit from the same cultivar, which was highly correlated to seed number per fruit. Although there was variation for each trait, interplanting with another unrelated cultivar sharing a similar bloom time remains the best recommendation to ensure early, high yield among these SHB cultivars.

Background The usual analysis of RNA sequencing (RNA-seq) reads is based on an existing reference genome and annotated gene models. However, when a reference for the sequenced species is not available, alternatives include using a reference genome from a related species or reconstructing transcript sequences with de novo assembly. In addition, researchers are faced with many options for RNA-seq data processing and limited information on how their decisions will impact the final outcome. Using both a diploid and polyploid species with a distant reference genome, we have tested the influence of different tools at various steps of a typical RNA-seq analysis workflow on the recovery of useful processed data available for downstream analysis. Findings At the preprocessing step, we found error correction has a strong influence on de novo assembly but not on mapping results. After trimming, a greater percentage of reads could be used in downstream analysis by selecting gentle quality trimming performed with Skewer instead of strict quality trimming with Trimmomatic. This availability of reads correlated with size, quality, and completeness of de novo assemblies and with number of mapped reads. When selecting a reference genome from a related species to map reads, outcome was significantly improved when using mapping software tolerant of greater sequence divergence, such as Stampy or GSNAP. Conclusions The selection of bioinformatic software tools for RNA-seq data analysis can maximize quality parameters on de novo assemblies and availability of reads in downstream analysis.

Most commercially important rootstocks for peach [Prunus persica (L.) Batsch] had been selected for resistance to one or more of the root-knot nematode (RKN) species: Meloidogyne incognita, M. arenaria, and M. javanica. The peach root-knot nematode, M. floridensis (MF), is a relatively newly discovered threat to peach and is not controlled by resistance genes in “Nemared,” “Nemaguard,” and “Okinawa.” The “Flordaguard” peach seedling rootstock, conventionally bred to provide resistance to MF, has solely been used for low-chill peach production in Florida for over 20 years and has already shown signs of resistance breakdown. A source of high resistance to the pathogenic MF isolate (“MFGnv14”) was identified from wild peach Prunus kansuensis Rehder (Kansu peach), thereby suggesting the potential for broadening spectrum and increasing durability of resistance in peach rootstocks through interspecific hybridization with P. kansuensis. Using 12 F2 and BC1F1 populations derived from crosses between Okinawa or Flordaguard peach and P. kansuensis populations, we examined the genetic control for MF resistance by identifying associated microsatellite markers and determining genomic location of the resistance locus. One microsatellite marker (UDP98-025) showed strong and consistent association with resistance based on root-galling index. The resistance locus was mapped on the subtelomeric region of linkage group 2, co-localizing with other previously reported RKN resistance genes in Prunus. Segregation of gall-index-based resistance observed in F2 and BC1F1 populations is compatible with the involvement of a multiallelic locus wherein a dominant (Mf1) or recessive (mf3) resistance allele is inherited from P. kansuensis, and susceptibility alleles (mf2) from peach.

A family of the cross of the northern highbush blueberry ‘Draper’ × the southern highbush ‘Jewel’ (D × J) was propagated and phenotyped for plant size, yield, rate of flower, bud, and fruit development, leafing ability, winter hardiness, and fruit quality for 2 years in the field in Florida (FL), Georgia (GA), Michigan (MI), and Oregon (OR). In addition, a controlled greenhouse study was conducted on these progenies to estimate their chilling requirements. Significant levels of genotypic variability were observed for all the traits and the majority showed significant location and genotype × environmental interactions. Most of these traits were normally distributed across genotypes. There were many more flower buds per cane in GA than FL and OR, and many more vegetative buds broke in OR than in the southeastern states. Most of the various yield and growth traits were significantly correlated, except for flower buds per cane with plant height and width, and strength of leafing with plant width and flower buds/cane. Plants in OR developed much more slowly than those in FL and GA. There was a significant G × E effect on days to early green tip, floral bud break, and full bloom. Significant correlations were observed between all the developmental rates except between floral bud break and the days to full flowering and first blue fruit. Most individuals were severely damaged by winter cold in MI, although a few showed good tolerance. Significant location effects were observed for pH, titratable acidity (TA), soluble solids (SS), and SS/TA. Fruit in FL were a little softer and had higher SS/TA ratios than those in GA. There were significant interactions between genotype and environment for all the fruit quality traits except for fruit scar, firmness, anthocyanin content (ACY), and % juice. Fruit scar had a significant positive relationship with firmness and a significant negative relationship with flavor. Fruit color was significantly associated positively with soluble solids and ACY. Firmer fruit had significantly lower levels of ACYs. Fruit pH showed significant positive correlations with TA, TA/SS, and % juice, and significant negative relationship with SS and ACY. TA was significantly associated negatively with TA/SS and positively with ACY and % juice. TA/SS and ACY were positively correlated significantly with % juice. Two or three individuals were identified at each location that had high yields, were very early or late ripening and had excellent overall fruit quality. There were significant levels of genotypic, environmental (chilling hours) and G × E interaction among vegetative and floral buds for numbers of buds per shoot, percentage that developed and their developmental rate. The chilling requirement of highbush blueberry appears to be regulated polygenically as the D × J family segregated normally. On average, genotypes did more poorly at 250 and 350 chilling hours than the other chilling treatments.

The strategy for breeding blueberries has been based on phenotypic selection without accounting for pedigree correlation information. A central premise of classical quantitative genetics is that through knowledge of the relationships among individuals in a population, we can make inferences about breeding values (BVs), estimate genetic parameters, and support phenotypic selection. Genetic evaluations using best linear unbiased prediction (BLUP) and restricted maximum likelihood (REML) are founded on pedigree information and have been the standard method used in livestock and forest breeding. Despite theoretical and practical benefits, their application in blueberry breeding programs remains unexploited. The objective of this study was to evaluate the use of REML/BLUP in the University of Florida blueberry breeding program in order to estimate genetic parameters and predict BVs of primary selection traits. To do this, we collected phenotypic data for eight selectable traits (yield, flower bud density, fruit weight, fruit firmness, fruit diameter, fruit soluble solids, fruit pH, and fruit scar diameter) from 1996 individuals. The highest narrow-sense heritabilities were found for fruit weight, scar diameter, and yield. The majority of genetic correlations between traits were under 0.20. The largest genetic gain was achieved when selections from early stages were used as parents and the top 5% of the population was selected. Compared to traditional phenotypic selection, our results are evidencing of the importance of implementing REML/BLUP to estimate genetic parameters that help and support the breeding strategy and maximize genetic gains.

The U.S. Department of Agriculture, Agricultural Research Service, National Clonal Germplasm Repository (NCGR), Corvallis, Oregon, maintains the national collection for Vaccinium L. germplasm. The NCGR genebank includes more than 1700 accessions, with representatives of 81 Vaccinium taxa from around the world. The primary collection of clonal blueberries and their wild relatives are maintained as plants in containers in greenhouses and screenhouses. While the primary genepool for highbush blueberry (V. corymbosum L.), the main crop of economic importance, is within Section Cyanococcus, breeders wish to expand gene accessibility to include representatives of the rich diversity present in other sections. Knowledge of ploidy level is paramount for this task, but has been limited. The objective of this research was to evaluate ploidy levels of approximately 50 species within the NCGR collection. Ploidy was evaluated through flow cytometry using cell preparations from leaf samples. The base haplotype for Vaccinium is x=12. Many species native to the South Pacific and Southeast Asia were diploid (2n=2x=24). Sections Cyanococcus and Myrtillus each included diploid, tetraploid, and hexaploid members. Section Oxycoccus had diploids and hexaploids. The clones of V. dependens (G. Don) Sleumer (sect. Brachyceratium) and V. poasanum (Donn. Sm.) (synonym = Symphysia poasanum (Donn. Sm.) Vander Kloet) were triploid. Pyxothamnus members from Meso- and South America, V. consanguineum Klotzsch and V. corymbodendron Dunal, were tetraploid. These two species are candidates for direct crosses with V. corymbosum. Ploidy levels from other species representatives and standards are reported.

Vaccinium arboreum (VA) is a wild blueberry species that exhibits wider soil pH tolerance and greater ability for iron and nitrate uptake than cultivated Vaccinium species, including southern highbush blueberry (SHB, V. corymbosum interspecific hybrids). The ability of VA and SHB to respond to iron deficiency by rhizosphere acidification was investigated. Rooted cuttings of the VA genotype FL09-502 and SHB ‘Emerald’ were transplanted to a hydroponic system filled with complete nutrient solution. After 14 days of acclimation at 45 µm iron, plants were transferred to unbuffered nutrient solutions containing 90 or 10 µm iron. ‘Emerald’ and FL09-502 plants grown in 10 µm iron exhibited less iron uptake and lower chlorophyll, total iron, and active iron contents than plants grown in 90 µm iron. Generally, there were no species-level differences in iron or nitrate uptake. Neither FL09-502 nor ‘Emerald’ acidified the rhizosphere in either the nutrient solution or in a gel-based assay, regardless of external iron concentration. A screen of 18 additional genotypes of VA and SHB confirmed that this response is absent in these taxa. Thus, rhizosphere acidification is not part of the iron deficiency response of SHB and VA. In addition, the ability to acidify the soil is not likely to be responsible for the wider soil pH tolerance of VA.

BACKGROUND: Blueberry cultivars with very firm, crisp fruit textures have been developed to increase consumer acceptance and as an aid in production and marketing. The basis for the crisp fruit texture is unknown. OBJECTIVES: The objective of this study was to compare the bioyield force (BF) and cell wall composition of crisp and standard texture blueberry genotypes. METHODS: Bioyield force of seven southern highbush blueberry genotypes having standard (‘Springhigh’, ‘Star’, Windsor’) and crisp (‘Sweetcrisp’, FL06-561, FL06-562, and FL98-325) fruit texture was measured on fresh, whole fruits. Dry weight, alcohol insoluble residue (AIR), uronic acids (UA), and neutral sugars (NS) were then measured on separated flesh and skin tissue. RESULTS: The BF of the standard texture genotypes was significantly less than all four crisp genotypes. There were differences in the dry weight and AIR among genotypes, but these differences did not correspond to crisp and standard texture classes. There was no significant difference among genotypes in the measurement of UA or NS. CONCLUSIONS: These results confirm that there is a phenotypic difference between crisp and standard texture blueberry genotypes that can be detected with BF measurements, but that quantitative differences among total cell wall material, pectins, and neutral sugars were not responsible for the variability of these texture types.

ADDITIONAL INDEX WORDS. floral development, floral initiation, growing degree days, reproductive buds, Vaccinium corymbosum ABSTRACT. Blueberry (Vaccinium spp.) production is increasing worldwide, particularly in subtropical growing regions,butinformationontimingandextentofinflorescence buddevelopmentduringsummerandfallandeffectson 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. Inflorescencebud initiation occurred earlier in'Emerald' compared with'Jewel'.Fivestages ofinternal 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 earlierin'Emerald'comparedwith'Jewel',thepatternofdevelopmentwasnotdifferent.Timingofinflorescencebud initiation influenced timing of bloom with earlier initiation resulting in earlier bloom.

Next-generation sequencing technologies have enabled the rapid generation of high-resolution genetic maps to enable the identification of genomic regions associated with traits of interest. In certain cases these regions of interest need to be narrowed down via fine mapping to increase resolution to the level of the individual gene. In those cases, there is a choice of genotyping options, whereby cost, time, and information content need to be considered. We developed detailed, customizable models to compare the cost of genotyping by sequencing and allele-specific PCR for fine-mapping genomic regions of interest. The models were validated experimentally with data from a fine-mapping experiment designed to identify candidate genes within a 3.2-Mb disease resistance locus in the cereal crop sorghum (Sorghum bicolor (L.). Moench), which has a sequenced genome. The size of the mapping population, genetic diversity of the parental lines, choice of reagents, and labor cost were shown to influence the overall cost of the two methods, and, consequently, which method would be most cost-effective for a given experiment. The model can be easily customized to reflect experiments with different species, genetic populations, experimental and personnel costs to determine the most cost-effective procedure for a new positional cloning project.

Background Blueberries are one of the few horticultural crops adapted to grow in acidic soils. Neutral to basic soil pH is detrimental to all commonly cultivated blueberry species, including Vaccinium corymbosum (VC). In contrast, the wild species V. arboreum (VA) is able to tolerate a wider range of soil pH. To assess the molecular mechanisms involved in near neutral pH stress response, plants from pH-sensitive VC (tetraploid) and pH-tolerant VA (diploid) were grown at near neutral pH 6.5 and at the preferred pH of 4.5. Results Transcriptome sequencing of root RNA was performed for 4 biological replications per species x pH level interaction, for a total of 16 samples. Reads were mapped to the reference genome from diploid V. corymbosum, transforming ~55% of the reads to gene counts. A quasi-likelihood F test identified differential expression due to pH stress in 337 and 4867 genes in VA and VC, respectively. Both species shared regulation of genes involved in nutrient homeostasis and cell wall metabolism. VA and VC exhibited differential regulation of signaling pathways related to abiotic/biotic stress, cellulose and lignin biosynthesis, and nutrient uptake. Conclusions The specific responses in VA likely facilitate tolerance to higher soil pH. In contrast, response in VC, despite affecting a greater number of genes, is not effective overcoming the stress induced by pH. Further inspection of those genes with differential expression that are specific in VA may provide insight on the mechanisms towards tolerance. Electronic supplementary material The online version of this article (doi:10.1186/s12864-017-3967-0) contains supplementary material, which is available to authorized users.

Sclerified stone cells with a thick and lignified secondary cell wall are known to vary in number among cultivars of northern highbush blueberry (Vaccinium corymbosum) and rabbiteye blueberry (Vaccinium virgatum), and may contribute to fruit texture. Variation in cell size can also contribute to differences in fruit firmness. Fruit from nine southern highbush blueberry [SHB (V. corymbosum interspecific hybrids)] cultivars determined by sensory and instrumental analysis to vary in fruit texture were harvested at mature green and ripe blue developmental stages. Paraffin embedded 12-μm sections were stained with Safranin O and Aniline Blue and microstructure was examined by light microscopy. Stone cells within ≈1.2 mm of the epidermis were counted and cell area was measured in the epidermal layer and three layers beneath the epidermis of the fruit. There was a significant difference in cell area among genotypes and cell layers for mature green fruit and among texture types, genotypes, and cell layers for ripe blue fruit. The average number of stone cells in a single berry ranged from zero to 95 among cultivars. Significant differences in the number of stone cells just below the epidermal layer did not correspond to standard or crisp fruit texture.

Additional index words. blueberry breeding, flavor, fruit quality, Vaccinium corymbosumAbstract.Blueberriesareahigh-valuefruitthathasexperiencedextraordinarygrowthinconsumption in the past decade. Maintaining this growing market requires an un-derstandingofthecurrentmarketanditspotentialforexpansion.Toassaytheimpactof36 specific blueberry sensory and psychological traits on consumer interest, a blueberryfruitqualitystudywasconstructedusingtechniquesthatallowmanyfeaturestobetestedin an analysis by combining specifics from different categories that describe a product.Individual traits that most impact the likelihood of fruit purchase were identified. Sweetand intense blueberry flavor yielded the most positive purchase interest, whereas badtexture attributes such as seediness were the most detrimental to interest. It was alsopossible to define two interest segments within the survey population that shared similarresponses to particular experimentally assayed traits. The larger segment of the samplepopulation (61%) was most interested in the aspects of blueberry flavor, whereas thesecond segment of respondents (39%) was most influenced by health aspects commonlyassociatedwithblueberryfruitconsumption.Bothsegmentsrespondednegativelytobadtexture. This study suggests that breeders and producers should exploit genetic andenvironmental variables that contribute to improved blueberry flavor and that market-ing strategies to sell blueberry cultivars of superior flavor may be appropriate.Blueberries [northernhighbush( Vacciniumcorymbosum), southern highbush (V. corym-bosum hybrids), rabbiteye (V. virgatum), andlowbush (V. angustifolium)] are an economi-cally important small fruit crop in the UnitedStates with 277 million pounds harvestedfor fresh production valued at $850.8 millionU.S. in 2012 (USDA, 2013). Blueberry acre-age continues to increase worldwide in ac-cordance with growing demand for theseantioxidant-rich fruit. Although native toNorth America, breeding programs have de-veloped blueberry cultivars that grow in awider array of climates, allowing productionto flourish in South America, Europe, Asia,and Australia. Global highbush blueberry pro-duction passed the one billion pound mark in2012 and continues to accelerate (Brazelton,2013). Historically, many traits have beenselected for in blueberry breeding programswith producers in mind, including climaticadaptation, yield, mechanical harvest poten-tial, and disease resistance. Conversely, thefruit quality traits of interest to the consumerarewhatshouldultimatelyfuelproductionandprofitability. In recent surveys, only 48% ofU.S. consumers had bought blueberries in thepast 12 months compared with 88% of con-sumers who had bought the highest sellingfruit, bananas (Fresh Trends, 2013). Of the48% of U.S. consumers who purchased blue-berries in the past year, 15% of these con-sumers were reportedly regular buyers ofblueberries (Brazelton, 2013; Fresh Trends,2013). Converting seldom purchasers intofrequent purchasers through product satisfac-tion could have a beneficial impact on theblueberry market. To provide this level ofproduct satisfaction, it is critical to assess theexpectations and desires of the current blue-berry consumer to make sure these parametersare being met. Increasing market penetrationfor the 50% of consumers who did notpurchase blueberries in the past 3 years willbeimportantto drive continuedexpansionofblueberryproductionaswell(Brazelton,2013;Fresh Trends, 2013).Developing a new blueberry cultivar withimproved traits for the producer or consumeris a long-termprocess.From thetimeaninitialcross between two blueberry parents is made,the earliest a resulting progeny is typical-ly considered for release is 10 years. Thisplant must then be marketed to nurseries orfarmerswhomasspropagatetheclones,whichmeansthattheblueberrybreederdesigningtheparental crosses is catering to an industrynearly two decades in the future. Breedersoften work closely with the producers and aretherefore aware of the changing needs offarmers. However, consumer satisfaction withthe end product is influencing new directionsin research and development of horticul-tural crops, encouraging breeder focus ontraits such as improved strawberry (Fragaria·ananassa) flavor (Colquhoun et al., 2012)andflowerfragrance(Levinetal.,2012).Withlengthy breeding cycles, it is critical to em-pirically assay the psychological influences ofconsumer blueberry purchases before com-mitting to years of manipulating traits thatmay not actually affect marketability. Addi-tionally, this information could be used totailor messages directed to the consumerthrough commercial marketing, in advertise-ments, and on packaging.When a consumer encounters a product,multiple attributes of the product may in-fluence their purchase decision. The con-sumer may not necessarily be rational orconsciously aware of the reasoning for thisdecision, and outright asking of the consumerto identify their desires may introduce cog-nitive bias (DellaVigna, 2009; Price and Riis,2012; Redelmeier and Dickinson, 2011).Additionally, attempting to test a high num-ber of variables for psychological impact cancause subject frustration and cognitive bur-den (Park and Lessig, 1981). Both of theseissues can be tackled using modified conjointanalysis and rule-developing experimenta-tion. In this approach, the consumer is pre-sented with sets of three to four individualdescriptive phrases or elements at a time,which reduces the variable load on the re-spondent. Byposingmanyscenarios inwhicha product has a few attributes in differentcombinations, it is then possible to pull outindividually impactful elements from thescheme (Behe, 2006; Behe et al., 1999,2013; Jaeger et al., 2011; Moskowitz, 2012;Moskowitz et al., 2006; Moskowitz andGofman, 2007). This method has been pre-viously implemented to analyze favorablecharacteristics of fresh strawberries andflowers as a tool to guide breeding efforts inthese horticultural crops (Colquhoun et al.,2012; Levin et al., 2012). The strawberrystudy identified sweetness and complex fla-vors as the most important traits to con-sumers, resulting in a large amount of effortand resources that have been devoted tobiochemically characterizing strawberry fla-vor for identification of enhanced qualitycultivars (Schwieterman et al., 2014).This study was conducted as part of anongoing effort to implement consumer-assisted selection in horticultural breedingprograms. Consumer-assisted selection is anapproach to product development that seeksto identify which features are of most impor-tance to the end user, an ambition that can besometimes be diluted along a complex supplychain. We sought to identify which blueberrytraits are of most importance to consumersand may motivate purchase likelihood. Weconducted two consumer-assisted marketing

In recent years, world blueberry (Vaccinium sp.) production has been split evenly between processing and fresh fruit markets. Machine harvest of highbush blueberry {northern highbush blueberry [NHB (V. corymbosum)], southern highbush blueberry [SHB (V. corymbosum interspecific hybrids)], and rabbiteye blueberry [RE (V. virgatum)]} typically has been used to obtain large volumes of fruit destined for processing. Because of financial and labor concerns, growers are interested in using machine harvesting for fruit destined to be fresh marketed. Bush architecture, harvest timing, loose fruit clusters, easy detachment of mature berries compared with immature berries, no stem retention, small stem scar, a persistent wax layer, and firm fruit are breeding goals to develop cultivars amenable to machine harvest. Progress in selecting for these traits has been made in existing highbush blueberry breeding programs, but will likely intensify as the need for cultivars suitable for machine harvest for the fresh market increases.

Field performance of southern highbush blueberry (Vaccinium corymbosum L. interspecific hybrids) cultivars Emerald, Jewel, and Primadonna derived from softwood cuttings (SW) and tissue culture (TC) was evaluated in Citra and Haines City, FL, in 2010–12. Both fields were planted in Apr. 2010 on sandy soil amended with pine bark. Plant height and width were recorded at both locations, from which plant canopy volume was calculated. Additionally, whole plants were harvested at planting and after the first growing season, after the first fruit harvest, and after the second growing season. Average plant height and width, number of major canes, and total shoot number were determined at each sampling date. Dry weights for roots, crowns, canes, shoots, and leaves were obtained. Although propagation method affected plant canopy volume during the first season, no effects were observed by the end of the second growing season. At planting and after the first and second growing seasons, TC plants of the three cultivars had more major canes. Total shoot number per plant was greater for TC ‘Jewel’ at all dates but ‘Emerald’ TC plants had more shoots only at planting and after the first growing and harvest seasons. Tissue culture resulted in increased plant dry weights of ‘Jewel’ and ‘Emerald’ after the first and second growing seasons. There were no significant differences in total number of shoots or plant dry weight between TC and SW-derived ‘Primadonna’ plants at any point during the study.

BACKGROUND Fruit texture is a primary selection trait in southern highbush blueberry (SHB) breeding to increase fresh fruit postharvest quality and consumer acceptance. A novel crisp fruit texture has recently been identified among SHB germplasm. In this study, we developed a common set of descriptors that align sensory evaluation of blueberry fruit texture with instrumental measures that could be used for quantitative measurements during pre- and postharvest evaluation. RESULTS Sensory and instrumental characteristics were measured in 36 and 49 genotypes in 2010 and 2011, respectively. A trained sensory panel evaluated fresh fruit based on five common textural attributes in 2010 and 2011: bursting energy, flesh firmness, skin toughness, juiciness and mealiness. Instrumental measures of compression and bioyield forces were significantly different among cultivars and correlated with sensory scores for bursting energy, flesh firmness and skin toughness (R > 0.7, except skin toughness in 2011), but correlations with sensory scores for juiciness and mealiness were low (R < 0.4). CONCLUSION The results of sensory and instrumental measures supported the use of both compression and bioyield force measures in distinguishing crisp from standard-texture genotypes, and suggest that crisp texture in SHB is related to the sensory perception of bursting energy, flesh firmness and skin toughness. © 2014 The Authors. Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Light intensity, duration, direction, and wavelength are informative to plants. The biochemical circuits that connect specific light wavelengths to expression of specific genes and the metabolic networks they govern have been well defined. However, little emphasis has been placed on how discrete wavelengths of light, alone or in combination, may be applied to manipulate postharvest qualities of high-value horticultural crops. Using narrow-bandwidth LED light we test the hypothesis that discrete light wavelengths can affect the accumulation of volatile compounds known to affect aroma or taste in select flower and fruit products. Volatile benzenoid/phenylpropanoid emission from petunia flowers could be altered with light application. Levels of a key floral volatile, 2-phenylethanol, increased with a red and far-red light treatment. Similar experiments demonstrated that fruit volatile profiles of tomato, strawberry, and blueberry can be manipulated with specific light treatments. These results suggest that compounds affecting sensory qualities of flowers and fruits can be modified by adjustment of ambient light conditions. These findings open new areas of inquiry about how the fragrance and flavor of flowers and fruits may be improved with simple changes in postharvest light conditions.

Because of financial and labor concerns, growers are interested in using machine harvesting for fruit destined to be fresh marketed. Machine harvest of highbush blueberry (Vaccinium corymbosum) has typically been used to obtain large volumes of fruit destined for processing. Bush architecture, easy detachment of mature berries compared with immature berries, loose fruit clusters, small stem scar, firm fruit, and a concentrated ripening period are breeding goals to develop cultivars amenable to machine harvest. In the University of Florida (UF) southern highbush blueberry [SHB (Vaccinium corymbosum hybrids)] breeding program, sparkleberry (Vaccinium arboreum) has been used in wide crosses in an attempt to introgress traits that may be valuable for machine harvesting, namely upright growth habit with a narrow crown and long flower and fruit pedicels creating loose fruit clusters. Two eras of sparkleberry hybridization experiments have occurred since the early 1980s. The first era used darrow’s evergreen blueberry (Vaccinium darrowii) as a bridge between sparkleberry and tetraploid SHB, with the recently released cultivar FL 01-173 (sold under the trademarked name Meadowlark) as an example of the end product. The second era has used chromosome doubling to develop polyploid sparkleberry selections that were directly crossed with tetraploid SHB. After 1 year of evaluation, a SHB × (SHB × sparkleberry) population developed for linkage and quantitative trait locus mapping showed abundant variation for length:width ratio of the plant, but similarity to the highbush phenotype for peduncle and pedicel length of the fruit. These first evaluations indicate evidence of introgression and provide an initial step toward improved cultivars for mechanical harvesting.

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.

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.

Vaccinium twig blight (caused by Phomopsis vaccinii, teleomorph Diaporthe vaccinii) is a major endemic disease on blueberries and cranberries in the Eastern and Northwestern USA and Canada. It has also been found in Europe, Chile and China. Publications on its occurrence in the USA and Canada indicate that the pathogen is limited to cool climates. Published data on worldwide occurrence were inventoried and supplemented with National Plant Diagnostic Network (NPDN) data in the USA. These occurrence and long-term climate data were entered in the niche models MaxEnt and Multi-Model Framework to predict the potential global distribution of the disease. Precipitation in the driest quarter and mean annual temperature contributed most to the prediction. The results indicate that P. vaccinii is not limited to cool climates, although the optimal annual average temperature is 10 °C according to the MaxEnt model. The models correctly predicted that the climate in the central and eastern USA and the west coast of the USA and Canada would be conducive to blueberry twig blight. Large areas in Europe, eastern Australia and New Zealand, and smaller areas in South America and East Asia would be conducive too. For the first time, the NPDN database was shown to be an important source of information for the prediction of the potential global distribution of a plant pathogen.

TheOutstandingFruitCultivarAwardisamedalpresentedannuallybytheFruitBreeding WorkingGroupofthe American Society for Horticultural Science (ASHS) for noteworthy new fruits released over the previous 35 years. Since 1987, 38 cultivars have been recognized with medals presented at the Annual Conference of the Society. The awards celebrate the progress achieved by fruit breeders and their contributions to the world's fruit industry. The world's fruit industry is based on distinct clones that have uniquely desirable horticultural characteristics. The genetic im- provement of fruits known as fruit breeding in its broadest sense has an ancient tradition that dates back to the domestication process of the Neolithic and Bronze Age, 8,000 to 10,000 years ago. Genetic improvement was achieved by selection, first from natural seed- ling populations and then from seedlings that occurred naturally in growers' fields with de- sirable genotypes fixed by vegetative propa- gation. In the middle of the 19th century, the English horticulturist Thomas Andrew Knight (1759-1838) initiated the science of fruit breeding by a combination of deliberate hy- bridization followed by selection and testing. Conventional fruit breeding is based on con- tinuous selection of superior phenotypes from genetically variable populations using cycles of hybridization and selection and including special techniques such as mutation induc- tion, interspecific hybridization, and back- cross breeding. Recently, biotechnological techniques have been used including in vitro propagation, embryo rescue, protoplast fu- sion, marker-assisted selection, and transgen- esis. The creation of new distinct cultivars as a result of the breeder's art has had an enor- mous influence on pomology and horticul- ture. Trait improvements have been associated with characters that are beneficial to con- sumers such as the improvement of edible quality and appearance and to growers, packers, and processors such as resistance to diseases and pests, increased yield, and postharvest quality.

The average American child eats fewer fruits than recommended. Although taste is the primary motivator for food intake among children, little research has systematically measured children's liking of fruit and determined whether their preferences differ from adults. We phenotyped 49 children and their mothers to determine: (1) their liking of the taste of 3 blueberry cultivars ("Arcadia," "Keecrisp," and "Kestrel") from 2 harvests for which total soluble solids were determined using a handheld Brix refractometer; (2) the association between liking and blueberry sugar content; and (3) the most preferred level of fructose, one of the primary sugars in blueberry fruit. Multiple methods, identical for all participants, assessed which cultivar they liked best. Dietary intake, determined via 24-h dietary recall, revealed most children (73%) and adults (92%) did not meet dietary guidelines for fruit intake. We found that during the 1st harvest, Keecrisp was sweeter by 4° Brix than either Arcadia or Kestrel and was the cultivar most preferred by both children and adults. For the 2nd harvest, mothers liked each of the cultivars equally, but children preferred Arcadia, which was 2° Brix sweeter than the other 2 cultivars. Like other sugars, children's most preferred concentration of fructose was significantly higher than that of adults. In sum, children appear to be more sensitive to smaller variations in sweetness than are adults. Identifying drivers of fruit preference and assessing children's liking for whole fruits are important steps in developing strategies to increase fruit consumption among children.

The construction of the first genetic map in autotetraploid blueberry has been made possible by the development of new SNP markers developed using genotyping by sequencing in a mapping population created from a cross between two key highbush blueberry cultivars, Draper × Jewel (Vaccinium corymbosum). The novel SNP markers were supplemented with existing SSR markers to enable the alignment of parental maps. In total, 1794 single nucleotide polymorphic (SNP) markers and 233 simple sequence repeat (SSR) markers exhibited segregation patterns consistent with a random chromosomal segregation model for meiosis in an autotetraploid. Of these, 700 SNPs and 85 SSRs were utilized for construction of the ‘Draper’ genetic map, and 450 SNPs and 86 SSRs for the ‘Jewel’ map. The ‘Draper’ map comprises 12 linkage groups (LG), associated with the haploid chromosome number for blueberry, and totals 1621 cM while the ‘Jewel’ map comprises 20 linkage groups totalling 1610 cM. Tentative alignments of the two parental maps have been made on the basis of shared SSR alleles and linkages to double-simplex markers segregating in both parents. Tentative alignments of the two parental maps have been made on the basis of shared SSR alleles and linkages to double-simplex markers segregating in both parents.