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Cultivated strawberry (Fragaria × ananassa) has a brief history of less than 300 yr, beginning with the hybridization of octoploids Fragaria chiloensis and Fragaria virginiana. Here we explored the genomic signatures of early domestication and subsequent diversification for different climates using whole-genome sequences of 289 wild, heirloom, and modern varieties from two major breeding programs in the United States. Four nonadmixed wild octoploid populations were identified, with recurrent introgression among the sympatric populations. The proportion of F. virginiana ancestry increased by 20% in modern varieties over initial hybrids, and the proportion of F. chiloensis subsp. pacifica rose from 0% to 3.4%. Effective population size rapidly declined during early breeding. Meanwhile, divergent selection for distinct environments reshaped wild allelic origins in 21 out of 28 chromosomes. Overlapping divergent selective sweeps in natural and domesticated populations revealed 16 convergent genomic signatures that may be important for climatic adaptation. Despite 20 breeding cycles since initial hybridization, more than half of loci underlying yield and fruit size are still not under artificial selection. These insights add clarity to the domestication and breeding history of what is now the most widely cultivated fruit in the world. Whole-genome sequences of 289 octoploid strawberry samples were used to explore the genomic signatures of domestication and subsequent diversification in different climates. [ABSTRACT FROM AUTHOR]

Strawberry (Fragaria ×ananassa Duchesne ex Rozier) is cultivated and enjoyed globally for its health properties and flavor. Improvements in agronomic performance and fruit quality attributes highlight the successes of strawberry breeding in recent decades. Nevertheless, sweetness and flavor continue to fall below the ideal for the average consumer. While flavor is an important trait of focus, it is one of many critical traits necessary for the success of a strawberry variety. In addition, the chemical complexity of flavor and the genetic complexity of octoploid strawberry have slowed the development of genomics tools for flavor improvement. Recent efforts to understand consumer preference and the chemical drivers of strawberry flavor have revealed the strong impact of sugar content and specific volatile compounds. These large‐scale sensory studies combined with multi‐omics resources have set the stage for new levels of flavor improvement. Marker‐assisted selection for volatile biosynthesis genes has begun to take place in breeding programs, along with genomic selection for increased sugar content. Enhancing levels of existing volatile compounds and targeted introgression of rare compounds using genomics tools will continue to improve flavor intensity and complexity. Core Ideas: Complex fruit chemistry and balancing many traits are challenges for improving strawberry flavor.Sensory‐chemical studies have identified volatile compounds that affect flavor and sweetness.An explosion of multi‐omics resources in strawberry is advancing the discovery of genes underlying volatiles.Marker‐assisted selection for volatiles and genomic selection for sugars forms an overall breeding strategy. [ABSTRACT FROM AUTHOR]

The article informs about different forms of Fragaria chiloensis cultivated by native individuals in South America also known as White-fruited strawberries. Topics include Newer cultivars with fruit sizes similar to that of red strawberries that have recently emerged as high-value products in Asia; and existing pineberry cultivars are not suitable for commercial production in Florida.

Summary: Flavor is essential to consumer preference of foods and is an increasing focus of plant breeding programs. In fruit crops, identifying genes underlying volatile organic compounds has great promise to accelerate flavor improvement, but polyploidy and heterozygosity in many species have slowed progress.Here we use octoploid cultivated strawberry to demonstrate how genomic heterozygosity, transcriptomic intricacy and fruit metabolomic diversity can be treated as strengths and leveraged to uncover fruit flavor genes and their regulatory elements.Multi‐omics datasets were generated including an expression quantitative trait loci map with 196 diverse breeding lines, haplotype‐phased genomes of a highly‐flavored breeding selection, a genome‐wide structural variant map using five haplotypes, and volatile genome‐wide association study (GWAS) with > 300 individuals. Overlaying regulatory elements, structural variants and GWAS‐linked allele‐specific expression of numerous genes to variation in volatile compounds important to flavor. In one example, the functional role of anthranilate synthase alpha subunit 1 in methyl anthranilate biosynthesis was supported via fruit transient gene expression assays.These results demonstrate a framework for flavor gene discovery in fruit crops and a pathway to molecular breeding of cultivars with complex and desirable flavor. [ABSTRACT FROM AUTHOR]

High-throughput phenotyping is an emerging approach in plant science, but thus far only a few applications have been made in horticultural crop breeding. Remote sensing of leaf or canopy spectral reflectance can help breeders rapidly measure traits, increase selection accuracy, and thereby improve response to selection. In the present study, we evaluated the integration of spectral analysis of canopy reflectance and genomic information for the prediction of strawberry (Fragaria × ananassa) powdery mildew disease. Two multi-parental breeding populations of strawberry comprising a total of 340 and 464 pedigree-connected seedlings were evaluated in two separate seasons. A single-trait Bayesian prediction method using 1001 spectral wavebands in the ultraviolet–visible–near infrared region (350–1350 nm wavelength) combined with 8552 single nucleotide polymorphism markers showed up to 2-fold increase in predictive ability over models using markers alone. The integration of high-throughput phenotyping was further validated independently across years/trials with improved response to selection of up to 90%. We also conducted Bayesian multi-trait analysis using the estimated vegetative indices as secondary traits. Three vegetative indices (Datt3, REP_Li, and Vogelmann2) had high genetic correlations (r A) with powdery mildew visual ratings with average r A values of 0.76, 0.71, and 0.71, respectively. Increasing training population sizes by incorporating individuals with only vegetative index information yielded substantial increases in predictive ability. These results strongly indicate the use of vegetative indices as secondary traits for indirect selection. Overall, combining spectrometry and genome-wide prediction improved selection accuracy and response to selection for powdery mildew resistance, demonstrating the power of an integrated phenomics–genomics approach in strawberry breeding. [ABSTRACT FROM AUTHOR]

Colletotrichum crown rot (CCR) caused by Colletotrichum gloeosporioides is a serious threat to the cultivated strawberry (Fragaria × ananassa). Our previous study reported that a major locus, FaRCg1 , increases resistance. However, the genomic structure of FaRCg1 and potential candidate genes associated with the resistance remained unknown. Here, we performed comparative transcriptome analyses of resistant 'Florida Elyana' and susceptible 'Strawberry Festival' after infection and identified candidate genes potentially involved in resistance. In 'Florida Elyana', 6,099 genes were differentially expressed in response to C. gloeosporioides. Gene ontology analysis showed that the most upregulated genes were functionally associated with signaling pathways of plant defense responses. Three genes in the genomic region of FaRCg1 were highly upregulated: a von Willebrand Factor A domain-containing protein, a subtilisin-like protease, and a TIFY 11A-like protein. Subgenome-specific markers developed for the candidate genes were tested with a diverse panel of 219 accessions from University of Florida and North Carolina State University breeding programs. Significant and positive associations were found between the high-resolution melting (HRM) marker genotypes and CCR phenotypes. These newly developed subgenome-specific functional markers for FaRCg1 can facilitate development of resistant varieties through marker-assisted selection. [ABSTRACT FROM AUTHOR]

Cultivated strawberry (Fragaria × ananassa) is one of our youngest domesticates, originating in early eighteenth-century Europe from spontaneous hybrids between wild allo-octoploid species (Fragaria chiloensis and Fragaria virginiana). The improvement of horticultural traits by 300 years of breeding has enabled the global expansion of strawberry production. Here, we describe the genomic history of strawberry domestication from the earliest hybrids to modern cultivars. We observed a significant increase in heterozygosity among interspecific hybrids and a decrease in heterozygosity among domesticated descendants of those hybrids. Selective sweeps were found across the genome in early and modern phases of domestication—59–76% of the selectively swept genes originated in the three less dominant ancestral subgenomes. Contrary to the tenet that genetic diversity is limited in cultivated strawberry, we found that the octoploid species harbor massive allelic diversity and that F. × ananassa harbors as much allelic diversity as either wild founder. We identified 41.8 M subgenome-specific DNA variants among resequenced wild and domesticated individuals. Strikingly, 98% of common alleles and 73% of total alleles were shared between wild and domesticated populations. Moreover, genome-wide estimates of nucleotide diversity were virtually identical in F. chiloensis,F. virginiana , and F. × ananassa (π = 0.0059–0.0060). We found, however, that nucleotide diversity and heterozygosity were significantly lower in modern F. × ananassa populations that have experienced significant genetic gains and have produced numerous agriculturally important cultivars. [ABSTRACT FROM AUTHOR]

The cultivated strawberry (Fragaria × ananassa) is an economically important fruit crop that is intensively bred for improved sensory qualities. The diversity of fruit flavors and aromas in strawberry results mainly from the interactions of sugars, acids, and volatile organic compounds (VOCs) that are derived from diverse biochemical pathways influenced by the expression of many genes. This study integrates multiomic analyses to identify QTL and candidate genes for multiple aroma compounds in a complex strawberry breeding population. Novel fruit volatile QTL was discovered for methyl anthranilate, methyl 2-hexenoate, methyl 2-methylbutyrate, mesifurane, and a shared QTL on Chr 3 was found for nine monoterpene and sesquiterpene compounds, including linalool, 3-carene, β-phellandrene, α-limonene, linalool oxide, nerolidol, α-caryophellene, α-farnesene, and β-farnesene. Fruit transcriptomes from a subset of 64 individuals were used to support candidate gene identification. For methyl esters including the grape-like methyl anthranilate, a novel ANTHANILIC ACID METHYL TRANSFERASE –like gene was identified. Two mesifurane QTL correspond with the known biosynthesis gene O-METHYL TRANSFERASE 1 and a novel FURANEOL GLUCOSYLTRANSFERASE. The shared terpene QTL contains multiple fruit-expressed terpenoid pathway-related genes including NEROLIDOL SYNTHASE 1 (FanNES1). The abundance of linalool and other monoterpenes is partially governed by a co-segregating expression-QTL (eQTL) for FanNES1 transcript variation, and there is additional evidence for quantitative effects from other terpenoid-pathway genes in this narrow genomic region. These QTLs present new opportunities in breeding for improved flavor in commercial strawberry. [ABSTRACT FROM AUTHOR]

Strawberries produce numerous volatile compounds that contribute to the unique flavors of fruits. Among the many volatiles, γ-decalactone (γ-D) has the greatest contribution to the characteristic fruity aroma in strawberry fruit. The presence or absence of γ-D is controlled by a single locus, FaFAD1. However, this locus has not yet been systematically characterized in the octoploid strawberry genome. It has also been reported that the volatile content greatly varies among the strawberry varieties possessing FaFAD1 , suggesting that another genetic factor could be responsible for the different levels of γ-D in fruit. In this study, we explored the genomic structure of FaFAD1 and determined the allele dosage of FaFAD1 that regulates variations of γ-D production in cultivated octoploid strawberry. The genome-wide association studies confirmed the major locus FaFAD1 that regulates the γ-D production in cultivated strawberry. With the hybrid capture-based next-generation sequencing analysis, a major presence–absence variation of FaFAD1 was discovered among γ-D producers and non-producers. To explore the genomic structure of FaFAD1 in the octoploid strawberry, three bacterial artificial chromosome (BAC) libraries were developed. A deletion of 8,262 bp was consistently found in the FaFAD1 region of γ-D non-producing varieties. With the newly developed InDel-based codominant marker genotyping, along with γ-D metabolite profiling data, we revealed the impact of gene dosage effect for the production of γ-D in the octoploid strawberry varieties. Altogether, this study provides systematic information of the prominent role of FaFAD1 presence and absence polymorphism in producing γ-D and proposes that both alleles of FaFAD1 are required to produce the highest content of fruity aroma in strawberry fruit. [ABSTRACT FROM AUTHOR]

Descriptive analysis via trained sensory panels has great power to facilitate flavor improvement in fresh fruits and vegetables. When paired with an understanding of fruit volatile organic compounds, descriptive analysis can help uncover the chemical drivers of sensory attributes. In the present study, 213 strawberry samples representing 56 cultivars and advanced selections were sampled over seven seasons and subjected to both sensory descriptive and chemical analyses. Principal component analysis and K-cluster analyses of sensory data highlighted three groups of strawberry samples, with one classified as superior with high sweetness and strawberry flavor and low sourness and green flavor. Partial least square models revealed 20 sweetness-enhancing volatile organic compounds and two sweetness-reducing volatiles, many of which overlap with previous consumer sensory studies. Volatiles modulating green, sour, astringent, overripe, woody, and strawberry flavors were also identified. The relationship between soluble solids content (SSC) and sweetness was modeled with Bayesian regression, generating probabilities for sweetness levels from varying levels of soluble solids. A hierarchical Bayesian model with month effects indicated that SSC is most correlated to sweetness toward the end of the fruiting season, making this the best period to make phenotypic selections for soluble solids. Comparing effects from genotypes, harvest months, and their interactions on sensory attributes revealed that sweetness, sourness, and firmness were largely controlled by genetics. These findings help formulate a paradigm for improvement of eating quality in which sensory analyses drive the targeting of chemicals important to consumer-desired attributes, which further drive the development of genetic tools for improvement of flavor. [ABSTRACT FROM AUTHOR]

The University of Florida strawberry (Fragaria × ananassa) breeding program has implemented genomic prediction (GP) as a tool for choosing outstanding parents for crosses over the last five seasons. This has allowed the use of some parents 1 year earlier than with traditional methods, thus reducing the duration of the breeding cycle. However, as the number of breeding cycles increases over time, greater knowledge is needed on how multiple cycles can be used in the practical implementation of GP in strawberry breeding. Advanced selections and cultivars totaling 1,558 unique individuals were tested in field trials for yield and fruit quality traits over five consecutive years and genotyped for 9,908 SNP markers. Prediction of breeding values was carried out using Bayes B models. Independent validation was carried out using separate trials/years as training (TRN) and testing (TST) populations. Single-trial predictive abilities for five polygenic traits averaged 0.35, which was reduced to 0.24 when individuals common across trials were excluded, emphasizing the importance of relatedness among training and testing populations. Training populations including up to four previous breeding cycles increased predictive abilities, likely due to increases in both training population size and relatedness. Predictive ability was also strongly influenced by heritability, but less so by changes in linkage disequilibrium and effective population size. Genotype by year interactions were minimal. A strategy for practical implementation of GP in strawberry breeding is outlined that uses multiple cycles to predict parental performance and accounts for traits not included in GP models when constructing crosses. Given the importance of relatedness to the success of GP in strawberry, future work could focus on the optimization of relatedness in the design of TRN and TST populations to increase predictive ability in the short-term without compromising long-term genetic gains. [ABSTRACT FROM AUTHOR]

The cultivated strawberry (Fragaria × ananassa) is an allo-octoploid species, originating nearly 300 years ago from wild progenitors from the Americas. Since that time the strawberry has become the most widely cultivated fruit crop in the world, universally appealing due to its sensory qualities and health benefits. The recent publication of the first high-quality chromosome-scale octoploid strawberry genome (cv. Camarosa) is enabling rapid advances in genetics, stimulating scientific debate and provoking new research questions. In this forward-looking review we propose avenues of research toward new biological insights and applications to agriculture. Among these are the origins of the genome, characterization of genetic variants, and big data approaches to breeding. Key areas of research in molecular biology will include the control of flowering, fruit development, fruit quality, and plant–pathogen interactions. In order to realize this potential as a global community, investments in genome resources must be continually augmented. [ABSTRACT FROM AUTHOR]

Octoploid strawberry (Fragaria ×ananassa) is a major specialty crop under intense annual selection for traits relating to plant vigor and fruit quality. Most functional validation experiments rely on transgenic or transient gene expression assays in the mature receptacle. These findings are not typically translatable to breeding without identifying a natural genetic source of transcript level variation, and developing reliable markers for selection in octoploids. Expression QTL (eQTL) analysis is a genetic/transcriptomic association approach for identifying sequence variants predicting differential expression. This eQTL study analyzed a wide array of mature receptacle-expressed genes, encompassing the majority of total mature receptacle transcript accumulation and almost all strawberry genes described in the literature. These results identified segregating genetic variants associated with the differential expression of hundreds of strawberry genes, many with known interest to breeders. Several of these eQTL pertain to published genes whose expression levels have been demonstrated to influence mature receptacle phenotypes. Many include key genes of the phenylpropanoid pathway, vitamin C, carotenoid, pectin, and receptacle carbohydrate/sugar metabolism. These subgenome-specific genetic markers may allow breeders to select for desired ranges of target gene expression. These results may also guide basic research efforts and facilitate the identification of causal genes underlying trait QTL. [ABSTRACT FROM AUTHOR]

Genomic prediction (GP) is the procedure whereby the genetic merits of untested candidates are predicted using genome wide marker information. Although numerous examples of GP exist in plants and animals, applications to polyploid organisms are still scarce, partly due to limited genome resources and the complexity of this system. Deep learning (DL) techniques comprise a heterogeneous collection of machine learning algorithms that have excelled at many prediction tasks. A potential advantage of DL for GP over standard linear model methods is that DL can potentially take into account all genetic interactions, including dominance and epistasis, which are expected to be of special relevance in most polyploids. In this study, we evaluated the predictive accuracy of linear and DL techniques in two important small fruits or berries: strawberry and blueberry. The two datasets contained a total of 1,358 allopolyploid strawberry (2n=8x=112) and 1,802 autopolyploid blueberry (2n=4x=48) individuals, genotyped for 9,908 and 73,045 single nucleotide polymorphism (SNP) markers, respectively, and phenotyped for five agronomic traits each. DL depends on numerous parameters that influence performance and optimizing hyperparameter values can be a critical step. Here we show that interactions between hyperparameter combinations should be expected and that the number of convolutional filters and regularization in the first layers can have an important effect on model performance. In terms of genomic prediction, we did not find an advantage of DL over linear model methods, except when the epistasis component was important. Linear Bayesian models were better than convolutional neural networks for the full additive architecture, whereas the opposite was observed under strong epistasis. However, by using a parameterization capable of taking into account these non-linear effects, Bayesian linear models can match or exceed the predictive accuracy of DL. A semiautomatic implementation of the DL pipeline is available at https://github.com/lauzingaretti/deepGP/. [ABSTRACT FROM AUTHOR]

A recent economic analysis predicted that the distribution of strawberry production in Florida that would maximize profit is very different from the current production distribution. An earlier start to the season in mid-November, peak production in early December and steadily decreasing production thereafter is predicted to create an improved balance of price and volume throughout the Florida market window. We propose that a combination of early short-day cultivars and low-chill day-neutral cultivars will help achieve this goal. Short-day varieties such as 'Florida Brilliance' produce earlier than previous varieties such as 'Strawberry Festival' and 'Florida Radiance.' Meanwhile, day-neutral varieties such as 'Florida Beauty' require more management but can be planted early and begin producing in mid-November with steady yields thereafter. All future varieties must have increased levels of fruit quality to drive market demand. [ABSTRACT FROM AUTHOR]

"Florida Brilliance" Strawberry. Fragaria ×ananassa, fruit breeding, small fruit. [Extracted from the article]

Optimal strategies for genetic improvement in crops depend on accurate assessments of the genetic architecture of traits. The overall objective of the present study was to determine the genetic architecture of anthracnose fruit rot (AFR) resistance caused by the fungus Colletotrichum acutatum in the University of Florida strawberry (Fragaria × ananassa) breeding germplasm. In 2016–2017, 33 full-sib families resulting from crosses between parents with varying levels of AFR resistance were tested. In 2017–2018, six full-sib families resulting from putative heterozygous resistant parents and homozygous susceptible parents were tested. Additionally, a validation population consisting of 77 advanced selections and ten cultivars was tested in the second season. Inoculation was performed using a mixture of three local isolates of the C. acutatum species complex. Phenotypes were scored weekly, and genotyping was performed using the IStraw35 Affymetrix Axiom® SNP array. A pedigree-based QTL analysis was performed using FlexQTL™ software. A major resistance locus, which we name FaRCa1, was detected in both seasons with a peak located at 55–56 cM on LG 6B and explaining at least 50% of the phenotypic variation across trials and seasons. The resistant allele exhibited partial dominance in all trials. The FaRCa1 locus is distinct from the previously discovered Rca2 locus, which mapped to LG 7B. While Rca2 is effective against European isolates from pathogenicity group 2, FaRCa1 appears to confer resistance to isolates of pathogenicity group 1. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • White-striped plastic mulch reduces root-zone temperatures during establishment. • White-striped mulch allows winter strawberry growers to advance transplanting. • Entirely black mulch and white-striped mulch exhibit comparable winter soil warming. • White-striped mulch increased early yield up to 46% and total yield up to 11%. • The magnitude of yield increase by white-striped mulch is cultivar-dependent. Abstract Early-season yields are critical to winter strawberry (Fragaria × ananassa Duch.) production in Florida and other winter and spring production regions around the world. Although advancing planting dates is a common practice to improve earliness, it can increase heat stress during establishment, especially on black plastic mulch. This problem could be addressed by adding a white center stripe to black plastic mulch. The white center stripe should cool the root zone during establishment while the black bed shoulders remain exposed to the sun to warm the soil during the winter. We conducted three field trials across two seasons to compare black plastic mulch (black mulch) to black plastic mulch with a white center stripe (white-striped mulch) using three cultivars (Florida Radiance, Florida Beauty, and Florida Brilliance). Bare-root transplants were planted on 26 Sept. in 2015 and 29 Sept. and 17 Oct. in 2016. Compared to black mulch, white-striped mulch reduced root-zone temperatures (10-cm depth) under the white stripe by up to 4.5 °C in November, while maintaining the same soil warming capacity on the bed shoulders throughout the growing season. White-striped mulch treatments resulted in increased growth, earliness, and yields, although the magnitude of improvement depended on cultivars and seasonal weather conditions. Early-season ambient temperatures were unusually high in the 2015–16 trial and the 2016–17 later-planted trial. In these two trials, white-striped mulch increased early yields by 20%–31% across cultivars. In the 2015–16 trial, white-striped mulch also increased canopy area by 11% during the early harvest period and root biomass by 26% at the end of the trial. Because late-season yields were unaffected in all trials, white-striped mulch only improved total yields for the second planting of 2016–17. By contrast, cultivar-specific effects were only observed for the first planting of 2016–17, in which white-striped mulch improved early and total yields of 'Florida Radiance' by 46% and 28%, respectively, compared to black mulch. Our results suggest that white-striped mulch is an easily implementable strategy for improving earliness of winter strawberry production in warm climates. [ABSTRACT FROM AUTHOR]

The aim of this study was to generate and evaluate the efficiency of improved field experiments while simultaneously accounting for spatial correlations and different levels of genetic relatedness using a mixed models framework for orthogonal and non-orthogonal designs. Optimality criteria and a search algorithm were implemented to generate randomized complete block (RCB), incomplete block (IB), augmented block (AB) and unequally replicated (UR) designs. Several conditions were evaluated including size of the experiment, levels of heritability, and optimality criteria. For RCB designs with half-sib or full-sib families, the optimization procedure yielded important improvements under the presence of mild to strong spatial correlation levels and relatively low heritability values. Also, for these designs, improvements in terms of overall design efficiency (ODE%) reached values of up to 8.7%, but these gains varied depending on the evaluated conditions. In general, for all evaluated designs, higher ODE% values were achieved from genetically unrelated individuals compared to experiments with half-sib and full-sib families. As expected, accuracy of prediction of genetic values improved as levels of heritability and spatial correlations increased. This study has demonstrated that important improvements in design efficiency and prediction accuracies can be achieved by optimizing how the levels of a treatment are assigned to the experimental units. [ABSTRACT FROM AUTHOR]

The article focuses on the Florida Beauty strawberry, a variety from the collaborative breeding effort between the University of Florida and the Queensland Department of Agriculture and Fisheries. Topics discussed include the variety's origin which came from a 2012 cross made by the breeding program between the university and the department, its description, and yield performance.

Background: Methyl anthranilate (MA) contributes an attractive fruity note to the complex flavor and aroma of strawberry (Fragaria spp.), yet it is rare in modern cultivars. The genetic basis for its biosynthesis has not been elucidated. Understanding the specific genes required for its synthesis could allow the development of gene/allelespecific molecular markers to speed breeding of flavorful strawberries. Results: Ripe fruits from individuals in an F1 population resulting from a cross between a MA producer and a non-producer were examined using a bulk-segregant transcriptome approach. MA producer and non-producer transcriptomes were compared, revealing five candidate transcripts that strictly co-segregated with MA production. One candidate encodes an annotated methyltransferase. MA levels are lower when this transcript is suppressed with RNAi, and bacterial cultures expressing the protein produced MA in the presence of anthranilic acid. Frozen fruit powders reconstituted with anthranilic acid and a methyl donor produced MA only if the transcript was detected in the fruit powder. A DNA-based molecular marker was developed that segregates with the MA-producing gene variant. Conclusions: These analyses indicate that the methyltransferase, now noted ANTHRANILIC ACID METHYL TRANSFERASE (FanAAMT), mediates the ultimate step of MA production in cultivated strawberry. Identification of this gene and its associated molecular marker may hasten breeding efforts to introduce this important volatile into modern cultivars. [ABSTRACT FROM AUTHOR]

BACKGROUND: The strawberry is an important commodity as well as a model plant species in the Rosaceae. DNA marker availability for various traits in octoploid cultivated strawberry has increased intensely in recent years. To date, laborious and expensive DNA extraction procedures have been required to achieve sufficient DNA quality in this recalcitrant species. When combined with gel-based marker systems, current genotyping methods are becoming a bottleneck for marker-assisted selection (MAS) in large strawberry breeding populations. OBJECTIVE: The main objective of this work was to develop a high-throughput marker system that combines 1) rapid DNA extraction and 2) rapid, cost-effective, and accurate genotyping, even when using crude strawberry DNA extracts. To this end, we aimed to develop high-throughput high-resolution melting (HRM) and SSR assays for selection at the FaFAD1 locus conferring peach-like aroma (γ-decalactone). METHODS: Eight cultivars and four advanced selections of strawberry (Fragaria×ananassa Duchesne) were used in this study. A rapid DNA extraction method from strawberry leaf discs was developed by modifying a previously published NaOH-based method. Three high-throughput HRM markers were developed for detecting the presence/absence of FaFAD1, and HRM analysis was performed using a Roche LightCycler 480. RESULTS: Rapid NaOH-based DNA extraction was successful for accurate and repeatable marker screening when diluted 5-fold prior to PCR and when non-acetylated BSA and PVP were added to the PCR reaction. Three HRM markers were successfully developed and used to detect the presence/absence of FaFAD1, with equivalent results to those obtained using the previously published gel-based marker. CONCLUSIONS: This high-throughput genotyping system has been successfully employed to screen approximately 6,000 seedlings in the University of Florida strawberry breeding program, and the method is being expanded for MAS at additional loci. The system should be adaptable to other berry crops for which fastDNAextraction, and low-cost and accurate genotyping are needed for large breeding populations. [ABSTRACT FROM AUTHOR]

Strawberry breeding programs are constantly engaged in the development of new cultivars with increased performance and improved quality traits. The recent release of Sensation ® ‘Florida127’ aims to accomplish these goals, yet its postharvest performance has not been rigorously studied. Therefore, the main objective of this study was to compare the sensory and physicochemical attributes and shelf life of Sensation ® ‘Florida127’ with that of commercial standards ‘Florida Radiance’ and ‘Strawberry Festival’. Overall, Sensation ® ‘Florida127’ showed superior or equal postharvest performance when compared to the standard cultivars depending on the trait, having the least decrease in appearance quality, firmness, and flavor. Sensation ® ‘Florida127’ consistently had a lighter red color, higher soluble solids and sugar contents, and lower acidity, ascorbic acid, polyphenols and anthocyanin contents. Sensation ® ‘Florida127’ shelf life was 1–3 days longer than that of ‘Florida Radiance’ and ‘Strawberry Festival’, respectively. Sensation ® ‘Florida127’ has lower levels of bioactive compounds but higher sugars content and lower acidity compared to the standard cultivars which result in a more flavorful fruit. The fruit also maintains an attractive light red coloration throughout storage, seldom looking overripe. The longer shelf life of Sensation ® ‘Florida127’ compared to the standard cultivars should be an advantage when the fruit are shipped to distant markets. [ABSTRACT FROM AUTHOR]

Plant breeding for disease resistance is crucial to sustain global crop production. For decades, plant breeders and researchers have extensively used host plant resistance genes (R-genes) to develop disease resistant cultivars. However, the general instability of R-genes in crop cultivars when challenged with diverse pathogen populations emphasizes the need for more stable means of resistance. Alternatively, non-host resistance is recognized as the most durable, broad-spectrum form of resistance against the majority of potential pathogens in plants and has gained great attention as an alternative target for managing resistance. While transgenic approaches have been utilized to transfer non-host resistance to host species, conventional breeding applications have been more elusive. Nevertheless, avenues for discovery and deployment of genetic loci for non-host resistance via hybridization are increasingly abundant, particularly when transferring genes among closely related species. In this mini review, we discuss current and developing applications of non-host resistance for crop improvement with a focus on the overlap between host and non-host mechanisms and the potential impacts of new technology. [ABSTRACT FROM AUTHOR]

New modulators of the strawberry flavonoid pathway were identified through correlation network analysis. The transcriptomes of red, ripe fruit from two parental lines and 14 of their progeny were compared, and uncharacterized transcripts matching the expression patterns of known flavonoid-pathway genes were identified. Fifteen transcripts corresponded with putative transcription factors, and several of these were examined experimentally using transient expression in developing fruits. The results suggest that two of the newly-identified regulators likely contribute to discrete nodes of the flavonoid pathway. One increases only LEUCOANTHOCYANIDIN REDUCTASE (LAR) and FLAVONOL 3'-HYDROXYLASE (F3'H) transcript accumulation upon overexpression. Another affects LAR and FLAVONOL SYNTHASE (FLS) after overexpression. The third putative transcription factor appears to be a universal regulator of flavonoid-pathway genes, as many pathway transcripts decrease in abundance when this gene is silenced. This report demonstrates that such systems-level approaches may be especially powerful when connected to an effective transient expression system, helping to provide rapid and strong evidence of gene function in key fruit-ripening processes. [ABSTRACT FROM AUTHOR]

The article offers information on the strawberry cultivar Sensation "Florida127" grown in Florida. Topics discussed include a description of the cultivar, the plant's origin and pedigree, and the advantage of its moderate plant size and long pedicels. Also mentioned are the marketable yield and average fruit weight of the variety.

Background: There is interest in improving the flavor of commercial strawberry (Fragaria × ananassa) varieties. Fruit flavor is shaped by combinations of sugars, acids and volatile compounds. Many efforts seek to use genomics-based strategies to identify genes controlling flavor, and then designing durable molecular markers to follow these genes in breeding populations. In this report, fruit from two cultivars, varying for presence-absence of volatile compounds, along with segregating progeny, were analyzed using GC/MS and RNAseq. Expression data were bulked in silico according to presence/absence of a given volatile compound, in this case γ-decalactone, a compound conferring a peach flavor note to fruits. Results: Computationally sorting reads in segregating progeny based on γ-decalactone presence eliminated transcripts not directly relevant to the volatile, revealing transcripts possibly imparting quantitative contributions. One candidate encodes an omega-6 fatty acid desaturase, an enzyme known to participate in lactone production in fungi, noted here as FaFAD1. This candidate was induced by ripening, was detected in certain harvests, and correlated with γ-decalactone presence. The FaFAD1 gene is present in every genotype where γ-decalactone has been detected, and it was invariably missing in non-producers. A functional, PCR-based molecular marker was developed that cosegregates with the phenotype in F1 and BC1 populations, as well as in many other cultivars and wild Fragaria accessions. Conclusions: Genetic, genomic and analytical chemistry techniques were combined to identify FaFAD1, a gene likely controlling a key flavor volatile in strawberry. The same data may now be re-sorted based on presence/absence of any other volatile to identify other flavor-affecting candidates, leading to rapid generation of gene-specific markers. [ABSTRACT FROM AUTHOR]

Fresh strawberries (Fragaria x ananassa) are valued for their characteristic red color, juicy texture, distinct aroma, and sweet fruity flavor. In this study, genetic and environmentally induced variation is exploited to capture biochemically diverse strawberry fruit for metabolite profiling and consumer rating. Analyses identify fruit attributes influencing hedonics and sensory perception of strawberry fruit using a psychophysics approach. Sweetness intensity, flavor intensity, and texture liking are dependent on sugar concentrations, specific volatile compounds, and fruit firmness, respectively. Overall liking is most greatly influenced by sweetness and strawberry flavor intensity, which are undermined by environmental pressures that reduce sucrose and total volatile content. The volatile profiles among commercial strawberry varieties are complex and distinct, but a list of perceptually impactful compounds from the larger mixture is better defined. Particular esters, terpenes, and furans have the most significant fits to strawberry flavor intensity. In total, thirty-one volatile compounds are found to be significantly correlated to strawberry flavor intensity, only one of them negatively. Further analysis identifies individual volatile compounds that have an enhancing effect on perceived sweetness intensity of fruit independent of sugar content. These findings allow for consumer influence in the breeding of more desirable fruits and vegetables. Also, this approach garners insights into fruit metabolomics, flavor chemistry, and a paradigm for enhancing liking of natural or processed products. [ABSTRACT FROM AUTHOR]

With 4 figures and 3 tables Abstract Many volatile compounds have been shown to influence the flavour of strawberry ( Fragaria spp.) fruit. A published study demonstrated that linalool, a critical flavour compound, is produced in cultivated F. × ananassa varieties owing to a truncated form of the NEROLIDOL SYNTHASE (NES) enzyme. The corresponding allele ( FaNES1) features a 5′-deletion that is detectable by PCR. Herein, we tested a broad set of strawberry genotypes to understand the origin of the allele and to identify materials that may be preferred candidates for molecular breeding. The results indicate that the FaNES1 allele (linalool+) is not present in any diploid, tetraploid or hexaploid accession tested. It is present in 112 F. × ananassa cultivars examined. The FaNES1 allele is present in all but three of 46 wild F. virginiana and F. chiloensis genotypes. Two of these three lines continue to produce linalool despite the absence of the allele. This survey suggests that the FaNES1 allele possibly arose following octoploidization and that linalool possibly is an important factor in strawberry biology, aside from its role in anthrocentric fruit quality attributes. [ABSTRACT FROM AUTHOR]

While hands-on, focus-group-based testing may be used to measure consumer preference, other computationally-based methods have also proven effective in testing opinions and sentiment toward a product. The IdeaMap® approach presents online, human subjects with a suite of attributes that define a given product. The subjects rate the product as these attributes change in various combinations. Upon analysis, individual attributes of the product, identified as consistently favorable or unfavorable, become apparent. In applying this methodology to strawberries, three-hundred and six subjects representing a broad cross-section of demographics from the United States were surveyed. The subjects rated perceived strawberry fruits based on appearance, texture, health benefits, flavor, point of purchase, and how they were consumed. Results from these experiments define the individual elements of a strawberry that contribute to or detract from an 'ideal' strawberry experience. Furthermore, the results of this study indicate that sweetness and complex flavors are the most important attributes, while perceived health benefits had little influence on consumer preference. The point of purchase can have a strong positive or negative effect, depending on the demographic fraction. Additional analysis of these results illustrate that there is not a single, perfect strawberry. Specific likes, dislikes and preferences change with ethnicity, age, gender, urban or suburban location, education and marital status. The results from this study can help shape breeding priorities as well as provide important guidance for marketing to specific demographics in the interest of increasing strawberry consumption. [ABSTRACT FROM AUTHOR]

The University of Florida strawberry (Fragaria xananassa Duch. ex Rosier) breeding program has maintained a continuous breeding effort since 1968 to develop cultivars that are highly adapted to winter production in west-central Florida. To gain insight into breeding progress over time, two advanced selections (UF1 and UF2) and 10 released cultivars, from Florida Belle (1975) to Florida Radiance (2008), were compared for various fruit quality traits in a two-location field study during the 2009-2010 season. Fruit size varied dramatically from 30.8 g for 'Elyana' to 16.2 g for 'Dover' at Balm, FL, and from 28.3 g for UF2 to 16.6 g for 'Dover' at Dover, FL. A linear regression of fruit size on year of release revealed an average gain of 2.6 g per year since 1975 for the cultivars and selections tested (R² = 0.44). A similar analysis revealed a reduction over time in the proportion of cull fruit (R² = 0.30). Gains were apparent for the redness of the internal flesh, from a colorimeter a* value of 16.1 for 'Florida Belle' (1975) to 34.7 for 'Carmine' (2002) but were not sustained for later releases and selections. Although there were significant differences among genotypes for all chemical traits affecting flavor, there were no discernable patterns over time. There were wide month-to-month variations in individual sugars and organic acids, except for citric acid, which was stable across months and locations. The ratio of soluble solids content to titratable acidity ranged widely among genotypes, from a high of 15.7 for 'Florida Belle' in February at Dover, FL, to a low of 6.4 for 'Winter Dawn' in January at Balm, FL. The observed variability and trends in fruit quality traits will help guide future genetic studies and inform decisions about future breeding priorities and selection procedures. [ABSTRACT FROM AUTHOR]

Regional, replicated cultivar trials of landscape roses are an ongoing component of the Earth-Kind® program, which was started at Texas A&M University in the 1990s to support environmental landscape stewardship. The rose trials within the Earth-Kind program identify and promote the most regionally adapted rose cultivars and are conducted without fertilizers or pesticides and greatly reduced irrigation. Black spot (caused by Diplocarpon rosae Wolf) is the most serious disease of outdoor-grown roses worldwide as a result of the potential for rapid leaf yellowing and defoliation. Earth-Kind designated cultivars for the south-central United States and roses under trial in other regions or considered for future Earth-Kind trials (n = 73 roses) and two susceptible control cultivars were challenged with North American Races 3, 8, and 9 of D. rosae, which were previously characterized at the University of Minnesota. Young expanded leaves were inoculated using detached leaf assays. Lesion length (LL) was measured for susceptible reactions and cultivar ploidy was determined using root tip squashes. Diploid, triploid, and tetraploid cultivars (n = 20, 30, and 23, respectively) were identified, and race-specific resistances and partial resistances were also identified. Race-specific resistance was generally more prevalent in newer rose cultivars and rose cultivars more recently included in Earth-Kind trials. Nine cultivars were resistant to all three races (Brite Eyes™, 'Grouse', Home Run®, Knock Out®, Paprika™, Peachy Cream™, Pink Knock Out®, Rainbow Knock Out®, and Yellow Submarine™. Blushing Knock Out®, a sport of Knock Out®, was susceptible to Race 8. Partial resistance rank for LL was generally consistent across races for roses susceptible to multiple races. The application of these data includes: characterizing the minimum resistance level needed for roses to warrant inclusion in Earth-Kind field trials, the identification of additional race-specific resistance genes, identifying resistance-breaking isolates of D. rosae, understanding race composition in field trials based on infection patterns of key cultivars, selection of parents for resistance breeding efforts, and continued comparisons between LL and growing bodies of Earth-Kind field resistance data. [ABSTRACT FROM AUTHOR]

The production system, especially fertilisation has an important effect on yield and quality of strawberries. In the present study, plants were fertilized with different doses of nitrogen (0–100% recommended doses), calcium chelate, as well as nano fertilizer Lithovit. Strawberry cultivar 'Clery' yield and quality parameters (fruit color and firmness) including nutritional indicators (total soluble solids, sugars, organic acids, phenolic and volatile compounds) were monitored. Volatiles were identified and monitored using headspace solid phase microextraction and analysed using gas chromatograph-mass spectrometry (SPME/GC-MS) and sugars, organic acids, and phenolic compounds with high performance liquid chromatography. Organic acids and phenolic compounds were detected with mass spectrometer (HPLC/MS). Both nitrogen and calcium fertilisation had altered sugars, organic acids, volatile and phenolic contents in strawberry fruits. Fertilisation with higher doses of nitrogen and calcium increased the content of unpleasant aromas aldehydes hexanal (up to 3.8-fold) and (E)-2-hexen-1- (up to 3.7-fold). The content of fruity esters was uppermost in fruits fertilised with nano-fertiliser Lithovit (up to 2.3-fold). Fertilisation with N and Ca decreased the strength of ketone and terpenoids fruity aroma. The highest content of total phenols, as well as all individual hydroxycinnamic and hydroxybenzoic acid derivatives were obtained in the nano-fertiliser Lithovit treatment. Fertilisation, especially with nitrogen, had mostly negative impact on strawberry flavour while nano-fertilization with Lithovit improved strawberry phenolic content and aroma. [ABSTRACT FROM AUTHOR]