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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.

Genetically Modified (GM) foods have been a debated topic for decades, and consumer concerns are widespread. Scientific proposals to increase consumer acceptance include the use of cisgenics, where GM technology is used but the inserted gene(s) originates from closely related organisms. Results from a choice experiment display greater willingness to pay (WTP) for cisgenics than transgenics, although traditional methods are preferred, and more accessible information about the technologies increases acceptance. The disutility from cisgenics and transgenics is offset by the utility from product quality improvement related to eating experience, indicating potential demand for cisgenic food, provided it improves the product in aspects of importance to the consumers.

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 study focuses on frost protection for early-season (early-ripening) peach (Prunus persica) varieties, which are an important crop for producers in the southeastern United States. Using in-depth interviews with four major Georgia peach producers, we explore their frost protection management strategies. This information is the first step in developing a comprehensive research agenda to advise cost-effective frost protection methods for peach cultivation. We found that peach producers are concerned about frost impacts on their crops. Although early-season peach varieties are particularly susceptible to frost impacts, producers still dedicate significant acreage to these varieties, aiming to extend the market window, satisfy sales contracts, and meet obligations for hired labor. However, early-season varieties do not result in high profits, so producers prefer to concentrate on frost protection for mid- and late-season varieties. Producers employ a variety of frost protection methods, including passive methods (such as planting sensitive varieties in areas less susceptible to frost and adjusting pruning/thinning schedules) and active methods (such as frost protection irrigation and wind machines). The choice among active frost protection methods is based on factors such as the planning horizon, initial investment needs, frequency of frost events, and the effectiveness of the frost protection method. Problem areas that producers identified included improving the effectiveness of frost protection methods; reducing initial investments required to install frost protection systems; and employing better spatial targeting and configuration of frost protection strategies (to reduce investment costs while maintaining or improving the effectiveness of frost protection). Although the initial investment costs of enhanced protection systems may limit producers from actually adopting such methods, the operating costs of such systems are relatively low and have a limited effect on the decision to employ frost protection during a particular frost event. However, producers use information about critical temperatures for different bud stages, and hence, improving the quality of information regarding frost susceptibility can help producers make better frost protection decisions (and potentially reduce electricity costs and water use for frost protection).

Background Nitrogen is a key component of crop production and is commonly related to increases in yield and fruit size. The N fertilization rates used for low-chill peach cultivars were adapted from other peach production regions, where environmental and soil conditions are different. The growth and production as well as the effect on fruit physical and compositional attributes of two low-chill peach cultivars - 'TropicBeauty' (TB) and 'UFSharp' (UFS) - with five different N fertilization rates (0 (N0), 45 (N1), 90 (N2), 179 (N3) and 269 (N4) kg ha-1 applied each year from 2011 to 2017) were examined. Results Peach trees under higher N rates had higher pruning weights compared to the lower N0 or N1 rates. Yield was only affected in 2017 for the two cultivars tested. Physical attributes were inconsistently affected by N. Fruit from the higher N rates had lower a* value (more green) than fruit from the trees under low or zero N. While fruit firmness was not affected by N, fruit from trees under zero/low N had higher total soluble solids in some years. Conclusion Considering that N is recycled in the trees, being retained and reused each season to resume growth, it is important to address peach orchard fertilization based on peach tree N status. The results of this experiment show that an increase in N beyond what is required for tree maintenance does not increase yield. In addition, reducing N does not strongly affect fruit quality, although the color and soluble solids results suggest that lower N rates may advance fruit maturation. © 2019 Society of Chemical Industry.

Bell peppers cultivated in Florida represent one third of the U.S. fresh-market production. Protected cultivation offers an advantage in a subtropical, humid climate to obtain high-quality colored bell peppers. However, multiple factors such as ventilation, high temperatures, and potting media volume can affect the success of bell pepper production under protected cultivation. The objective of this study was to evaluate the combination of two ventilation types and four pine bark volumes on bell pepper yield, plant growth and fruit quality. No significant effects of ventilation or pine bark volume on plant growth or commercial yield were found. This study suggested bell pepper can be cultivated in small pots as long as the plants are in non-limiting water and nutrient conditions. Moreover, a ventilation system with only a central roof vent in the ridge of the tunnel with a metallic gutter has no additional beneficial effect on colored bell pepper yields.

The Genome Database for Rosaceae (GDR, https://www.rosaceae.org) is an integrated web-based community database resource providing access to publicly available genomics, genetics and breeding data and data-mining tools to facilitate basic, translational and applied research in Rosaceae. The volume of data in GDR has increased greatly over the last 5 years. The GDR now houses multiple versions of whole genome assembly and annotation data from 14 species, made available by recent advances in sequencing technology. Annotated and searchable reference transcriptomes, RefTrans, combining peer-reviewed published RNA-Seq as well as EST datasets, are newly available for major crop species. Significantly more quantitative trait loci, genetic maps and markers are available in MapViewer, a new visualization tool that better integrates with other pages in GDR. Pathways can be accessed through the new GDR Cyc Pathways databases, and synteny among the newest genome assemblies from eight species can be viewed through the new synteny browser, SynView. Collated single-nucleotide polymorphism diversity data and phenotypic data from publicly available breeding datasets are integrated with other relevant data. Also, the new Breeding Information Management System allows breeders to upload, manage and analyze their private breeding data within the secure GDR server with an option to release data publicly.

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.

Despite production of the first domestically produced peach of the calendar year in the United States, the subtropical peach industry faces marketing challenges, particularly with small fruit size. Although important, size is only one aspect of fruit quality, and not inclusive of all possible fruit quality attributes. Thus, this research asked consumers to identify an “ideal” peach given a combination of possible peach fruit quality attributes to help determine their influence on consumer purchase. These attributes were verified with farmers’ market intercept studies. The top attributes that fostered purchase likelihood included flavor, texture, size, and firmness. Psychophysics studies showed that consumers preferred peaches that were sweet, juicy, round, with freestone or semifreestone characteristics, whereas consumers were less likely to purchase peaches with mealy, dry, or meaty textures. Young consumers (ages 18–24) preferred crisp, firm peaches with good flavor, whereas older consumers (ages 51–65) preferred sweet, melting-texture peaches. Farmers’ market intercept studies found consumers (ages 45–65) preferred melting-texture peaches with good flavor that led to increased overall liking. In addition, in the farmers’ market studies, aroma and flavor were important attributes and were highly correlated with overall liking. Objective measurements of total soluble solids (TSS) were not correlated with overall liking, indicating that although the nationwide experiment found consumers desired sweet peaches, other attributes may contribute more favorably to overall liking.

This four-year study tested whether the physiological demand of fruit ripening may interfere with grapevine cold acclimation in autumn or with midwinter hardiness. Three harvest time treatments were established in a mature vineyard of own-rooted Cabernet Sauvignon vines: clusters were removed after fruit set, at veraison, or after the first fall frost. Average yield of the late harvested vines varied from 4.2 to 5.1 kg/vine (7.5 to 9.2 t/ha) among years, and soluble solids varied from 23.4 to 25.6 Brix. The presence of fruit during ripening delayed leaf senescence, measured as chlorophyll decline. The fruit also tended to delay the senescence-associated decrease in photosynthesis. All vines showed typical patterns of autumn cold acclimation, midwinter hardiness, and spring deacclimation. Cold hardiness of buds, cane phloem, and cane xylem varied during winter depending on prevailing temperature, and during the coldest winter reached levels of −27°C for 50% bud damage and −28°C for the onset of xylem injury. Early fruit removal had no effect on cane nonstructural carbohydrates and, with few exceptions, failed to enhance cold hardiness. Depending on the year, early fruit removal improved bud hardiness on 5 to 15% and xylem hardiness on 8 to 38% of all measurement dates. On those dates, the early harvested vines tended to be 1 to 2°C hardier than the late harvested vines, irrespective of the time of crop removal. No trend was found for phloem hardiness. These results indicate that cropping, at least within commercially acceptable limits in regions with sufficiently long or warm growing seasons, rarely impacts cold acclimation and maximum hardiness. Grapevines appear to adjust seasonal leaf physiology to meet their carbon demand for both fruit ripening and cold acclimation.

The Genome Database for Rosaceae (GDR, http:/www.rosaceae.org), the long-standing central repository and data mining resource for Rosaceae research, has been enhanced with new genomic, genetic and breeding data, and improved functionality. Whole genome sequences of apple, peach and strawberry are available to browse or download with a range of annotations, including gene model predictions, aligned transcripts, repetitive elements, polymorphisms, mapped genetic markers, mapped NCBI Rosaceae genes, gene homologs and association of InterPro protein domains, GO terms and Kyoto Encyclopedia of Genes and Genomes pathway terms. Annotated sequences can be queried using search interfaces and visualized using GBrowse. New expressed sequence tag unigene sets are available for major genera, and Pathway data are available through FragariaCyc, AppleCyc and PeachCyc databases. Synteny among the three sequenced genomes can be viewed using GBrowse_Syn. New markers, genetic maps and extensively curated qualitative/Mendelian and quantitative trait loci are available. Phenotype and genotype data from breeding projects and genetic diversity projects are also included. Improved search pages are available for marker, trait locus, genetic diversity and publication data. New search tools for breeders enable selection comparison and assistance with breeding decision making.

Florida has a large and diverse horticulture industry, with large quantities of fruit and vegetables produced from November to February. Diversification strategies have come to the forefront in perennial horticulture sectors, such as citrus (Citrus sp.), where several diseases have reduced productivity and acreage. Many growers are considering diversification of their groves to other fruit crops, such as peach (Prunus persica). To understand the state of the industry and provide perspective for transitional Florida growers to mitigate risk, a survey was conducted in 2011. A total of 27 completed survey questionnaires were returned which represented 68% of 2011 Florida peach orchard owners and managers. On average, responding peach orchard size was 18 acres, ranging from 1 to 100 acres, with ‘TropicBeauty’, ‘UFSun’, ‘UFOne’, and ‘UFBeauty’ comprising the main varieties. Production and marketing challenges were key issues identified by growers as they sought to mitigate risk in an uncertain economic climate. Key sources of production information were university personnel, followed by fellow growers, indicating that stone fruit (Prunus sp.) extension programs are effective in information delivery. Tree production expertise combined with geographic proximity to concentrated market segments, access to established fresh fruit distribution routes, and existing relationships with retail market customers are expected to provide the Florida tree-ripened peach grower with unique marketing opportunities. Findings from this survey effort will be used by the project team to develop educational materials and outreach programs, designed to better address the production and marketing risks facing Florida peach growers. In addition, project results will provide new information for regional and national perennial crop producers who are interested in diversifying production practices to meet increased consumer demand for access to locally sourced horticultural products.

Consumer demand for organic and sustainably produced products has increased the interest in organic wine grape (Vitis vinifera) production. However, organic production can be challenging, and weed management is a critical issue during the establishment of an organic vineyard. In 2009, the effectiveness of five cover crop treatments and cultivation regimes was evaluated for two years for weed control in a newly established organic vineyard of ‘Pinot noir précoce’ and ‘Madeleine angevine’ grape cultivars in northwestern Washington State. Alleyway management treatments were cultivation in alleyways with hand weeding in the vine row (control), grass cover crop which included perennial ryegrass (Lolium perenne ssp. perenne) and red fescue (Festuca rubra ssp. arenaria) seeded in the alleyway and in-row tillage with a specialty offset-type cultivator, winter wheat (Triticum aestivum) cover crop with in-row string-trimming, austrian winter pea (Pisum sativum ssp. sativum var. arvense) cover crop with in-row string-trimming, and winter wheat–austrian winter pea cover crop mix with in-row string-trimming. In 2009, weed dry biomass was lowest in the alleyway of the control (0.8 g·m−2) and offset cultivator treatments (6.3 g·m−2) on 3 Aug. and tended to be lowest in the alleyway of the control (4.8 g·m−2) and offset cultivator treatments (16.0 g·m−2) on 27 Sept. In the second year of establishment (2010), winter wheat and austrian winter pea were eliminated from the plots by mid-July, and white clover (Trifolium repens) and perennial ryegrass were the dominant weed species and accounted for a majority of the total weeds. On average over the two-year period, the control treatment required the most time for alleyway management (92 h·ha−1) followed by the offset cultivator treatment (64 h·ha−1), while the winter wheat, austrian winter pea, and winter wheat–austrian winter pea mixture required 32 to 42 h·ha−1. ‘Madeline angevine’ produced more shoot growth than ‘Pinot noir précoce’ in Sept. 2010 (42.3 and 25.9 cm respectively), and shoot growth of both cultivars in the control treatment was significantly longer (125.0 cm) than under any other treatment (55.4 to 93.0 cm), illustrating the importance of weed control during vineyard establishment. In this study, the most effective weed management regime, although also the most time consuming, included a vegetative-free zone around the vines (e.g., in-row) maintained by hand weeding and a cultivated alleyway.

In composite (scion–rootstock) dwarfing fruit trees, an overgrowth at the graft union is often observed, the severity of which is correlated with degree of dwarfing. The graft union of dwarfing sweet cherry ( Prunus avium L.) rootstocks may limit soluble sugar transport or starch mobilization, leading to localized accumulation. Soluble sugars and starch were measured in the tissues surrounding the graft union of young ‘Rainier’ (2002) and ‘Lapins’ (2003) sweet cherry trees on ‘Gisela 5’ (‘Gi 5’; dwarfing) and ‘Colt’ (vigorous) rootstocks. Separate rootstock shank, rootstock, graft union, and scion tissues were analyzed for both starch and soluble sugar content throughout the growing season in both years. Starch concentrations did not vary among locations within the graft union for ‘Rainier’ on either the dwarfing or vigorous rootstock, or for ‘Lapins’ on the dwarfing stock. However, for ‘Lapins’ on ‘Colt’, starch was highest in the rootstock shank and declined vertically (rootstock shank ≫ rootstock > union > scion). Soluble sugar concentrations were generally similar to or higher in scions on ‘Gi 5’ than on ‘Colt’, and were similar to or lower in the rootstock and rootstock shank on ‘Gi 5’ than on ‘Colt’. Results suggest that rootstock has a significant effect of localized accumulations of carbohydrates above and within the graft union of ‘Gi 5’ and below the graft union of ‘Colt’.

Estimates of canopy and fruit fresh mass are useful for more accurate interpretation of data from the Trellis Tension Monitor, a tool for real-time monitoring of plant growth and predicting yield in trellised crops. In grapevines (Vitis labruscana Bailey), measurements of shoot and fruit fresh mass were collected at frequent intervals (14 to 21 days) over 5 years, and these data were correlated with variables that could be obtained nondestructively: shoot length, number of leaves per shoot, and number of clusters per shoot. Shoot length provided a good estimator of shoot fresh mass in all years. Nonlinear logistic regression models described the dynamics of canopy growth from bloom to the early stages of ripening, which often is poorly represented by simple linear regression approaches to seasonal data. A generalized function indicated a lower bound of ≈600 degree-days, after which an increase in shoot fresh mass could be considered on average to contribute only slightly to further increases in trellis wire tension. The dynamics of fruit mass were captured adequately by a nonlinear function, but not as well as vegetative mass because of larger variances in fruit mass. The number of clusters per shoot was associated with fruit mass only after the accumulation of ≈550 degree-days or, equivalently, the time at which fruit mass exceeded ≈25 g per shoot. Seasonal dynamics of the ratio of fruit to vegetative fresh mass were not sufficiently discernable by the logistic models because of the dominance of fruit mass and its large interannual variation.

Florida hybrid (Vitis spp.) and muscadine (V. rotundifolia Michx.) grape acreage is increasing in the south-eastern United States for the fresh market, wine production, and other diversified products. There is little research on determining leaf area in Muscadine grapes that could be used to assess canopy balance. Previous research on nondestructive methods of assessing canopy leaf area in V. vinifera L. and V. labrusca L. varieties may not apply to V. rotundifolia and Florida hybrid varieties. Thus this research sought to verify the accuracy previous non-destructive methods for V. rotundifolia and Vitis spp. varieties grown in Florida. Linear measurements were taken on fully expanded leaf of ‘Blanc Du Bois’ (Vitis spp.), ‘Carlos’ (V. rotundifolia Michx.) and ‘Southern Home’ (interspecific V. rotundifolia × V. vinifera hybrid). Maximum length and width were used to predict leaf area using linear regressions. For each cultivar, 5 linear regression equations were developed to estimate leaf area using length and width. Length and width were log transformed and an additional 3 linear equations were developed. Equations with the product of length and width had a higher coefficient of determination for all three varieties. Therefore, these equations are recommended for use when conducting non-destructive leaf area measurements of muscadine and Florida hybrid grape varieties.

Xylem vessel anatomy was examined in tissues surrounding the graft union of sweet cherry (Prunus avium L.) scion (stem) and nondwarfing, semi-dwarfing, or dwarfing rootstock (root) combinations, to characterize potential changes in anatomical features during the initial stages of graft union formation. Vessel element length, frequency, diameter, lumen area (LAV), and mean vessel hydraulic diameter (VDh) were examined in `Rainier' (P. avium) scion wood grafted onto nondwarfing `Colt' (P. pseudocerasus L. × P. avium) or `F 12/1' (P. avium) rootstock and semi-dwarfing `Gisela 6' [`Gi 6' (P. cerasus L. × P. canescens L.)], or dwarfing `Gisela 5' [`Gi 5' (P. cerasus × P. canescens)] rootstock systems in: heterograft combinations (commercial scion-rootstock combinations); homografts (scion and rootstock are the same genetic material); and reciprocal heterografts (rootstock tissue grafted onto scion tissue). Vessel element length was not affected by rootstock, but vessel frequency and lumen area in graft union tissues were smaller in `Rainier'/`Gi 5' (dwarfing combination) than in `Rainier'/`Colt' (nondwarfing combination). The heterograft combination of `Rainier'/`Gi 5' had smaller scion LAV, lower VDh and narrower vessels than homograft or reciprocal heterograft combinations. As callus differentiated into vascular elements, xylem rays in `Rainer'/`Gi 5' tended to develop at an acute angle to the longitudinal axis of the tree and there was an increase in nonfunctional phloem in `Rainer'/`Gi 5' compared to `Rainer'/`F 12/1'. Collectively, the data provides further evidence that a combination of smaller and fewer vessels in the scion and graft union, as well as irregular vessel orientations in the vascular tissue within dwarfing combinations could contribute to hydraulic resistance in the graft union resulting in reduced scion growth (dwarfing).

Dye transport through vascular pathways was examined in tissues surrounding the graft union of second-leaf, field-grown trees of `Lapins'/Gisela 5 (`Gi 5') (dwarfing) and `Lapins'/'Colt' (nondwarfing). Excavated, intact trees were allowed to take up xylemmobile dye via transpiration for 6 h before sectioning the tree into scion, graft union, and rootstock tissue. `Lapins'/'Gi 5' had a significantly larger stem cross-sectional area in the central graft union than did `Lapins'/'Colt'. Per unit cross section, dye transport of both `Lapins'/'Gi 5' and `Lapins'/'Colt' was significantly less in the graft union than in rootstock sections, with still less transported to scion tissues in `Lapins'/'Gi 5'. `Lapins'/'Gi 5' had a tendency to produce vascular elements oriented obliquely to the longitudinal axis of the tree. Dye was distributed more uniformly axially and radially across the graft union in `Lapins'/'Colt' than in `Lapins'/'Gi 5', with an apparent accumulation of dye in `Lapins'/'Gi 5' graft union. Xylem vessel diameters and vessel hydraulic diameters (VDh) were smaller overall in `Lapins'/'Gi 5' than in `Lapins'/'Colt'; however, graft unions in both had smaller VDh than did rootstock sections. These observations suggest reduced transport efficiency of xylem vessels in the graft union in `Lapins'/'Gi 5' may be due to smaller vessels, vascular abnormalities and/or increased amounts of callus and parenchyma tissue.

Traditionally, vegetative cover has been subjectively assessed by visual assessment. However, visual assessment is thought to overestimate percent vegetative cover. Thus, a repeatable method to objectively quantify percent cover is desirable. In two vineyards near Prosser, Wash., the percentage of ground surface covered by up to 15 different cover crops was assessed both visually and by computer-assisted digital image analysis. Quadrats in the cover crop were photographed digitally and the images analyzed with commercially available software. Areas of green vegetation in each image were identifi ed and measured. Weeds in some images were differentiated from the cover crop by user- defi ned thresholds. Subjective visual estimates of percent vegetative cover were generally higher than those digitally estimated. Values for the visual estimates ranged from 5% to 70% in 1998 (mean = 52.4%) and 7.5% to 55% in 1999 (mean = 30.7%), compared to digital readings ranging from 0.5% to 24% (mean = 11.1%) and 10.3% to 36.6% cover (mean = 20.1%), respectively. The visual assessments had lower coeffi cients of variability in 1998 (CV 28.1) than the digital image analysis (CV 52.3), but in 1999, the values for the two techniques were similar (CV 41.2 vs. CV 45.7). Despite initial variations between the two methods, the accuracy of digital image analysis for measuring percentage vegetative cover is superior. Soil erosion by wind is a signifi cant concern in vineyards in eastern Washington, in part, because of low rainfall. Both the Columbia and Yakima valleys, where the majority of the stateʼs vineyards are located, lie in the rainshadow of the Cascade Mountains and experience frequent high winds. In some seasons, 2 to 5 cm of topsoil can be lost by wind erosion. Soil eroded from bare ground accumulates in areas with vegetative cover (Coldwell et al., 1942). Cover crops mitigate

Protected cultivation has been used to modify the microclimate to advance maturity, increase yields, and expand areas of production for many horticultural crops. Ancillary benefits of protected cultivation can include reduced numbers of pests and lower disease pressure. This discussion will limit the term “protected cultivation” to row covers, low tunnels, and individual plant shelters (“grow tubes”), addressing their applications in the production of small fruit. The foremost biological response of crops grown under protected cultivation is an increase in growth rate, induced primarily by elevated soil and air temperatures within the shelter and around the plant. The protected environment often has lower vapor pressure deficits between crop and atmosphere, resulting in less plant stress. Although many reports detail the biological responses of crops grown under protected cultivation, few include measurements of environmental variables within plant shelters. Understanding the physical principles ...

Dwarfing rootstocks in sweet cherry (Prunus avium L.) have been planted worldwide. No single theory has emerged to answer why scion dwarfing occurs in fruit trees. This research examines the vascular pathway in a dwarfing cherry system to determine if physical limitations alter water transport as a possible dwarfing mechanism. Second-leaf `Lapins' trees grafted onto Gisela 5 (Gi5; dwarfing) and Colt (vigorous) rootstocks were field-grown in East Lansing, Mich. During maximum shoot elongation, trees were dug, placed into containers with safranin dye solution (0.1% w/v) for 6 hours and then removed for division (3-5 cm in length) based on location in scion, graft union, and rootstock tissue. Tissues were sectioned using a sliding microtome (120 μm) for examination with a laser confocal microscope (Zeiss LSM Pascal). Mean stem area and vessel diameter were measured; and mean hydraulic diameter was calculated for vessels in the area of dye translocation. Overall, Lapins/Gi5 stem area in the graft union was larger compared to Lapins/Colt; however dye translocation in Lapins/Gi5 was reduced compared to other tissues in the tree. Confocal microscopy indicated dye uptake through the grafted region was more uniformly distributed in Lapins/Colt than in Lapins/Gi5, with dye accumulation in areas of maximum translocation. Vessel diameter did not differ in these areas of translocation. However, in both combinations there was a reduction in mean hydraulic diameter of graft union sections, suggesting a reduction in vessel efficiency to translocate water in this region. Vascular system anomalies were more frequent in Lapins/Gi5, disrupting acropetal dye translocation. This suggests the greatest reduction in vascular transport is in Lapins/Gi5.

TreeGenes and tree fruit Genome Database Resources serve the international forestry and fruit tree genomics research communities, respectively. These databases hold similar sequence data and provide resources for the submission and recovery of this information in order to enable comparative genomics research. Large-scale genotype and phenotype projects have recently spawned the development of independent tools and interfaces within these repositories to deliver information to both geneticists and breeders. The increase in next generation sequencing projects has increased the amount of data as well as the scale of analysis that can be performed. These two repositories are now working towards a similar goal of archiving the diverse, independent data sets generated from genotype/phenotype experiments. This is achieved through focused development on data input standards (templates), pipelines for the storage and automated curation, and consistent annotation efforts through the application of widely accepted ontologies to improve the extraction and exchange of the data for comparative analysis. Efforts towards standardization are not limited to genotype/phenotype experiments but are also being applied to other data types to improve gene prediction and annotation for de novo sequencing projects. The resources developed towards these goals represent the first large-scale coordinated effort in plant databases to add informatics value to diverse genotype/phenotype experiments.