North American Cranberry Researcher and Extension Workers Conference

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Recent Submissions

Now showing 1 - 5 of 36
  • Publication
    Quantifying nitrogen export from a large agricultural watershed to a coastal bay in southeastern Massachusetts
    (2017-08-29) Wilderotter, Sophie; Kennedy, Casey
    Abstract: Mitigating nonpoint pollution is the single greatest challenge to improving coastal waters in the United States. In southeastern Massachusetts, the effects of nonpoint pollution are clearly evident in the degradation of water quality in Buzzards Bay, a large (~600 km2) coastal bay where nonpoint nitrogen (N) pollution is a matter of the utmost concern. Although septic effluent is considered the largest nonpoint source of N pollution, cranberry agriculture is often implicated as a prominent source of N to the bay. For instance, the heavily agricultural Weweantic River watershed is estimated to export 107,300 kg N yr-1, or 22% of the annual N load to the bay. Although the Wewenatic River is closely connected to water quality in the bay, field-based measurements of N export from the Weweantic River are lacking. To fill this gap, we initiated a 2-yr monitoring study of N export from the Weweantic River in July of 2016. The location of our water quality monitoring station was ~3.5 km upstream of a former milldam, which eliminated the potentially confounding effects of tidal fluctuations. A stage-discharge rating curve was established for continuous measurement of streamflow, and stream water samples were collected 3 d per week to determine concentrations of total N (TN), total dissolved N (TDN), nitrate (NO3-), ammonium (NH4+), dissolved inorganic N (DIN = NH4+ + NO3-), dissolved organic N (DON = TDN – DIN), and particulate N (PN = TN – TDN). Streamflow exhibited considerable seasonal variation, ranging from 90 L s-1 in the summer (August) to 7600 L s-1 in the spring (April). Concentrations of TN were highest in the summer (mean = 0.46 N L-1), intermediate between November and February (mean = 0.34 mg N L-1), and lowest from March to April (mean = 0.28 mg N L-1). The majority of N exported by the Weweantic River was in the form of DON, which represented, on average, 77% of TN (per sample basis). Measured TN load of 1.8 kg N ha-1 yr-1 (1.7 kg N ha-1 yr-1as DON) was about half the model predicted mean TN load of 4.8 (±0.8) kg N ha-1 yr-1 (1 standard deviation in parentheses). Lower observed loading could be due to the 2016 drought, supporting the need for further monitoring, or to uncertainty in model inputs (i.e., model simulations assume N fertilizer use of 84 kg N ha-1 for cranberry agriculture, whereas grower records indicate N fertilizer use between 40-50 kg N ha-1). Answers to these questions, as well as inverse modeling to estimate cranberry agriculture N loading rates and in-stream N uptake, will be the focus of the monitoring in year 2 of the study. This poster is not available for downloading.
  • Publication
    Population Densities of Lepidopteran Pests in Selected Cranberry Cultivars in Wisconsin
    (2017-08-29) McMahan, Erin; Steffan, Shawn; Guedot, Christelle
    Abstract: Host plant resistance, an important strategy of integrated pest management, was examined in the American cranberry, Vaccinium macrocarpon Aiton (Ericaceae). Despite the pressure on cranberry growers to reduce pesticide usage, host plant resistance is not used to help manage insect populations. This study measured field population densities of the three most economically important pest insects in Wisconsin, namely, cranberry fruitworm (Acrobasis vaccinii Riley), sparganothis fruitworm (Sparganothis sulfureana Clemens), and blackheaded fireworm (Rhopobota naevana Hu¨bner), in five different cranberry cultivars, i.e., ‘Stevens’, ‘Ben Lear’, ‘GH1’, ‘Mullica Queen’, and ‘HyRed’. Population densities of male moths of all three species were assessed using pheromone traps in beds of the different cranberry cultivars in commercial marshes in central Wisconsin. For each cultivar, damaged cranberries were collected, and the number of damaged berries and the number of larvae feeding within berries were compared among cultivars. More than 99% of larvae collected were cranberry fruitworm. Mullica Queen and Ben Lear had more damaged berries than Stevens or GH1, and had more larvae than GH1. Conversely, fewer adult male sparganothis fruitworm were found in Ben Lear and Mullica Queen beds than in beds of Stevens or GH1. Adult populations of cranberry fruitworm and blackheaded fireworm were not different among cultivars. Our findings provide evidence of different levels of resistance in common cranberry cultivars, which should inform future plantings and breeding programs.
  • Publication
    Identification and mapping of fruit rot resistance QTL in American cranberry using GBS
    (2017-08-29) Daverdin, Guillaume; Johnson-Cicalese, Jennifer; Zalapa, Juan; Vorsa, Nicholi; Polashock, James
    Abstract: Sustainability of the cranberry industry is threatened by widespread and increasing losses due to fruit rot in the field, as well as increasing restrictions on fungicide inputs. Breeding for resistance offers a partial solution, but is challenging because fruit rot is caused by a complex of pathogenic fungi that can vary by location and from year to year. We identified four genetically diverse germplasm accessions that exhibit broad-spectrum fruit rot resistance under field conditions. Three of these accessions were used in biparental crosses to develop four populations segregating for resistance. Genotyping by sequencing was used to generate SNP markers for development of high density genetic maps and QTL analyses. Nineteen QTL associated with fruit rot resistance, distributed on nine linkage groups, were discovered in our populations. Three of these QTL matched previously reported fruit rot resistance QTL. Four newly reported QTL found on linkage group 8 (Vm8), which explain between 21 and 33% of the phenotypic variance for fruit rot, are of particular interest to our breeding program. The populations described herein were also phenotyped for other horticulturally important traits, and QTL associated with yield and berry weight were identified. These QTL provide markers for candidate gene discovery and for future breeding efforts to enhance and pyramid disease resistance and other traits into elite horticultural backgrounds.
  • Publication
    Exploring Cranberry Cold Hardiness Using Differential Thermal Analysis
    (2017-08-29) Villouta, Camilo; Workmaster, Beth Ann; Bolivar-Medina, Jenny; Atucha, Amaya
    Abstract: To date, cranberry terminal bud cold hardiness has been assessed by controlled freezing tests where levels of damage are evaluated from tissue samples exposed to a range of predetermined sub-freezing temperatures. As in many woody plant buds, freezing stress damage in cranberry is variable across different structures of the bud, often making evaluation challenging. The buds of many woody plant species survive freezing stress by the mechanism of supercooling, the maintenance of water in the liquid state in specific tissues to temperatures below 0°C. The eventual freezing of this supercooled water is lethal to the tissue. The exotherm released from this phase change of water is detectable by the technique of differential thermal analysis (DTA). As part of a larger study on cranberry bud cold hardiness changes concurrent with the plant’s transitions into and out of endodormancy, our initial objective has been to assess the supercooling capability of cranberry buds and the applicability of DTA to quantify this phenomenon. The study was conducted with samples of ‘Stevens’ and ‘HyRed’ collected weekly from two farms in central Wisconsin from ice-off until bud swell in early 2017. Eleven DTA tests were run in custom-built equipment, with controlled freezing tests also performed on the last four sample dates. Low temperature exotherms (LTEs) were detected, supporting the hypothesis that cranberry bud tissue supercools. However, the observed number of LTEs was lower than expected, being detected in only 20 to 40% of the total number of buds tested on a given date (n = 90 to 100). Based on these results, LT10, LT50, and LT90 values were calculated. Over the course of the sampling period, the range of LT50 values remained stable (from -11.3 to -7.3 °C in ‘HyRed’ and from -12.7 to -5.8 °C in ‘Stevens’ ) and did not fluctuate in response to changes in air temperature or the observed variations in leaf pigments. This is in contrast with the results of our controlled freezing tests and those of Workmaster et al. (2006) where LT50 values by showed important shifts from tight bud to bud swell. We are considering technical and physiological explanations for the reduced number of LTEs. Despite efforts to maximize equipment sensitivity, technical challenges may remain. Alternatively, changes in water relations of many woody plant buds occur in response to both endodormancy and prolonged exposure to freezing temperatures. These changes are known to involve the mobilization of water from primordia to other organs, such as bud scales, increasing the ability of primordia to supercool, a process known as extraorgan freezing. Additionally, anatomical observations support this freezing stress survival hypothesis in cranberry buds. This poster is not available for downloading.
  • Publication
    Metabolomic Analysis of Commercial Cranberry Supplements
    (2017-08-29) Turbitt, John; Neto, Catherine; Killday, Brian; Colson, Kim
    Abstract. The potential health benefits of cranberries (Vaccinium macrocarpon) can be attributed to a variety of secondary metabolites, including proanthocyanidins (PACs), flavonoids, organic acids, and triterpenoids. Commercial cranberry supplements can provide a low-sugar alternative to juices and sweetened fruit products, however the phytochemical content can be expected to vary due to widely differing manufacturing processes. Selected commercial cranberry supplements were analyzed for secondary metabolite profile in comparison to a whole cranberry powder reference standard material, using 1H qNMR with Bruker AssureNMR software. HPLC-DAD and the DMAC assay were employed for total anthocyanin and PAC content respectively. Principal component analysis of 1H NMR spectra showed overlap between several supplements and whole cranberry powder, whereas others varied widely from the standard. Total PAC content varied widely, with four supplements ranging 5 - 10 mg PAC/g dry weight, one at 100 mg PAC/g dry weight, and insignificant PAC content in the rest. Several supplements contained only minimal amounts of organic acids and flavonoids. Cranberry peel constituents ursolic acid (8.0-16.3 mg/g) and oleanolic acid (0.3-5.1 mg/g), were detected in the whole cranberry reference standard but only about half of the supplements. Study results suggest significant variation in phytochemical composition among commercial cranberry supplements, reinforcing the need for reliable industry standards. This poster is not available for downloading.