Horticultural Crops Research Unit

Corvallis, OR, United States

Horticultural Crops Research Unit

Corvallis, OR, United States
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Cohen S.D.,Oregon State University | Cohen S.D.,Appalachian State University | Tarara J.M.,Horticultural Crops Research Unit | Gambetta G.A.,University of California at Davis | And 3 more authors.
Journal of Experimental Botany | Year: 2012

Little is known about the impact of temperature on proanthocyanidin (PA) accumulation in grape skins, despite its significance in berry composition and wine quality. Field-grown grapes (cv. Merlot) were cooled during the day or heated at night by +-8 °C, from fruit set to véraison in three seasons, to determine the effect of temperature on PA accumulation. Total PA content per berry varied only in one year, when PA content was highest in heated berries (1.46 mg berry-1) and lowest in cooled berries (0.97 mg berry-1). In two years, cooling berries resulted in a significant increase in the proportion of (-)-epigallocatechin as an extension subunit. In the third year, rates of berry development, PA accumulation, and the expression levels of several genes involved in flavonoid biosynthesis were assessed. Heating and cooling berries altered the initial rates of PA accumulation, which was correlated strongly with the expression of core genes in the flavonoid pathway. Both heating and cooling altered the rate of berry growth and coloration, and the expression of several structural genes within the flavonoid pathway. © 2012 The Author.


Keller K.E.,Horticultural Crops Research Unit | Mosier N.J.,Horticultural Crops Research Unit | Thomas A.L.,University of Missouri | Martin R.R.,Horticultural Crops Research Unit
Acta Horticulturae | Year: 2015

Cuttings of nine elderberry (Sambucus spp.) cultivars were sent from Missouri (USA) to the USDA-ARS laboratory in Corvallis, Oregon (USA) to be tested for the presence of viruses. Double-stranded RNA (dsRNA) was extracted from the nine cultivars and all showed a similar electrophoretic banding pattern, with bands of about 8000 base pairs (bp) in addition to several smaller bands. The dsRNA from 'Bob Gordon' was used as template for next generation sequencing (NGS) and further analysis. DsRNA was converted to cDNA using reverse transcription with degenerate oligonucleotide primers. The cDNA was further amplified by PCR, prepared for NGS using the Illumina format. Sequencing yielded approximately 75 million 80 bp, paired end reads. Reads were assembled into contigs using SCRAPE.pl and two large contigs of 8521 and 8425 nucleotides were obtained. Each contig displayed significant levels of identity to several carlaviruses and about 50% nucleotide sequence identity between each other. From nucleotide sequence and translated amino acid sequence data, it is clear that there are two distinct carlaviruses infecting elderberry. Elderberry carlavirus 145 (EBCV145) showed less homology to known carlaviruses both at the nucleotide and amino acid level. Elderberry carlavirus 153 (EBCV153) had numerous coding regions that were homologous to American hop latent virus. Specific primers were developed for each of the two carlaviruses. All nine cultivars tested were positive for both viruses with the exception of 'Marge', which only had EBCV145. Meristem tips were collected from 'Wyldewood' and used to regenerate plants in tissue culture. Plants were obtained that tested negative for one or both carlaviruses, demonstrating the ability to produce elderberries free of these viruses.


Choi M.-Y.,Horticultural Crops Research Unit | Choi M.-Y.,U.S. Department of Agriculture
Physiological Entomology | Year: 2015

Alarm pheromones of social insects are best known for their role in the defence and maintenance of colony integrity. Previous studies with the fire ant Solenopsis invicta Buren (Hymenoptera: Formicidae) demonstrate that the mandibular glands of workers (sterile females) and male and female sexuals produce an alarm pheromone, 2-ethyl-3,6-dimethylpyrazine. The function of alarm pheromones in worker ants is well understood and divergent from the function of these compounds in the winged sexual forms. The present study quantifies the amount of pyrazine in the mandibular glands from male and female alate sexuals, as well as queens. Pyrazine production in female alates starts in the late pupal stage and increases until they reach mating flight-ready maturity; however, after mating flight participation, the pyrazine level declines by >50%. Interestingly, mature male alates lose >85% of their mandibular gland pyrazine during mating flight activity. The results of the present study indicate that male and female sexuals use mandibular gland secretions for mating flight initiation and during mating flights. Furthermore, the ontogeny of mandibular gland products (pyrazine as the marker) from newly-mated queens to mature colony queens shows a more than two-fold increase in the amount of pyrazine by 6months after mating. However, this is followed by a decline to trace amounts in mature colony queens (>2years old), suggesting a function for mandibular gland products during colony development. Multifunctional use of social insect pheromones is well documented and data are reported in the present study suggesting new roles for mandibular gland products in fire ants. © 2015 The Royal Entomological Society.


PubMed | Lassen Canyon Nursery Breeding Program, National Clonal Germplasm Repository, Michigan State University, University of Peradeniya and 2 more.
Type: | Journal: Frontiers in plant science | Year: 2016

Much of the cost associated with marker discovery for marker assisted breeding (MAB) can be eliminated if a diverse, segregating population is generated, genotyped, and made available to the global breeding community. Herein, we present an example of a hybrid, wild-derived family of the octoploid strawberry that can be used by other breeding programs to economically find and tag useful genes for MAB. A pseudo test cross population between two wild species of Fragaria virginiana and F. chiloensis (FVC 11) was generated and evaluated for a set of phenotypic traits. A total of 106 individuals in the FVC 11 were genotyped for 29,251 single nucleotide polymorphisms (SNPs) utilizing a commercially available, genome-wide scanning platform (Affymetrix Axiom IStraw90(TW)). The marker trait associations were deduced using TASSEL software. The FVC 11 population segregating for daughters per mother, inflorescence number, inflorescence height, crown production, flower number, fruit size, yield, internal color, soluble solids, fruit firmness, and plant vigor. Coefficients of variations ranged from 10% for fruit firmness to 68% for daughters per mother, indicating an underlying quantitative inheritance for each trait. A total of 2,474 SNPs were found to be polymorphic in FVC 11 and strong marker trait associations were observed for vigor, daughters per mother, yield and fruit weight. These data indicate that FVC 11 can be used as a reference population for quantitative trait loci detection and subsequent MAB across different breeding programs and geographical locations.


Olmstead J.W.,University of Florida | Finn C.E.,Horticultural Crops Research Unit
HortTechnology | Year: 2014

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


Keller M.,Washington State University | Tarara J.M.,Horticultural Crops Research Unit
Annals of Botany | Year: 2010

Background and Aims: The influence of temperature on the timing of budbreak in woody perennials is well known, but its effect on subsequent shoot growth and architecture has received little attention because it is understood that growth is determined by current temperature. Seasonal shoot development of grapevines (Vitis vinifera) was evaluated following differences in temperature near budbreak while minimizing the effects of other microclimatic variables. Methods: Dormant buds and emerging shoots of field-grown grapevines were heated above or cooled below the temperature of ambient buds from before budbreak until individual flowers were visible on inflorescences, at which stage the shoots had four to eight unfolded leaves. Multiple treatments were imposed randomly on individual plants and replicated across plants. Shoot growth and development were monitored during two growing seasons. Key Results: Higher bud temperatures advanced the date of budbreak and accelerated shoot growth and leaf area development. Differences were due to higher rates of shoot elongation, leaf appearance, leaf-area expansion and axillary-bud outgrowth. Although shoots arising from heated buds grew most vigorously, apical dominance in these shoots was reduced, as their axillary buds broke earlier and gave rise to more vigorous lateral shoots. In contrast, axillary-bud outgrowth was minimal on the slow-growing shoots emerging from buds cooled below ambient. Variation in shoot development persisted or increased during the growing season, well after temperature treatments were terminated and despite an imposed soil water deficit. Conclusions: The data indicate that bud-level differences in budbreak temperature may lead to marked differences in shoot growth, shoot architecture and leaf-area development that are maintained or amplified during the growing season. Although growth rates commonly are understood to reflect current temperatures, these results demonstrate a persistent effect of early-season temperatures, which should be considered in future growth models.


Keller M.,Washington State University | Tarara J.M.,Horticultural Crops Research Unit | Mills L.J.,Washington State University
Australian Journal of Grape and Wine Research | Year: 2010

Background and Aims: Climate variation contributes to fluctuations in reproductive output, and spring temperature is thought to influence flower production in grapevines. For 3 years, we studied the influence of temperature from before budswell through to the appearance of individual flowers on reproductive development in field-grown Cabernet Sauvignon while minimising the influence of other microclimatic variables. Methods and Results: Dormant buds and emerging shoots were heated or cooled from before budswell until individual flowers were visible. Flower number per inflorescence was inversely related to pre-budburst temperature. Conversely, flower size, percent fruit set, and berry size increased with higher temperatures. Fruit set also increased as flower size and leaf area per flower increased; fruit set was erratic below 4 cm2 leaf area per flower. Berry mass and sugar content per berry increased with increasing flower size. Although yield per shoot varied threefold among treatments, differences in fruit composition were minor. Conclusions: Variations in early-season temperatures may alter substantially grapevine yield formation. The temperature effect may be a combination of direct effects on floral development and indirect effects arising from differences in shoot growth. Significance of the Study: This study shows that variations in temperature near budburst may be an important cause of large variations in grapevine yield.


Choi M.-Y.,U.S. Department of Agriculture | Choi M.-Y.,Horticultural Crops Research Unit | Kohler R.,University of Cologne | Vander Meer R.K.,U.S. Department of Agriculture | And 2 more authors.
PLoS ONE | Year: 2014

Recent genome analyses suggested the absence of a number of neuropeptide genes in ants. One of the apparently missing genes was the capa gene. Capa gene expression in insects is typically associated with the neuroendocrine system of abdominal ganglia; mature CAPA peptides are known to regulate diuresis and visceral muscle contraction. The apparent absence of the capa gene raised questions about possible compensation of these functions. In this study, we re-examined this controversial issue and searched for a potentially unrecognized capa gene in the fire ant, Solenopsis invicta. We employed a combination of data mining and a traditional PCR-based strategy using degenerate primers designed from conserved amino acid sequences of insect capa genes. Our findings demonstrate that ants possess and express a capa gene. As shown by MALDI-TOF mass spectrometry, processed products of the S. invicta capa gene include three CAPA periviscerokinins and low amounts of a pyrokinin which does not have the C-terminal WFGPRLa motif typical of CAPA pyrokinins in other insects. The capa gene was found with two alternative transcripts in the CNS. Within the ventral nerve cord, two capa neurons were immunostained in abdominal neuromeres 2-5, respectively, and projected into ventrally located abdominal perisympathetic organs (PSOs), which are the major hormone release sites of abdominal ganglia. The ventral location of these PSOs is a characteristic feature and was also found in another ant, Atta sexdens.


Ferguson J.C.,Washington State University | Tarara J.M.,Horticultural Crops Research Unit | Mills L.J.,Washington State University | Grove G.G.,Washington State University | Keller M.,Washington State University
Annals of Botany | Year: 2011

Background and AimsGrapevine (Vitis spp.) cold hardiness varies dynamically throughout the dormant season, primarily in response to changes in temperature. The development and possible uses of a discrete-dynamic model of bud cold hardiness for three Vitis genotypes are described.MethodsIterative methods were used to optimize and evaluate model parameters by minimizing the root mean square error between observed and predicted bud hardiness, using up to 22 years of low-temperature exotherm data. Three grape cultivars were studied: Cabernet Sauvignon, Chardonnay (both V. vinifera) and Concord (V. labruscana). The model uses time steps of 1 d along with the measured daily mean air temperature to calculate the change in bud hardiness, which is then added to the hardiness from the previous day. Cultivar-dependent thermal time thresholds determine whether buds acclimate (gain hardiness) or deacclimate (lose hardiness).Key ResultsThe parameterized model predicted bud hardiness for Cabernet Sauvignon and Chardonnay with an r2 0·89 and for Concord with an r 2 0·82. Thermal time thresholds and (de-)acclimation rates changed between the early and late dormant season and were cultivar dependent but independent of each other. The timing of these changes was also unique for each cultivar. Concord achieved the greatest mid-winter hardiness but had the highest deacclimation rate, which resulted in rapid loss of hardiness in spring. Cabernet Sauvignon was least hardy, yet maintained its hardiness latest as a result of late transition to eco-dormancy, a high threshold temperature required to induce deacclimation and a low deacclimation rate.ConclusionsA robust model of grapevine bud cold hardiness was developed that will aid in the anticipation of and response to potential injury from fluctuations in winter temperature and from extreme cold events. The model parameters that produce the best fit also permit insight into dynamic differences in hardiness among genotypes. © The Author 2011. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved.


Bushakra J.M.,USD A ARS | Bassil N.,USD A ARS | Finn C.E.,Horticultural Crops Research Unit | Hummer K.E.,USD A ARS
Acta Horticulturae | Year: 2015

The U.S. Department of Agriculture (USDA), Agricultural Research Service (ARS), National Clonal Germplasm Repository (NCGR-Corvallis) preserves the genetic diversity of elderberry (Sambucus spp.). This genebank preserves representatives of seven of the nine major world Sambucus species and 50 cultivars, including genotypes selected for fruit, as well as ornamental gold, purple, and cut-leaf forms. The priority emphasis of the collection is to maintain diverse species and edible cultivars. Recent USDA plant collecting trips in the Russian Far East, Republic of Georgia, Armenia, and Japan have obtained seed accessions of Sambucus. The genebank collection includes plant material from 31 different countries, with most accessions stemming from the U.S., Russia, China, Japan, Ukraine, the United Kingdom, and Canada. The primary clonal collection is preserved as plants in a field genebank, and seedlots of wild-collected material that are stored at -20°C, thus preserving species diversity. Recent evaluation projects have documented horticultural morphological descriptors and phytochemical fruit components for selected American elderberry (Sambucus nigra subsp. canadensis) individuals. Origin and evaluation information are maintained on the Germplasm Resources Information Network (GRIN), which is a publicly accessible database. Orders for limited propagules for research purposes can be placed through GRIN. Import permits may be required for non-US requestors.

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