http://hdl.handle.net/1957/16374 2013-05-25T19:20:54Z http://hdl.handle.net/1957/38571 A national survey of managed honey bee 2011-12 winter colony losses in the United States: results from the Bee Informed Partnership Spleen, Angela M.; Lengerich, Eugene J.; Rennich, Karen; Caron, Dewey; Rose, Robyn; Pettis, Jeff S.; Henson, Mark; Wilkes, James T.; Wilson, Michael; Stitzinger, Jennie; Lee, Kathleen; Andree, Michael; Snyder, Robert; vanEngelsdorp, Dennis; Bee Informed Partnership Estimates of winter loss for managed honey bee (Apis mellifera) colonies are an important measure of honey bee health and productivity. We used data from 5,500 US beekeepers (5,244 backyard, 189 sideline and 67 commercial beekeepers) who responded to the April 2012 Bee Informed Partnership Winter Colony Loss Survey and calculated loss as the difference in the number of colonies between October 1, 2011 and April 1, 2012, adjusting for increases and decreases over that period. In the US, the total colony loss was 22.5% for the 2011-12 winter; 45.1% (n = 2,482) of respondents reported no colony loss. Total loss during 2011-12 was substantially lower than loss during 2010-11 (29.9%). Of the 4,484 respondents who kept bees in 2010-11 and 2011-12, 72.0% reported that the loss during 2011-12 was smaller or similar to the loss during 2010-11. There was substantial variation in total loss by state (range 6.2% to 47.7%). The average loss per beekeeping operation was 25.4%, but the average loss was not significantly different by operation type (backyard, sideline, commercial). The average self-reported acceptable loss per respondent was 13.7%; 46.8% (n = 2,259) of respondents experienced winter colony losses in excess of the average acceptable loss. Of beekeepers who reported losing at least one colony during 2011-12, the leading self-identified causes of mortality were weak condition in the fall and queen failure. Respondents who indicated poor wintering conditions, CCD, or pesticides as a leading cause of mortality suffered a higher average loss when compared to beekeepers who did not list these as potential causes. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by International Bee Research Association and can be found at: http://www.ibra.org.uk/. 2013-01-01T00:00:00Z http://hdl.handle.net/1957/38565 Improving initiation and mineral nutrition for hazelnut (Corylus avellana) micropropagation Hand, Charles R. Corylus avellana L. is a global commodity and a valuable crop for the U.S. Pacific Northwest. A tremendous amount of work has been put into the development of healthy disease free, high yielding and tasty hazelnuts for the in-shell and confectionary markets. Clonal propagation is required to provide nursery trees of these improved hazelnut cultivars. The rapid multiplication provided by micropropagation methods is an important part of meeting the demand. One challenge of hazelnuts micropropagation is the wide variation in growth response among the cultivars. The studies described in this thesis were involved in improving the mineral nutrients in the growth medium and to better determine culture initiation procedures. The first study was designed to determine what mineral nutrients are driving C. avellana in vitro shoot growth using a response surface design. Hazelnut genotypes 'Dorris,' 'Felix,' 'Jefferson', OSU 880.054, and 'Sacajawea' were used. Driver and Kuniyuki Walnut medium (DKW) mineral nutrients were separated into five factors: NH₄NO₃, Ca(NO₃)₂, mesos (MgSO₄ and KH₂PO₄), K₂SO₄, and minor nutrients (B, Cu, Mn, Mo, and Zn). The concentrations ranged from 0.5x to 2.0x the standard DKW concentrations with 33 treatments for use in modeling. Multifactor response surface analysis projected that optimum shoot proliferation was greatly influenced by the NH₄NO₃ to Ca(NO₃)₂ ratios, mesos, and minors. These factors were important to overall quality and shoot length for all genotypes. Improved shoot quality was observed with increased Ca(NO₃)₂, mesos, and minors for most of the cultivars tested. For 'Sacajawea' only the mesos components significantly improved shoot quality. Lower Ca(NO₃)₂ improved shoot multiplication while higher amounts increased shoot length for most cultivars. New media formulations will require higher Ca(NO₃)₂, mesos and minors as well as changes in the NH₄NO₃ to Ca(NO₃)₂ ratios. The second study determined the effects of individual minor-mineral nutrients including nickel on hazelnut shoot growth. Three hazelnut cultivars 'Dorris,' 'Jefferson,' and 'Sacajawea' were used. Six factors at 0.5x to 4.0x DKW concentrations, H₃BO₃, CuSO₄, MnSO₄, Na₂MoO₄, Zn(NO₃)₂, and NiSO₄, were tested in a response surface design with 39 treatment combinations. Ni, not present in DKW, ranged from 0 to 6 µM. Higher concentrations (4x) of B, Mo, and Zn increased overall shoot quality, length and multiplication. There were many significant interactions. High B concentrations significantly improved shoot quality for 'Jefferson'; shoot quality, length and number for 'Dorris'; and shoot length and number for 'Sacajawea'. Increased Mo improved some responses for each cultivar, and it also interacted with Cu and Zn. Interactions of Ni with other minor nutrients resulted in improved shoot quality and length in 'Sacajawea.' Ni interactions were significant for the other cultivars as well, altered the requirements for other nutrients, but did not necessarily improve the overall shoot response. Improved growth and shoot quality in 'Dorris' and 'Jefferson' required increased amounts of B, Mo, and Zn; 'Sacajawea' required increased B, Cu, Zn, and Ni. The diverse responses of these cultivars further confirmed that nutrient uptake or utilization was genotype dependent. Hazelnuts are generally difficult to initiate into culture due to internal microbial contaminants and a general lack of viability of the explants. The third study was designed to determine the effect of nodal position and collection techniques on the viability and contamination of shoot explants. Explants were collected from scion wood grafted onto seedling rootstocks and grown in the greenhouse. Single-node explants were collected from different locations on the scion wood. After surface sterilization, explants were first held in a liquid contaminant-detection medium for one week and the effect on explant viability was evaluated. Node position influenced the number of viable contaminant-free explants. Bacterial contamination increased with the distance from the shoot tip. The use of liquid detection medium as a part of the initiation procedure did not affect viability. Bacteria sampled from surface sterilized explants were identified as Brevundimonas vesicularis, Brevundimonas sp., and two Pseudomonas sp., by 16S ribosomal DNA sequences and API® 20CHB tests. The best procedure for collecting axenic, viable hazelnut explants was to collect from the first three nodes of actively-growing greenhouse plants and use detection medium to identify contaminant-free tissue. As a result of these studies several suggested growth media formulations are now available for use that may produce improved hazelnut shoot quality, multiplication and elongation for a wide range of C. avellana genotypes. Two base macro nutrient formulations, Hazelnut A and B, are likely to be suitable for many genotypes. Three micronutrient formulations provide options for growth of difficult genotypes with and without Ni. Continued optimization and testing of mesos and N components are needed for final medium formulations. Graduation date: 2013 2013-04-18T00:00:00Z http://hdl.handle.net/1957/38302 Needs Assessment for Future US Pear Rootstock Research Directions Based on the Current State of Pear Production and Rootstock Research Elkins, Rachel; Bell, Richard; Einhorn, Todd The area devoted to pear production in the United States (U.S.) is declining due to lack of precocity and high cost of production. The U.S. pear industry currently lacks "modern" orchard systems characterized by compact trees that produce early, high yields of large, high quality fruit. Tall, shaded canopies are not economically sustainable and are at a competitive disadvantage for attracting and sustaining a labor supply. There is broad and deep consensus in the pear industry that developing size-controlling rootstocks is imperative to remain competitive nationally and globally. Currently employed rootstocks in the U.S. are Pyrus communis seedlings and clones, none of which achieve more than about a one-third size reduction, and P betulifolia seedlings. Quince (C. oblonga), used with interstems in Europe and South America, is utilized commercially (without interstems) in the U.S. only for 'Cornice' in southern Oregon and northern California. This is due primarily to a lack of cold hardiness needed in more northern production areas, a lack of graft-compatibility with the other major scion cultivars, fire blight and iron chlorosis susceptibility, and relative lack of productivity versus other rootstocks, especially in California. Current evaluative trials rely on older U.S. and imported selections, and include the NC-140 Multistate Rootstock Research Project and several individual programs in California, New York, Oregon and Washington. A fundamental deficiency is the lack of a mature pear rootstock breeding program, despite access to the USDAARS National Clonal Germplasm Repository (NCGR), which holds a major worldwide collection of Pyrus and related genera. International breeding programs focus on increasing yield efficiency, but also graft compatibility, fruit quality and size, high soil pH tolerance, winter hardiness, warm climate/low chilling adaptation, drought and salt tolerance, and resistance to fire blight, pear decline, and pear scab. An intensive planning and implementation effort is needed to develop the necessary contacts, collaborations, explorations, and importation logistics to acquire the most promising clonal selections for propagation and testing. Basic research needs include effects of dwarfing rootstock on tree architecture and fruiting, the underlying mechanisms of dwarfing functional in pear, the inheritance of key traits, and selection criteria for breeding. Propagation and orchard systems have also been identified as major research needs. This is a scanned version of a published article. The original can be found at: http://www.americanpomological.org/. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. 2012-07-01T00:00:00Z http://hdl.handle.net/1957/38294 Transitional Effects of Double-lateral Drip Irrigation and Straw Mulch on Irrigation Water Consumption, Mineral Nutrition, Yield, and Storability of Sweet Cherry Yin, Xinhua; Long, Lynn E.; Huang, Xiao-Lan; Jaja, Ngowari; Bai, Jinhe; Seavert, Clark F.; le Roux, Jac A field trial was conducted on a Cherryhill silt loam soil at The Dalles, OR, from 2006 to 2008. The impacts of switching from the traditional micro sprinkler irrigation (MS) to double-lateral drip irrigation (DD) and from no groundcover with herbicide control of weeds (NC) to in-row wheat (Triticum aestivum) straw mulching (ST) were evaluated in a split-plot design with four replicates. Irrigation water use, mineral nutrition, and productivity of ‘Lapins’ sweet cherry (Prunus avium) on ‘Mazzard’ rootstock (P. avium) and soil quality were measured on a plot basis. DD reduced irrigation water consumption by 47.6% to 58.2% compared with MS. Straw mulch lowered irrigation water use by 9.7% relative to NC. Total fruit yield and fruit quality of firmness, size, and sugar at harvest were similar for the irrigation treatments. Straw mulch increased fruit size by 0.6 mm on average relative to NC, which could result in increased grower profitability. The DD system enhanced percentage of marketable fruit by 8.6% relative to MS. Leaf phosphorus (P), boron (B), zinc (Zn), and iron (Fe) concentrations were reduced with DD over MS; consequently, more P, B, Zn, and Fe fertilizers might be needed under DD. Straw mulch markedly decreased the populations of flagellates and amoebae but slightly increased the population of ciliates. Straw mulch resulted in a soil microbial community with remarkably less protozoa. Overall, DD is a viable alternate irrigation system for producing sweet cherry orchards with limited water resources for irrigation. Switching from NC to ST could lower irrigation water use, reduce herbicide runoff, and protect soil from erosion. This is a scanned version of a published article. The original can be found at: http://horttech.ashspublications.org/. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. 2012-08-01T00:00:00Z