Breaking tuber dormancy in Helianthus tuberosus L. and interspecific hybrids of Helianthus Annuus L. × Helianthus tuberosus
Tubers of Helianthus tuberosus L. are dormant after production in the late fall until the next spring. In the wild, tuber dormancy is broken after exposure to winter cold, resulting in sprouting and shoot development in the spring when conditions are favorable. The dormancy period typically limits H. tuberosus populations to one growth cycle per year. An efficient method for breaking tuber dormancy is needed to have an additional growth cycle per year in a breeding program, which could take place in winter inthenurseryorthegreenhouse allowingforincreased breedingefficiency.Theobjective of thisresearch was to compare chemicaland cold temperature treatments for artificially breaking tuber dormancy in 12 genotypes of H. tuberosus and interspecific hybrids of Helianthus annuus L. 3 H. tuberosus. Five cold exposures (2, 4, 6, 8, 10 weeks at 2 8C), three plant hormones (ethylene, cytokinin, and gibberellic acid), and one untreated control were examined. Gibberellic acid was the best chemical treatment, initiating plant growthwithin6.5to11.5daysinthemajorityofgenotypestested.Thebestcoldtreatment was exposure to 2 8C for 8 weeks, where plant growth began 63.6 to 67.5 days after treatment initiation. Although longer cold treatments shortened the time to emergence while in the greenhouse, the penalty of the long cold treatment per se was too long to be useful. The gibberellic acid treatment strategy described here may not need further optimization, because it is short enough to allow for two growth cycles of H. tuberosus per year.
Potential Use of Perennial Sunflower to Reduce Blackbird Damage to Sunflower
Author(s): Linz, George; Hulke, Brent; Kantar, Michael; Homan, Jeffrey; Stupar, Robert; Wyse, Donald | Abstract: Wildlife Conservation Sunflower Plots (WCSP) have shown potential to reduce blackbird (Icteridae) damage in commercial sunflower. Also known as lure, decoy, or trap crops, WCSP are strategically placed food plots that provide an easily available and proximate food source that entices blackbirds away from valuable commercial crops. By providing an alternative food source, WCSP reduce direct damage to commercial fields, while also lowering indirect costs that producers incur attempting to prevent blackbird damage. However, cost inefficiencies have deterred widespread use of WCSP. Cost-benefit ratios of using WCSP would be greatly improved if a perennial sunflower were used instead of the annual types currently available. Perennial sunflower would reduce seed cost and planting cost, and perhaps lower opportunity costs, if able to thrive on poorer quality soils. In the near-term, scientists are focused on producing a perennial sunflower sufficiently productive to replace annual WCSP plantings. In 2013, scientists from the University of Minnesota, USDA-Agricultural Research Service, and USDA Wildlife Services National Wildlife Research Center evaluated a test plot of an open-pollinated variety of perennial sunflower resulting from genetic crossing of a domesticated annual species (Helianthus annuus) and a perennial wild species (H. tuberosus). Here, we report on results from the 2013 field test and discuss the outlook for development of perennial sunflower, which would help lessen damage to commercial sunflower when used in WCSP; provide a pesticide-free food source for beneficial insects, such as honey bees; help stabilize highly erodible lands near wetlands; and provide year-round habitat for wildlife. Lastly, we provide an initial strategy for using perennial sunflower to reduce blackbird damage in commercial sunflower.
Instrumentation and Automated Photometric Titration Procedure for Total Acidity Determination in Red Wine Employing a Multicommuted Flow System
An automated procedure for photometric titration of red wine and associated instrumentation is described. The procedure was based on the flow-batch approach implemented employing multicommutation. The photometric detection was carried out using a homemade LED-based photometer. The mixing device, LED, and photodetector were attached to the titration chamber in order to form a compact and small-sized unit. The flow system comprised an automatic injector and three-way solenoid valves, which were controlled by a microcomputer through an electronic interface card. The software, written in Quick BASIC 4.5, was designed with abilities to accomplish all steps of the titration procedure including data acquisition and real-time processing to decide about the course of titration in the following step and so forth, until the titration endpoint was reached. The usefulness of the proposed titration system was demonstrated by analyzing red wine samples. When results were compared with those obtained using the AOAC reference method, no significant difference was observed at the 95% confidence level. A relative standard deviation of ca  2% (n=9 ) was obtained when processing a typical red wine sample containing 7.3 gl -1 total acidity expressed as tartaric acid.