The development of dicamba-tolerant and other auxin-tolerant crops will enable the use of these effective herbicides in soybean and cotton at application timings such as at planting or over-the-top that are not currently possible. This research examined the effect of various factors on detection of postapplication amounts of dicamba in the air under field conditions by coupling a sample collection system with advanced chemical analysis of those samples. The quantity of dimethylamine salt of dicamba that was detected within 48 hr after application was two times greater (P < 0.05) than the quantity of diglycoamine salt formulation based on field studies in 2009. Regardless of application timing, the amount of detected dicamba was greatest during the 0 to 12 hr time period after application. However, the total detected after 48 hr was less for evening applications (5 micrograms [µg]) compared with midday (17 µg) or morning (14 µg) applications based on 2010 field trials. Average ambient air temperature (and other weather variables) correlated with higher detection levels of dicamba in the air in the field.

grains, a number greatly in excess of that needed for fertilization (Uribelarrea et al., 2002). However, the pol-Development of improved genetic traits in maize (Zea mays L.) relen of maize is among the largest and heaviest of the quires robust measures to prevent pollen-mediated gene flow (PMGF) grasses, with a diameter of about 90 m. For compariand assure isolation of new traits, whether these traits are the result son, the pollen grains of ragweed (Ambrosia spp.) and of conventional breeding or of modern genetic techniques. Studies were conducted in California and Washington to evaluate the relation-Timothy (Phleum pratense L.) are 20 and 34 m in ship of distance and temporal separation for isolation from PMGF. diameter, respectively (Raynor et al., 1972). Most maize Kernel color was used to detect outcrossing from source plots of 0.4 pollen is dispersed by gravity downward from the tassel, to 1.2 ha in size to receptor plots planted at distances up to 750 m falling in the vicinity of the originating plant. Bateman and planting intervals of up to 3 wk from the pollen source. Outcross- 1947) found pollen deposition at 27 m was Ͻ1% of ing from source to receptor plots was observable to 0.0002% (1 kernel that close to the source plants. Raynor et al. (1972) in ≈500 000 kernels). Increasing temporal separation reduced the disestimated that 98% of maize pollen remains close to tance required to achieve genetic isolation. Outcrossing was Ͻ0.01% the originating plant, and that Ͻ1% would be found at 500 m when source and receptors flowered at the same time, whereas beyond 60 m. Jarosz et al. (2003) estimated that 95% this level of confinement was achieved at 62 m or less when 2 wk of of the pollen produced was deposited within 10 m of temporal separation was used. No outcrossing was detected at 750 m and 2 wk of temporal separation. This is the first practical evaluation M. Qualls, Qualls Ag Labs, Ephrata, WA 98823; S.A. Berberich, Chesterfield, MO 63017. Received 12 Dec. 2003. *Corresponding au-color inside yellow maize fields. The farthest distance thor (Philip.j.eppard@monsanto.com).studied was 50 m from the edge of the source plot, and a low but undefined level of outcrossing was observed

An empirical approach is given for specifying coexistence requirements for genetically modified (GM) maize (Zea mays L.) production, to ensure compliance with the 0.9% labeling threshold for food and feed in the European Union. Field data were considered in which pollen-mediated gene flow (PMGF) was measured within maize receptor fields at a series of distances from source fields having a marker. An empirical model is presented that fits the observed decrease of gene flow with distance. The model was parameterized to provide both reasonable worst case and expected case predictions of gene flow for various combinations of isolation distance, use of non-GM border rows in the GM field and/or separately harvested border rows in the receptor field. Based on the data assessed, the model is used to show that the effect of scale is minimal for source fields of surface area 4 ha and greater. Combinations of isolation distance and border rows of 20 m or more are predicted to result in gene flow of less than 0.9%, as a blended average for receptor fields 1 ha or larger. Lesser requirements are necessary when the source field is much smaller than the receptor, and an extension to the model is provided to estimate such effects.

This report presents the results of ventilation rate studies of eight passively ventilated high-level radioactive waste tanks using tracer gases. Headspace ventilation rates were determined for Tanks A-101, AX-102, AX-103, BY-105, C-107, S-102, U-1 03, and U-105 using sulfur hexafluoride (SF,) and/or helium (He) as tracer gases. Passive ventilation rates are needed for the resolution of several key safety issues. These safety issues are associated with the rates of flammable gas production and ventilation, the rates at which organic salt-nitrate salt mixtures dry out, and the estimation of organic solvent waste surface areas. This tracer gas study involves injecting a tracer gas into the tank headspace and measuring its concentration at different times to establish the rate at which the tracer is removed by ventilation. Tracer gas injection and sample collection were performed by SGN Eurisys Service Corporation and/or Lockheed Martin Hanford Corporation, Characterization Project Operations. Headspace samples were analyzed for He and SF, by Pacific Northwest National Laboratory (PNNL). The tracer gas method was first demonstrated on Tank S-102. Tests were conducted on Tank S-102 to verify that the tracer gas was uniformly distributed throughout the tank headspace before baseline samples were collected, and that mixing was sufficiently vigorous to maintain an approximately uniform distribution of tracer gas in the headspace during the course of the study. Headspace samples, collected from a location about 4 m away from the injection point and 15,30, and 60 minutes after the injection of He and SF,, indicated that both tracer gases were rapidly mixed. The samples were found to have the same concentration of tracer gases after 1 hour as after 24 hours, suggesting that mixing of the tracer gas was essentially complete within 1 hour. Given this evidence for vigorous mixing, inhomogeneities produced by the influx of fresh air during normal ventilation would be expected to be restricted to a small region near the influx.

2005). Testing for adventitious presence of transgenic material in conventional seed or grain lots using quantitative laboratory methods: statistical procedures and their implementation. AbstractWhen the laboratory methods employed are qualitative, the statistical methodologies used in testing for the adventitious presence (AP) of transgenic material in conventional seed and grain lots are well defined. However, when the response from the method used by the laboratory is quantitative (e.g. percent transgenic DNA), the statistical methodologies developed for qualitative laboratory methods are not fully appropriate. In this paper, we present the details of procedures specific to quantitative laboratory methods. In particular we consider: (1) the assessment of quantitative laboratory method errors using linear modelling; and (2) the process of deciding whether or not a lot meets pre-specified purity standards, including the development of probability calculations needed to develop operating characteristic curves and estimate consumer and producer risks for a given lower quality limit (LQL), acceptable quality limit (AQL) and testing plan. We also describe implementation of this approach in a useful spreadsheet application.