The Paddlefish Polyodon spathula is an ancient species that is native to the Mississippi River and its larger tributaries. This species exhibits a unique combination of morphology and life history characteristics that leaves it vulnerable to river modifications and potential overexploitation, which has led to population declines in portions of the historic range. Concern regarding unknown exploitation rates from recreational and commercial fisheries has increased in recent decades, and the Convention on International Trade of Endangered Species is now requesting information from state agencies regarding the sustainability of commercially harvested Paddlefish populations. The Missouri Department of Conservation addressed this, in part, through the implementation of a 5-year mark-recapture study to estimate exploitation and nonreporting rates, evaluate movement patterns, and provide a baseline estimate of abundance for Paddlefish in the Mississippi River basin. A total of 2,224 Paddlefish were jaw-banded, and 102 were also implanted with transmitters in the Mississippi River basin within the borders of Missouri. Of those, 139 Paddlefish were caught by commercial or recreational anglers and 92 were harvested, resulting in an average annual exploitation estimate of 2.5% (SE = 0.6). Jaw band returns and telemetry information demonstrated that Paddlefish moved great distances (maximum 2,359 km) and crossed many regulatory boundaries (14 states). Despite relatively low exploitation rate estimates, a precautionary adjustment of regulations is advised to protect Paddlefish through maturation and ensure sustainability. In addition, regulations for this species should be assessed across the entire Mississippi River basin, as they differ within and between regulatory authorities. A combination of population monitoring (e.g., exploitation and population dynamics) and telemetry efforts have potential to help inform future basin-wide management approaches.

Asian carps continue to expand their range in North America, necessitating efforts to limit the spread and establishment of reproducing populations. Mississippi River Lock and Dam 19 is a high-head dam that represents a population ‘pinch-point’ as passage through the lock chamber is the only means by which fishes can complete upstream movement. As such, this location could be a pivotal control point for minimizing the spread of invasive fishes in the Upper Mississippi River and a possible candidate site for installation of deterrent measures. Our objectives were (1) to study the timing (i.e., weekly and diel) and behavior of fishes in the downstream lock approach, (2) evaluate the relation of presence in the downstream lock approach with environmental factors and lock operation, and (3) identify any upstream or downstream passage events through the lock chamber and the relation between these events and the operation of the lock. Acoustic transmitters were surgically implanted into 262 Asian carps and 216 native fishes to monitor fish activity on a telemetry receiver array deployed around and within the lock for 622 days during 2017–2018. One hundred eighty-six telemetered fish were detected in the downstream lock approach. We documented 14 upstream Asian carp passages and 10 upstream native fish passages; these passages coincided with a specific sequence of large vessel lockages. The results of this study advance our understanding of fish presence and behavior at a Mississippi River mainstem lock and dam and inform the development and testing of deterrent systems at this location or at similar pinch-point lock and dams.

The hairy vetch (Vicia villosa Roth) cultivars 'Purple Bounty' (Reg. no. CV-12, PI 648342) and 'Purple Prosperity' (Reg. no. CV-11, PI 654047) were released in 2007 and 2008, respectively, by the USDA-ARS in collaboration with the Rodale Institute and the agricultural experiment stations of Pennsylvania State University and Cornell University. Hairy vetch is a commonly used annual legume cover crop grown for its cold tolerance, fast growth, large biomass production, and ability to fix N-2. However, this species has not been selected for the traits needed to optimize its use as a cover crop. Our breeding program focused on developing a cultivar that was both early flowering and had adequate winter survival and therefore adapted to mechanical termination in organic no-till production in the U.S. Northeast and Mid-Atlantic. Purple Bounty and Purple Prosperity were developed between 1998 and 2005 using recurrent selection at nurseries in Beltsville and Keedysville, MD. In 2005-2006, selections were evaluated against commercial checks for flowering time in Maryland and Pennsylvania, and in the 2006-2007 and 2007-2008 seasons they were evaluated in 10 locations (12 total site-years) across the United States for winter survival. Purple Bounty and Purple Prosperity both flowered earlier than the commercial material against which they were tested (significance depended on the date and site); Purple Bounty was the earlier flowering of the two cultivars. Purple Bounty and Purple Prosperity also had equivalent or improved winter survival compared with 'AU Early Cover', an early-maturing cultivar developed in the southern United States, at all test locations. Purple Prosperity is no longer commercially available, but Purple Bounty is currently licensed and distributed by Allied Seed (Nampa, ID).

ABSTRACTUnderstanding the association between genotype and agronomically important phenotypes (early flowering, hard seed, and winter hardiness) will facilitate cultivar selection and inform breeding programs concerned with the cover crop hairy vetch (Vicia villosa Roth). We used molecular, observational, and biochemical techniques to identify and evaluate 64 accessions of hairy vetch that originated throughout the world and comprise the USDA National Plant Germplasm System. Time to flowering, percent C, and percent N were measured on plants of each accession grown in the field at Beltsville, MD. Amplified fragment length polymorphisms were assayed on each accession. We related parameters of genetic, phenotypic, and biochemical diversity to the geographical origins of the accessions. Country of origin explained little of the marker genetic diversity in this collection. Climate factors of geographical origins, however, explained larger amounts of the marker genetic diversity observed. These results provide baseline information to identify a core genetic subset of the V. villosa germplasm collection. Information presented here may facilitate future V. villosa breeding efforts and directly assist farmers in cover crop varietal selection.

Several genes that restrict nodulation with specific Bradyrhizobiumstrains are known in Glycine max (soybean), and a similar system of nodulation restriction has recently been discovered in the related North American legume Amphicarpaea bracteata. We analyzed how nodulation-restrictive genotypes of each plant interacted with Bradyrhizobium strains sampled from the other host species. Ten bacterial isolates from A. bracteata that nodulated differentially with genotypes of their homologous host legume showed uniform responses to two soybean isogenic lines that differed at the Rj4 locus controlling nodulation restriction: all isolates formed nodules of normal size and morphology on both isolines. However, little or no nitrogen fixation occurred in any of these symbioses. A. bracteata genotypes that displayed broad vs. restricted symbiotic phenotypes toward naturally-associated bradyrhizobia were also tested with two bacterial isolates from soybean (USDA 76 and USDA 123). Both isolates formed nodules and fixed nitrogen in association with both A. bracteata genotypes. However, symbiotic effectiveness (as measured by acetylene reduction assays) was normal only for the combination of USDA 76 with the restrictive A. bracteata genotype. Overall, these results indicate that plant genes that restrict nodulation by certain naturally-associated bradyrhizobia do not confer comparable specificity when plants interact with bacteria from another related legume species.