Current knowledge of yield potential and best agronomic management practices for perennial bioenergy grasses is primarily derived from small-scale and short-term studies, yet these studies inform policy at the national scale. In an effort to learn more about how bioenergy grasses perform across multiple locations and years, the U.S. Department of Energy (US DOE)/Sun Grant Initiative Regional Feedstock Partnership was initiated in 2008. The objectives of the Feedstock Partnership were to (1) provide a wide range of information for feedstock selection (species choice) and management practice options for a variety of regions and (2) develop national maps of potential feedstock yield for each of the herbaceous species evaluated. The Feedstock Partnership expands our previous understanding of the bioenergy potential of switchgrass, Miscanthus, sorghum, energycane, and prairie mixtures on Conservation Reserve Program land by conducting long-term, replicated trials of each species at diverse environments in the U.S. Trials were initiated between 2008 and 2010 and completed between 2012 and 2015 depending on species. Field-scale plots were utilized for switchgrass and Conservation Reserve Program trials to use traditional agricultural machinery. This is important as we know that the smaller scale studies often overestimated yield potential of some of these species. Insufficient vegetative propagules of energycane and Miscanthus prohibited farm-scale trials of these species. The Feedstock Partnership studies also confirmed that environmental differences across years and across sites had a large impact on biomass production. Nitrogen application had variable effects across feedstocks, but some nitrogen fertilizer generally had a positive effect. National yield potential maps were developed using PRISM-ELM for each species in the Feedstock Partnership. This manuscript, with the accompanying supplemental data, will be useful in making decisions about feedstock selection as well as agronomic practices across a wide region of the country.

The mechanisms by which natural populations generate adaptive genetic variation are not well understood. Some studies propose that microsatellites can function as drivers of adaptive variation. Here, we tested a potentially adaptive role for transcribed microsatellites with natural populations of the common sunflower (Helianthus annuus L.) by assessing the enrichment of microsatellites in genes that show expression divergence across latitudes. Seeds collected from six populations at two distinct latitudes in Kansas and Oklahoma were planted and grown in a common garden. Morphological measurements from the common garden demonstrated that phenotypic variation among populations is largely explained by underlying genetic variation. An RNA-Seq experiment was conducted with 96 of the individuals grown in the common garden and differentially expressed (DE) transcripts between the two latitudes were identified. A total number of 825 DE transcripts were identified. DE transcripts and nondifferentially expressed (NDE) transcripts were then scanned for microsatellites. The abundance of different motif lengths and types in both groups were estimated. Our results indicate that DE transcripts are significantly enriched with mononucleotide repeats and significantly depauperate in trinucleotide repeats. Further, the standardized mononucleotide repeat motif A and dinucleotide repeat motif AG were significantly enriched within DE transcripts while motif types, C, AT, ACC and AAC in DE transcripts, are significantly differentiated in microsatellite tract length between the two latitudes. The tract length differentiation at specific microsatellite motif types across latitudes and their enrichment within DE transcripts indicate a potential functional role for transcribed microsatellites in gene expression divergence in sunflower.

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Increased salinity from irrigation and poor drainage has led to reduced production in semi‐arid and arid irrigated areas of the world. The narrow genetic variation among domestic barley (Hordeum vulgare L.) genotypes slows progress in developing varieties tolerant to biotic and abiotic stresses. A wild barley relative (H. bulbosum L.) is a genetic resource with tolerance to multiple stress conditions, especially salinity. New germplasm added to the USDA barley collection allows novel breeding opportunities. However, crosses between these species require embryo rescue. Crosses were made between diploid and tetraploidized domestic barley ♀ and tetraploid bulbous barley ♂. Immature embryos were rescued and placed on Murashige and Skoog (MS) or Gamborg's B‐5 (B‐5) media (no plant growth regulators, PGRs). Analysis of variance of families showed significant effects for the genotype × medium interactions, indicating each genotype responded to each medium type independently. Significant effects were observed for some traits due to both genotype and medium; and significant effects between media for some traits were observed indicating that those traits were affected by media type. Murashige and Skoog was found to be the better medium for most crosses compared to B‐5. Generally, results from this study indicated that it is difficult to draw broad conclusions about the most suitable medium composition for a broad spectrum of genotypes due to individual genotypes responding differently to the media type. Subsequent manuscripts by these authors will address the success of fertile crossed  progeny.

Stormwater runoff raises concern over potential downstream impacts of selenium (Se) on aquatic ecosystems. Constructed wetland phytoremediation is a sustainable, inexpensive, eco-friendly technology with potential to remove Se from stormwater. The objectives of this study were to: 1) evaluate the bioavailability of Se chemical form and concentration on plant uptake and 2) determine the potential of aquatic macrophytes to improve water quality in a constructed wetland 4. The experiment was arranged as a 2 X 2 factorial nested within a split-split plot design replicated three times. Cattail (CT; Typha angustifolia L.), duckweed (DWD; Lemna minor L.), fanwort (CAB; Cabomba caroliniana A. Gray), soft rush (SR; Juncus effuses L.), muskgrass (MG; Chara spp.), and unplanted controls (UNP) were acclimatized 14 d in 115-L microcosms containing 0.035 m 3 of Catalpa silty clay loam with 26 L of water supplemented with 0.1 N Hoagland's solution. Selenium treatments were applied as a 4-L solution of either sodium selenite (SeO3 2-) or sodium selenate (SeO4 2-) to a total volume of 30 L at 0, 500, or 1000 μg Se L-1. Water samples were collected daily for six days. Plant and soil samples were collected prior to Se application and at three-day intervals post Se application. Water, plant, and soil samples were analyzed for total [Se] by inductively coupled plasma-mass spectrometry. Data were analyzed with PROC GLM at α=0.05. After six days, CT and MG-planted microcosms significantly decreased aqueous [Se] by 75 and 74%, respectively, compared to 61% for UNP. The aqueous fraction of microcosms planted to CAB, DWD, and SR were similar to UNP controls. Plant tissue Se content in CT was significantly less than CAB, DWD, or MG, suggesting CT has the potential to volatilize Se. Given its abundance and efficacy, CT is likely a suitable species for Se removal in constructed wetlands supplied with either selenite or selenate-impacted waters.