QTL Mapping and Phenotypic Variation for Seedling Vigour Traits in Barley (Hordeum vulgare L.).

Seed vigour is considered a critical stage for barley production, and cultivars with early seedling vigour (ESV) facilitate rapid canopy formation. In this study, QTLs for 12 ESV-related traits were mapped using 185 RILs derived from a Xena x H94061120 evaluated across six independent environments. DArT markers were used to develop a genetic map (1075.1 cM; centimorgans) with an average adjacent-marker distance of 3.28 cM. In total, 46 significant QTLs for ESV-related traits were detected. Fourteen QTLs for biomass yield were found on all chromosomes, two of them co-localized with QTLs on 1H for grain yield. The related traits: length of the first and second leaves and dry weight of the second leaf, biomass yield and grain yield, had high heritability (>30%). Meanwhile, a significant correlation was observed between grain yield and biomass yield, which provided a clear image of these traits in the selection process. Our results demonstrate that a pleiotropic QTL related to the specific leaf area of the second leaf, biomass yield, and grain yield was linked to the DArT markers bPb-9280 and bPb-9108 on 1H, which could be used to significantly improve seed vigour by marker-assisted selection and facilitate future map-based cloning efforts.

Adsorption of ammonium in aqueous solutions by pine sawdust and wheat straw biochars.

Ammonium (NH4+) is a common form of reactive nitrogen in wastewater, and its discharge to water bodies can lead to eutrophication. This study was conducted to understand NH4+ adsorption mechanisms of pine sawdust and wheat straw biochars in aqueous solutions and the factors affecting NH4+ removal. Biochars were produced by pyrolysing pine sawdust at 300 °C (PS300) and 550 °C (PS550) and wheat straw at 550 °C (WS550). Pseudo-second-order and Redlich-Peterson models best fitted the adsorption data. The PS300 showed the highest NH4+ adsorption capacity (5.38 mg g-1), followed by PS550 (3.37 mg g-1) and WS550 (2.08 mg g-1). Higher H/C and O/C ratios of PS300 (0.78 and 0.32, respectively) indicated the greater presence of functional groups on the biochar's surface as compared to PS550 (0.35 and 0.10, respectively) and WS550 (0.36 and 0.08, respectively), resulting in different NH4+ adsorption through electrostatic interactions. The dominant mechanism for NH4+ adsorption by the biochars was likely chemical bonding and electrostatic interaction of NH4+ with the surface functional groups. Lower pyrolysis temperature resulted in a higher NH4+ adsorption capacity by the pine sawdust biochar. At the same pyrolysis temperature (550 °C), the biochar made with pine sawdust as the feedstock had a higher NH4+ adsorption capacity than biochar made from wheat straw. We conclude that biochars can be efficient absorbents for NH4+ removal from wastewater, and the removal efficiency can be optimised by selecting different feedstocks or the pyrolysis condition for biochar production.

Mapping thermomechanical pulp sludge (TMPS) biochar characteristics for greenhouse produce safety.

This study evaluates the existence of toxic compounds in thermomechanical pulp sludge (TMPS) derived biochars obtained through a slow pyrolysis process and establishes the criteria for manufacturing benign-quality biochar for safe greenhouse-based food production. Accordingly, nine TMPS biochars generated at different temperatures (450, 500, 550 °C) and residence times (30, 60, 120 min) were investigated. Depending on the production conditions, the polycyclic aromatic hydrocarbons (PAHs) sum varied from 0.4 to 236 µg/g biochar. Interestingly, correlations between the PAH content, toxicity, and process conditions were derived in the form of process toxicity relationships (PTRs). On the basis of the learning garnered in this study, it is recommended that TMPS feedstock will yield benign quality biochar when processed at a minimum 500 °C temperature for an optimum residence time of 30 min.

Interconnected carbon nanosheets derived from hemp for ultrafast supercapacitors with high energy.

We created unique interconnected partially graphitic carbon nanosheets (10-30 nm in thickness) with high specific surface area (up to 2287 m(2) g(-1)), significant volume fraction of mesoporosity (up to 58%), and good electrical conductivity (211-226 S m(-1)) from hemp bast fiber. The nanosheets are ideally suited for low (down to 0 °C) through high (100 °C) temperature ionic-liquid-based supercapacitor applications: At 0 °C and a current density of 10 A g(-1), the electrode maintains a remarkable capacitance of 106 F g(-1). At 20, 60, and 100 °C and an extreme current density of 100 A g(-1), there is excellent capacitance retention (72-92%) with the specific capacitances being 113, 144, and 142 F g(-1), respectively. These characteristics favorably place the materials on a Ragone chart providing among the best power-energy characteristics (on an active mass normalized basis) ever reported for an electrochemical capacitor: At a very high power density of 20 kW kg(-1) and 20, 60, and 100 °C, the energy densities are 19, 34, and 40 Wh kg(-1), respectively. Moreover the assembled supercapacitor device yields a maximum energy density of 12 Wh kg(-1), which is higher than that of commercially available supercapacitors. By taking advantage of the complex multilayered structure of a hemp bast fiber precursor, such exquisite carbons were able to be achieved by simple hydrothermal carbonization combined with activation. This novel precursor-synthesis route presents a great potential for facile large-scale production of high-performance carbons for a variety of diverse applications including energy storage.

Quantitative trait loci for water-use efficiency in barley (Hordeum vulgare L.) measured by carbon isotope discrimination under rain-fed conditions on the Canadian Prairies.

Barley (Hordeum vulgare L.) yield is commonly limited by low rainfall and high temperature during the growing season on the Canadian Prairies. Empirical knowledge suggests that carbon isotope discrimination (Δ(13)C), through its negative relationship with water-use efficiency (WUE), is a good index for selecting stable yielding crops in some rain-fed environments. Identification of quantitative trait loci (QTL) and linked markers for Δ(13)C will enhance its use efficiency in breeding programs. In the present study, two barley populations (W89001002003 × I60049 or W × I, six-row type, and Merit × H93174006 or M × H, two-row type), containing 200 and 127 recombinant inbred lines (RILs), were phenotyped for leaf Δ(13)C and agronomic traits under rain-fed environments in Alberta, Canada. A transgressive segregation pattern for leaf Δ(13)C was observed among RILs. The broad-sense heritability (H (2)) of leaf Δ(13)C was 0.8, and there was no significant interaction between genotype and environment for leaf Δ(13)C in the W × I RILs. A total of 12 QTL for leaf Δ(13)C were detected in the W × I RILs and 5 QTL in the M × H RILs. For the W × I RILs, a major QTL located on chromosome 3H near marker Bmag606 (9.3, 9.4 and 10.7 cM interval) was identified. This major QTL overlapped with several agronomic traits, with W89001002003 alleles favoring lower leaf Δ(13)C, increased plant height, and reduced leaf area index, grain yield, harvest index and days to maturity at this locus or loci. This major QTL and its associated marker, when validated, maybe useful in breeding programs aimed at improving WUE and yield stability of barley on the Canadian Prairies.

Gene discovery in cereals through quantitative trait loci and expression analysis in water-use efficiency measured by carbon isotope discrimination.

Drought continues to be a major constraint on cereal production in many areas, and the frequency of drought is likely to increase in most arid and semi-arid regions under future climate change scenarios. Considerable research and breeding efforts have been devoted to investigating crop responses to drought at various levels and producing drought-resistant genotypes. Plant physiology has provided new insights to yield improvement in drought-prone environments. Crop performance could be improved through increases in water use, water-use efficiency (WUE) and harvest index. Greater WUE can be achieved by coordination between photosynthesis and transpiration. Carbon isotope discrimination (Δ(13) C) has been demonstrated to be a simple but reliable measure of WUE, and negative correlation between them has been used to indirectly estimate WUE under selected environments. New tools, such as quantitative trait loci (QTL) mapping and gene expression profiling, are playing vital roles in dissecting drought resistance-related traits. The combination of gene expression and association mapping could help identify candidate genes underlying the QTL of interest and complement map-based cloning and marker-assisted selection. Eventually, improved cultivars can be produced through genetic engineering. Future efficient and effective breeding progress in cereals under targeted drought environments will come from the integrated knowledge of physiology and genomics.