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1.
Integrated gasification and catalytic reforming syngas production from corn straw with mitigated greenhouse gas emission potential.
Hu, J, Li, D, Lee, DJ, Zhang, Q, Wang, W, Zhao, S, Zhang, Z, He, C
Bioresource technology. 2019;:371-377
Abstract
The syngas that is produced from waste biomass often has high levels of CH4 and CO2, which are greenhouse gases. This investigation presents an integrated gasification and catalytic reforming process with a closed gas loop that can improve quality of syngas from corn straw and mitigate CH4 and CO2 emission. The effects of the support type, reforming temperature, steam-to-biomass (S/B) ratio, and catalyst-to-biomass ratio (C/B) ratio on gas yield and composition were experimentally examined with waste corn straw as the feedstock gasified at 850 °C in the proposed closed-loop apparatus. Reformation of syngas using Ni/γ-Al2O3 at 850 °C, S/B = 1 and C/B = 0.5 yielded 1.16 m3/kg of syngas, which contained 48.5% H2, 33.9% CO, 12.2% CO2 and 5.3% CH4, corresponding to 71.0% and 81.5% enhancements of the first two and -77.8% and -58.1% reductions of the last two components.
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2.
Maize Crop Coefficient Estimated from UAV-Measured Multispectral Vegetation Indices.
Zhang, Y, Han, W, Niu, X, Li, G
Sensors (Basel, Switzerland). 2019;(23)
Abstract
The rapid, accurate, and real-time estimation of crop coefficients at the farm scale is one of the key prerequisites in precision agricultural water management. This study aimed to map the maize crop coefficient (Kc) with improved accuracy under different levels of deficit irrigation. The proposed method for estimating the Kc is based on multispectral images of high spatial resolution taken using an unmanned aerial vehicle (UAV). The analysis was performed on five experimental plots using Kc values measured from the daily soil water balance in Ordos, Inner Mongolia, China. To accurately estimate the Kc, the fraction of vegetation cover (fc) derived from the normalized difference vegetation index (NDVI) was used to compare with field measurements, and the stress coefficients (Ks) calculated from two vegetation index (VI) regression models were compared. The results showed that the NDVI values under different levels of deficit irrigation had no significant difference in the reproductive stage but changed significantly in the maturation stage, with a decrease of 0.09 with 72% water applied difference. The fc calculated from the NDVI had a high correlation with field measurement data, with a coefficient of determination (R2) of 0.93. The ratios of transformed chlorophyll absorption in reflectance index (TCARI) to renormalized difference vegetation index (RDVI) and TCARI to soil-adjusted vegetation index (SAVI) were used, respectively, to establish two types of Ks regression models to retrieve Kc. Compared to the TCARI/SAVI model, the TCARI/RDVI model under different levels of deficit irrigation had better correlation with Kc, with R2 and root-mean-square error (RMSE) values ranging from 0.68 to 0.80 and from 0.140 to 0.232, respectively. Compared to Kc calculated from on-site measurements, the Kc values retrieved from the VI regression models established in this study had greater ability to assess the field variability of soil and crops. Overall, use of the UAV-measured multispectral vegetation index approach could improve water management at the farm scale.
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3.
Productivity and flavor of diverse genotypes of Ustilago maydis "cuitlacoche" for human consumption.
Castañeda de León, V, Martínez-Carrera, D, Morales, P, Sobal, M, Gil-Muñoz, A, Severiano-Pérez, P, Leal-Lara, H
Fungal biology. 2019;(6):481-488
Abstract
Maize plants infected by Ustilago maydis develop galls known as "cuitlacoche", a food product appreciated in the Mexican gastronomy. The virulence of different U. maydis isolates was assessed, as well as the development of the infection on one commercial maize variety. Sporidia were isolated of wild galls collected in Mexico. Sexual compatibility patterns were determined using the Fuzz reaction, showing a 1:1:1:1 segregation of mating type specificities. Ten U. maydis compatible strains were selected on the basis of their virulence, namely: four wild-type compatible sporidia, one multi-teliosporic strain, two hybrids between wild-type and tester strains, and three tester strains. Maize plants of a commercial hybrid (Tornado XR™) were inoculated with these strains of U. maydis, using a randomized complete block experimental design. Phenological and phenotypic characteristics of plants, as well as production, quality and sensory attributes of the resulting galls, were evaluated. Greater yields of galls were recorded in tester strains (incidence >90 %, severity >80 %, productivity >12 t/ha), a hybrid strain (EM1-6 × FB1) [incidence 82.6 %, severity 51.8 %, productivity 5.6 t/ha] and a wild-type strain (EM4-10 × EM2-4) [incidence 68.2 %, severity 44.0 %, productivity 4.8 t/ha]. Wild-type strains showed better flavor, characterized by less bitterness and acidity, but prevailing sweet, umami and maize flavor.
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4.
Doubled haploid technology for line development in maize: technical advances and prospects.
Chaikam, V, Molenaar, W, Melchinger, AE, Boddupalli, PM
TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik. 2019;(12):3227-3243
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Abstract
Increased efficiencies achieved in different steps of DH line production offer greater benefits to maize breeding programs. Doubled haploid (DH) technology has become an integral part of many commercial maize breeding programs as DH lines offer several economic, logistic and genetic benefits over conventional inbred lines. Further, new advances in DH technology continue to improve the efficiency of DH line development and fuel its increased adoption in breeding programs worldwide. The established method for maize DH production covered in this review involves in vivo induction of maternal haploids by a male haploid inducer genotype, identification of haploids from diploids at the seed or seedling stage, chromosome doubling of haploid (D0) seedlings and finally, selfing of fertile D0 plants. Development of haploid inducers with high haploid induction rates and adaptation to different target environments have facilitated increased adoption of DH technology in the tropics. New marker systems for haploid identification, such as the red root marker and high oil marker, are being increasingly integrated into new haploid inducers and have the potential to make DH technology accessible in germplasm such as some Flint, landrace, or tropical material, where the standard R1-nj marker is inhibited. Automation holds great promise to further reduce the cost and time in haploid identification. Increasing success rates in chromosome doubling protocols and/or reducing environmental and human toxicity of chromosome doubling protocols, including research on genetic improvement in spontaneous chromosome doubling, have the potential to greatly reduce the production costs per DH line.
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5.
Divergence with gene flow is driven by local adaptation to temperature and soil phosphorus concentration in teosinte subspecies (Zea mays parviglumis and Zea mays mexicana).
Aguirre-Liguori, JA, Gaut, BS, Jaramillo-Correa, JP, Tenaillon, MI, Montes-Hernández, S, García-Oliva, F, Hearne, SJ, Eguiarte, LE
Molecular ecology. 2019;(11):2814-2830
Abstract
Patterns of genomic divergence between hybridizing taxa can be heterogeneous along the genome. Both differential introgression and local adaptation may contribute to this pattern. Here, we analysed two teosinte subspecies, Zea mays ssp. parviglumis and ssp. mexicana, to test whether their divergence has occurred in the face of gene flow and to infer which environmental variables have been important drivers of their ecological differentiation. We generated 9,780 DArTseqTM SNPs for 47 populations, and used an additional data set containing 33,454 MaizeSNP50 SNPs for 49 populations. With these data, we inferred features of demographic history and performed genome wide scans to determine the number of outlier SNPs associated with climate and soil variables. The two data sets indicate that divergence has occurred or been maintained despite continuous gene flow and/or secondary contact. Most of the significant SNP associations were to temperature and to phosphorus concentration in the soil. A large proportion of these candidate SNPs were located in regions of high differentiation that had been identified previously as putative inversions. We therefore propose that genomic differentiation in teosintes has occurred by a process of adaptive divergence, with putative inversions contributing to reduced gene flow between locally adapted populations.
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Fibre-enriched buckwheat pasta modifies blood glucose response compared to corn pasta in individuals with type 1 diabetes and celiac disease: Acute randomized controlled trial.
Vetrani, C, Bozzetto, L, Giorgini, M, Cavagnuolo, L, Di Mattia, E, Cipriano, P, Mangione, A, Todisco, A, Inghilterra, G, Giacco, A, et al
Diabetes research and clinical practice. 2019;:156-162
Abstract
AIM: People with type 1 diabetes and celiac disease (T1D&CD) have high blood glucose variability. Processed gluten-free foods have shown to induce a worse metabolic profile whereas naturally gluten-free foods may represent healthier options. On the other hand, dietary fibre has shown to reduce postprandial glycemic excursions in individuals with diabetes. Thus, we evaluated the acute effect of fibre-enriched buckwheat (FBP) and corn pasta (CP) on postprandial blood glucose response (PP-BGR). METHODS Ten adult patients with T1D&CD consumed two meals with the same amount of carbohydrate while differing only for pasta type (FBP or CP) preceded by the same insulin bolus. Participants utilized continuous glucose monitoring (CGM) and data over 6 h after meal were analyzed. RESULTS PP-BGR differed between the two meals, being significantly lower in the first period (0-3 h) after the CP than the FBP meal (iAUC: -38 ± 158 vs. 305 ± 209 mmol/L · 180 min, p = 0.040), whereas significantly higher in the second period (3-6 h) after the CP than the FBP meal (iAUC: 432 ± 153 vs. 308 ± 252 mmol/L · 180 min, p = 0.030). Overall, a less variable postprandial profile was observed after FBP than CP consumption. CONCLUSIONS In individuals with T1D&CD, the acute consumption of FBP induces significant differences in PP-BGR compared with CP that may be clinically relevant.
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7.
Contamination of the guttation liquid of two common weeds with neonicotinoids from coated maize seeds planted in close proximity.
Mörtl, M, Darvas, B, Vehovszky, Á, Győri, J, Székács, A
The Science of the total environment. 2019;:1137-1143
Abstract
Neonicotinoid uptake by maize plants emerged from coated seeds and by two common weeds grown in close proximity to coated seeds has been studied. Uptake of thiamethoxam (TMX) and clothianidin (CLO) have been characterized via guttation liquid measurements. The creeping thistle (Cirsium arvense), a well-known maize weed, as well as red poppy or Flanders poppy (Papaver rhoeas) were chosen as model species. The results confirmed that cross-contamination may occur by uptake of the neonicotinoid AIs through soil from neighbouring plants that emerged from coated seeds. Although the levels of these neonicotinoids were substantially lower in the guttation liquid of the weeds than in that of maize plants emerged from coated seeds, the compounds were detected up to 36th day after planting of the maize seeds. The highest peak concentrations of TMX were around 150 and 21 mg L-1, while similar data for CLO were around 70 and 21 mg L-1 for maize and creeping thistle, respectively. Mostly due to its higher guttation intensity significantly lower values were determined for red poppy (0.740 mg L-1).
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8.
The cover crop determines the AMF community composition in soil and in roots of maize after a ten-year continuous crop rotation.
Hontoria, C, García-González, I, Quemada, M, Roldán, A, Alguacil, MM
The Science of the total environment. 2019;:913-922
Abstract
Intensive agricultural practices are responsible for soil biological degradation. By stimulating indigenous arbuscular mycorrhizal fungi (AMF), cover cropping enhances soil health and promotes agroecosystem sustainability. Still, the legacy effects of cover crops (CCs) and the major factors driving the AM fungal community are not well known; neither is the influence of the specific CC. This work describes a field experiment established in Central Spain to test the effect of replacing winter fallow by barley (Hordeum vulgare L.) or vetch (Vicia sativa L.) during the intercropping of maize (Zea mays L.). We examined the community composition of the AMF in the roots and rhizosphere soil associated with the subsequent cash crop after 10 years of cover cropping, using Illumina technology. The multivariate analysis showed that the AMF communities under the barley treatment differed significantly from those under fallow, whereas no legacy effect of the vetch CC was detected. Soil organic carbon, electrical conductivity, pH, Ca and microbial biomass carbon were identified as major factors shaping soil AMF communities. Specific AMF taxa were found to play a role in plant uptake of P, Fe, Zn, Mn, and Cd, which may shed light on the functionality of these taxa. In our conditions, the use of barley as a winter CC appears to be an appropriate choice with respect to promotion of AMF populations and biological activity in agricultural soils with intercropping systems. However, more research on CC species and their legacy effect on the microbial community composition and functionality are needed to guide decisions in knowledge-based agriculture.
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Corn silk decoction for blood lipid in patients with angina pectoris: A systematic review and meta-analysis.
Shi, S, Yu, B, Li, W, Shan, J, Ma, T
Phytotherapy research : PTR. 2019;(11):2862-2869
Abstract
The aims of this study were to evaluate the efficacy of corn silk decoction on lipid profile in patients with angina pectoris. PubMed, Cochrane, Embase, Google Scholar, Chongqing VIP Chinese Science and Technology Periodical Database, China National Knowledge Infrastructure, and Wanfang database were searched up to January 2019 for randomized controlled trials that assessed the impact of corn silk decoction on total cholesterol, triglycerides, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol in patients with angina pectoris. Study evaluation and synthesis methods were in accordance with the Cochrane Handbook, and data were analyzed using Review Manager (version 5.3) software. Random effects model was applied in this systematic review and meta-analysis to compensate for potential heterogeneity among the included studies. A total of four randomized controlled trials were eligible for meta-analysis. Pooled results of these studies indicated that corn silk decoction might improve high-density lipoprotein cholesterol and reduce total cholesterol, triglycerides, and low-density lipoprotein cholesterol in patients with angina pectoris. Subgroup analyses showed that corn silk decoction or modified corn silk decoction plus conventional pharmaceutical treatment could have favorable effects on blood lipids. However, the lack of blinding in most studies may have led to overestimation of these effects. Further studies with better design are needed to confirm these findings.
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10.
Genome-Wide Association Study of 13 Traits in Maize Seedlings under Low Phosphorus Stress.
Wang, QJ, Yuan, Y, Liao, Z, Jiang, Y, Wang, Q, Zhang, L, Gao, S, Wu, F, Li, M, Xie, W, et al
The plant genome. 2019;(3):1-13
Abstract
Low P stress is a global issue for grain production. Significant phenotypic differences were detected among 13 traits in 356 maize lines under P-sufficient and P-deficient conditions. Significant single nucleotide polymorphisms (SNPs) and low-P stress-responsive genes were identified for 13 maize root traits based on a genome-wide association study. Hap5, harboring 12 favorable SNPs, could enhance strong root systems and P absorption under low-P stress. Phosphorus is an essential macronutrient required for normal plant growth and development. Determining the genetic basis of root traits will enhance our understanding of maize's (Zea mays L.) tolerance to low-P stress. Here, we identified significant phenotypic differences for 13 traits in maize seedlings subjected to P-sufficient and P-deficient conditions. Six extremely sensitive and seven low-P stress tolerant inbreds were selected from 356 inbred lines of maize. No significant differences were observed between temperate and tropical-subtropical groups with respect to trait ratios associated with the adaptation to low-P stress. The broad-sense heritability of these traits ranged from relatively moderate (0.59) to high (0.90). Through genome-wide association mapping with 541,575 informative single nucleotide polymorphisms (SNPs), 551, 1140 and 1157 significant SNPs were detected for the 13 traits in 2012, 2016 and both years combined, respectively, along with 23 shared candidate genes, seven of which overlapped with reported quantitative trait loci and genes for low-P stress. Five haplotypes located in candidate gene GRMZM2G009544 were identified; among these, Hap5, harboring 12 favorable SNP alleles, showed significantly greater values for the root traits studied than the other four haplotypes under both experimental conditions. The candidate genes and favorable haplotypes and alleles identified here provide promising resources for genetic studies and molecular breeding for improving tolerance to abiotic stress in maize.