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In the context of advocating carbon neutrality, there are new requirements for sustainable management of municipal sludge (MS). Hydrothermal carbonization (HTC) is a promising technology to deal with high-moisture MS considering its low energy consumption (without drying pretreatment) and value-added products (i.e., hydrochar). This study applied machine learning (ML) methods to conduct a holistic assessment with higher heating value (HHV) of hydrochar, carbon recovery (CR), and energy recovery (ER) as model targets, yielding accurate prediction models with R

The potential for electrochemical conversion of bio-oil was overlooked for a long period due to the poor electrical conductivity and unclear reaction mechanism. This study aimed to provide an insight into bio-oil of electrochemical conversion mechanism and product distribution. In this study, using walnut shell bio-oil with enhanced electrical conductivity by ammonium carbonate as raw material, electrolysis experiments were carried out using different electrolysis times by constant current method (20 mA) in H-type electrolytic cell at a stable temperature (0 °C). The results showed that phenols, aldehydes, and lignin were copolymerized; meanwhile, unsaturated fatty acids such as oleic acid underwent decarbonylation and decarboxylation. The hydrogen-releasing electrode reaction also occurred at the cathode during the conversion process. Besides, the properties of products were characterized by elemental analysis, GC-TCD/FID, GC/MS, 1H NMR, FTIR, and TG-FTIR. Solid products were of possibility for application in new materials owing to containing copolymers with lignin structure, and gas products could be utilized as gas fuels with the combustible gas (H2, CO, CH4, and olefins) content as 79.24%.

Advances in genome sequencing technology, particularly restriction-site associated DNA sequence (RAD-seq) and whole-genome resequencing, have greatly aided the construction of cotton interspecific genetic maps based on single nucleotide polymorphism (SNPs), Indels, and other types of markers. High-density genetic maps can improve accuracy of quantitative trait locus (QTL) mapping, narrow down location intervals, and facilitate identification of the candidate genes.In this study, 249 individuals from an interspecific FOur research illustrates the efficiency of constructing a genetic map using binmap and QTL mapping on the basis of a certain size of the early-generation population. High-density genetic map features high recombination exchanges in number and distribution. The QTLs and the candidate genes identified based on this high-density genetic map may provide important gene resources for the genetic improvement of cotton.

A CC-NBS-LRR gene underlies the Le4 locus for interspecific hybrid lethality between Gossypium barbadense and G. hirsutum, and appears to act by triggering autoimmune responses., Hybrid lethality forms a reproductive barrier that has been found in many eukaryotes. Most cases follow the Bateson–Dobzhansky–Muller genetic incompatibility model and involve two or more loci. In this study, we demonstrate that a coiled-coil nucleotide-binding site leucine-rich repeat (CC-NBS-LRR) gene is the causal gene underlying the Le4 locus for interspecific hybrid lethality between Gossypium barbadense and G. hirsutum (cotton). Silencing this CC-NBS-LRR gene can restore F1 plants from a lethal to a normal phenotype. A total of 11 099 genes were differentially expressed between the leaves of normal and lethal F1 plants, of which genes related to autoimmune responses were highly enriched. Genes related to ATP-binding and ATPase were up-regulated before the lethal syndrome appeared; this may result in the conversion of Le4 into an active state and hence trigger immune signals in the absence of biotic/abiotic stress. We discuss our results in relation to the evolution and domestication of Sea Island cottons and the molecular mechanisms of hybrid lethality associated with autoimmune responses. Our findings provide new insights into reproductive isolation and may benefit cotton breeding.

In this study, a bio-oil model compound of walnut shell pyrolysis oil was selected. The microemulsions of diesel and model compound were produced using Span80 and Tween 80 as surfactants. The microemulsions were quantificationally analyzed to investigate the solubilization capacity of bio-oil characteristic components in diesel. The effects of surfactant concentration and initial volume ratio of bio-oil model compound to diesel (B/D ratio) on the solubilization capacity of bio-oil characteristic components in diesel were investigated. The heating value, kinematic viscosity, elemental analysis and thermogravimetric analysis of microemulsion were also conducted. Experimental results indicated that the suitable concentration of surfactant was 0.3 mol/L–0.45 mol/L, and the optimum B/D ratio was 4:12 for the bio-oil model compound. The dissolubility of m-cresol and guaiacol in microemulsion was much better than that of water and acetic acid. The heating value and the kinematic viscosity of microemulsion decreased slightly as the B/D ratio increased. Increasing the surfactant concentration contributed to a more pronounced increase in the kinetic viscosity and a significant decrease in the heating value. The influence of surfactant concentration on the fuel properties and thermogravimetric characteristics was stronger than that of B/D ratio.

In this study, the effects of induction conditions on the distribution characteristics of graded bio-oil derived from the co-pyrolysis of bio-oil distillation residue and bituminous coal were investigated in a fixed pyrolysis reactor with a three-stage condenser. Based on the central composite design and statistical analysis, it could be found that a quadratic model was recommended to depict the total bio-oil yield, whereas the linear model was the best-fitting model for the graded bio-oil yield of different condensation stages. As for total bio-oil yield, all the combined effects of induction conditions played a negative role, and all second-order effects were advantageous. Moreover, the high percentage of distillation residue contributed to the bio-oil yield at each condenser and had the greatest impact on the bio-oil yield of the first condenser. However, high temperatures and high gas flow rates reduced the bio-oil yield of the first condenser and favored the increase in bio-oil yield of subsequent condensers. In addition, the products derived from distillation residue were more abundant than bituminous coal. And the addition of bituminous coal did not significantly increase the type of compounds in bio-oil from the blends, but disturbed the distribution of bio-oil products. The condensers with different temperatures facilitated the separation and enrichment of different compounds.

The genetic basis of heterosis has not been resolved for approximately a century, although the role of loci with overdominant (ODO) effects has continued to be discussed by biologists. In the present investigation, a proposed model was studied in Gossypium hirsutum L. introgression lines (ILs) harbouring a segment of G. barbadense. These introgressions were confirmed by a single marker of G. barbadense. These ILs contained 396 quantitative trait loci (QTLs) for 11 yield and non-yield traits that were recorded in the field on homozygous and heterozygous plants for 5 years. After comparing the different types of QTLs between the yield group and the non-yield group, it was found that the yield group had significantly higher ODO QTL ratios. Moreover, 16 ODO QTLs identified for 5 yield-related traits were consistently detected during 5 cotton growing seasons (2010-2011 and 2013-2015): 6 of 7 for boll weight, 3 of 11 for seed-cotton yield per plant, 4 of 17 for boll number, 2 of 13 for lint yield per plant and 1 of 11 for lint percentage. Therefore, we propose that overdominance is the major genetic basis of lint yield heterosis in interspecific hybrids between G. barbadense and G. hirsutum. These findings have important implications in cotton breeding in that the boll weight can be improved by utilizing ODO QTLs via heterosis; thus, the stagnant yield barrier can be smashed to achieve sustainable increases in cotton production. Additionally, this concept can be translated to other field crops for improving their yield potential.

At present, it is very common to wear mask outdoors in order to avoid coronavirus disease 19 (COVID-19) infection. However, this leads to the formation of numerous plastic wastes that threaten humans and ecosystem. Against this major background, a novel co-pyrolysis coupled chemical vapor deposition (CVD) strategy is proposed to systematically convert mask and heavy fraction of bio-oil (HB) into biochar, bio-oil, and three-dimensional graphene films (3DGFs) is proposed. The biochar exhibits high higher heating value (HHV) (33.22-33.75 MJ/kg) and low ash content (2.34%), which is obviously superior to that of the walnut shell and anthracite coal. The bio-oil contains rich aromatic components, such as 1,2-dimethylbenzene and 2-methylnaphthalene, which can be used as chemical feedstock for insecticides. Furthermore, the 3DGF800 has a wide range of applications in the fields of oil spill cleanup and oil/water separation according to its fire resistance, high absorbability (40-89 g g-1) and long-term cycling stability. This research sheds new light on converting plastic wastes and industrial by-products into high added-value chemicals.

Enriching high-value chemicals from the pyrolysis of agricultural and forestry waste is an efficient way to achieve sustainable development and large-scale application of biomass pyrolysis. Phenols, as important chemical raw materials, spices and food additives, have attracted widespread attention. Herein, a novel technical route of torrefaction pretreatment combined with fractional condensation in pyrolysis loop was proposed to enrich the phenols in liquid products. In this study, the enrichment of phenols from the pyrolysis loop of walnut shell under the combination of torrefaction and fractional condensation was explored using a fixed-bed pyrolysis reactor equipped with a three-stage condensation system. Simultaneously, the effects of torrefaction on feedstocks were investigated through a thermogravimetric analyzer based on the characteristics of feedstocks. The results showed that the torrefaction and pyrolysis loop had a negative impact on the pyrolysis efficiency and the yield of liquid products, while the change in the condensation efficiency depended on the combined effects of torrefaction and pyrolysis loop. In addition, phenols tended to be enriched in the second condensation stage, especially phenol, o-cresol, 4-ethylphenol. Importantly, torrefaction could significantly enrich phenols in the liquid products, and the enrichment of phenols is relatively increased by 109.44% at least. Moreover, the pyrolysis loop was also beneficial to the enrichment of phenols, which was at least 90% higher than that of walnut shell. This study provided a potential route to enrich high value-added products from the pyrolysis loop of lignocellulosic biomass.

During the coronavirus 2019 (COVID-19) pandemic, there has been a dramatic increase in the use of medical products and personal protective equipment, such as masks, gowns, and disposable syringes, to treat patients or administer vaccines. However, this may lead to generation of large quantities of biohazardous medical waste. Here, an alternating-magnetic-field-initiated catalytic strategy is proposed to convert disposable syringes into hydrogen-rich gases and high-value graphite. Specifically, in addition to selecting heavy fraction of bio-oil as initiator, disposable syringe needles are used as radio frequency electromagnetic wave receptors to initiate the deconstruction of disposable syringe plastic. The highest H

The floral nectary, first recognized and described by Carl Linnaeus, is a remarkable organ that serves to provide carbohydrate-rich nectar to visiting pollinators in return for gamete transfer between flowers. Therefore, the nectary has indispensable biological significance in plant reproduction and even in evolution. Only two genes, CRC and STY, have been reported to regulate floral nectary development. However, it is still unknown what genes contribute to extrafloral nectary development. Here, we report that a nectary development gene in Gossypium (GoNe), annotated as an APETALA 2/ethylene-responsive factor (AP2/ERF), is responsible for the formation of both floral and extrafloral nectaries. GoNe plants that are silenced via virus-induced gene silencing technology and/or knocked out by Cas9 produce a nectariless phenotype. Point mutation and gene truncation simultaneously in duplicated genes Ne1 Ne2 lead to impaired nectary development in tetraploid cotton. There is no difference in the expression of the CRC and STY genes between the nectary TM-1 and the nectariless MD90ne in cotton. Therefore, the GoNe gene responsible for the formation of floral and extrafloral nectaries may be independent of CRC and STY. A complex mechanism might exist that restricts the nectary to a specific position with different genetic factors. Characterization of these target genes regulating nectary production has provided insights into the development, evolution, and function of nectaries and insect-resistant breeding.

Summary Interspecific genomic variation can provide a genetic basis for local adaptation and domestication. A series of studies have presented its role of interspecific haplotypes and introgressions in adaptive traits, but few studies have addressed their role in improving agronomic character. Two allotetraploid Gossypium species, Gossypium barbadense (Gb) and G. hirsutum (Gh) originating from the Americas, are cultivated independently. Here, through sequencing and the comparison of one GWAS panel in 229 Gb accessions and two GWAS panels in 491 Gh accessions, we found that most associated loci or functional haplotypes for agronomic traits were highly divergent, representing the strong divergent improvement between Gb and Gh. Using a comprehensive interspecific haplotype map, we revealed that six interspecific introgressions from Gh to Gb were significantly associated with the phenotypic performance of Gb, which could explain 5%–40% of phenotypic variation in yield and fibre qualities. In addition, three introgressions overlapped with six associated loci in Gb, indicating that these introgression regions were under further selection and stabilized during improvement. A single interspecific introgression often possessed yield‐increasing potential but decreased fibre qualities, or the opposite, making it difficult to simultaneously improve yield and fibre qualities. Our study not only has proved the importance of interspecific functional haplotypes or introgressions in the divergent improvement of Gb and Gh, but also supports their potential value in further human‐mediated hybridization or precision breeding.

In this study, bituminous coal was added as an additive to the pyrolysis of bio-oil distillation residue in order to optimize the production of pyrolysis syngas using a lab-scale fixed pyrolysis reactor. Response surface methodology was introduced to investigate the main and interaction effects of induction conditions (the percentage of bio-oil distillation residue, pyrolysis temperature and gas flow rate) on syngas based on central composite design. The results showed that the quadratic model was the optimal model to describe the yield and distribution of syngas through statistical analysis. All induction conditions were favorable for the yield of syngas, while had different effects on the syngas distribution. Among them, temperature had the greatest influence on the yield of different components of syngas, and the percentage of bio-oil distillation residue played a secondary role. Meanwhile, pyrolysis temperature contributed to the formation of hydrogen and methane, while it exhibited a negative linear effect on carbon monoxide and a negative parabolic effect on carbon dioxide. Optimized experimental conditions were recommended and further validated for maximum hydrogen, carbon monoxide, methane and minimum carbon dioxide, respectively. The highest calorific value of syngas (16.82 MJ/Nm3) was obtained by adding 40% bituminous coal under 550 °C and the gas flow rate of 500 ml/min. And the corresponding yields of biochar, bio-oil and syngas were 48.16%, 29.98% and 21.86%, respectively.

In this study, biochar was produced by co-pyrolysis of bio-oil distillation residue and bituminous coal under different induction temperature and gas flow rate in a tube furnace. Central composite design was introduced to explore the combined effects of experimental conditions on biochar. The physicochemical properties of biochar from different induction conditions were comprehensively evaluated by elemental analysis, Fourier transform infrared spectrometry (FTIR) and Raman spectroscopy based on response surface methodology. The results showed that bituminous coal was beneficial to the increase in biochar yield, whereas temperature had the opposite effect and the effect of gas flow rate was not obvious. Moreover, C/O ratio increased with the increase of pyrolysis temperature and bio-oil distillation residue in feedstocks, while C/H ratio increased only with increasing temperature. Gas flow rate had a more pronounced descent effect on C/H compared with C/O. In addition, induction conditions caused a relative weakening of C C stretching vibration and the relative enrichment of C H in biochar. Bituminous coal, temperature and gas flow rate all contributed to the conversion of small aromatic rings of biochar to large aromatic rings during the co-pyrolysis process.

In this study, the pyrolysis and co-pyrolysis characteristics of walnut shell and bio-oil distillation residue were investigated by means of thermogravimetric analysis followed by Fourier transform infrared spectrophotometer (TGA-FTIR). Multiple reaction models were employed to fit individual pyrolysis experiment of walnut shell and bio-oil distillation residue to find the optimal model for further analysis of co-pyrolysis. The results showed that the pyrolysis behavior of bio-oil distillation residue was different from that of walnut shell. Compared to the pyrolysis of walnut shell, bio-oil distillation residue retained more biochar and a relatively lower rate of mass loss. However, the best fitting models for walnut shell and bio-oil distillation residue were all five-reaction model through comparing the fitting effect and the component complexity. Moreover, five-reaction model was introduced to analyze the co-pyrolysis of walnut shell and bio-oil distillation residue, indicating that the co-pyrolysis had good adaptability to five-reaction model. The thermal degradation of the co-pyrolysis shoulder and spike peaks could be accurately predicted. In addition, the gas products of bio-oil distillation residue and walnut shell had the same absorption band by infrared spectroscopy, indicating that the pyrolysis of two raw materials had similar products while the different absorption intensities represented different concentrations of gas products. Based on Flynn–Wall–Ozawa (FWO) and Kissinger–Akahira–Sunose (KAS) methods, as the proportion of walnut shell in blend sample increased, the average activation energy gradually increased except for the pure walnut shell.

Hydrothermal carbonization (HTC) provides a promising alternative to valorize food waste digestate (FWD) and avoid disposal issues. Although hydrochar derived from FWD alone had a low calorific content (HHV of 13.9 MJ kg-1), catalytic co-HTC of FWD with wet lignocellulosic biomass (e.g., wet yard waste; YW) and 0.5 M HCl exhibited overall superior attributes in terms of energy recovery (22.7 MJ kg-1), stable and comprehensive combustion behaviour, potential nutrient recovery from process water (2-fold higher N retention and 129-fold higher P extraction), and a high C utilization efficiency (only 2.4% C loss). In contrast, co-HTC with citric acid provided ∼3-fold higher autogenous pressure, resulting in a superior energy content of 25.0 MJ kg-1, but the high C loss (∼74%) compromised the overall environmental benefits. The results of this study established a foundation to fully utilize FWD and YW hydrochar for bioenergy application and resource recovery from the process water.

In the study, biochar was easily produced from bio-oil distillation residue through a tube furnace at a broad induction temperature range of 200–700 °C under nitrogen and carbon dioxide. The comparative evolution of biochar was characterized by evaluating its physicochemical properties including elements, calorific values, functional groups, graphitization degree and thermal stability. The results showed that compared with nitrogen atmosphere, carbon dioxide first contributed to biochar yield. After 600 °C, biochar yield in carbon dioxide dropped rapidly, while nitrogen had little effect on biochar yield. Through bomb calorimeter, the maximum calorific value of biochar was 34.13 MJ·kg −1 at 200 °C under carbon dioxide. Based on elements analysis, O/C, H/C and N/C of biochar induced by nitrogen were higher than those of carbon dioxide. Fourier transform infrared spectrometry (FTIR) indicated that induction temperature and atmosphere selectively affected the evolution of biochar functional groups. C O stretching vibration in carbon dioxide was more durable than that in nitrogen, whereas the stretching vibration of CH 2 and C C had opposite phenomenon. In addition to 200 °C, the biochar under nitrogen possessed less graphitization with temperature increasing by Raman spectra analysis. Furthermore, the biochar induced by nitrogen was more stable than that induced by carbon dioxide according to the thermogravimetric analysis.

Co-pyrolysis characteristics of bio-oil distillation residue and bituminous coal were investigated through thermogravimetric analysis coupled with Fourier transform infrared spectrophotometer (TGA-FTIR). The addition of bituminous coal changed the behaviors and kinetics of pyrolysis reaction. With temperature increasing, synergistic effects rapidly increased at relatively low temperatures, and then kept a decreasing tendency with different rates until a relatively steady state. The results of the quantitative analysis of chemical functional group by the peak area of infrared spectroscopy indicated that the addition of bituminous coal had a positive effect on the production of CO2 and CO, and a negative effect on the functional groups containing C H, C C and C O bond. The co-pyrolysis mechanism and kinetics parameters were calculated by the Coats-Redfern and Flynn-Wall-Ozawa method, suggesting that the activation energy and the reaction order of co-pyrolysis increased with mixing ratio increasing in main step. The lowest activation energy (73.17 kJ/mol by Coast-Redfern method and 71.46 kJ/mol by Flynn-Wall-Ozawa method) was obtained by blending 20 wt% bituminous coal.

Upland cotton (Gossypium hirsutum) is the most important natural fiber crop in the world. The overall genetic diversity among cultivated species of cotton and the genetic changes that occurred during their improvement are poorly understood. Here we report a comprehensive genomic assessment of modern improved upland cotton based on the genome-wide resequencing of 318 landraces and modern improved cultivars or lines. We detected more associated loci for lint yield than for fiber quality, which suggests that lint yield has stronger selection signatures than other traits. We found that two ethylene-pathway-related genes were associated with increased lint yield in improved cultivars. We evaluated the population frequency of each elite allele in historically released cultivar groups and found that 54.8% of the elite genome-wide association study (GWAS) alleles detected were transferred from three founder landraces: Deltapine 15, Stoneville 2B and Uganda Mian. Our results provide a genomic basis for improving cotton cultivars and for further evolutionary analysis of polyploid crops.

This work optimized the physicochemical properties of fraction and effectively separated guaiacols compounds from bio-oil. It aimed to improve the quality and application value of bio-oil fraction. Several kinds of additives were added into the walnut shell bio-oil in the same mass ratio before the bio-oil distillation. The results showed that all additives, except for (NH4)2SO4, increased the pH value of fractions by facilitating the conversion of acidic compounds to salts. Adding additives could decrease the content of ketones and furfural in the fraction and increase the stability of fraction. Meanwhile, the moisture content of fractions was decreased and the content of high-value guaiacols compounds was increased. Among these additives, the minimum moisture content (7.48%), the maximum pH (5.10) of fraction and the maximum yield of high-value guaiacols compounds (increased by 85.89%) all were obtained by adding CO(NH2)2. According to this study, among these additives, CO(NH2)2 could be used into bio-oil pretreatments for enhancing downstream bio-oil processing and separation.

The fluidization behaviors and their differences for walnut shell (WS) assisted by different-sized sands at various blending proportions were investigated experimentally in a cold visual fluidized bed at ambient temperature and pressure. Through analyzing the fluidization characteristic curves, it was found that the WS/sand mixtures were clearly characterized by stratified fluidization during the fluidization process, presenting a velocity interval rather than a threshold for transition from fixed to fluidized bed. Sand-3, as the fluidizing medium, showed better performance for WS fluidization in terms of the relative difference between initial (Umf,i) and final fluidization velocity (Umf,f) as well as the average fluidization rate (Rf). Furthermore, the regularity and mechanism of mixing and segregation of WS/sand mixtures in two fluidized regions (semi and completed) are discussed in detail based on the flow pattern diagram, the axial and radial distribution of the components, as well as the mixing index.

Allotetraploid cotton is an economically important natural-fiber-producing crop worldwide. After polyploidization, Gossypium hirsutum L. evolved to produce a higher fiber yield and to better survive harsh environments than Gossypium barbadense, which produces superior-quality fibers. The global genetic and molecular bases for these interspecies divergences were unknown. Here we report high-quality de novo-assembled genomes for these two cultivated allotetraploid species with pronounced improvement in repetitive-DNA-enriched centromeric regions. Whole-genome comparative analyses revealed that species-specific alterations in gene expression, structural variations and expanded gene families were responsible for speciation and the evolutionary history of these species. These findings help to elucidate the evolution of cotton genomes and their domestication history. The information generated not only should enable breeders to improve fiber quality and resilience to ever-changing environmental conditions but also can be translated to other crops for better understanding of their domestication history and use in improvement.

Overuse of a small number of Upland cotton cultivars has narrowed cotton's genetic base, leading to major difficulties in developing cotton cultivars with diverse genetic backgrounds that are able to adapt to adverse conditions. To effectively broaden the genetic base, chromosome introgression lines (ILs) were developed, where TM-1, the genetic standard of Upland cotton, was used as the common recipient and its two feral landraces, TX-256 and TX-1046, were used as the donors. A total of 115 ILs, with an average segment length of 11.15 cM, were first developed via intraspecific hybridization by marker-assisted selection (MAS) in BC3F2 generations, spanning 3887.75 cM of the cotton genome. Association analysis showed that 63 markers were found to be associated with boll weight (BW), lint percentage (LP) and seed index. The percent of phenotypic variance explained by 148 QTLs detected was 4.12% on average. Eleven and five new QTLs for BW and LP (one stable QTL identified for LP in all environments) were detected, respectively, which can be used for efficiently pyramiding favourable alleles into one cultivar by MAS.

Linkage disequilibrium-based association mapping is a powerful tool for dissecting the genetic basis underlying complex traits. In this study, an association mapping panel consisting of 180 elite Upland cotton cultivars was constructed, evaluated in three locations across 2 years and genotyped using 228 SSRs to detect molecular markers associated with seed oil and protein contents. A total of 86 significant (a = 0.01) marker-trait associations were detected between 58 SSR markers and two seed quality traits in six environments. Fifteen SSR markers distributed on ten chromosomes (A3, A7, A9, A10, A12, A13, D2, D5, D6 and D9) and 12 across 9 chromosomes (A3, A7, A9, A10, A12, D2, D3, D5 and D9) associated with seed oil and protein contents, respectively, could be detected in more than one environment. Among the 18 SSR markers significantly associated with seed oil and/or protein contents, nine loci were associated with both seed traits simultaneously. The results of this study provide useful information for further understanding the genetic basis of cottonseed oil and protein traits, and they should facilitate future efforts to breed cotton containing seeds with high oil or high protein contents using MAS.

In this study, the physicochemical properties of biochars derived from different pyrolysis temperatures were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscope (SEM). The gasification reactivity of biochars and composition of gas products were investigated by thermogravimetric analyzer (TGA) and a lab-scale tube furnace. The results manifested that the carbonization degree and order degree of biochars strengthened by increasing pyrolysis temperature. Thermogravimetric analysis and kinetic parameters indicated that biochar treated by 400 °C had the optimal gasification reactivity and required the minimum activation energy to surmount energy barrier for initiating reaction. Moreover, the gas chromatograph further found that pyrolysis temperature of 400 °C corresponded to the maximum carbon monoxide yield. At the same time, it also illustrated that the gasification temperature higher than 1000 °C would hamper the enhancement of biochar gasification reactivity. More importantly, the volume fraction of CO produced by walnut shell chars was not related to the volatile content, but to the microcrystalline structure of biochars. The crystallite diameter and order degree of biochars showed a strong linear relationship with the volume fraction of carbon monoxide.

Quantitative trait locus (QTL) mapping lays the foundation for marker-assisted selection (MAS) for lint yield and fiber quality in cotton (Gossypium hirsutum). Boll-related traits affect yield and fiber quality, but few studies have focused on boll-related traits. Here, we detected QTLs related to cotton boll, yield and fiber quality traits using intraspecific F2 and F2:3 populations from the cross AQ × 08-10604. A total of 91 QTLs for 17 traits related to boll, yield and fiber quality in the F2 and F2:3 populations were mapped, including 37 significant QTLs. Six pairs of common QTLs were detected, including two pairs for boll coat weight (BCW) in the same or similar positions on Chr. A10 and D1, two pairs for boll length (BL) in similar positions on Chr. A10 and A13, with a higher percentage of phenotype variation and two pairs for boll diameter (BD) in similar positions on Chr. A10 and D1. These results suggest that the traits BCW, BL and BD have high levels of stability. Five QTL clusters for the same or different traits were also identified on Chr. A10 (2), A13, D1 and D5. We also detected 64 epistatic QTLs for boll- and yield-related traits that play important roles in genetic variation. Correlation analysis revealed significant positive correlations between seed yield and boll number per plant and between boll weight and BCW, BL and BD. The results of this study enhance our understanding of the genetic basis of boll-related traits and will enable further MAS of upland cotton.

In this study, torrefaction combined with co-pyrolysis was proposed to produce biochar from walnut shell and bio-oil distillation residue in a tube furnace. The effect of torrefaction and co-pyrolysis on the yield and properties of biochar was investigated in the torrefaction-pyrolysis process including the evaluation of the properties and yield of torrefied feedstocks. The results showed that the positive synergistic effect between walnut shell and distillation residue on the yield of torrefied blends was found in the torrefaction stage, while the torrefaction had a negative synergistic effect on the hydrogen to carbon atom effective ratio of torrefied blends. The torrefied walnut shell and the torrefied distillation residue had most of the same infrared absorption peaks, and torrefaction did not change the type of infrared absorption peaks of torrefied feedstocks. Furthermore, the positive synergistic effect on the yield and the hydrogen to carbon atom effective ratio of biochar from the blends was confirmed to exist in the co-pyrolysis stage. However, the combined effect of torrefaction and co-pyrolysis had a positive effect on the yield of walnut shell biochar, and had a negative effect on the yield of distillation residue biochar. In addition, torrefaction pretreatment was beneficial to the evolution of large aromatic rings in biochar to small aromatic rings and the formation of ordered carbon.

This study demonstrates the first practical use of CSILs for the transfer of fiber quality QTLs into Upland cotton cultivars using SSR markers without detrimentally affecting desirable agronomic characteristics. Gossypium hirsutum is characterized by its high lint production and medium fiber quality compared to extra-long staple cotton G. barbadense. Transferring valuable traits or genes from G. barbadense into G. hirsutum is a promising but challenging approach through a traditional interspecific introgression strategy. We developed one set of chromosome segment introgression lines (CSILs), where TM-1, the genetic standard in G. hirsutum, was used as the recipient parent and the long staple cotton G. barbadense cv. Hai7124 was used as the donor parent by molecular marker-assisted selection (MAS). Among them, four CSILs, IL040-A4-1, IL080-D6-1, IL088-A7-3 and IL019-A2-6, found to be associated with superior fiber qualities including fiber length, strength and fineness QTL in Xinjiang were selected and backcrossed, and transferred these QTLs into three commercial Upland cotton cultivars such as Xinluzao (XLZ) 26, 41 and 42 grown in Xinjiang. By backcrossing and self-pollinating twice, five improved lines (3262-4, 3389-2, 3326-3, 3380-4 and 3426-5) were developed by MAS of background and introgressed segments. In diverse field trials, these QTLs consistently and significantly offered additive effects on the target phenotype. Furthermore, we also pyramided two segments from different CSILs (IL080-D6-1 and IL019-A2-6) into cultivar 0768 to accelerate breeding process purposefully with MAS. The improved lines pyramided by these two introgressed segments showed significant additive epistatic effects in four separate field trials. No significant alteration in yield components was observed in these modified lines. In summary, we first report that these CSILs have great potential to improve fiber qualities in Upland cotton MAS breeding programs.

Whole-genome analysis of genetic introgressions in allotetraploid cotton. (PDF 111 kb)

A phylogenetic tree with full accession names. (PDF 180 kb)

Supplementary Figures S1â S11. (DOCX 4378 kb)

Gossypium hirsutum L. is a widely cultivated species characterized by its high yield and wide environmental adaptability, while Gossypium barbadense is well known for its superior fiber quality. In the present report, we, for the first time, developed G. hirsutum chromosome segment introgression lines (ILs) in a G. barbadense background (GhILs_Gb) and genetically dissected the inheritance of lint yield and fiber quality of G. hirsutum in G. barbadense background. The GhILs_Gb contains introgressed segments spanning 4121.20 cM, which represents 82.20% of the tetraploid cotton genome, with an average length of 18.65 cM. A total of 39 quantitative trait loci (QTLs) for six traits are identified in this IL population planted in Xinjiang. Four QTL clusters are detected. Of them, however, three clusters have deleterious effects on fiber length and strength and boll weight, and only one cluster on Chr. D9 can be used in marker-assisted selection (MAS) to increase lint percentage and decrease micronaire value in G. barbadense. QTL mapping showed that most of yield-related QTLs detected have positive effects and increase lint yield in G. barbadense, while most of fiber quality-related QTLs have deleterious effects except for micronaire. It suggested that G. hirsutum evolved to have a high lint yield. Several lines improved in lint percentage and boll size in G. barbadense by introgressed one fragment of G. hirsutum have been developed from the GhILs_Gb. The ILs developed, and the analyses presented here will enhance the understanding of the genetics of lint yield and fiber quality in G. hirsutum and facilitate further molecular breeding to improve lint yield in G. barbadense.

Fiber quality improvement is a driving force for further cotton domestication and breeding. Here, QTLs for fiber quality were mapped in 115 introgression lines (ILs) first developed from two intraspecific populations of cultivated and feral cotton landraces. A total of 60 QTLs were found, which explained 2.03–16.85% of the phenotypic variance found in fiber quality traits. A total of 36 markers were associated with five fiber traits, 33 of which were found to be associated with QTLs in multiple environments. In addition, nine pairs of common QTLs were identified; namely, one pair of QTLs for fiber elongation, three pairs for fiber length, three pairs for fiber strength and two pairs for micronaire (qMICs). All common QTLs had additive effects in the same direction in both IL populations. We also found five QTL clusters, allowing cotton breeders to focus their efforts on regions of QTLs with the highest percentages of phenotypic variance. Our results also reveal footprints of domestication; for example, fourteen QTLs with positive effects were found to have remained in modern cultivars during domestication, and two negative qMICs that had never been reported before were found, suggesting that the qMICs regions may be eliminated during artificial selection.

Asiatic cotton (Gossypium arboreum L.) is an Old World cultivated cotton species. The sinense race was planted extensively in China. Due to the advances in spinning technology during the last century, the species was replaced by the New World allotetraploid cotton G. hirsutum L. Gossypium arboreum is still grown in India and Pakistan and also used as an elite in current cotton breeding programs. In addition, G. arboreum serves as a model for genomic research in Gossypium. In the present study, we generated an A-genome diploid cotton intraspecific genetic map including 264 SSR loci with three morphological markers mapped to 13 linkage groups. The map spans 2,508.71 cM with an average distance of 9.4 cM between adjacent loci. A population containing 176 F(2:3) families was used to perform quantitative trait loci (QTL) mapping for 17 phenotypes using Multiple QTL Model (MQM) of MapQTL ver 5.0. Overall, 108 QTLs were detected on 13 chromosomes. Thirty-one QTLs for yield and its components were detected in the F2 population. Forty-one QTLs for yield and its components were detected in the F(2:3) families with a total of 43 QTLs for fiber qualities. Two QTLs for seed cotton weight/plant and lint index and three QTLs for seed index were consistently detected both in F2 and F(2:3). Most QTLs for fiber qualities and yields were located at the same interval or neighboring intervals. These results indicated that the negative correlation between fiber qualities and yield traits may result from either pleiotropic effect of one gene or linkage effects of multiple closely linked genes.

The purpose of the research presented here was to explore the genetic basis of cotton (Gossypium hirsutum L.) fiber quality traits through quantitative trait locus (QTL) analysis and epistasis effects dissection, and further discuss the mechanism of heterosis. An immortalized F 2 population was developed by intercrossing Xiangzamian 2-derived recombinant inbred lines (RILs) (XZM2). Fiber quality traits were investigated in F 1 and F 2 generations of hybrid XZM2, its two parents, and the immortalized F 2 population in multiple environments in China. The low level of heterosis in XZM2 and in the immortalized F 2 population suggested a lack of dominant and dominant x dominant interaction. In general, the low correlations of genotypic heterozygosity with trait performance and mid-parent heterosis showed that heterozygosity was not always advantageous for performance, and they excluded overdominance as a major genetic basis of heterosis. A total of 50 QTLs for fiber quality were identified by single-locus QTL analysis. Although partial dominance and overdominance were detected, additive genetic variance was predominant. Common QTLs were detected both in the homozygous RILs and in the heterozygous immortalized F 2 populations. Additionally, single-locus heterotic effects and epistasis effects at the two-locus level were detected. Our results indicated that additive gene action was the primary mechanism responsible for genetic variability in fiber quality traits. Additionally, we found that single-locus heterotic effects and epistasis effects contributed to heterosis of fiber quality traits in XZM2.