Construction of genetic map in barley using sequence-related amplified polymorphism markers, a new molecular marker technique

Sequence-related amplified polymorphism (SRAP) markers, a novel polymerase chain reaction (PCR)-based molecular marker technique, were successfully applied in map construction, cultivar identification, diversity evaluation, comparative genomics and gene location of different plant species. The molecular genetic map of SRAP markers in Steptoe / Morex doubled haploid (DH) population was constructed in this study, using 216 SRAP markers and 312 simple sequence repeat (SSR) markers. Overall, 21 of the 216 SRAP markers generated 78 polymorphic loci, and 98 of 312 SSR markers produced 107 polymorphic loci. Among the 185 loci, 175 loci (70 SRAP loci and 105 SSR loci) were assigned to nine linkage groups. The map covered 1475 cM with a mean density of 8.7 cM per locus. In total, 33 of all the loci (17.84%) showed significant segregation distortion. Moreover, 23 of the 33 loci (69.7%) skewed towards the parent Steptoe, whereas the remaining loci (21.3%) deviated towards the parent Morex and some of these distorted loci tended to cluster at the end of linkage groups, while others were dispersed on linkage groups in a decentralized fashion. The three putative segregation distortion regions (SDRs) were detected on chromosomes 2H, 4H and 5H, respectively. This linkage map indicates its importance in quantitative trait loci (QTLs) mapping, marker-assisted selection (MAS) and integrative analysis for further genetic studies with other linkage maps in barley.Keywords: Barley, sequence-related amplified polymorphism (SRAP), molecular genetic map, simple sequence repeat (SSR), doubled haploid (DH) populatio

Repeatable use assessment of silicon carbide as permanent susceptor bed in ex situ microwave remediation of petroleum-impacted soils

Efficiency of microwave-enabled ex situ soil remediation can be improved by dielectric susceptors. Cost, and environmental burden of these susceptors can be minimized if they are used repeatedly in a permanent bed set-up. In this study, carbon nanofibers, activated carbon, magnetite, and silicon carbide were tested at the lab scale for repeated use in permanent microwave-induced thermal soil remediation. Despite their superior ability to convert microwaves into heat, carbon nanofibers experienced electrokinesis and activated carbon partially combusted in the microwave cavity, which complicates their pragmatic use in remediation applications. Magnetite was also able to convert microwaves into heat effectively and it was relatively more stable; however, repeated heating/and cooling cycles changed its physicochemical properties, which was attributed to oxidation of iron oxides at the air-soil interface. Silicon carbide, on the other hand, was an efficient heating agent and was stable during repeatable heating and cooling cycles. Through 25 heating/cooling cycles, an average peak temperature of 329 ± 55°C was achieved for a 29 cm3 sample and analysis of dielectric properties after every 10th and 25th cycle indicated that there were no significant losses in thermal conductivity or permittivity of the material. Subsequent remediation experiments with silicon carbide demonstrated that between 89 and 97% of the total petroleum hydrocarbons were removed from soil including a marked fraction of heavy hydrocarbons when 20.2 kJ g−1 of microwave energy was introduced. In addition, post-treatment experiments demonstrated that soil conditions were capable of supporting seed germination indicating that some conditions of soil were recovered after microwave remediation

Holmium doped yttria transparent ceramics for 2-μm solid state lasers

0.7 at.% Ho:Y2O3 transparent ceramics were fabricated by using vacuum sintering plus hot isostatic pressing (HIPing) process. Vacuum sintered at 1500 °C for 12 h followed by HIPing at 1450 °C for 4 h, the Ho:Y2O3 ceramics showed excellent in-line transmission and uniform grain size, with an average grain size of about 1 μm. The Ho:Y2O3 ceramics showed good thermal conductivity thanks to the identical effective ionic radius between Ho3+ and Y3+. For the first time, room temperature laser oscillation from Ho:Y2O3 transparent ceramics was demonstrated. The uncoated 0.7 at.% Ho:Y2O3 ceramic slabs were in-band pumped by a Tm:fiber laser at 1941 nm, and a maximum output power of 1.3 W at 2116.8 nm was achieved with a slope efficiency of 31.2%. It indicates that Ho:Y2O3 transparent ceramics could be excellent laser gain medias for 2 μm solid-state laser applications.Accepted versio

Genetic and QTL analysis of flower color and pigments in small-flowered chrysanthemum based on high-density genetic map

Flower color is an important trait for ornamental plants and is determined by pigments. Variations in the flower color of chrysanthemum are abundant, which is an important feature related to its ornamental and commercial value. However, few reports have elucidated the inheritance of the flower color and pigmentation of chrysanthemum. In this study, an F1 hybrid population, including 319 hybrids of small-flowered chrysanthemum cultivars with different flower color, was constructed. The genetic variation rules for some color and pigment-related traits were discussed based on major gene and polygene mixed inheritance analyses. Both the total anthocyanin and carotenoid contents were controlled by two pairs of additive dominant major genes and the heritability of the major genes was 70.44% and 86.03%, respectively. Based on the high-density genetic map constructed for the hybrid population, QTL analysis for the above traits was carried out using the interval mapping method. A total of 25 related QTLs and 517 closely linked markers were detected, including three QTLs controlling the total anthocyanin content and two QTLs controlling the total carotenoid content, all of which were major QTLs. Furthermore, 17 unigenes related to pigments were identified via BLAST searches with Chrysanthemum nankingense genome. For such genes, the collinearity was observed in four chromosome level genomes, including three genomes of the genus Chrysanthemum and the first genome of cultivated chrysanthemum. The results lay a foundation for in-depth exploration of flower color and pigmentation in chrysanthemum and provide a reference for future research in other ornamental plants

Fabrication of Er:Y₂O₃ transparent ceramics for 2.7 μm mid-infrared solid-state lasers

Laser grade 7 at.% Er:Y2O3 transparent ceramics with submicron grain size were fabricated by using one-step vacuum sintering followed by hot isostatic pressing (HIPing) technique. Through studying the sintering trajectory of Er:Y2O3 ceramics, the sintering temperature zone where sufficient relative density (>96%), no pore-boundary separation, and sub-micron grain size (<1 μm) ceramic samples could be identified. The samples pre-sintered in this zone were readily densified by HIPing. To maximum the densification and achieve high transparency, it is critical to suppress the final-stage grain growth. After HIPing at 1520 °C, the Er:Y2O3 ceramics were fully densified without further grain growth, and exhibited in-line transmission of about 81.6% at 2000 nm. Continuous wave (CW) room temperature laser operation of the Er:Y2O3 transparent ceramic at 2.7 μm was demonstrated.Agency for Science, Technology and Research (A*STAR)Ministry of Education (MOE)The research is partially supported by the fund of A*Star of Singapore (Grant No. A1883C0003), the fund of Ministry of Education (MOE), Singapore (Grant No. 2018-T1-001-145), the National Natural Science Foundation of China (Grant Nos. 61875078 and 61861136007) and the Priority Academic Program Development of Jiangsu Higher Education Institutions

Materials development and potential applications of transparent ceramics: A review

International audienc