Wild soybean is a typical short-day plant that begins flowering when the days are shorter than its critical photoperiod. Soybean was domesticated in the temperate region of East Asia at the relatively high latitude, and the breeding and release of soybean varieties have historically centered on mid-and high-latitude temperate regions. Low-latitude areas with tropical and subtropical climates were previously considered unsuitable for soybean production because most temperate soybean varieties exhibited precocious flowering and early maturity and suffered from low yields. The discovery and introduction of the long juvenile trait into soybean varieties in the 1970s (Hartwig and Kiihl, 1979) fundamentally changed global soybean production in a way that has had an enormous influence on commodity markets. This trait delays flowering and thereby ensures sufficient vegetative growth prior to the developmental transition to reproductive growth. The long juvenile trait thus solved the early maturation and low yield problems that had hitherto prevented economically viable soybean production in lowlatitude regions (Destro et al., 2001). The United States and Brazil pioneered the introduction of the long juvenile trait in low-latitude soybean breeding programs. Brazil has expanded its soybean production enormously, from 1 million hectares in 1970 (Brown, 2004) to over 33 million hectares in 2016 (http:// gain.fas.usda.gov/Recent%20GAIN%20Publications/Oilseeds %20and%20Products%20Update_Brasilia_Brazil_12-1-2016. pdf).

BackgroundOne of the overarching goals of soybean breeding is to develop lines that combine increased yield with improved quality characteristics. High-density-marker QTL mapping can serve as an effective strategy to identify novel genomic information to facilitate crop improvement. In this study, we genotyped a recombinant inbred line (RIL) population (Zhonghuang 24 × Huaxia 3) using a restriction-site associated DNA sequencing (RAD-seq) approach. A high-density soybean genetic map was constructed and used to identify several QTLs that were shown to influence six yield-related and two quality traits.ResultsA total of 47,472 single-nucleotide polymorphisms (SNPs) were detected for the RILs that were integrated into 2639 recombination bin units, with an average distance of 1.00 cM between adjacent markers. Forty seven QTLs for yield-related traits and 13 QTLs for grain quality traits were found to be distributed on 16 chromosomes in the 2 year studies. Among them, 18 QTLs were stable, and were identified in both analyses. Twenty six QTLs were identified for the first time, with a single QTL (qNN19a) in a 56 kb region explaining 32.56% of phenotypic variation, and an additional 10 of these were novel, stable QTLs. Moreover, 8 QTL hotpots on four different chromosomes were identified for the correlated traits.ConclusionsWith RAD-sequencing, some novel QTLs and important QTL clusters for both yield-related and quality traits were identified based on a new, high-density bin linkage map. Three predicted genes were selected as candidates that likely have a direct or indirect influence on both yield and quality in soybean. Our findings will be helpful for understanding common genetic control mechanisms of co-localized traits and to select cultivars for further analysis to predictably modulate soybean yield and quality simultaneously.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-017-3854-8) contains supplementary material, which is available to authorized users.

Key message This review provides a comprehensive atlas of QTLs, genes, and alleles conferring resistance to 28 important diseases in all major soybean production regions in the world. Abstract Breeding disease-resistant soybean [Glycine max (L.) Merr.] varieties is a common goal for soybean breeding programs to ensure the sustainability and growth of soybean production worldwide. However, due to global climate change, soybean breeders are facing strong challenges to defeat diseases. Marker-assisted selection and genomic selection have been demonstrated to be successful methods in quickly integrating vertical resistance or horizontal resistance into improved soybean varieties, where vertical resistance refers to R genes and major effect QTLs, and horizontal resistance is a combination of major and minor effect genes or QTLs. This review summarized more than 800 resistant loci/alleles and their tightly linked markers for 28 soybean diseases worldwide, caused by nematodes, oomycetes, fungi, bacteria, and viruses. The major breakthroughs in the discovery of disease resistance gene atlas of soybean were also emphasized which include: (1) identification and characterization of vertical resistance genes reside rhg1 and Rhg4 for soybean cyst nematode, and exploration of the underlying regulation mechanisms through copy number variation and (2) map-based cloning and characterization of Rps11 conferring resistance to 80% isolates of Phytophthora sojae across the USA. In this review, we also highlight the validated QTLs in overlapping genomic regions from at least two studies and applied a consistent naming nomenclature for these QTLs. Our review provides a comprehensive summary of important resistant genes/QTLs and can be used as a toolbox for soybean improvement. Finally, the summarized genetic knowledge sheds light on future directions of accelerated soybean breeding and translational genomics studies.

In this work, a type of doped carbon material with rich edged P atoms co-functionalized by O and N atoms was synthesized via simple solvothermal treatment of P2O5 in formamide,...

Although heteroatom doping and pore management separately influence the Li + adsorption and Li + diffusion properties, respectively, merging their functions into a single unit is intriguing and has not been fully investigated. Herein, we have successfully incorporated both heteroatom doping and pore management within the same functional unit of N 4 -vacancy motifs, which is realized via acid etching of formamide-derived Zn−N 4functionalized carbon materials (Zn 1 NC). The N 4 -vacancy-rich porous carbon (V-NC) renders multiple merits: (1) a high N content of 13.94 atom % for large Li-storage capacity, (2) edged unsaturated N sites favoring highly efficient Li + adsorption and desolvation, and (3) a shortening of the Li + diffusion length through N 4 vacancy, thereby enhancing the Li-storage kinetics and high-rate performance. This work serves as an inspiration for the creation of heteroatom-edged porous structures with controllable pore sizes for high-rate alkali-ion battery applications.

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