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Abstract Soybean is a major source of protein and edible oil worldwide. Originating from the Huang-Huai-Hai region, which has a temperate climate, soybean has adapted to a wide latitudinal gradient across China. However, the genetic mechanisms responsible for the widespread latitudinal adaptation in soybean, as well as the genetic basis, adaptive differentiation, and evolutionary implications of theses natural alleles, are currently lacking in comprehensive understanding. In this study, we examined the genetic variations of fourteen major gene loci controlling flowering and maturity in 103 wild species, 1048 landraces, and 1747 cultivated species. We found that E1, E3, FT2a, J, Tof11, Tof16, and Tof18 were favoured during soybean improvement and selection, which explained 75.5% of the flowering time phenotypic variation. These genetic variation was significantly associated with differences in latitude via the LFMM algorithm. Haplotype network and geographic distribution analysis suggested that gene combinations were associated with flowering time diversity contributed to the expansion of soybean, with more HapA clustering together when soybean moved to latitudes beyond 35°N. The geographical evolution model was developed to accurately predict the suitable planting zone for soybean varieties. Collectively, by integrating knowledge from genomics and haplotype classification, it was revealed that distinct gene combinations improve the adaptation of cultivated soybeans to different latitudes. This study provides insight into the genetic basis underlying the environmental adaptation of soybean accessions, which could contribute to a better understanding of the domestication history of soybean and facilitate soybean climate-smart molecular breeding for various environments.

Soybeans (Glycine max L.), originating in China, were introduced to South America in the late 19th century after passing through North America. South America is now a major soybean-producing region, accounting for approximately 40% of the global soybean production. Crops like soybeans gradually adapt to the local climate and human-selected conditions, resulting in beneficial variations during cultivation in different regions. Comparing the phenotypic and genetic variations in soybeans across different regions is crucial to determining the variations that may enhance soybean productivity. This study identified seed-related traits and conducted a genetic diversity analysis using 46 breeding soybean varieties from China and Uruguay. Compared to the Chinese soybean germplasm, the Uruguayan equivalent had a lower 100-grain weight, higher oil content, lower protein content, and higher soluble sugar content. Using ZDX1 gene chips, genetic typing was performed on the 46 breeding varieties. Cluster analysis based on SNP sites revealed significant differences in the genetic basis of Sino-Uruguayan soybean germplasm. Selection analysis, including nucleotide polymorphism (π) and fixation indexes (Fst), identified several genomic regions under selection between Sino-Uruguayan soybean germplasm. The selected intervals significantly enriched gene ontology (GO) terms related to protein metabolism. Additionally, differentiation occurred in genes associated with the oil content, seed weight, and cyst nematodes between Sino-Uruguayan soybean germplasm, such as GmbZIP123 and GmSSS1. These findings highlight the differences in seed-related phenotypes between Sino-Uruguay soybean germplasm and provide genomic-level insights into the mechanisms behind phenotypic differences, offering valuable references for understanding soybean evolution and molecular breeding.

Abstract This paper provides an analysis of China’s land border cultural heritage, aiming to offer guidance for its protection and development. The study compiled a comprehensive database of heritage sites and analyzed their mathematical characteristics based on quantity, type, and quality. The spatial pattern of the cultural heritage was described using kernel density analysis, spatial variability, and spatial correlation, while the driving mechanism was measured based on Geo-Detector model. The findings revealed that the land border areas of China have a total of 1227 cultural heritage, comprising two main types and 18 subtypes. National cultural heritage accounted for 22.74%, with ancient city ruins being the largest type of cultural heritage. The Southwest and Northeast regions of China exhibited high-high clusters and low-low clusters, respectively. Moreover, the study identified history of administrative succession, evolution of historical and cultural, altitude, distance from the city, population density, minority population ratio, urbanization process, and per capita GDP as significant factors impacting the spatial pattern of land border cultural heritage in China. Based on these findings, the study suggests that the government should invest more in border cultural heritage, improve transportation infrastructure in border areas, ensure dynamic inheritance and protection of cultural heritage, and promote the joint development of different types of cultural heritage. The research results will provide data support and decision-making reference for the sustainable development of cultural heritage in land border areas, and can provide a new perspective for the management of cultural heritage in similar areas.

Soybeans are grown worldwide owing to their protein, oil, and beneficial bioactive compounds. Genetic and environmental factors influence soybean seed isoflavones. In the present study, we profiled the seed isoflavones in world diverse soybean germplasm grown in two locations over two years in China. Significant differences (p < 0.001) were observed between the accessions, accession origins, seed coat colors, and maturity groups for individual and total isoflavone (TIF) content. TIF content of the soybean accessions ranged from 677.25 μg g−1 to 5823.29 μg g−1, representing an 8-fold difference. USA soybean accessions showed the highest mean TIF content (3263.07 μg g−1), followed by Japan (2521.26 μg g−1). Soybean with black seed coat showed the highest (3236.08 μg g−1) TIF concentration. Furthermore, isoflavone levels were significantly higher in late-maturity groups. Correlation analysis revealed significant positive associations between individual and TIF content. Malonyldaidzin and malonylgenistin showed higher correlations with TIF content (r = 0.92 and r = 0.94, respectively). The soybean accessions identified as having high and stable TIF content can be utilized in the food and pharmaceutical industries and breeding programs to develop soybean varieties with enhanced isoflavone content.

The assessment of suitability is the cornerstone for the development of ecotourism in nature reserves. This paper adopts the Delphi method to invite 30 experts to score and screen a series of indicators and then calculates the weight of each indicator through the hierarchical analysis method (AHP) to establish a comprehensive evaluation index system for the suitability of ecotourism development. The AHP method includes four constraints layers (tourism resources, socio-economic environment, ecological conditions, and tourism market), in addition to eleven element layers and thirty-eight indicators. It establishes overarching criteria for evaluating ecotourism suitability. Our research focuses on Dinghushan, Xilin Gol Grassland, Hongze Lake Wetland, and Jiuzhai valley, and the results are as follows: (1) Ecotourism suitability evaluation level is divided into five levels, level I (0 ≤ S < 30) ecotourism development suitability is the lowest, meaning an area is extremely unsuitable for ecotourism development. Level V (90 ≤ S < 100) has a very high ecotourism value, meaning an area is highly suitable for ecotourism development. (2) Jiuzhai valley scored the highest ecotourism suitability evaluation score of 87.63, and Xilingol Grassland scored the lowest score of 81.27. However, the composite scores of all the nature reserves were above 80, placing them at Suitability Level IV, and thereby indicating a high suitability for ecotourism development. (3) Divergences in ecotourism suitability emerge among various nature reserve types, with grassland and meadow reserves exhibiting lower suitability levels. Addressing this, a robust management and monitoring system is imperative, alongside intensified efforts in ecological restoration, vegetation protection, community engagement, education, awareness, and increased policy support and tourism capital investment. (4) The results of the expert questionnaire showed that the maximum weight of the indicators affecting the evaluation of the suitability of ecotourism was the satisfaction of tourists (0.120), and the minimum weight was the accommodation facilities (0.002), which illustrated the important role of tourists in the ecotourism development carried out in the nature reserve. (5) Through empirical analysis of numerous cases, the study validates the practicality and effectiveness of the index system and provides scientific guidelines for the suitability of existing nature reserves for further ecotourism development. This contributes to the research theory on the suitability evaluation of ecotourism development and serves as a valuable reference for the future ecotourism development of diverse nature reserves.

This article presents the data utilized in a study focused on identifying an optimal bus dispatching strategy in light of epidemic impacts. The study specifically examines the Xi'an Xiaozhai central business district (CBD) street network, which consists of 33 major signalized intersections and 112 bus stops associated with 12 bus routes. The dataset includes details of intersection and bus stop geospatial data, street segment and intersection design, intersection signal timing plans, bus route operational properties such as dispatching frequencies, fleet sizes, loading bay capacities, and bus-specific parameters. It also encompasses data on passenger boarding and alighting counts, as well as travelers’ origin and destination (O-D) locations, routes, and departure times during three time periods: 10:00-11:00 PM, 1:00-2:00 PM, and 7:00-8:00 PM on Monday, June 7, 2021. These times represent off-peak (10:00 PM–1:00 AM the next day), adjacent-to-peak (9:00–11:00 AM, 1:00–4:00 PM, and 8:00–10:00 PM), and peak (7:00–9:00 AM, 11:00 AM–1:00 PM, and 4:00–8:00 PM) periods, respectively. Data collection involves searching government and organizational records, utilizing Alibaba Cloud's Amap platform, conducting onsite measurements, and performing a field survey. The dataset is a valuable resource for studying the integrated operations of various urban mass transit services, including buses, bus rapid transit (BRT), and fixed guideway transit, under both normal and epidemic-affected travel conditions. Additionally, it can be used to investigate multimodal integrated urban passenger services offered by automobiles, transit, ridesharing, and active transportation modes.

As the most popular power source to energy storage equipment Lithium-ion battery (LIB), it has the advantages of high-energy density, high power, long cycle life, as well as low pollution output. However, owing to increased battery impedance under low-temperature conditions, the lithium-ion diffusion in the battery is reduced, and the polarization of the electrode materials is accelerated, resulting in poor electrochemical activity and a drop in capacity during cycling. This issue is greatly hindering the further advancement of LIBs. In this review, we comprehensively review the factors affecting the performance of LIBs at low temperatures and introduce key methods and related mechanisms for improving the capacity of various electrode materials. Our overview aims to fully elucidate the basic principles of the low-temperature property of LIBs from a material point of view and to facilitate the advancement of high-performance LIB electrode materials that can be used in the wide working temperature range.

IntroductionIsoflavones are the secondary metabolites synthesized by the phenylpropanoid biosynthesis pathway in soybean that benefits human and plant health.MethodsIn this study, we have profiled seed isoflavone content by HPLC in 1551 soybean accessions grown in Beijing and Hainan for two consecutive years (2017 and 2018) and in Anhui for one year (2017).ResultsA broad range of phenotypic variations was observed for individual and total isoflavone (TIF) content. The TIF content ranged from 677.25 to 5823.29 µg g-1 in the soybean natural population. Using a genome-wide association study (GWAS) based on 6,149,599 single nucleotide polymorphisms (SNPs), we identified 11,704 SNPs significantly associated with isoflavone contents; 75% of them were located within previously reported QTL regions for isoflavone. Two significant regions on chromosomes 5 and 11 were associated with TIF and malonylglycitin across more than 3 environments. Furthermore, the WGCNA identified eight key modules: black, blue, brown, green, magenta, pink, purple, and turquoise. Of the eight co-expressed modules, brown (r = 0.68***), magenta (r = 0.64***), and green (r = 0.51**) showed a significant positive association with TIF, as well as with individual isoflavone contents. By combining the gene significance, functional annotation, and enrichment analysis information, four hub genes Glyma.11G108100, Glyma.11G107100, Glyma.11G106900, and Glyma.11G109100 encoding, basic-leucine zipper (bZIP) transcription factor, MYB4 transcription factor, early responsive to dehydration, and PLATZ transcription factor respectively were identified in brown and green modules. The allelic variation in Glyma.11G108100 significantly influenced individual and TIF accumulation.DiscussionThe present study demonstrated that the GWAS approach, combined with WGCNA, could efficiently identify isoflavone candidate genes in the natural soybean population.

With the popularization of autonomous vehicle (AV) technology, mixed traffic flows that consist of AVs and human-driven vehicles (HDVs) will appear in the real world. Although many studies of the features of mixed traffic flow have been carefully evaluated, few studies have focused on the effect of aggressive driving performance on mixed traffic flow. This study aims to develop an approach to evaluate the effects of aggressive driving on the stability and capacity performance under the conditions of AV and HDV mixed traffic flow. First, since a car-following model can describe the relationship between vehicles, we calibrate a car-following model for aggressive driving and nonaggressive driving behaviors based on real traffic data and previous research results. Then, in a mixed traffic flow environment, a basic linear stability formula and capacity calculation expression are developed that consider the effects of vehicle order on the capacity. Finally, because the proportion of aggressive driving and aggressive driving parameters may change, nine combinations of three aggressive driving proportions and three driving parameter cases are used for the sensitivity analysis. The results indicate that the effect of aggressive driving on mixed traffic flow is complex. When the proportion of aggressive driving is less than 35%, the increase in the proportion of aggressive driving increases the traffic capacity and reduces the unstable part. However, when the proportion of aggressive driving is greater than 35%, the increase in the proportion of aggressive driving increases the unstable part. When the penetration rate of AVs exceeds 0.490, mixed traffic flow remains stable at all aggressive driving proportions. In addition, the capacity of a mixed traffic flow may be improved as the penetration rate of AVs increases. To a certain extent, these conclusions provide a theoretical basis for formulating different management modes of AVs and HDVs.

The current lake environmental problem of harmful cyanobacterial blooms cannot be mitigated effectively despite numerous eutrophication control strategies, and climate warming may have been considered as a potential key driver. However, it is still unclear how climate change and associated natural processes influence cyanobacterial development. Here we use a sedimentary pigment record from a remote, alpine, small and eutrophic lake (Lake Mayinghai) on the Chinese Loess Plateau and take the mid-Holocene as an analog to explore the possible influences of temperature, precipitation and terrestrial vegetation on in-lake and catchment processes, algal compositional changes and cyanobacterial development. The pigment data indirectly suggest that a distinctly low β-carotene to chlorophyll a ratio during the mid-Holocene is likely due to an increase in non-nitrogen-fixing colonial coccoid cyanobacteria at the expense of nitrogen-fixing filamentous cyanobacteria. There are two probable synergistic driving mechanisms, of which one is high temperatures and associated increased lake thermal stratification and the other is high inorganic nitrogen supply and resultant increased lake nitrogen to phosphorus ratio. This study provides implications for the potential influences of future climate change on cyanobacterial development under a warmer, wetter and re-forested environment on the Chinese Loess Plateau.

IntroductionGlobal malnutrition continues to be a canker owing to poor eating habits and over-reliance on the major staple crops. Vegetable soybean (maodou) is gaining popularity globally as an affordable snack and vegetable.MethodsIn this study, we profiled the nutritional composition of 12 soybean cultivars at the vegetable (R6-R7) and mature (R8) stages. We also conducted an RNA-seq analysis during seed development, focusing on key biosynthesis enzymes for quality traits.ResultsThe results showed that 100 g of maodou contained 66.54% moisture, 13.49% protein, 7.81% fatty acids, 2.47% soluble sugar, abundant content of minerals, and micronutrients, including folate (462.27 μg FW) and carotenoids (3,935.41 μg FW). Also, the isoflavone content of maodou ranged between 129.26 and 2,359.35 μg/g FW. With regard to the recommended daily allowance, 100 g fresh weight of maodou can contribute 26.98, 115.57, and 11.60% of protein, folate, and zinc, respectively, and significant proportions of other nutrients including linoleic acid (21.16%), linolenic acid (42.96%), zinc (11.60%), and iron (18.01%). On a dry weight basis, maodou has two to six folds higher contents of folate, tocopherol, and carotenoid than the mature soybean. Furthermore, RNA-seq analysis revealed that key biosynthesis enzymes of quality traits are differentially expressed during seed development and may contribute to variations in the content of quality traits at the vegetable and mature stages. Correlation analysis of quality traits at both stages revealed that protein only correlated positively with zinc at the vegetable stage but negatively correlated with total tocopherol and total fatty acid at the mature stage. Complex associations among folates, soluble sugar, and isoflavones were also identified.DiscussionThis study provides insight into the nutritional contents of vegetable soybean and demonstrates that maodou is essential for meeting the nutritional requirements of most countries.

Soybean cyst nematode (SCN) has devastating effects on soybean production, making it crucial to identify genes conferring SCN resistance. Here we employed next-generation sequencing-based bulked segregant analysis (BSA) to discover genomic regions, candidate genes, and diagnostic markers for resistance to SCN race 4 (SCN4) in soybean. Phenotypic analysis revealed highly significant differences among the reactions of 145 recombinant inbred lines (RILs) to SCN4. In combination with euclidean distance (ED) and Δsingle-nucleotide polymorphism (SNP)-index analyses, we identified a genomic region on Gm11 (designated as rhg1-paralog) associated with SCN4 resistance. Overexpression and RNA interference analyzes of the two candidate genes identified in this region (GmPLAC8 and GmSNAP11) revealed that only GmSNAP11 significantly contributes to SCN4 resistance. We developed a diagnostic marker for GmSNAP11. Using this marker, together with previously developed markers for SCN-resistant loci, rhg1 and Rhg4, we evaluated the relationship between genotypes and SCN4 resistance in 145 RILs and 30 soybean accessions. The results showed that all the SCN4-resistant lines harbored all the three loci, however, some lines harboring the three loci were still susceptible to SCN4. This suggests that these three loci are necessary for the resistance to SCN4, but they alone cannot confer full resistance. The GmSNAP11 and the diagnostic markers developed could be used in genomic-assisted breeding to develop soybean varieties with increased resistance to SCN4.

Tocopherol plays an important role as a powerful antioxidant in human beings and in plants. This study investigated the genetic basis of tocopherol content in soybean. A RIL population of 192 lines derived from 2 cultivars, ZH13 and ZH35, was evaluated for tocopherol content across 3 environments. QTL mapping identified 38 QTL for tocopherol, with stable QTL identified on Chromosomes 5 and 12. Ninety polymorphic genes were identified from these regions. Further SNP variation of a natural population identified 47 SNPs, with missense variants in 19 genes, including the heat shock transcription factor gene (GmHSFA8) and gamma-tocopherol methyltransferase (GmVTE4), potentially related to tocopherol accumulation in soybean. Haplotype analysis revealed significant variations in these missense variants in the natural population. This study provides insights into the genetic mechanisms underlying tocopherol content in soybean, which is important for breeding high tocopherol soybean cultivars.

Soybean cyst nematode (SCN, Heterodera glycines Ichinohe) is the most economically damaging disease of soybean worldwide, and breeding host plant resistance is the most feasible option for SCN management. In this review, we summarise the progress made so far in identifying nematode-resistance genes, the currently available sources of resistance, possible mechanisms of SCN resistance and strategies for soybean breeding. To date, only two sources of SCN resistance have been widely used, from the accessions PI 88788 and Peking, which has resulted in a shift in SCN resistance and created a narrow genetic base for SCN resistance. These resistant germplasms for SCN are classified into two types according to their copy number variation in a 31-kb genomic region: PI 88788-type resistance requires high copy numbers of a rhg1 resistance allele (rhg1-b) and Peking-type resistance requires both low copy numbers of a different rhg1 resistance allele (rhg1-a) and a resistant allele at another locus, Rhg4. Resistance related to rhg1 primarily involves impairment of vesicle trafficking through disruption of soluble NSF-attachment protein receptor (SNARE) complexes. By contrast, resistance via Rhg4 involves disturbance of folate homeostasis at SCN feeding sites due to alteration of the enzymatic activity of serine hydroxymethyltransferase (SHMT). Other potential mechanisms, including plant defences mediated by salicylic acid (SA) and jasmonic acid (JA) signalling modulation, have also been suggested for SCN resistance. Indeed, genome-wide association studies (GWAS) have identified other candidate SCN resistance genes, such as GmSNAP11. Although gene functional analysis in a transient expression system could increase the efficiency of candidate gene identification, information on novel genes and mechanisms for SCN resistance remains limited. Any beneficial candidate genes identified might, when fully exploited, be valuable for improving the efficiency of marker-assisted breeding and dissecting the molecular mechanisms underlying SCN resistance.

Folate deficiency is a significant global health issue that affects millions of people and causes severe adverse effects. Major staple crops, which provide significant amounts of calories, often contain inadequate folate levels. Synthetic fortification has contributed to a reduction in low-folate populations, but a more sustainable solution is needed. Biofortification, or the breeding of crops to naturally increase their nutrient content, is a promising alternative. Soybean is a highly nutritious crop and a good candidate for folate biofortification. However, studies on folate have been limited due to the challenges in folate analysis. The development of sensitive and selective tools, reference materials, and studies on the stability of folate vitamers in crops has facilitated the development of improved folate determination methods. Additionally, the soybean folate biofortification program can be improved by leveraging previous studies in major cereals, common bean and pea, as well as combining conventional breeding with new genomics approaches. In this review, we discuss the folate content, composition, and analytical challenges in soybean and suggest possible frameworks and strategies for folate biofortification in soybean. We also conducted an in silico analysis of key folate biosynthesis enzymes in soybean.

The scientific evaluation of tourism resources provides the basic conditions for the rational development and utilization of tourism resources, which is significant for the sustainable development of tourism. On the basis of obtaining a large sample of tourism resource data, this study constructed an evaluation index system of regional tourism resources from four aspects: quantity, type, grade, and a combination of regional tourism resources, taking the township scale as the spatial evaluation unit. The combination weighting method was used to evaluate the grade of tourism resources in each township, and the hierarchical clustering method and spatial autocorrelation method were used to analyze the spatial patterns of the tourism resource values. On the basis of the evaluation’s results and spatial pattern analysis, this paper analyzed the influencing factors of tourism resource patterns and puts forward a tourism development model suitable for Hainan tourism development. The results showed that the overall value of tourism resources on Hainan Island was low, and the spatial pattern was obviously different, showing that the northern piedmont plain area was higher than the southern hilly area, and the east coast area was higher than the west coast area. Based on the analysis of quantity density, type abundance, grade advantage, and spatial combination, the tourism resource values of Hainan Island was divided into four combination areas: the first area was diversity and good combination, the second area was large quantity and good combination, the third area was diversity and high-quality resources, and the fourth area was large quantity. In addition, from the analysis of the spatial agglomeration effect, the phenomena of high and low agglomerations of tourism resource values were obvious. Finally, this paper puts forward a tourism development model for Hainan Island by grading, classification, and zoning. The results of this study can determine the time sequence and mode of regional tourism resources development and provide spatial implications and suggestions for regional tourism planning and management.

The stability of soybean (Glycine max L. Merrill) oil is determined mainly by its fatty acid (FA) composition. We evaluated the FA composition of 1025 Chinese soybean accessions collected from diverse ecoregions and grown in multiple locations and years. We observed highly significant differences (P

This study aims to explore factors affecting passenger car and truck driver injury severity in passenger car-truck crashes. Police-reported crash data from 2007 to 2017 in Canada are collected. Two-vehicle crashes involving one truck and one passenger car are extracted for modeling. Different injury severities are not equally represented. To address the data imbalance issue, this study applies four different data imbalance treatment approaches, including over-sampling, under-sampling, a hybrid method, and a cost-sensitive learning method. To test the performances of different classifiers, five classification models are used, including multinomial logistic regression, Naive Bayes, Classification and Regression Tree, support vector machine, and eXtreme Gradient Boosting (XGBoost). In both the passenger car driver and truck driver injury severity analysis, XGBoost combined with cost-sensitive learning generates the best results in terms of G-mean, area under the curve, and overall accuracy. Additionally, the Shapley Additive Explanations (SHAP) approach is adopted to interpret the result of the best-performing model. Most of the explanatory variables have similar effects on passenger car and truck driver fatality risks. Nevertheless, six variables exhibit opposite effects, including the age of the passenger car driver, crash hour, the passenger car age, road surface condition, weather condition and the truck age. Results of this study could provide some valuable insights for improving truck traffic safety. For instance, properly installing traffic control devices could be an effective way to reduce fatality risks in passenger car-truck crashes. Besides, passenger car drivers should be extremely cautious when driving between midnight to 6 am on truck corridors.

Soybean seeds are primary sources of natural tocopherols used by the food and pharmaceutical industries, owing to their beneficial impacts on human health. Selection for higher tocopherol contents in seeds along with other desirable traits is an important goal in soybean breeding. In order to identify the genomic loci and candidate genes controlling tocopherol content in soybean seeds, the bulked-segregant analysis technique was performed using a natural population of soybean consisting of 1525 accessions. We constructed the bulked-segregant analysis based on 98 soybean accessions that showed extreme phenotypic variation for the target trait, consisting of 49 accessions with extremely-high and 49 accessions with extremely-low tocopherol content. A total of 144 variant sites and 109 predicted genes related to tocopherol content were identified, in which a total of 83 genes were annotated by the gene ontology functions. Furthermore, 13 enriched terms (p < 0.05) were detected, with four of them found to be highly enriched: response to lipid, response to abscisic acid, transition metal ion transmembrane transporter activity, and double-stranded DNA binding. Especially, six candidate genes were detected at 41.8–41.9 Mb genomic hotspots on chromosome 5 based on ANNOtate VARiation analysis. Among the genes, only Glyma.05G243400 carried a non-synonymous mutation that encodes a “translation elongation factor EF1A or initiation factor IF2gamma family protein” was identified. The haplotype analysis confirmed that Glyma.05G243400 exhibited highly significant variations in terms of tocopherol content across multiple experimental locations, suggesting that it can be the key candidate gene regulating soybean seed tocopherols. The present findings provide novel gene resources related to seed tocopherols for further validation by genome editing, functional characterization, and genetic improvement targeting enhanced tocopherol composition in soybean molecular breeding.

Soybean (Glycine max (L.) Merrill) seeds are abundant in physiologically active metabolites, including carotenoids and chlorophylls, and are used as an affordable source of functional foods that promote and maintain human health. The distribution and variation of soybean seed metabolites are influenced by plant genetic characteristics and environmental factors. Here, we investigated the effects of germplasm origin, genotype, seed coat color and maturity group (MG) on the concentration variation of carotenoid and chlorophyll components in 408 soybean germplasm accessions collected from China, Japan, the USA and Russia. The results showed that genotype, germplasm origin, seed color, and MG were significant variation sources of carotenoid and chlorophyll contents in soybean seeds. The total carotenoids showed about a 25-fold variation among the soybean germplasms, with an overall mean of 12.04 µg g−1. Russian soybeans yielded 1.3-fold higher total carotenoids compared with Chinese and Japanese soybeans. Similarly, the total chlorophylls were substantially increased in Russian soybeans compared to the others. Soybeans with black seed coat color contained abundant concentrations of carotenoids, with mainly lutein (19.98 µg g−1), β-carotene (0.64 µg g−1) and total carotenoids (21.04 µg g−1). Concentrations of lutein, total carotenoids and chlorophylls generally decreased in late MG soybeans. Overall, our results demonstrate that soybean is an excellent dietary source of carotenoids, which strongly depend on genetic factors, germplasm origin, MG and seed coat color. Thus, this study suggests that soybean breeders should consider these factors along with environmental factors in developing carotenoid-rich cultivars and related functional food resources.

We investigate the dynamic performance of traffic flow using a modified optimal velocity car-following model. In the car-following scenarios, the following vehicle must continuously adjust the following distance to the preceding vehicle in real time. A new optimal velocity function incorporating the desired safety distance instead of a preset constant is presented first to describe the abovementioned car-following behavior dynamically. The boundary conditions of the new optimal velocity function are theoretically analyzed. Subsequently, we propose an improved car-following model by combining the heterogeneity of driver’s sensitivity based on the new optimal velocity function and previous car-following model. The stability criterion of the improved model is obtained through the linear analysis method. Finally, numerical simulation is performed to explore the effect of the desired safety distance and the heterogeneity of driver’s sensitivity on the traffic flow. Results show that the proposed model has considerable effects on improving traffic stability and suppressing traffic congestion. Furthermore, the proposed model is compatible with the heterogeneity of driver’s sensitivity and can enhance the average velocity of traffic flow compared with the conventional model. In conclusion, the dynamic performance of traffic flow can be improved by considering the desired safety distance and the heterogeneity of driver’s sensitivity in the car-following model.

Exploring the spatial pattern of tourism resources and tourism economy is vital to improve the utilization efficiency of tourism resources and promote sustainable tourism development. This research investigated the quantity and types of tourism resources and analyzed the spatial patterns of tourism resources on Hainan Island from the perspectives of spatial variation and spatial association. The spatial and temporal pattern of the number of tourists and tourism revenue during 2010-2019 were further analyzed. The influencing factors of tourism development were explored based on the geographic detector. The results showed that 10425 tourism resources exist on Hainan Island, and the type of buildings and facilities had the largest number of tourism resources. The geological landscape, astronomical phenomena and meteorological landscapes, buildings and facilities, ruins and remains, tourism commodities, and human activities showed significant spatial agglomeration. Domestic tourism was far more developed than inbound tourism in terms of the number of tourists and tourism revenue. However, the spatial difference of tourism resources and tourism economy was apparent on Hainan Island. Factor analysis showed that the quantity of hotels, the proportion of tertiary industry in the GDP, and the regional population were the most influential factors for the distribution of tourism resources, while the density of the road network, the quantity of hotels, the per capita GDP, the proportion of tertiary industry in GDP, the regional population, and the quantity of tourism resources showed obvious influences on the tourism economy of Hainan Island. Interactions of the factors mainly fell into three types: synergistic increases, single factor weakening, and nonlinear weakening. It is suggested that the local government should fully exploit diversity types of tourism resources on Hainan Island to attract more tourists and improve the tourism revenue; improving the inbound tourism, and to strengthen the construction of road network on Hainan Island.

Tocopherols are natural antioxidants that increase the stability of fat-containing foods and are well known for their health benefits. To investigate the variation in seed tocopherol composition of soybeans from different origins, 493 soybean accessions from different countries (China, USA, Japan, and Russia) belonging to 7 maturity groups (MG 0–VI) were grown in 2 locations (Beijing and Hainan Provinces of China) for 2 years (2017 and 2018). The results showed that significant differences (p < 0.001) were observed among the accessions and origins for individual and total tocopherol contents. The total tocopherol content ranged from 118.92 μg g−1 to 344.02 μg g−1. Accessions from the USA had the highest average concentration of γ- and total tocopherols (152.92 and 238.21 μg g−1, respectively), whereas a higher level of α-tocopherol (12.82 μg g−1) was observed in the Russian accessions. The maturity group of the accession significantly (p < 0.001) influenced all tocopherol components, and higher levels of α-, γ-, and total tocopherols were observed in early maturing accessions, while late-maturing accessions exhibited higher levels of δ-tocopherol. The inclination of tocopherol concentrations with various MGs provided further evidence of the significance of MG in soybean breeding for seed tocopherol components. Furthermore, the correlation between the seed tocopherol components and geographical factors revealed that α-, γ-, and total tocopherols had significant positive correlations with latitude, while δ-tocopherol showed an opposite trend. The elite accessions with high and stable tocopherol concentrations determined could be used to develop functional foods, industrial materials, and breeding lines to improve tocopherol composition in soybean seeds.

Soybean is one of the most important oilseed crops worldwide. Fertilization severely restricts the yield potential of soybean in the arid regions of Northwest China. A two-year field experiment was conducted to investigate the effects of fertilization on soybean yield in arid areas under a drip irrigation system. The treatment consisted of 14 fertilizer combinations comprising of four rates each of nitrogen (N) (0, 225, 450, and 675 kg ha−1), phosphorus (P) (0, 135, 270, and 405 kg ha−1), and potassium (K) (0, 75, 150, and 225 kg ha−1). The results revealed that grain yield was more sensitive to N fertilizer than to P and K fertilizers. The P and K fertilizers influenced harvest index and biomass, respectively. The optimized combination of fertilizers for high yield, as well as biological and quality traits was obtained by quadratic polynomial regression analysis. The theoretical grain yields based on the performed statistical calculations and plant biomass were greater than 7.21 tons ha−1 and 16.38 tons ha−1 with 300,000 plants ha−1 and were obtained under a fertilization combination of 411.62–418.39 kg ha−1 N, 153.97−251.03 kg ha−1 P2O5, and 117.77−144.73 kg ha−1 K2O. Thus, our findings will serve as a guideline for an effective fertilizer application in order to achieve a balance between grain yield and plant biomass as well as to contribute to the promotion of large-scale cultivation of soybean under drip irrigation.

With the implementation of the Belt and Road Initiative and the national strategy of "Ecological Protection and High-Quality Development in the Yellow River Basin", the tourism development of the Yellow River basin of China is facing important opportunity. However, the spatial differences of tourism economy and the unbalanced development of interprovincial resources has become a threat for the sustainable development of the basin. By using the statistical data from 2003 to 2018, this paper aims to identify the numerical feature and spatial patterns of tourism development in the Yellow River Basin from the aspects of tourist volume (domestic tourists and inbound tourists) and tourism income (income from domestic tourism and inbound tourism) at provincial and prefectural scales. Analysis of spatial autocorrelation reveals significant clusters and outliers of tourist volume and tourism income at prefectural scale. Location condition, terrain condition, culture resources, regional policies, the interregional relationship and tourism infrastructure were the main factors influencing the spatial differences of tourism development in the Yellow River Basin. The study could offer useful information for the regional tourism management in the Yellow River Basin.

This paper introduces an improved car-following speed (CFS) model that simultaneously considers speed of the lead vehicle, vehicle spacing, and driver’s sensitivity to them. Specifically, the proposed model extends the Helbing-Tilch model and Yang et al. model developed based on the principle of grey relational analysis where vehicle spacing is considered as the primary factor contributing to car-following speed choices. A computational experiment is conducted for model calibration using vehicle spacing, speed, and acceleration data derived from vehicle trajectory data of the Next Generation Simulation (NGSIM) project sponsored by the Federal Highway Administration (FHWA). It shows that speed of the lead vehicle and vehicle spacing significantly affect speed of the lag vehicle. Further, model validation is carried out using an independent NGSIM dataset by comparing vehicle speed predictions made by the calibrated CFS model with Helbing-Tilch model and Yang et al. model as benchmarks. Compared with speed prediction results of the benchmark models, mean relative errors, root mean square errors, and equal coefficient of speed predictions of the CFS model have reduced by 72.41% and 61.85%, 70.14% and 57.99%, and 33.15% and 14.48%, respectively. The findings of model validation reveal that the CFS model could improve the accuracy of speed predictions in the car-following process.

Soybean isoflavones are essential secondary metabolites synthesized in the phenylpropanoid pathway and benefit human health. In the present study, high-resolution QTL mapping for isoflavone components was performed using specific-locus amplified fragment sequencing (SLAF-seq) with a recombinant inbred line (RIL) population (F5:7) derived from a cross between two cultivated soybean varieties, Luheidou 2 (LHD2) and Nanhuizao (NHZ). Using a high-density genetic map comprising 3541 SLAF markers and the isoflavone contents of soybean seeds in the 200 lines in four environments, 24 stable QTL were identified for isoflavone components, explaining 4.2%–21.2% of phenotypic variation. Of these QTL, four novel stable QTL (qG8, qMD19, qMG18, and qTIF19) were identified for genistin, malonyldaidzin, malonylgenistin, and total isoflavones, respectively. Gene annotation revealed three genes involved in isoflavone biosynthesis (Gm4CL, GmIFR, and GmCHR) and 13 MYB-like genes within genomic regions corresponding to stable QTL intervals, suggesting candidate genes underlying these loci. Nine epistatic QTL were identified for isoflavone components, explaining 4.7%–15.6% of phenotypic variation. These results will facilitate understanding the genetic basis of isoflavone accumulation in soybean seeds. The stable QTL and tightly linked SLAF markers may be used for marker-assisted selection in soybean breeding programs. Keywords: Soybean (Glycine max L. Merrill), QTL mapping, Isoflavones, Specific-locus amplified fragment sequencing (SLAF-seq)

In order to ensure an ongoing and long-term breeding progress of soybean, stable sources of major quality traits across multi-environments need to be identified. Here, a panel of 135 soybean genotypes was tested in three different Chinese environments, including Beijing, Anhui, and Hainan during the 2017 and 2018 growing seasons to identify stable genotypes for cultivation under varying environmental conditions. The weighted average of absolute scores biplot (WAASB) for the best linear unbiased predictions of the genotype-environment interaction and multi-trait stability index (MTSI) were utilized to determine the stability of the soybeans for seven seed composition traits viz; protein content, oil content, and five fatty acids (palmitic, stearic, oleic, linoleic, and linolenic acids). Based on the WAASB index, the following genotypes were identified as stable genotypes for some specific traits; ZDD12828 and ZDD12832 for protein content, WDD01583 and WDD03025 for oil content, ZDD23040 for palmitic acid, WDD00033 for stearic acid, ZDD23822 for oleic acid, ZDD11183 for linoleic acid, and ZDD08489 for linolenic acid. Furthermore, based on MTSI at a selection intensity of 10%, 14 soybean genotypes were selected for their average performance and stability. Overall, the MTSI was shown to be a powerful and simple tool for identifying superior genotypes in terms of both performance and stability, hence, identifying stable soybean genotypes for future breeding programs of quality traits.

Soybean contains nutritional bioactive compounds, including carotenoids associated with human health benefits. Carotenoids are applicable in pharmaceuticals/nutreceuticals, cosmetic, and mainly food industries. However, an efficient and accurate method for carotenoid and chlorophyll detection and quantification has not yet been developed and validated for soybean seeds. The need for a rapid and reliable analysis method has become increasingly important. Thus, this study was initiated to develop and validate a simple, rapid, and selective reversed-phase high-performance liquid chromatographic (RP-HPLC) method for the simultaneous determination of lutein, zeaxanthin, α-carotene, β–carotene, β–cryptoxanthin, and chlorophyll–a and –b in soybean flour sample (100.00 mg) extracted using ethanol-acetone (1:1) solvents at a volume of 1.50 mL. Interestingly, the effective separation technique was achieved using the mobile phases of methyl tert-butyl ether, methanol containing 10 mM ammonium acetate, and water delivered at a 0.90 mL min−1 flow rate through a C30YMC Carotenoid (250 × 4.6 mm I.D., S-5 µm) column coupled with a UV-VIS detector set at 450 nm. The detector response was linear from 0.05–30.00 μg mL−1 with a coefficient of determination (R2) of 0.9993–0.9999. The validated method was sensitive with a detection limit (LOD) of 0.0051–0.0300 μg mL−1 and 0.0155–0.0909 μg mL−1 for the quantification limit (LOQ). The recovery values were from 83.12–106.58%, and the repeatability precision ranged from 1.25–4.20% and 0.15–0.81% for the method and system, respectively. The method showed adequate precision with a relative standard deviation smaller than 3.00%. This method was also found to be applicable for profiling carotenoids and chlorophylls in other legumes. In summary, this method was successfully implemented for qualitative and quantitative determination of major carotenoids and chlorophylls in soybean and other legume seeds, which are beneficial to food industry and quality breeding programs to meet human nutrition demands globally.

As part of the cultural landscape, administrative toponyms do not only reflect natural and sociocultural phenomena, but also help with related management and naming work. Historically, county-level administrative districts have been stable and basic administrative regions in China, playing a role in the country's management. We explore the spatio-temporal evolutionary characteristics of the county-level administrative toponyms cultural landscape in China's eastern plains areas. A Geographical Information System (GIS) analysis, Geo-Informatic Tupu, Kernel Density Estimation, and correlation coefficients were conducted. We constructed a GIS database of county-level administrative toponyms from the Sui dynasty onward using the Northeast China, North China, and Yangtze Plains as examples. We then summarized the spatio-temporal evolutionary characteristics of the county-level administrative toponyms cultural landscape in China's eastern plains areas. The results indicate that (1) the number of toponyms has roughly increased over time; (2) toponym densities on the three plains are higher than the national average in the corresponding timeframe since the Sui; and (3) county-level administrative toponyms related to mountains and hydrological features accounted for more than 30% of the total in 2010. However, the percentage of county-level administrative toponyms related to natural factors on the three plains has decreased since the Sui. To explore the factors influencing this spatio-temporal evolution, we analyzed the correlations between the toponyms and natural factors and human/social factors. The correlation degree between toponym density and population density is the highest, and that between toponym density and Digital Elevation Model (DEM) the lowest. Temperature changes were important in toponym changes, and population changes have influenced toponym changes over the last 400 years in China.

The traffic flow prediction is becoming increasingly crucial in Intelligent Transportation Systems. Accurate prediction result is the precondition of traffic guidance, management, and control. To improve the prediction accuracy, a spatiotemporal traffic flow prediction method is proposed combined with k-nearest neighbor (KNN) and long short-term memory network (LSTM), which is called KNN-LSTM model in this paper. KNN is used to select mostly related neighboring stations with the test station and capture spatial features of traffic flow. LSTM is utilized to mine temporal variability of traffic flow, and a two-layer LSTM network is applied to predict traffic flow respectively in selected stations. The final prediction results are obtained by result-level fusion with rank-exponent weighting method. The prediction performance is evaluated with real-time traffic flow data provided by the Transportation Research Data Lab (TDRL) at the University of Minnesota Duluth (UMD) Data Center. Experimental results indicate that the proposed model can achieve a better performance compared with well-known prediction models including autoregressive integrated moving average (ARIMA), support vector regression (SVR), wavelet neural network (WNN), deep belief networks combined with support vector regression (DBN-SVR), and LSTM models, and the proposed model can achieve on average 12.59% accuracy improvement.

Model-based quantitative reconstruction of past plant cover in Europe has shown great potential for: (i) testing hypotheses related to Holocene vegetation dynamics, biodiversity, and their relationships with climate and land use; (ii) studying long term interactions between climate and land use. Similar model-based quantitative reconstruction of plant cover in China has been restricted due to the lack of standardized datasets of existing estimates of relative pollen productivity (RPP). This study presents the first synthesis of all RPP values available to date for 39 major plant taxa from temperate China and proposes standardized RPP datasets that can be used for model-based quantitative reconstructions of past plant cover using fossil pollen records for the region. We review 11 RPP studies in temperate China based on modern pollen and related vegetation data around the pollen samples. The study areas include meadow, steppe and desert vegetation, various woodland types, and cultural landscapes. We evaluate the strategies of each study in terms of selection of study areas and distribution of study sites; pollen- and vegetation-data collection in field; vegetation-data collection from satellite images and vegetation maps; and data analysis. We compare all available RPP estimates, select values based on precise rules and calculate mean RPP estimates. We propose two standardized RPP datasets for 31 (Alt1) and 29 (Alt2) plant taxa. The ranking of mean RPPs (Alt-2) relative to Poaceae (= 1) for eight major taxa is: Artemisia (21) > Pinus (18.4) > Betula (12.5) > Castanea (11.5) > Elaeagnaceae (8.8) > Juglans (7.5) > Compositae (4.5) > Amaranthaceae/Chenopodiaceae (4). We conclude that although RPPs are comparable between Europe and China for some genera and families, they can differ very significantly, e.g., Artemisia, Compositae, and Amaranthaceae/Chenopodiaceae. For some taxa, we present the first RPP estimates e.g. Castanea, Elaeagnaceae, and Juglans. The proposed standardized RPP datasets are essential for model-based reconstructions of past plant cover using fossil pollen records from temperate China.

Distinctness, uniformity and stability (DUS) testing of cultivars through morphological descriptors is an important and compulsory part of soybean breeding. Molecular markers are usually more effective and accurate in describing the genetic features for the identification and purity assessment of cultivars. In the present study, we assessed the distinctness and uniformity of five soybean cultivars using both single nucleotide polymorphism (SNP) markers developed by specific-locus amplified fragment sequencing (SLAF-seq) technology, and simple sequence repeat (SSR) markers. The phylogenetic tree and principal component analysis (PCA) from both the SLAF-seq and SSR methods showed a clear distinction among cultivars Zhonghuang 18, Zhonghuang 68 and Zhonghuang 35, while no clear distinction was observed between cultivars Zhonghuang 13 and Hedou 13. Using the SLAF-seq method, we determined the proportion of homozygous loci for the five soybean cultivars. The heterozygosity of each individual plant was estimated for the assessment of cultivar purity and the purity levels of the five soybean cultivars ranged from 91.89% to 93.96%. To further validate the applicability of the SLAF-seq approach for distinctness testing, we used the SNP information of 150 soybean cultivars with different origins. The cultivars were also distinguished clearly. Taken together, SLAF-seq can be used as an accurate and reliable method in the assessment of the distinctness and uniformity of soybean cultivars.

Soybean (Glycine max L. Merr.) is one of the most important crops in the world. Its major content of vegetable oil made it widely used for human consumption and several food industries. To investigate the variation in seed fatty acid composition of soybeans from different origins, a set of 633 soybean accessions originated from four diverse germplasm collections—including China, United States of America (USA), Japan, and Russia—were grown in three locations, Beijing, Anhui, and Hainan for two years. The results showed significant differences (P < 0.001) among the four germplasm origins for all fatty acid contents investigated. Higher levels, on average, of palmitic acid (PA) and linolenic acid (LNA) were observed in Russian germplasm (12.31% and 8.15%, respectively), whereas higher levels of stearic acid (SA) and oleic acid (OA) were observed in Chinese germplasm (3.95% and 21.95%, respectively). The highest level of linoleic acid (LA) was noticed in the USA germplasm accessions (56.34%). The largest variation in fatty acid composition was found in LNA, while a large variation was observed between Chinese and USA germplasms for LA level. Maturity group (MG) significantly (P < 0.0001) affected all fatty acids and higher levels of PA, SA, and OA were observed in early maturing accessions, while higher levels of LA and LNA were observed in late maturing accessions. The trends of fatty acids concentrations with different MG in this study further provide an evidence of the importance of MG in breeding for such soybean seed components. Collectively, the unique accessions identified in this study can be used to strengthen the soybean breeding programs for meeting various human nutrition patterns around the globe.

A hit-and-run (HR) crash occurs when the driver of the offending vehicle flees the crash scene without reporting it or aiding the victims. The current study aimed at contributing to existing literatures by comparing factors which might affect the crash severity in HR and non-hit-and-run (NHR) crashes. The data was extracted from the police-reported crash data from September 2017 to August 2018 within the City of Chicago. Two multinomial logistic regression models were established for the HR and NHR crash data, respectively. The odds ratio (OR) of each variable was used to quantify the impact of this variable on the crash severity. In both models, the property damage only (PDO) crash was selected as the reference group, and the injury and fatal crash were chosen as the comparison group. When the injury crash was taken as the comparison group, it was found that 12 variables contributed to the crash severities in both HR and NHR model. The average percentage deviation of OR for these 12 variables was 34%, indicating that compared with property damage, HR crashes were 34% more likely to result in injuries than NHR crashes on average. When fatal crashes were chosen as the comparison group, 2 variables were found to be statistically significant in both the HR and the NHR model. The average percentage deviation of OR for these 2 variables was 127%, indicating that compared with property damage, HR crashes were 127% more likely to result in fatalities than NHR crashes on average.

Red light running at signalized intersections is a major safety concern in the United States. Statistics show that approximately 45 percent of crashes at intersections caused by red light running result in severe injuries and fatalities, while only approximately 30 percent of all other types of intersection crashes cause injuries or fatalities. Over the past decade, many US cities and counties have deployed red light running photo enforcement systems for signalized intersections within their jurisdictions to potentially reduce red light running related crashes. This study proposes an empirical Bayesian (EB) before-after analysis method that computes a weighed sum of crashes observed in the field and crashes predicted by safety performance functions (SPFs) to mitigate regression-to-mean biases for analyzing crash reduction effects of red light running enforcement. The analysis explicitly considers red light running related crash types, including head-on, rear-end, angle, turning, sideswipe in the same direction, and sideswipe in the opposite direction; and crash severity levels classified as fatal, injury, and property damage only (PDO). A computational study is conducted to examine the effectiveness of the Chicago program with red light running photo enforcement systems deployed for nearly two hundred signalized intersections. It is revealed that the use of red light running photo enforcement on the whole is positive, as demonstrated by reductions in all types of fatal crashes by 4–48 percent, and injury-related angle crashes by 1 percent. However, it slightly raises PDO-related angle crashes and moderately increases injury and PDO related rear-end crashes. The safety effectiveness of red light running photo enforcement is sensitive to intersection location.

BACKGROUND: Cynanchum komarovii Al Iljinski is a desert plant that has been used as analgesic, anthelminthic and antidiarrheal, but also as a herbal medicine to treat cholecystitis in people. We have found that the protein extractions from C. komarovii seeds have strong antifungal activity. There is strong interest to develop protein medication and antifungal pesticides from C. komarovii for pharmacological or other uses. METHODOLOGY/PRINCIPAL FINDINGS: An antifungal protein with sequence homology to thaumatin-like proteins (TLPs) was isolated from C. komarovii seeds and named CkTLP. The three-dimensional structure prediction of CkTLP indicated the protein has an acid cleft and a hydrophobic patch. The protein showed antifungal activity against fungal growth of Verticillium dahliae, Fusarium oxysporum, Rhizoctonia solani, Botrytis cinerea and Valsa mali. The full-length cDNA was cloned by RT-PCR and RACE-PCR according to the partial protein sequences obtained by nanoESI-MS/MS. The real-time PCR showed the transcription level of CkTLP had a significant increase under the stress of abscisic acid (ABA), salicylic acid (SA), methyl jasmonate (MeJA), NaCl and drought, which indicates that CkTLP may play an important role in response to abiotic stresses. Histochemical staining showed GUS activity in almost the whole plant, especially in cotyledons, trichomes and vascular tissues of primary root and inflorescences. The CkTLP protein was located in the extracellular space/cell wall by CkTLP::GFP fusion protein in transgenic Arabidopsis. Furthermore, over-expression of CkTLP significantly enhanced the resistance of Arabidopsis against V. dahliae. CONCLUSIONS/SIGNIFICANCE: The results suggest that the CkTLP is a good candidate protein or gene for contributing to the development of disease-resistant crops.

The analysis of the spatial distribution of tourism resources and the identification of its influencing factors are crucial for supporting the sustainable development of regional tourism. This study established a comprehensive database of tourism resources in Ningxia Hui Autonomous Region (Ningxia) through a combination of literature review and field research. It examined the quantitative, qualitative, and categorical characteristics of tourism resources in Ningxia, and determined the spatial patterns based on kernel density and spatial association analysis. This study also comprehensively evaluated the societal, economic, and environmental factors influencing the spatial distribution of tourism resources in the entire region by employing the geographical detector model to quantify the influence of each factor. The following results were obtained. (1) There were 29218 individual tourism resources in Ningxia, comprising eight main types, 23 subtypes, and 105 fundamental types, and they exhibit a hierarchical pyramidal structure. (2) The tourism resources in Ningxia displayed characteristics of "widespread regional dispersion and limited regional agglomeration". The spatial distribution of tourism resources was highly imbalanced, and most types of tourism resources exhibit strong positive spatial correlation. (3) The altitude, annual precipitation, population density, distance from urban centers, urbanization rate, and per capita GDP were identified as significant factors influencing the spatial distribution of tourism resources in Ningxia. Based on the results, we recommend that the government should formulate tourism development policies in Ningxia based on local conditions to effectively address the spatial imbalances, enhance the sustainability of tourism development, and continue to promote high-quality tourism development in Ningxia. [ABSTRACT FROM AUTHOR]