[Genetic background of lily germplasm resources based on SSR markers]

To study the genetic background of lily (Lilium spp.) germplasm resources, and accurately evaluate and select excellent germplasm for genetic improvement of lily, we analyzed the genetic background of 62 lily germplasm accessions from 11 provinces of China by using simple sequence repeat (SSR) molecular markers. The results showed that 15 out of 83 pairs of lily SSR primers were polymorphic. A total of 157 allelic loci were amplified, with the number of alleles per locus ranging from 5 to 19 and the average number of effective alleles per locus being 4.162 8. The average observed heterozygosity and expected heterozygosity were 0.228 2 and 0.694 1, respectively. The average polymorphic information content was 0.678 8. The average Nei's diversity index and Shannon's information index were 0.694 1 and 1.594 9, respectively, indicating that the tested lily germplasm had high genetic diversity. The 62 germplasm accessions were classified into 5 groups by the unweighted pair group method with arithmetic mean (UPGMA) and into 3 groups by the principal component analysis. The two analyses revealed a geographic correlation among different groups. The majority of lily germplasm accessions from the same source tended to cluster together. The population structure analysis classified the lily accessions into 4 populations and 1 mixed population. The above results provide a theoretical basis and genetic resources for the precise identification and breeding of lily germplasm resources.

Bringing Barley Back: Analysis of Heritage Varieties for Use as Germplasm Sources to Improve Resistance against the Most Devastating, Contemporary Disease in Canada, Fusarium Head Blight (Fusarium graminearum)

Fusarium head blight (FHB), caused by Fusarium graminearum, is currently the most devastating disease for barley (Hordeum vulgare) in Canada. Associated mycotoxins can compromise grain quality, where deoxynivalenol (DON) is considered particularly damaging due to its frequency of detection. Breeding barley with a lower DON content is difficult, due to the poor adaptation and malt quality of resistance sources. A set of European-derived heritage varieties were screened in an FHB nursery in Charlottetown, PE, with selections tested at Brandon, MB, between 2018-2022. Genetic evaluation demonstrated a distinct clustering of Canadian varieties from the heritage set. At Brandon, 72% of the heritage varieties ranked lower for DON content than did the moderately resistant Canadian check 'AAC Goldman', but resistance was associated with later heading and taller stature. In contrast with Canadian modern malting variety 'AAC Synergy', general deficiencies were observed in yield, enzyme activity, and extract, along with higher protein content. Nonetheless, several resistant varieties were identified with reasonable a heading date and yield, including 'Chevallier Chile', 'Domen', 'Djugay', 'Hannchen', 'Heils Franken', 'Moravian Barley', 'Loosdorfer' with 'Golden Melon', 'Nutans Moskva', and 'Vellavia', these being some of the most promising varieties when malting quality characteristics were also considered. These heritage resources could be used as parents in breeding to develop FHB-resistant malting barley varieties.

Current progress in research focused on salt tolerance in Vitis vinifera L

Soil salinization represents an increasingly serious threat to agronomic productivity throughout the world, as rising ion concentrations can interfere with the growth and development of plants, ultimately reducing crop yields and quality. A combination of factors is driving this progressive soil salinization, including natural causes, global climate change, and irrigation practices that are increasing the global saline-alkali land footprint. Salt stress damages plants both by imposing osmotic stress that reduces water availability while also inducing direct sodium- and chlorine-mediated toxicity that harms plant cells. Vitis vinifera L. exhibits relatively high levels of resistance to soil salinization. However, as with other crops, grapevine growth, development, fruit yields, and fruit quality can all be adversely affected by salt stress. Many salt-tolerant grape germplasm resources have been screened in recent years, leading to the identification of many genes associated to salt stress and the characterization of the mechanistic basis for grapevine salt tolerance. These results have also been leveraged to improve grape yields through the growth of more tolerant cultivars and other appropriate cultivation measures. The present review was formulated to provide an overview of recent achievements in the field of research focused on grapevine salt tolerance from the perspectives of germplasm resource identification, the mining of functional genes, the cultivation of salt-tolerant grape varieties, and the selection of appropriate cultivation measures. Together, we hope that this systematic review will offer insight into promising approaches to enhancing grape salt tolerance in the future.

[DNA barcode screening, identification of germplasm resources, and analysis of genetic diversity of Anemarrhena asphodeloides]

Anemarrhena asphodeloides is a common medicinal material used in clinical prescriptions and Chinese patent medicine. In this study, the Illumina platform was used to obtain the chloroplast genome sequences of seven kinds of A. asphodeloides from different areas. The specific DNA barcodes were screened by comparative genomics analysis, and the DNA barcodes were used to identify the germplasm resources and analyze the genetic diversity of A. asphodeloides samples from different areas in China. All the seven chloroplast genomes had a ring structure. The total length was 156 801-156 930 bp, and 113 genes were annotated, including 79 protein-coding genes, 30 tRNA genes, and four rRNA genes. The comparative genomics analysis showed that rps16, trnG-GCC, atpF, rpoB, ycf3, rpl16, ndhF, trnS-GCU＿trnG-GCC, petN-psbM, and ndhF-rpl32 were potential candidates for specific DNA barcodes of A. asphodeloides. In this study, the second intron of ycf3 and atpF intron sequences with a sequence length of 700-800 bp and easy amplification were selected for polymerase chain reaction(PCR) amplification and sequencing of 594 samples from 26 areas. The sequence analysis showed that six and eight haplotypes of ycf3 and atpF sequences could be identified, respectively, and 17 haplotypes could be identified by combined analysis of the two sequences, which were named Hap1-Hap17. The haplotype diversity(H_d), nucleotide diversity(P_i), and genetic distance of A. asphodeloides in 26 populations were 0.68, 0.93×10~(-3), and 0-0.003 1, respectively, indicating that the genetic diversity within the species of A. asphodeloides is rich. The intermediary adjacent network analysis showed that Hap5 was the oldest haplotype, which was mainly distributed in Yixian county of Baoding, Hebei province, Hequ county of Xinzhou, Shanxi province, and Xiangfen county of Linfen, Shanxi province. This study has important guiding significance for the identification of A. asphodeloides species, the protection and development of germplasm resources, and the identification of production areas, and it provides a research basis for further revealing the genetic evolution law of A. asphodeloides.

Germplasm resources and secondary metabolism regulation in Reishi mushroom (Ganoderma lucidum)

Ganoderma lucidum is a valuable medical macrofungus with a myriad of diverse secondary metabolites, in which triterpenoids are the major constituents. This paper introduced the germplasm resources of genus Ganoderma from textual research, its distribution and identification at the molecular level. Also we overviewed G. lucidum in the components, the biological activities and biosynthetic pathways of ganoderic acid, aiming to provide scientific evidence for the development and utilization of G. lucidum germplasm resources and the biosynthesis of ganoderic acid.

Study on the Phenotypic Diversity of 33 Ornamental Xanthoceras sorbifolium Cultivars

Xanthoceras sorbifolium, belonging to the family Sapindaceae, has a beautiful tree shape, elegant leaves, large and many brightly colored flowers, and a long flowering duration. This plant is widely applied in gardens. In this study, 33 cultivars of Xanthoceras sorbifolium were selected from the perspective of ornamental properties, and their phenotypic traits, such as leaves, flowers, and branches, were measured and analyzed, and their phenotypic diversity was comprehensively evaluated using principal component analysis, in order to investigate the phenotypic diversity characteristics of Xanthoceras sorbifolium. The results showed that the genetic diversity index of the qualitative traits varied from 0.14 to 1.50, and that of quantitative traits varied from 1.76 to 2.05. The quantitative traits were more diverse than the qualitative traits. The coefficient of variation of the qualitative traits ranged from 16.90% to 57.96%, and that of quantitative traits ranged from 12.92% to 32.87%. The phenotypic traits of the tested cultivars had relatively rich variation. Furthermore, the level of the phenotypic diversity index of Xanthoceras sorbifolium was not consistent with the level of coefficient of variation, indicating large variation and uneven distribution of variation. Through principal component analysis, 17 quantitative characters were extracted into five principal components, with a cumulative contribution rate of 79.82%, representing the primary information on the quantitative characters of ornamental Xanthoceras sorbifolium cultivars. The F value of the 33 samples ranged from -2.79 to 1.93, and the comprehensive scores of seven cultivars were greater than 1, indicating that these cultivars had rich phenotypic diversity. Therefore, the screening, development, and utilization of fine germplasm resources of Xanthoceras sorbifolium should focus on these cultivars. The 33 cultivars were subsequently clustered into five categories through systematic clustering. The cluster analysis provided references for breeding ornamental Xanthoceras sorbifolium cultivars with different utilization values, such as large white flowers, small red flowers, large red flowers, large orange flowers, and double-petaled flowers.

Construction of SNP fingerprint and population genetic analysis of honeysuckle germplasm resources in China

INTRODUCTION

The flower buds of Lonicera japonica Thunb. are widely used in Chinese medicine for their anti-inflammatory properties, and they have played an important role in the fight against SARS COVID-19 and other major epidemics. However, due to the lack of scientific and accurate variety identification methods and national unified standards, scattered and non-standardized management in flower bud production has led to mixed varieties that have caused significant difficulties in the cataloging and preservation of germplasm resources and the identification, promotion, and application of new L. japonica varieties.

METHODS

In this study, we evaluated the population structure, genetic relationships, and genetic fingerprints of 39 germplasm resources of Lonicera in China using simplified genome sequencing technology.

RESULTS

A total of 13,143,268 single nucleotide polymorphisms (SNPs) were identified. Thirty-nine samples of Lonicera were divided into four subgroups, and the population structure and genetic relationships among existing Lonicera germplasm resources were determined using principal component analysis, population structure analysis, and phylogenetic tree analysis. Through several stringent selection criteria, 15 additional streamlined, high-quality DNA fingerprints were filtered out of the validated 50 SNP loci and verified as being able to effectively identify the 39 Lonicera varieties.

DISCUSSION

To our knowledge, this is the first comprehensive study measuring the diversity and population structure of a large collection of Lonicera varieties in China. These results have greatly broadened our understanding of the diversity, phylogeny, and population structure of Lonicera. The results may enhance the future analysis of genetic diversity, species identification, property rights disputes, and molecular breeding by providing a scientific basis and reference data for these efforts.

Germplasm Resources of Oaks (Quercus L.) in China: Utilization and Prospects

Oaks exhibit unique biological characteristics and high adaptability to complex climatic and soil conditions. They are widely distributed across various regions, spanning 40 degrees latitude and 75 degrees longitude. The total area of oak forest in China is 16.72 million hm². There are 60 lineages of Quercus in China, including 49 species, seven varieties, and four subgenera. Archaeological data indicate that oaks were already widely distributed in ancient times, and they are dominant trees in vast regions of China's forests. In addition, the acorn was an important food for ancestral humans, and it has accompanied human civilization since the early Paleolithic. Diverse oak species are widely distributed and have great functional value, such as for greening, carbon sequestration, industrial and medicinal uses, and insect rearing. Long-term deforestation, fire, diseases, and pests have led to a continuous decline in oak resources. This study discusses the Quercus species and their distribution in China, ecological adaptation, and the threats facing the propagation and growth of oaks in a changing world. This will give us a better understanding of Quercus resources, and provide guidance on how to protect and better utilize germplasm resources in China. The breeding of new varieties, pest control, and chemical and molecular research also need to be strengthened in future studies.

Genetic Diversity Evaluation and Conservation of Topmouth Culter (Culter alburnus) Germplasm in Five River Basins in China

To study the genetic diversity of Culter alburnus (C. alburnus) populations, we analyzed the genetic diversity of five C. alburnus populations from Songhua Lake (SH), Huaihe River (HH), Changjiang River (CJ), Taihu Lake (TH), and Gehu Lake (GH) based on mitochondrial COI gene sequences. The results showed that the average contents of bases T, C, A, and G in the 526 bp COI gene sequence were 25.3%, 18.1%, 28.1%, and 28.6%, respectively, which showed AT bias. A total of 115 polymorphic sites were detected in the five populations, and 11 haplotypes (Hap) were defined. The nucleotide diversity (P_i) of the five populations ranged from 0.00053 to 0.01834, and the haplotype diversity (H_d) ranged from 0.280 to 0.746, with the highest genetic diversity in the TH population, followed by the SH population, with lower genetic diversity in the HH, CJ and GH populations. The analysis of the fixation index (Fst) and the genetic distance between populations showed that there was significant genetic differentiation between the SH population and the other populations, and the genetic distances between all of them were far; the genetic diversity within populations was higher than that between populations. Neutral tests, mismatch distributions, and Bayesian skyline plot (BSP) analyses showed that the C. alburnus populations have not experienced population expansion and are relatively stable in historical dynamics.

Current Situation and Utilization of Velvet Deer Germplasm Resources in China

Velvet deer are not only a representative special economic animal but also an important part of livestock. With the increasing awareness of international competition for germplasm resources in China, more and more attention has been paid to the protection and utilization of germplasm resources. However, there is poor understanding about velvet deer resources. Therefore, we are providing a comprehensive introduction of Chinese velvet deer germplasm resources from the aspects of ecological distribution, domestication and breeding.

Characterization of a Collection of Colored Lentil Genetic Resources Using a Novel Computer Vision Approach

The lentil (Lens culinaris Medik.) is one of the major pulse crops cultivated worldwide. However, in the last decades, lentil cultivation has decreased in many areas surrounding Mediterranean countries due to low yields, new lifestyles, and changed eating habits. Thus, many landraces and local varieties have disappeared, while local farmers are the only custodians of the treasure of lentil genetic resources. Recently, the lentil has been rediscovered to meet the needs of more sustainable agriculture and food systems. Here, we proposed an image analysis approach that, besides being a rapid and non-destructive method, can characterize seed size grading and seed coat morphology. The results indicated that image analysis can give much more detailed and precise descriptions of grain size and shape characteristics than can be practically achieved by manual quality assessment. Lentil size measurements combined with seed coat descriptors and the color attributes of the grains allowed us to develop an algorithm that was able to identify 64 red lentil genotypes collected at ICARDA with an accuracy approaching 98% for seed size grading and close to 93% for the classification of seed coat morphology.

Development of a Multi-Criteria Decision-Making Approach for Evaluating the Comprehensive Application of Herbaceous Peony at Low Latitudes

The growing region of herbaceous peony (Paeonia lactiflora) has been severely constrained due to the intensification of global warming and extreme weather events, especially at low latitudes. Assessing and selecting stress-tolerant and high-quality peony germplasm is essential for maintaining the normal growth and application of peonies under adverse conditions. This study proposed a modified multi-criteria decision-making (MCDM) model for assessing peonies adapted to low-latitude climates based on our previous study. This model is low-cost, timesaving and suitable for screening the adapted peony germplasm under hot and humid climates. The evaluation was conducted through the analytic hierarchy process (AHP), three major criteria, including adaptability-related, ornamental feature-related and growth habits-related criteria, and eighteen sub-criteria were proposed and constructed in this study. The model was validated on fifteen herbaceous peonies cultivars from different latitudes. The results showed that 'Meiju', 'Hang Baishao', 'Hongpan Tuojin' and 'Bo Baishao' were assessed as Level I, which have strong growth adaptability and high ornamental values, and were recommended for promotion and application at low latitudes. The reliability and stability of the MCDM model were further confirmed by measuring the chlorophyll fluorescence of the selected adaptive cultivars 'Meiju' and 'Hang Baishao' and one maladaptive cultivar 'Zhuguang'. This study could provide a reference for the introduction, breeding and application of perennials under everchanging unfavorable climatic conditions.

rugosa

Rosa rugosa (Rosaceae) is an important functional plant used in food products, tea, and aromatherapy. Characteristics of R. rugosa varieties based on the biological traits and floral fragrant components were studied by applying an analytic hierarchy process, headspace solid-phase microextraction gas chromatography-mass spectrometry, and metabolomic analysis. The 77 Rosa accessions (comprising 27 R. rugosa varieties, 43 scented R. hybrida cultivars, and seven fragrant R. species) were grouped into nine classes based on 17 morphological characters and 16 targeted fragrant substances by cluster analysis. Three R. rugosa cultivars differing in fragrance type were selected for volatile metabolomics analysis at four stages of flower development. In total, 156 differential volatile organic compounds (VOC) were detected and the VOC content patterns were further investigated in two important metabolic pathways (the monoterpenoid biosynthetic pathway, and the phenylalanine, tyrosine, and tryptophan biosynthesis pathway). The results provide a foundation for efficient use of Rosa germplasm and insights into the utilization of R. rugosa as a functional flower.

[Germplasm resource evaluation of Chrysanthemi Indici Flos based on color and chemical components]

This study explored the correlation between color and chemical components of Chrysanthemi Indici Flos(CIF), aiming at providing a reference for its procurement, evaluation, and breeding. Colorimeter and ultra-performance liquid chromatograph(UPLC) were used to determine the color(lightness-shade chromaticity value L~*, red-green chromaticity value a~*, yellow-blue chromati-city value b~*) and chemical components(cynaroside, linarin, luteolin, apigenin, and chlorogenic acid) of 84 CIF germplasms, respectively. Diversity analysis, correlation analysis, regression analysis, and cluster analysis were performed. The results showed that the color and chemical components of CIF were diversified. Chlorogenic acid was in significantly positive correlation with L~* and b~* and significantly negative correlation with a~*. Cynaroside and grey relational grade γ_i of chemical components were in significantly po-sitive correlation with b~* and L~*, respectively, whereas linarin, luteolin, and apigenin had no significant correlation with L~*, a~*, or b~*. The 84 CIF germplasms were clustered into 4 clades. In addition, germplasms in clade Ⅲ had higher γ_i and total color value(E~*_(ab)) than those in other clades, with the best quality and color, and a germplasm with the highest quality, bright yellow color, and highest content of linarin was screened out in this clade. Thus, CIF with bright yellow color had high content of cymaroside and chlorogenic acid and thereby high quality. In summary, the color can be used to quickly predict the quality of CIF. Our results provided data for the evaluation of CIF quality by color and a reference for its procurement and breeding.

A Review of the Stress Resistance, Molecular Breeding, Health Benefits, Potential Food Products, and Ecological Value of Castanea mollissima

Chestnut (Castanea spp., Fagaceae family) is an economically and ecologically valuable species. The main goals of chestnut production vary among species and countries and depend on the ecological characteristics of orchards, agronomic management, and the architecture of chestnut trees. Here, we review recent research on chestnut trees, including the effects of fungal diseases (Cryphonectria parasitica and Phytophthora cinnamomi) and insect pests (Dryocosmus kuriphilus Yasumatsu), molecular markers for breeding, ecological effects, endophytic fungi, and extracts with human health benefits. We also review research on chestnut in the food science field, technological improvements, the soil and fertilizer used for chestnut production, and the postharvest biology of chestnut. We noted differences in the factors affecting chestnut production among regions, including China, the Americas, and Europe, especially in the causal agents of disease and pests. For example, there is a major difference in the resistance of chestnut to C. parasitica in Asian, European, and American countries. Our review provides new insights into the integrated disease and pest management of chestnut trees in China. We hope that this review will foster collaboration among regions and help to clarify differences in the direction of breeding efforts among countries.

Identification of Fusarium verticillioides Resistance Alleles in Three Maize Populations With Teosinte Gene Introgression

Fusarium ear rot (FER) is a common fungal disease in maize (Zea mays L.) caused by Fusarium verticillioides. Resistant germplasm resources for FER are rare in cultivated maize; however, teosintes (Z. mays ssp. parviglumis and Z. mays ssp. diploperennis), which are wild-type species of maize, have the potential to offer a novel source of resistance alleles to enhance pathogen resistance in modern maize. Therefore, the aim of this study was to identify favorable alleles that confer significant levels of resistance toward FER. Three populations of BC₂F₈ recombinant inbred lines (RILs) were developed by crossing two different teosintes, Z. diploperennis and Z. parviglumis, with maize inbred lines B73 and Zheng58, and were screened for FER resistance. We found that Z. diploperennis and Z. parviglumis had higher resistance toward F. verticillioides in the leaves than B73 and Zheng58. However, the resistance toward F. verticillioides in the leaf and ear was unrelated among RILs. FER resistance was positively correlated with grain yield in the B73 × diploperennis (BD) and Zheng58 × parviglumis (ZP) populations, partly because the quantitative trait loci (QTLs) of FER resistance and yield traits were located close together. Four coincident QTLs (qFERbd5.177, qFERbd10.140, qFERzp4.066, and qFERzp5.116) and two highly reliable resistance-yield synergistic QTLs (qFERbd10.140 and qFERzp4.066) were identified in the BD and ZP populations, opening up the possibility of breeding for FER resistance without reducing yield.

[Evaluation of genetic diversity of ginseng fruit color germplasm resources: based on SSR analysis]

Illumina Xten was employed for shallow sequencing of Panax ginseng(ginseng) samples, MISA for screening of SSR loci, and Primer 3 for primer design. Polymorphic primers were screened from 180 primers. From the successfully amplified polymorphic primers, 15 primers which featured clear peak shape, good polymorphism, and ease of statistics were selected and used to evaluate the genetic diversity and germplasm resources of 36 ginseng accessions with different fruit colors from Jilin province. The results showed that red-fruit ginseng population had high genetic diversity with the average number of alleles(N_a) of 1.031 and haploid genetic diversity(h) of 0.172. The neighbor-joining cluster analysis demonstrated that the germplasms of red-fruit and yellow-fruit ginseng populations were obviously intermixed, and pick-fruit ginseng germplasms clustered into a single clade. The results of STRUCTURE analysis showed high proportion of single genotype in pick-fruit ginseng germplasm and abundant genotypes in red-fruit and yellow-fruit ginseng germplasms with obvious germplasm mixing. AMOVA revealed that genetic variation occurred mainly within populations(62.00%, P<0.001), and rarely among populations(39%, P<0.001), but homogenization was obvious among different populations. In summary, pink-fruit ginseng population may contain rare genotypes, which is the basis for breeding of high-quality high-yield, and multi-resistance varieties, genetic improvement of varieties, and sustainable development and utilization of ginseng germplasm resources.

[Content of mineral elements in different Artemisia argyi germplasms and their relationship with quality properties]

To clarify the content characteristics of mineral elements in different Artemisia argyi germplasm resources and their relationship with the quality properties of Artemisiae Argyi Folium, this study measured the content of 10 mineral elements including nitrogen(N), phosphorus(P), potassium(K), calcium(Ca), magnesium(Mg), aluminum(Al), manganese(Mn), iron(Fe), copper(Cu), and zinc(Zn) in 100 Artemisia argyi germplasm samples. Besides, their relationship with the quality properties of Artemisiae Argyi Folium was explored by correlation analysis, path analysis, and cluster analysis. The results demonstrated that the variation coefficient of the 10 mineral elements in Artemisiae Argyi Folium ranged from 12.23% to 64.38%, and the genetic diversity index from 0.97 to 3.09. The genetic diversities of N, P, and Zn were obvious. As revealed by the correlation analysis, N, P, and K showed strong positive correlations with each other. Except that Mg and Al were negatively correlated, Ca, Mg, Al, Mn, Fe, Cu, and Zn were positively correlated. The correlation analysis of mineral elements with the quality properties of Artemisiae Argyi Folium proved the significant correlations of 17 pairs of characters. According to the path analysis, P, K, Ca, and Mn greatly affected the yield of Artemisiae Argyi Folium, P, K, and Mg the output rate of moxa, N, P, and K the content of total volatile oil, P and K the content of eucalyptol, and P, K, and Ca the content of eupatilin. The 100 germplasm samples were clustered into three groups. Specifically, in cluster Ⅰ, the enrichment capacity of P, K, and Mg elements was strong, and the comprehensive properties of mineral elements were better, implying good development potential. Ca, Mn, Fe, and Zn elements in cluster Ⅱ and N and Al in cluster Ⅲ displayed strong enrichment capacities. This study has provided new ideas for resource evaluation and variety breeding of A. argyi and also reference for fertilizer application.

[Fruit variation and geographical distribution of citron]

The ripe dried fruit of citron(Citrus medica) is one of the important sources of Chinese herb Citri Fructus. At the same time, it is also grown for edible and ornamental uses. There are many species and abundant genetic variation. To clarify the intraspecific variation and resource distribution of citron, this study investigated the variation in 11 citron fruits, basically covering the main species in China, including Xiaoguo citron(C. medica var. ethrog), Goucheng(C. medica var. yunnanensis), Muli citron(C.medica var. muliensis), Dehong citron(C.medica×Citrus spp.), Fuzhou citron(C.medica×C.grandis?), Mawu(C.medica×C.grandis?), Cangyuan citron, Binchuan citron, Sweet citron, Big citron, and Small citron. The natural communities of citron were proved to be mainly distributed in the southwestern and western Yunnan and southeastern Tibet of China, with Yunnan, Sichuan, Guangxi, Chongqing, Hubei, and Zhejiang identified as the main production areas. Citron has also been widely grown in India, the Mediterranean region, and the Caribbean coast countries. The field investigation revealed the large-scale intraspecific variation of citron fruits. Most of the fruits are oval-like or sphere-like in shape. The fruits are green when raw and yellow when ripe, with oil cell dots on the skin, stripe-likes running from top to bottom, and bulge at the top. Usually, in the smaller citron fruits, the pulp and juice vesicles are better developed and the central columella is tighter. By contrast, the juice vesicles and central columella in larger fruits became more vacant, with carpels visible, and the apex segregation and development of the carpels is one of the reasons for variation. These variations should be given top priority in the future variety selection and breeding, and the quality differences of different citron species and their mechanisms should be further studied. In particular, variety selection and classification management according to their medicinal or edible purposes will provide scientific and technological supports for the orderly, safe, and effective production of citron products consumed as food and medicine.

Cold Conditioned: Discovery of Novel Alleles for Low-Temperature Tolerance in the Vavilov Barley Collection

Climate changes leading to higher summer temperatures can adversely affect cool season crops like spring barley. In the Upper Midwest region of the United States, one option for escaping this stress factor is to plant winter or facultative type cultivars in the autumn and then harvest in early summer before the onset of high-temperature stress. However, the major challenge in breeding such cultivars is incorporating sufficient winter hardiness to survive the extremely low temperatures that commonly occur in this production region. To broaden the genetic base for winter hardiness in the University of Minnesota breeding program, 2,214 accessions from the N. I. Vavilov Institute of Plant Industry (VIR) were evaluated for winter survival (WS) in St. Paul, Minnesota. From this field trial, 267 (>12%) accessions survived [designated as the VIR-low-temperature tolerant (LTT) panel] and were subsequently evaluated for WS across six northern and central Great Plains states. The VIR-LTT panel was genotyped with the Illumina 9K SNP chip, and then a genome-wide association study was performed on seven WS datasets. Twelve significant associations for WS were identified, including the previously reported frost resistance gene FR-H2 as well as several novel ones. Multi-allelic haplotype analysis revealed the most favorable alleles for WS in the VIR-LTT panel as well as another recently studied panel (CAP-LTT). Seventy-eight accessions from the VIR-LTT panel exhibited a high and consistent level of WS and select ones are being used in winter barley breeding programs in the United States and in a multiparent population.

Licorice Germplasm Resources Identification Using DNA Barcodes Inner-Variants

Based on the gradual transformation from wild growth to artificial cultivation, the accurate authentication of licorice seeds contributes to the first committed step of its quality control and is pivotal to ensure the clinical efficacy of licorice. However, it is still challenging to obtain genetically stable licorice germplasm resources due to the multi-source, multi-heterozygous, polyploid, and hybrid characteristics of licorice seeds. Here, a new method for determining the heterozygosity of licorice seed mixture, based on the various sites, and finding the composition characteristics of licorice seed is preliminarily designed and proposed. Namely, high-throughput full-length multiple DNA barcodes(HFMD), based on ITS multi-copy variation exist, the full-length amplicons of ITS2, psbA-trnH and ITS are directly sequenced by rDNA through the next-generation sequence(NGS) and single-molecule real-time (SMRT) technologies. By comparing the three sequencing methods, our results proved that SMRT sequencing successfully identified the complete gradients of complex mixed samples with the best performance. Meanwhile, HFMD is a brilliant and feasible method for evaluating the heterozygosity of licorice seeds. It shows a perfect interpretation of DNA barcoding and can be applied in multi-base multi-heterozygous and polyploid species.

[Analysis and evaluation of volatile oil content in leaves of different Artemisia argyi germplasm resources]

Volatile oil is the main effective component and an important quality indicator of Artemisia argyi leaves. In this study, 100 germplasm resources of A. argyi were collected from all the related habitats in China. The total volatile oils in A. argyi leaves were extracted by steam distillation and the content was determined by GC-MS. The result demonstrated that the content of total volatile oils was in the range of 0.53%-2.55%, with the average of 1.43%. A total of 39 chemical constituents were identified from the volatile oils, including 13 shared by the 100 germplasm resources. Clustering analysis of the 39 constituents showed that the 100 A. argyi samples were categorized into groups Ⅰ(9), Ⅱ(2), Ⅲ(66) and Ⅳ(23), and group Ⅲ had the most volatile medicinal components, with the highest content. Five principal components(PCs) were extracted from 13 shared constituents, which explained 73.454% of the total variance. PC1, PC2, and PC3 mainly reflected the pharmacological activity of volatile oils and the rest two the aroma information. The volatile oils identified in this study lay a foundation for variety breeding of and rational utilization of volatile oils in A. argyi leaves.

[Analysis and evaluation of mineral elements of Chrysanthemum morifolium for medicinal and tea use of different germplasm resources]

In this study, 23 germplasm resources of Chrysanthemum morifolium used in medicine and tea were collected from Dabie Mountains and its surrounding producing areas, and the contents of 13 mineral elements were determined and compared. The thermal maps of correlation analysis, principal component analysis and cluster analysis were used for comprehensive evaluation. The results showed that the average content of each element in Ch. morifolium of different germplasm resources was: K>N>P>Mg>Ca>Fe>Mn>Zn>Cu>Ni>Cr>Pb>Cd, and the leaves were: K>N>Ca>Mg>P>Fe>Mn>Zn>Cr>Cu>Ni>Pb>Cd. There are rich contents of N, P, K, Ca, Mg and Fe in Ch. morifolium flowers and their leaves, among them, K element has the largest change range, while N, Ca, Fe, Mg and Zn elements have a larger change range. The absorption and accumulation of each element in the leaves of different germplasm resources varied greatly. The correlation analysis shows that there is a strong positive correlation between Ca element, Mg, Mn and Cd element.Principal component analysis in Ch. morifolium flowers characteristic elements for Mn, Cr, Cu, P, K, can be used as a Ch. morifolium resources to identify the characteristics of the elements, choose top five principal component(F1-F5) comprehensive evalua-tion of medicinal Ch. morifolium, scored in the top five varieties for Hangiu-Fuhuangju, Hangju-Xiaoyangju, Hangju-Sheyangju, Hangju-Dayanghua, Hangju-Subeiju,indicates that in terms of mineral elements, the five medicinal Ch. morifolium resources quality is better. The PCA score chart can divide 23 Ch. morifolium resources into 4 groups, and the cluster analysis heat map divides 23 Ch. morifolium resources into 5 groups. All the Ch. morifolium resources of the same type can be well clustered together, indicating that the difference in mineral element content of Ch. morifolium germplasm resources is closely related to genetic factors.

The History and Diversity of Rice Domestication as Resolved From 1464 Complete Plastid Genomes

The plastid is an essential organelle in autotrophic plant cells, descending from free-living cyanobacteria and acquired by early eukaryotic cells through endosymbiosis roughly one billion years ago. It contained a streamlined genome (plastome) that is uniparentally inherited and non-recombinant, which makes it an ideal tool for resolving the origin and diversity of plant species and populations. In the present study, a large dataset was amassed by de novo assembling plastomes from 295 common wild rice (Oryza rufipogon Griff.) and 1135 Asian cultivated rice (Oryza sativa L.) accessions, supplemented with 34 plastomes from other Oryza species. From this dataset, the phylogenetic relationships and biogeographic history of O. rufipogon and O. sativa were reconstructed. Our results revealed two major maternal lineages across the two species, which further diverged into nine well supported genetic clusters. Among them, the Or-wj-I/II/III and Or-wi-I/II genetic clusters were shared with cultivated (percentage for each cluster ranging 54.9%∼99.3%) and wild rice accessions. Molecular dating, phylogeographic analyses and reconstruction of population historical dynamics indicated an earlier origin of the Or-wj-I/II genetic clusters from East Asian with at least two population expansions, and later origins of other genetic clusters from multiple regions with one or more population expansions. These results supported a single origin of japonica rice (mainly in Or-wj-I/II) and multiple origins of indica rice (in all five clusters) for the history of rice domestication. The massive plastomic data set presented here provides an important resource for understanding the history and evolution of rice domestication as well as a genomic resources for use in future breeding and conservation efforts.

Genetic relationships and low diversity among the tea-oil Camellia species in Sect. Oleifera, a bulk woody oil crop in China

Tea-oil Camellia is one of the four woody oil crops in the world and has high ecological, economic and medicinal values. However, there are great differences in the classification and merging of tea-oil Camellia Sect. Oleifera species, which brings difficulties to the innovative utilization and production of tea-oil Camellia resources. Here, ISSR, SRAP and chloroplast sequence markers were analyzed in 18 populations of tea-oil Camellia Sect. Oleifera species to explore their phylogenetic relationships and genetic diversity. The results showed that their genetic diversity were low, with mean H and π values of 0.16 and 0.00140, respectively. There was high among-population genetic differentiation, with ISSR and SRAP markers showing an Fst of 0.38 and a high Nm of 1.77 and cpDNA markers showing an Fst of 0.65 and a low Nm of 0.27. The C. gauchowensis, C. vietnamensis and Hainan Island populations formed a single group, showing the closest relationships, and supported being the same species for them with the unifying name C. drupifera and classifying the resources on Hainan Island as C. drupifera. The tea-oil Camellia resources of Hainan Island should be classified as a special ecological type or variety of C. drupifera. However, cpDNA marker-based STRUCTURE analysis showed that the genetic components of the C. osmantha population formed an independent, homozygous cluster; hence, C. osmantha should be a new species in Sect. Oleifera. The C. oleifera var. monosperma and C. oleifera populations clustered into two distinct clades, and the C. oleifera var. monosperma populations formed an independent cluster, accounting for more than 99.00% of its genetic composition; however, the C. oleifera populations contained multiple different cluster components, indicating that C. oleifera var. monosperma significantly differs from C. oleifera and should be considered the independent species C. meiocarpa. Haplotype analysis revealed no rapid expansion in the tested populations, and the haplotypes of C. oleifera, C. meiocarpa and C. osmantha evolved from those of C. drupifera. Our results support the phylogenetic classification of Camellia subgenera, which is highly significant for breeding and production in tea-oil Camellia.

Construction of Gossypium barbadense Mutant Library Provides Genetic Resources for Cotton Germplasm Improvement

Allotetraploid cotton (Gossypium hirsutum and Gossypium barbadense) are cultivated worldwide for its white fiber. For centuries, conventional breeding approaches increase cotton yield at the cost of extensive erosion of natural genetic variability. Sea Island cotton (G. barbadense) is known for its superior fiber quality, but show poor adaptability as compared to Upland cotton. Here, in this study, we use ethylmethanesulfonate (EMS) as a mutagenic agent to induce genome-wide point mutations to improve the current germplasm resources of Sea Island cotton and develop diverse breeding lines with improved adaptability and excellent economic traits. We determined the optimal EMS experimental procedure suitable for construction of cotton mutant library. At M₆ generation, mutant library comprised of lines with distinguished phenotypes of the plant architecture, leaf, flower, boll, and fiber. Genome-wide analysis of SNP distribution and density in yellow leaf mutant reflected the better quality of mutant library. Reduced photosynthetic efficiency and transmission electron microscopy of yellow leaf mutants revealed the effect of induced mutations at physiological and cellular level. Our mutant collection will serve as the valuable resource for basic research on cotton functional genomics, as well as cotton breeding.

[Cultivars breeding and production of non-psychoactive medicinal cannabis with high CBD content]

The shortage of new cannabis varieties with low THC and high CBD content and irregular planting techniques have become the bottleneck for he development of non-psychoactive medicinal cannabis industry. Based on the cannabis germplasm resources,this paper proposes strategies for breeding high CBD content,seed-type and high-efficiency,dwarf non-psychoactive medicinal cannabis varieties through molecular marker development,assisted breeding,genetic engineering breeding and traditional breeding. According to the suitable ecological factors of non-psychoactive medicinal cannabis,the CBD content and grain yield of non-psychoactive medicinal cannabis can be improved by regulating the nutritional structure and illumination properties of non-psychoactive medicinal cannabis,scientific harvesting and storage. At the same time,in order to further accelerate the application of non-psychoactive medicinal cannabis,we can accelerate the selection of new varieties of non-psychoactive medicinal cannabis by mining genetic information of cannabis,and strengthen the application of information technology and automation of modern agriculture in the production of non-psychoactive medicinal cannabis. Provide basis for the cultivation and wide application of new non-psychoactive medicinal cannabis varieties with high quality and high yield.

[Progress on germplasm enhancement and breeding of Rehmannia glutinosa]

The history of Rehmannia glutinosa breeding has already beyond 100 years. There are rich cultivated varieties and wild germplasm resources in R. glutinosa. However, there also exist a lot of problems, such as, the pedigree of the existing varieties is not clear, the genetic basis is narrow, backward method of germplasm enhancement and breeding. Breeding of new varieties has been unable to meet the demand of R. glutinosa production in the new era. This paper summarizes the species of Rehmannia and their distribution, the diversity of plant morphology and the quality of R. glutinosa germplasm resources, as well as the progress of R. glutinosa breeding in recent 100 years. For ensuring the orderly, effective and safe production of R. glutinosa, the authors suggest to establish the wild resources protection area and germplasm resources garden, deeply study the genetic base of quality, strengthen application of new breeding method such as mutation breeding, haploid breeding and gene editing.

[Genetic diversity of 6 species in Polygonatum by SSR marker]

Polygonatum is a genus of the perennial herb family Liliaceae, with great potential in food, medicine and other field. In this study, genetic diversity and cluster structure analysis of 6 species in Polygonatum were investigated the molecular marker technique of simple sequence repeat (SSR). A total of 49 SSR makers were used to study genetic diversity and population structure within 60 germplasm resources which obtained from 38 counties and cities in 14 provinces of China. A total of 211 alleles were identified and the number of alleles ranged from 2 to 10, with an average of 4.306 1 alleles per SSR. The range of polymorphism information content (PIC) varied from 0.731 8 to 0.031 7, with the average of 0.309 6. The cluster analysis classified 60 germplasm resources into four defined groups at the genetic distance value of 0.26, among which most species with relatives were clustered into the same group. Extraordinarily, there were 6 germplasm resources clustered into other species, indicating that the classification of inter-genus and geographical distribution was crossed in Polygonatum. The genetic diversity index of the 4 geographical populations from high to low was: Western region, Central China, Southern China, Eastern China. The population structure analysis, also indicating divided the entire collection into four groups, which was similar to the assignment pattern of cluster structure analysis. These results suggested that the Polygonatum germplasm resources used in this study is rich in relatively high genetic diversity with large variation range, relatively fuzzy boundaries of species. It appeared the phenomenon that there is a difference decreases between the alternate leaf system and the rotation leaf system. The genetic diversity in the western region was higher than that in other regions, and the western region may be the origin center of the genus Polygonatum.

[Establishment of fingerprint of Astragali Radix polysaccharides based on endo-1,4-β-mannanase hydrolysis and identification of Astragali Radix of different germplasm resources]

The polysaccharides of different germplasm resources of Astragalus membranaceus var. mongholicus〓(cultured Astragalus Radix (RA) and natural RA) and A. membranaceus (MJ) (cultured RA and natural RA) were studied by using the optimal enzymatic conditions of endo-1,4-β-mannanase. Saccharide fingerprints were obtained for the identification and evaluation of the germplasm resources of RA by Fluorophore-assisted Carbohydrate Electrophoresis (FACE). The data were analyzed by principal component analysis to obtain the difference between RA of different germplasm resources. The results showed that trisaccharide, tetrasaccharide and pentasaccharide of endo-1,4-β-mannanase hydrolyzate could be used as the differential fragments to distinguish MG (cultured RA and natural RA); the pentasaccharide and hexasaccharide can be used as differentially expressed carbohydrate fragments that distinguish MJ (cultured RA and natural RA); the trisaccharide and tetrasaccharide can be used as the differential fragments to distinguish the cultured MG and cultured MJ. Studies have shown that polysaccharide products degraded by endo-1,4-β-mannanase can well distinguish RA species (MG and MJ), growth mode (cultured RA and natural RA). This study laid the foundation for the quality evaluation of Astragalus medicinal herbs and screening of active oligosaccharides.

Transcriptomic analysis, genic SSR development, and genetic diversity of proso millet (Panicum miliaceum; Poaceae)

PREMISE OF THE STUDY

Proso millet (Panicum miliaceum; Poaceae) is a minor crop with good nutritional qualities and strong tolerance to drought stress and soil infertility. However, studies on genetic diversity have been limited due to a lack of efficient genetic markers.

METHODS

Illumina sequencing technology was used to generate short read sequences of proso millet, and de novo transcriptome assemblies were used to develop a de novo assembly of proso millet. Genic simple sequence repeat (SSR) markers were identified and used to detect polymorphism among 56 accessions. Population structure and genetic similarity coefficient were estimated.

RESULTS

In total, 25,341 unique gene sequences and 4724 SSR loci were obtained from the transcriptome, of which 229 pairs of SSR primers were validated, which resulted in 14 polymorphic genic SSR primers exhibiting 43 total alleles. According to the ratio of polymorphic markers (6.1%, 14/229), there are potentially 288 polymorphic genic SSR markers available for genetic assay development in the future. Bayesian population analyses showed that the 56 accessions comprised two distinct groups.

DISCUSSION

A genetic structure and cluster assay indicated that the accessions from the Loess Plateau of China shared a high genetic similarity coefficient with those from other regions and that there was no correlation between genetic diversity and geographic origin. The transcriptome sequencing data and millet-specific SSR markers developed in this study establish an excellent resource for gene discovery and may improve the development of breeding programs in proso millet in the future.

The identification and evaluation of two different color variations of tea

BACKGROUND

The tea plant, Camellia sinensis (L.) O. Kuntz, is a perennial woody plant widely cultivated for the production of a popular non-alcoholic beverage. To rapidly identify and evaluate two different color tea varieties (yellowish and purplish), the main phenotypic traits and quality components were tested in the present study. The metabolic profiles of tea shoots and leaves were also analyzed using liquid chromatography-tandem mass spectrometry.

RESULTS

The yellowish variation had a higher active level with respect to metabolism of catechins, and the contents of luteolin and kaempferol 3-α-d-glucoside were much higher compared to in the other variations. However, the purplish variation had a low content of theanine and a high content of caffeine. The contents of quercetin and kaempferol 3-α-d-galactoside were highest in purplish leaves. Moreover, the yellowish variation had the highest total quality scores for green teas and black teas, whereas the purplish variation had the highest scores for oolong teas.

CONCLUSION

Both the yellowish variation and the purplish variation represent excellent breeding materials and are worthy of breeding as new tea cultivars. The yellowish variation is more suitable for making high-grade green teas or black teas, whereas the purplish variation is suitable for producing fine quality oolong teas. © 2016 Society of Chemical Industry.

Isolation and characterization of microsatellite loci for a bioenergy grass, Miscanthus sacchariflorus (Poaceae)

PREMISE OF THE STUDY

Microsatellite loci were developed for the biomass C4 grass, Miscanthus sacchariflorus, and proved to be suitable markers for population genetic studies and germplasm management of this species. •

METHODS AND RESULTS

Twenty-three polymorphic microsatellite loci were identified from an enriched genomic library of M. sacchariflorus. The polymorphism was assessed in 50 individuals from two populations in China. The number of alleles per locus varied from two to 18, with a mean of 8.13. The observed and expected heterozygosities ranged from 0.2 to 1.0 and from 0.198 to 0.898, respectively. •

CONCLUSIONS

These new markers will be useful for further investigation of genetic diversity and population genetic structure as well as molecular breeding of Miscanthus species.

Genome-wide genetic dissection of germplasm resources and implications for breeding by design in soybean

"Breeding by Design" as a concept described by Peleman and van der Voort aims to bring together superior alleles for all genes of agronomic importance from potential genetic resources. This might be achievable through high-resolution allele detection based on precise QTL (quantitative trait locus/loci) mapping of potential parental resources. The present paper reviews the works at the Chinese National Center for Soybean Improvement (NCSI) on exploration of QTL and their superior alleles of agronomic traits for genetic dissection of germplasm resources in soybeans towards practicing "Breeding by Design". Among the major germplasm resources, i.e. released commercial cultivar (RC), farmers' landrace (LR) and annual wild soybean accession (WS), the RC was recognized as the primary potential adapted parental sources, with a great number of new alleles (45.9%) having emerged and accumulated during the 90 years' scientific breeding processes. A mapping strategy, i.e. a full model procedure (including additive (A), epistasis (AA), A × environment (E) and AA × E effects), scanning with QTLNetwork2.0 and followed by verification with other procedures, was suggested and used for the experimental data when the underlying genetic model was usually unknown. In total, 110 data sets of 81 agronomically important traits were analyzed for their QTL, with 14.5% of the data sets showing major QTL (contribution rate more than 10.0% for each QTL), 55.5% showing a few major QTL but more small QTL, and 30.0% having only small QTL. In addition to the detected QTL, the collective unmapped minor QTL sometimes accounted for more than 50% of the genetic variation in a number of traits. Integrated with linkage mapping, association mappings were conducted on germplasm populations and validated to be able to provide complete information on multiple QTL and their multiple alleles. Accordingly, the QTL and their alleles of agronomic traits for large samples of RC, LR and WS were identified and then the QTL-allele matrices were established. Based on which the parental materials can be chosen for complementary recombination among loci and alleles to make the crossing plans genetically optimized. This approach has provided a way towards breeding by design, but the accuracy will depend on the precision of the loci and allele matrices.