Genetic relationships among Arachis hypogaea L. (AABB) and diploid Arachis species with AA and BB genomes

The cultivated peanut (Arachis hypogaea L.) is an allotetraploid, with two types of genomes, classified as AA and BB, according to cytogenetic characters. Similar genomes to those of A. hypogaea are found in the wild diploid species of section Arachis, which is one of the nine Arachis sections. The wild species have resistances to pests and diseases that affect the cultivated peanut and are a potential source of genes to increase the resistance levels in peanut. The aim of this study was to analyze the genetic variability within AA and BB genome species and to evaluate how they are related to each other and to A. hypogaea, using RAPD markers. Eighty-seven polymorphic bands amplified by ten 10-mer primers were analyzed. The species were divided into two major groups, and the AA and the BB genome species were, in general, separated from each other. The results showed that high variation is available within species that have genomes similar to the AA and the BB genomes of A. hypogaea.     

Karyotype analysis and chromosomal evolution in Asian species of Corchorus (Malvaceae s. l.)

Here, we report the karyotypes and mean haploid idiograms of the ten Asian Corchorus species (2n = 2x = 14). Chromosomes were small, with a mean chromosome length of 2.30 μm. The largest chromosome was recorded in C. pseudo-olitorius (3.50 μm) and the shortest in C. pseudocapsularis (1.60 μm). The karyotypes of the two cultivated species (C. capsularis and C. olitorius) and C. pseudo-olitorius were the most diverse and specialized, whereas those of C. depressus and C. trilocularis were the least diverse. C. fascicularis had the most asymmetrical and C. urticifolius the most symmetrical karyotypes. An increase in genome size was accompanied by increasing karyotype diversity in terms of morphologically distinct chromosome types and interchromosomal asymmetry, with uneven distribution of additional DNA throughout the karyotype. A positive correlation between interchromosomal asymmetry and dispersion index suggested that size differences between chromosomes were mainly associated with karyotype asymmetry. Karyotypes of the Corchorus species became progressively asymmetrical in the course of evolution. Relationships among the ten Corchorus species were defined by using a neighbor-joining tree inferred from inter-simple sequence repeat data. C. fascicularis and C. pseudocapsularis, with shorter karyotypes and smaller genomes, were closely related to C. pseudo-olitorius and C. capsularis, respectively, which were characterized by relatively longer karyotypes and larger genomes. However, the two cultivated species with different levels of interchromosomal asymmetries, dispersion indices and genome sizes were distantly related. Taking this molecular evidence into consideration, we have discussed chromosomal evolution in relation to karyological data including genome size.     

Impact of a Variable Tungsten Pollution on the Elemental Uptake of Two Plant Species

A radish and a grass species were grown in identical substrates either unpolluted or polluted by tungsten (W) at 1, 5, and 10 μg/g levels of watering solutions during 1 month under controlled laboratory conditions. Initially, at 4.1 μg/g, the W content in grass leaves reached 16 μg/g at the highest rate of W supply to the substrate. For radish, the content of W reached 22 and 29 μg/g in the leaves and roots, respectively. The overall W pollution increased significantly the mobility of major elements from substrate to grass leaves, especially at the 5 μg/g pollution level, whereas the W impact on radish leaves resulted in an increase of most contents, only Mn remaining unaffected. The roots from polluted radishes were enriched in Si by 21% and Al by 42% at low pollution, and in Si by 15% at high supply, whereas the uptake of the other elements remained unchanged. It looks like the W pollution at the levels chosen does not impact the transfer of the major and trace elements from roots to leaves of Raphanus sativus. Alternatively, metallic trace elements (Ba, Ni, Cr, Zn, W, Co) of the Raphanus sativus and Chloris gayana leaves outline similar content changes depending on the amount of W pollution. The total rare-earth element contents of the leaves of Raphanus sativus grown in the polluted substrates are lower than those of the leaves from unpolluted substrate. Their normalization in the leaves and roots of Raphanus sativus from the polluted substrates to those of the radish from non-polluted substrate provides flat patterns for both with a positive Eu anomaly for leaves, as for those of the grass and a negative Gd anomaly for roots. Also, addition of soluble W to the substrates induced an increase in the bacterial activity of the soil.     

Genetic variation within and among species of genus Arachis, section Rhizomatosae

The genus Arachis is endemic to South America and comprises 80 species, 69 of which have already been described and eleven not yet published. The genus includes the cultivated peanut (A. hypogaea) and several forage species, the most important ones being A. glabrata and A. pintoi. Accessions of section Rhizomatosae, including three tetraploid species 2n = 4x = 40 (A. glabrata, A. pseudovillosa and A. nitida nom. nud.) and one diploid species 2n = 2x = 20 (A. burkartii), were evaluated using RAPD markers to assay genetic variability within and among species. The ten random primers used yielded a total of 113 polymorphic bands. The data were scored as the presence or absence of each band in each sample. A distance matrix and dendrogram were obtained using Link's coefficient and the neighbor-joining method. Most accessions analyzed grouped into two major clusters: the first comprised most accessions of A. glabrata and accessions of A. nitida, and the second cluster comprised accessions of A. burkartii. Arachis pseudovillosa and a few accessions of A. glabrata and A. nitida were placed between these major clusters. The diploid and tetraploid species were grouped quite separately, suggesting that the tetraploids did not originate from the diploid species analyzed.     

RAPD-based assessment of genetic relationships among and within American ginseng (Panax quinquefolius L.) populations and their implications for a future conservation strategy

American ginseng (Panax quinquefolius) is a native North American medicinal plant that is becoming increasingly vulnerable despite government harvest restrictions. To better understand the genetic diversity and gene flow of American ginseng, we studied RAPD variation in cultivated and wild populations. Classical and Bayesian analogues of genetic diversity statistics were estimated in seven wild and two cultivated populations. The wild populations were more highly structured (G _stβ  = 0.41) than the cultivated populations (G _stβ  = 0.24). The genetic diversity within populations ranged from H _eβ  = 0.05 to 0.38. Based on genetic pairwise distances, six of the wild populations clustered with the locally-derived cultivated population, while one wild population was more similar to the non-local cultivated population than the local populations. This wild population was highly diverse (P = 1.0; U = 1.0) suggesting that it was supplemented from exotic seed. A set of eight RAPD markers was identified that differentiated plants of local and non-local origin. As a conservation strategy, we recommend that regional gene banks be established based on molecular and geographic diversity to preserve the locally adapted germplasm. These regional gene banks would serve as a conservation tool and also provide a source of genes for genetic improvement of cultivated ginseng.     

Effectiveness of Natural Compounds on DNA Damage in <Emphasis Type="Italic">Coris julis</Emphasis> (Linneaus 1758) from a Polluted Marine Area

The evaluation of DNA damage in aquatic organisms represents one of the most widely used biomarkers in the assessment and monitoring of marine pollution. Our previous research highlighted the presence of DNA damage in hepatic nuclei and blood cells of Coris julis specimens collected from Augusta harbor (Syracuse, Italy), a site highly polluted. In this work, we investigated on the ability of different natural compounds with antioxidant and immunostimulating properties, such as resveratrol (50 μM, 100 μM), amygdalin (100 μM, 200 μM), and Urtica dioica roots extract (50 and/or 100 μg/ml), in reducing DNA damage of C. julis. Blood cells were analyzed by atypical cellular comet assay. The results confirmed that Augusta specimens are the most damaged and showed that resveratrol, followed by amygdalin and U. dioica roots extract, drastically reduced DNA damage. This finding evidences the effectiveness of three natural compounds for DNA protection suggesting the possible use of feed enriched with antioxidant compounds in aquaculture practices for organisms damaged by natural and anthropic insults.     

Domestication and saponins contents in a gradient of management intensity of agaves: <Emphasis Type="Italic">Agave cupreata</Emphasis>, <Emphasis Type="Italic">A. inaequidens</Emphasis> and <Emphasis Type="Italic">A. hookeri</Emphasis> in central Mexico

Saponins occur in numerous plants, including agaves, determining benefic and harmful properties to humans; their presence may favor using plants as soap and other products, but also they may cause caustic effects producing contact dermatitis. In domestication, favorable and unfavorable properties of saponins may cause an increase or decrease of their content, respectively. This study quantified and identified saponins among wild and managed populations of three agave species: A. cupreata Trel. et Berger, A. inaequidens Koch with wild and cultivated populations used for mescal production, and A. hookeri Jacobi, existing exclusively cultivated, used for production of the fermented beverage pulque. We studied 272 plants from 19 populations, quantifying contents of crude saponins through spectrometry. In 12 populations, the saponins types were identified by High Performance Liquid Chromatography–Mass-Spectrography-Time-of-Flight HPLC-MS-TOF. The highest crude saponins content was recorded in A. hookeri (26.09 mg/g), followed by A. cupreata (19.85 and 15.17 mg/g in wild and cultivated populations, respectively). For A. inaequidens, we recorded 14.21, 12.95, and 10.48 mg/g in wild, silvicultural managed and cultivated populations, respectively. We identified 18 saponins types, A. inaequidens showing all of them. A hecogenin glycoside (HG1) is found in high amounts in A. hookeri but in low quantities in A. inaequidens and A. cupreata. A. inaequidens had the greatest diversity of saponins. The contents of crude saponins in A. inaequidens and A. cupreata decrease with management intensity, but contrarily to what we expected, it was the highest in A. hookeri. We hypothesize that such high amount could be due to some saponins, probably HG1, may be precursors of sugars.     

Cadmium Phytoextraction Efficiency of Arum (Colocasia antiquorum), Radish (Raphanus sativus L.) and Water Spinach (Ipomoea aquatica) Grown in Hydroponics

Selection of a phytoextraction plant with high Cd accumulation potential based on compatibility with mechanized cultivation practice and local environmental conditions may provide more benefits than selection based mainly on high Cd tolerance plants. In this hydroponics study, the potential of Cd accumulation by three plant species; arum (Colocasia antiquorum), radish (Raphanus sativus L.) and water spinach (Ipomoea aquatica) were investigated. Arum (Colocasia antiquorum L.) plants were grown for 60 days in a nutrient solution with 0, 10 or 50 μM Cd, while radish and water spinach plants grew only 12 days in 0, 1.5, 2.5, 5 or 10 μM Cd. Growth of radish and water spinach plants decreased under all Cd treatments (1.5 to 10 μM), while arum growth decreased only at 50 μM Cd. At 10 μM Cd treatment, the growth of arum was similar to the control treatment indicating higher tolerance of arum for Cd than radish and water spinach. Cadmium concentrations in different plant parts of all plant species increased significantly with Cd application in the nutrient solution. Arum and water spinach retained greater proportions of Cd in their roots, while in radish, Cd concentration in leaves was higher than in other plant parts. Cadmium concentrations in arum increased from 158 to 1,060 in the dead leaves, 37 to 280 in the normal leaves, 108 to 715 in the stems, 42 to 290 in the bulbs and 1,195 to 3,840 mg kg^?1 in the roots, when the Cd level in the solution was raised from 10 μM Cd to 50 μM Cd. Arum accumulated (dry weight?×?concentration) 25 mg plant^?1 at 10 μM, while the corresponding values for radish and water spinach were 0.23 and 0.44 mg plant^?1, respectively. With no growth retardation at Cd concentrations as high as 166 mg kg^?1 measured in entire plant (including root) of arum at 10 μM Cd in the nutrient solution, arum could be a potential Cd accumulator plant species and could be used for phytoremediation.     

Improvement of Sclerotinia sclerotiorum resistance in Brassica napus by using B. oleracea

Sclerotinia stem rot is one of the most serious diseases in rapeseed (Brassica napus) due to the lack of resistance sources. A high level of resistance was reported in Brassica oleracea cytodeme, one of parental species of rapeseed. In this study, a panel of 55 resynthesized lines of B. napus (RS lines) derived from seven wild and two cultivated types of B. oleracea was evaluated for Sclerotinia resistance over 2 years. Relative to ‘Zhongyou 821’, a cultivar of B. napus with partial resistance against S. sclerotiorum, RS lines exhibited stronger stem resistance. Although the resistant level of RS lines was lower than that of corresponding parental B. oleracea, a moderate correlation between resistance of RS line and corresponding parental B. oleracea type was found both for leaf (r = 0.74, P = 0.02) and stem (r = 0.69, P = 0.04). Our data suggests that the RS lines are important resources to improve Sclerotinia resistance of current rapeseed. A breeding strategy is discussed to enhance the Sclerotinia resistance of rapeseed by using B. oleracea.     

Glucosinolate Profiles of Arabidopsis thaliana in Response to Cadmium Exposure

The influence of cadmium on growth, cadmium accumulation, composition, and content of glucosinolates was investigated in Arabidopsis thaliana after 4 weeks of growth in hydroponics. Accumulation of 3,820 and 321 μg Cd g^?1 dry weight in the roots and leaves of A. thaliana, respectively, exposed to 50 μM Cd. Cadmium treatment significantly decreased the total concentration of glucosinolates both in the leaves and roots. Cd-induced alteration of total glucosinolate content in the roots was mainly due to the decrease of indolyl-glucosinolates. In the Cd treatment leaves, significant decreases were, respectively, detected for glucoibervirin and 4-methoxyglucobrassicin (P?<?0.01), while other glucosinolate levels did not decrease significantly. In response to cadmium, the three indolyl-glucosinolates all showed significant decreases in the roots. The distinctive influence of cadmium on glucosinolate profiles in Cd-sensitive A. thaliana may be of great ecological importance, decreasing the resistance to phytophage attack. Taken together, our data is discussed in relation to jasmonic acid and salicylic acid as possible molecules that modulate the alteration of glucosinolate profiles in response to cadmium. The similar effects of Cd treatment on the levels of individual glucosinolates in leaves and roots were observed at higher-concentration cadmium treatment (100 μM Cd).     

Uptake of Uranium by Lettuce (Lactuca sativa L.) in Natural Uranium Contaminated Soils in Order to Assess Chemical Risk for Consumers

Uranium mining activity in Cunha Baixa (Portugal) village has left a legacy of polluted soils and irrigation water. A controlled field experiment was conducted with lettuce (Lactuca sativa L.) in an agricultural area nearby the abandoned mine in order to evaluate uranium uptake and distribution in roots and leaves as well as ascertain levels of uranium intake by the local inhabitants from plant consuming. Two soils with different average uranium content (38 and 106 mg/kg) were irrigated with non-contaminated and uranium contaminated water (<20 and >100 μg/l). A non-contaminated soil irrigated with local tap water (<1 μg/l uranium) was also used as a control. Uranium in lettuce tissues was positively correlated with soil uranium content, but non-significant differences were obtained from contaminated soils irrigated with different water quality. Uranium in plants (dry weight) growing in contaminated soils ranged from 0.95 to 6 mg/kg in roots and 0.32 to 2.6 mg/kg in leaves. Lettuce bioconcentration is more related to available uranium species in water than to its uranium concentration. Translocated uranium to lettuce leaves corresponds to 30% of the uranium uptake whatever the soil or irrigation water quality. A maximum uranium daily intake of 0.06 to 0.12 μg/kg bodyweight day was estimated for an adult assuming 30 to 60 g/day of lettuce is consumed. Although this value accounts for only 10% to 20% of the recommended Tolerable Daily Intake for ingested uranium, it still provides an additional source of the element in the local inhabitants’ diet.     

花生根、茎中白藜芦醇含量影响因素

为了获得含白藜芦醇较多的花生根、茎作为提取白藜芦醇的原料。该文考察了华东不同地区、不同品种、不同采收时间以及采后存放、提取环境对花生根、茎中的白藜芦醇含量的影响。结果表明:白藜芦醇富集在花生根表皮,木质部含量较少;不同生长环境、不同品种对花生中白藜芦醇的含量影响较大;同一品种,采收时间越晚,白藜芦醇含量越高。采收后的花生根霉变会提高其中的白藜芦醇含量;花生中白藜芦醇在酸性条件下较为稳定,而碱性条件下易变性。采用合适品种的晚收花生根在酸性条件下提取可得到白藜芦醇含量较高的原料。     

A measure of genetic diversity of goldenseal (Hydrastis canadensis L.) by RAPD analysis

Goldenseal (Hydrastis canadensis L.) is a medicinal plant valued for the treatment of sore eyes and mouths. Although cultivation of the plant has helped meet growing demand, goldenseal is still considered a threatened or endangered species throughout much of its range in North America. In an effort to assess possible conservation strategies for goldenseal genetic resources, levels of genetic diversity within and among cultivated and wild populations were quantified. RAPD analysis was used to examine six cultivated and 11 wild populations sampled from North Carolina, Ohio, Pennsylvania, and West Virginia. The average percentage of polymorphic bands in cultivated and wild populations was low (16.8 and 15.5 %, respectively), and geographic range did not predict the level of genetic diversity. Most of the genetic variation (81.2 %) was within populations; only 3.6 % was partitioned between cultivated and wild populations. Our results differed from a previous study which concluded that genetic differences were greater among than within populations. The results of the current study indicate that, although goldenseal grows clonally and in dense patches, a mixed mating system in which both selfing and outcrossing occur is also operating. We therefore suggest that the ex situ conservation of individual plants within populations, chosen carefully to account for clonal propagation in situ, is an appropriate strategy for sustaining the genetic diversity of goldenseal.     

Genetic variation within and among species of five sections of the genus Arachis L. (Leguminosae) using RAPDs

Some Arachis species are widely used as commercial plants, e.g. the groundnut A. hypogaea, an important source of good quality protein and oil, and A. pintoi and A. glabrata, that are utilized as forage species. Germplasm of most Arachis species is available in germplasm banks. However, little it is known about the genetic attributes of this germplasm, and mainly about its genetic variability, which is very important for its maintenance. In the present study RAPDs were used to assay the genetic variation within and among 48 accessions of five sections of the genus Arachis and to establish the genetic relationships among these accessions. Ten of 34 primers tested were selected for DNA amplification reactions since they yielded the largest numbers of polymorphic loci. A dendrogram was constructed based on data from the 10 primers selected. Eighty RAPD polymorphic bands were analyzed among the accessions studied. The relationships among species based on RAPDs were similar to those previously reported based on morphological, cytological and crossability data; demonstrating that RAPDs can be used to determine the genetic relationships among species of the different sections of the genus Arachis. In general, wide variation was found among accessions and low variation was found within the accessions that had two or more plants analyzed. However, higher polymorphism was found in the section Trierectoides and in one accession of A. major, indicating that generalizations should be avoided and each species should be analyzed in order to establish collection and maintenance strategies.     

Genomic affinities of <Emphasis Type="Italic">Arachis</Emphasis> genus and interspecific hybrids were revealed by SRAP markers

The Arachis genus is native to South America, and contains 70–80 described species assembled into nine sections. A better understanding of the level of speciation and taxonomic relationships is a prerequisite to the effective use of Arachis species in peanut breeding programs. Forty-eight genotypes representing 19 species in 6 sections were evaluated to assay the genetic variability within and among species, and 10 recombinant lines and those parents were identified with introgression of Arachis species chromosome segments into A. hypogaea genome using SRAP markers. Sixty of sixty-four SRAP primers tested were selected for DNA amplification reactions. A dendrogram and principal component analysis were constructed based on 353 SRAP polymorphic bands of the accessions. The number of scored polymorphic bands per each primer combination varied from 1 to 25 with an average of 5.9 per reaction. Estimates of genetic distance among the 48 accessions Arachis species ranged from 0.11 to 0.76. A-genome accessions 475845 (A. duranensis), and 331197 (A. villosa) were most closely associated to A. hypogaea. The first two PCAs accounted for 77.74% (62.02 and 15.72%) of the total variation observed and separated the different genomic groups. SRAPs also identified introgression of Arachis species chromosome segments into A. hypogaea. genome with 10 recombinant lines and those parents. The present results indicated that SRAPs can be used to determine the genetic relationships among species of the different sections of the genus Arachis and to identify introgression of Arachis genus chromosome segments into A. hypogaea genome.     

Evaluation of genetic relationships among botanical varieties of cultivated peanut (Arachis hypogaea L.) using AFLP markers

Forty-four accessions of cultivated peanut (Arachis hypogaea L.) representing sixbotanical varieties of two subspecies along with three accessions ofthe wild relative A. monticola Krapov et Rigoni were evaluated for their genetic relationships using theAFLP marker technology. Fifteen AFLP primer pairs (EcoRI/MseI) generated 28distinct polymorphic markers that were employed to develop uniqueprofiles of all accessions and to construct a phenogram. The resultsshowed that the botanical varieties aequatoriana and peruviana werecloser to subspecies hypogaea than subspeciesfastigiata Waldr. to which they belong, and the wildA. monticola was notdistinct from the cultivated A.hypogaea. Although the extent of geneticdiversity in peanut is low compared to many other crops, our studiesshow that by employing the AFLP approach, sufficient DNA variationcan be detected in the cultivated peanut germplasm to conductevolutionary studies.     

Diversity of the European indigenous wild apple (Malus sylvestris (L.) Mill.) in the East Ore Mountains (Osterzgebirge), Germany: II. Genetic characterization

In the present study genetic diversity and hybridization with cultivars were investigated in a population of the endangered European wild apple species Malus sylvestris (L.) Mill. with the aim to establish a basis for the implementation of conservation activities and to ensure its long-term preservation. A total of 284 putative M. sylvestris trees located in the East Ore Mountains were investigated along with a standard set of reference apple genotypes proposed by the European Cooperative Program for Plant Genetic Resources (ECPGR) and 13 old apple cultivars often cultivated in Saxony. The genetic analysis was performed using 12 microsatellite markers also recommend by the ECPGR. To differentiate ‘true type’ M. sylvestris individuals, hybrids and apple cultivars (Malus × domestica Borkh.) a model-based cluster analysis was performed using STRUCTURE. Two clusters were identified consisting of M. sylvestris and M. × domestica genotypes. About 40 % of the putative M. sylvestris showed an admixture of the species-specific allele frequencies and were defined as hybrids. The genetic diversity of the ‘true type’ M. sylvestris population was still high but slightly lower than in the apple cultivars especially since some SSR loci were fixed on one or few alleles in the M. sylvestris population. The differentiation parameters between ‘true type’ wild apple and cultivars indicated a clear discrimination between the wild and cultivated apple individuals. This fact confirms our expectation of the existence of ‘true type’ M. sylvestris individuals in the East Ore Mountains and argues for the realization of preservation measures in this area.     

Genetic diversity and species delimitation in the cultivated and wild Guinea yams (Dioscorea spp.) from Southwest Ethiopia as determined by AFLP (amplified fragment length polymorphism) markers

Yams (Dioscorea spp.) rank as the fourth most important root and tuber crop after potatoes, cassava and sweet potatoes. They are an economic crop in most of the tropics especially in West Africa, which produces over 95 % of the world output. Despite their cultural and economic importance there is taxonomic confusion regarding Guinea yams. The currently used classification scheme, which relies on vegetative and inflorescence characters, does not consistently delimit species boundaries between members of Guinea yams (D. cayenensis Lam.–D. rotundata Poir. complex), their wild relatives (D. abyssinica Kunth and D. praehensilis Benth.,) and D. sagittifolia Pax. Establishing the taxonomic identity of the germplasm and understanding the systematic relationships among crops is vital to the management of genetic resources and the utilization of accessions. In this study, amplified fragment length polymorphism (AFLP) genetic fingerprinting was used to evaluate and characterize 43 individual plants, belonging to different populations of wild and cultivated Guinea yams. The three primer combinations used in the AFLP analyses generated 158 scorable bands, with an overall polymorphism of 78 %. Ordination and cluster analyses of AFLP data failed to produce any clear species boundary between either the Guinea yam accessions or between them and their wild relatives. The average genetic similarity between the study individuals of Guinea yams and their wild relatives ranged from 60 to 100 %. The first, second and third principal coordinates axes cumulatively account for 77.45 % of the total variation. AFLP analyses also revealed a higher genetic divergence among cultivated Guinea yam accessions of the Sheko cultivars. Ordination and cluster analysis using UPGMA revealed no clear species boundaries between members of the complex. Thus, the taxonomy of these “species” needs to be revisited using other markers.     

Phylogenetic relationships, interspecific hybridization and origin of some rare characters of wild soybean in the subgenus Glycine soja in China

The Glycine subgenus Soja includes two species, cultivated soybean [(Glycine max (L.) Merr.)] and the progenitor wild soybean (G. soja). However, a morphologically intermediate form, the semi-wild soybean (G. gracilis), exists between the two species, and its taxonomic position is under debate. In this study, we evaluated phylogenetic relationships and occurrence events within the subgenus Soja based on genetic variation of SSR loci using a set of accessions comprising wild soybeans (≤3.0?g 100-seed weight), semi-wild soybeans (>3.0?g) and soybean landraces (≥4.0?g). The results showed that semi-wild soybean accessions collected in natural fields should be treated as a variant of G. soja and not of G. max, and were genetically differentiated from the soybean landraces, even large-seeded semi-wild soybean accessions (6.01–9.0?g) with seed weights overlapping with or exceeding those of soybean landraces. Evolutionary bottleneck analysis indicated that semi-wild soybean is not a transitional form in the domestication of cultivated soybeans from wild soybean. G. soja contained two genetically differentiated forms, small-seeded type (typical, plus 2.01–2.50?g) and a large-seeded type (2.51–3.0?g). Genetically, the large-seeded wild soybean was closer to the semi-wild soybean, although in morphology it resembled the typical wild soybean. Ancestry analysis confirmed that cultivated soybean genes have introgressed into modern wild soybean populations. The green cotyledon character and other rare characters such as white flower, grey pubescence, no-seed bloom, and coloured seed-coats (brown, green, and yellow) in wild soybean were shown to be involved in introgression from cultivated soybeans.