Study on Genetic Diversity of Agronomic Traits and Genetic Relationships among Core Collections of Bitter Gourd

[Objective] This study aimed to investigate the genetic diversity of agronomic traits and genetic relationships among core collections of bitter gourd.[Method] Total 141 germplasms of bitter gourd were selected,and the genetic diversity of 13 agronomic traits was analyzed.In addition,total 46 core collections of bitter gourd were employed,and their genetic relationships were analyzed based on the phenotypic values and genotypic values of 5 agronomic traits,respectively.[Result] The genetic diversity analysis of agronomic traits showed that the genetic diversity indexes of the 4 qualitative traits of bitter gourd germplasms ranged from 0.46 to 1.34;the distribution of the 9 quantitative traits data was more dispersed with average coefficient of variation of 20.02%.The genetic relationship analysis showed that based on the phenotypic values and genotypic values of the 5 quantitative traits,the genetic distances among the 46 core collections of bitter gourd were different.Based on the genotypic values,the genetic distances among the 46 bitter gourd core collections ranged from 0.84 to 10.71.The 46 germplasms were divided into 17 groups with the rescaled distance of 8.5,which further classified the relationships among different germplasms.[Conclusion] This study will lay a solid foundation for the effective utilization of core collections and new variety breeding in bitter gourd.

Analysis of genetic diversity and structure across a wide range of germplasm reveals genetic relationships among seventeen species of Malus Mill,native to China

China is a center of diversity for Malus Mill,with 27 native species including 21 wild species and six domesticated species.We applied a set of 19 simple sequence repeat markers to genotype 798 accessions of 17 species(12 wild species and five cultivated species)of Malus originating from 14 provinces in China.A total of 500 alleles were detected.Diversity statistics indicated a high level of genetic variation as quantified by the average values of the effective allele number(N_(e)).expected heterozygosity(H_(e)),and Shannon's Information Index(I)(10.309,0.886,and 2.545,respectively).Malus sieversii(MSR;H_(e)=0.814,I=2.041,N_(e)=6.054),M.baccata(MBB;H_(e)=0.848,/=2.350,N_(e)=8.652),M.toringoides(MTH;He=0.663,I=1.355,N_(e)=3.332),and M.hupehensis(MHR;H_(e)=0.539,I=0.912,N_(e)=0.579)showed a higher level of genetic diversity in this study than the previous studies.MSR and MBB contributed to the origin and evolution of some accessions of M.domestica subsp.chinensis(MDC).However,other accessions of MDC showed a closer genetic distance with MBB and cultivated species,especially M.robusta(MRB),M.asiatica(MAN),and M.prunifolia(MPB).Not all accessions of MDC were descended from MSR in Xinjiang Uygur Autonomous Region of China.This research provides novel insights into the genetic relationships of Malus native to China,which will be useful for genetic association studies,germplasm conservation,and breeding programs.

Evaluation of the effect of genetic diversity and phylogenetic relationships on different strains of Staphylococcus aureus in clinical specimens

Introduction:Staphylococcus aureus is one of the main pathogens in humans.Also,this bacterium can be colonized in the nose.The spa gene is present in all strains of Staphylococcus aureus(S.aureus)and can be used to identify species and toxins such as Panton-Valentine Leukocidin(PVL)that can affect a wide range of skin,soft tissue,and necrotizing pneumonia.Arthritis and life-threatening infections.This study aimed to investigate the effect of genetic diversity and phylogenetic relationships on different strains of Staphylococcus aureus in clinical specimens.Methods:This review study was conducted in 2021 by searching for keywords such as genetic diversity,phylogenetics,and Staphylococcus aureus in reputable databases such as pub med and google scholar.Finally,30 articles were found,of which 30 articles were used out of 26 articles.Results:In general,23%and 18%of health care workers and patients were carriers,respectively.The incidence of methicillin-resistant Staphylococcus aureus(MRSA)is higher in the relevant population.The molecular types of MRSA isolates indicate that the most common virulence gene is Hla,and the most common type of SCCmec is SCCmec type III.Conclusion:Sites with high risk of Staphylococcus aureus should be highly protected,and relevant personnel should be paid attention and health management.

Evaluation of Genetic Diversity and Genetic Relationship of Large Fruited Tomato Core Germplasms Based on Genotypic Value

[Objective] The paper aimed to analyze genetic diversity and genetic relationship of large fruited tomato core germplasms based on genotypic value.[Method] Taking 55 large fruited tomato core germplasms as tested materials, the genetic diversity of seven agronomic traits was analyzed, and the correlation between traits and genetic relationship between germplasms were analyzed based on genotypic effect value.[Result] The diversity indexes of seven agronomic traits were 3.98, 3.97, 3.99, 3.99, 3.97, 3.98 and 3.87, respectively, indicating there were rich genetic diversities in large fruited tomato core germplasms. Correlation analysis of traits was conducted based on genotypic effect value. The results showed that there was extremely significant positive correlation between leaf length and leaf width, and the correlation coefficient was 0.66. There was extremely significant positive correlation between fruit length and fruit width, with a correlation coefficient of 0.49. There was extremely significant positive correlation between weight per fruit and fruit width, with a correlation coefficient of 0.46. The genetic distance between large fruited tomato core germplasms was calculated based on the phenotypic value of traits. When the distance was 5, 55 large fruited tomato core germplasms were divided into three groups. The genetic distance between large fruited core germplasms tomato was calculated based on genotypic predictive value of traits. When the distance was 10, 55 large fruited tomato core germplasms were divided into six groups. Comparing the results of two clustering analysis, it was found that the clustering analysis based on genotypic value could better explain the genetic relationship between germplasms.[Conclusion] The results could provide some basis for understanding the population variation of large fruited tomato and genetic improvement of tomato cultivars.

Analysis on Genetic Diversity of 40 Flowering Cherry Cultivars and Construction of Molecular ID Based on SSR Markers

Studying on the genetic diversity and genetic relationship of flowering cherry cultivars is extremely important for germplasm conservation, cultivar identification and breeding. Flowering cherry is widely cultivated as an important woody ornamental plant in worldwide, especially Japan, China. However, owning to the morphological similarity, many cultivars are distinguished hardly in non-flowering season. Here, we evaluated the genetic diversity and genetic relationship of 40 flowering cherry cultivars, which are mainly cultivated in China. We selected 13 polymorphicprimers to amplify to allele fragments with fluorescent-labeled capillary electrophoresis technology. The population structure analysis results show that these cultivars could be divided into 4 subpopulations. At the population level, Na and Ne were 6.062, 4.326, respectively. Ho and He were 0.458 and 0.670, respectively. The Shannon’s information index (I) was 1.417. The Pop3, which originated from P. serrulata, had the highest Ho, He, and I among the 4 subpopulations. AMOVA showed that only 4% of genetic variation came from populations, the 39% variation came from individuals and 57% (p < 0.05) came from intra-individuals. 5 polymorphic SSR primers were selected to construct molecular ID code system of these cultivars. This analysis on the genetic diversity and relationship of the 40 flowering cherry cultivars will help to insight into the genetic background, relationship of these flowering cherry cultivars and promote to identify similar cultivars.

Assessment of the Genetic Relationship and Diversity of Mango and Its Relatives by cpISSR Marker

Chloroplast inter-simple sequence repeat markers in mango were developed and used to analyze the genetic relationship and diversity of mango and its relatives. Thirty-six mango cultivars （Mangifera indica L.） and its relative species collected from the fruit germplasm collection in the Guangxi Academy of Agricultural Sciences, China, were examined by ISSR-PCR with chloroplast DNA （cpDNA）. Eight better primers for chloroplast DNA that provided reproducible, polymorphic DNA amplification patterns were screened from 50 ISSR primers and used for UPGMA analysis. According to the band patterns with 8 primers for chloroplast DNA, all cultivars tested were distinguished from each other and these showed ample genetic diversity; the average percentage of polymorphism was 77.2%. The 36 samples could be clustered into four groups by UPGMA analysis at the coefficient 0.74. The results indicated that the cplSSR marker was a new powerful tool for the identification of mango cultivars or its relative species, and their genetic relationship analysis and diversity evaluation.

Genetic relationship and pedigree of Chinese watermelon varieties based on diversity of perfect SNPs

Watermelon(Citrullus lanatus)is one of the world’s most important fruit crops,and China produces the most watermelons in the world.Recently,a watermelon variome consisting of 414 key resequenced accessions was reported.However,the genetic relationships and pedigree of Chinese watermelon varieties in the seed market remain unclear.In this study,241 evenly distributed perfect single nucleotide polymorphisms(SNPs)derived from the watermelon variome were selected for variety identification.The diversity of 247 Chinese watermelon varieties was identified based on their SNP genotypes.The 247 watermelon varieties were clustered into five subpopulations:the East Asian ecotype,intermediate ecotype,small fruit with red flesh ecotype,small fruit with yellow flesh ecotype,and American ecotype.We further established the pedigree of four subpopulations,of which JingXinNo.1,ZaoChunHongYu,HuangXiaoYu and XiaoLan,and Sugarlee were the main doner of the East Asian ecotype,small fruit with red flesh ecotype,small fruit with yellow flesh ecotype,and American ecotype,respectively.Thirty-two core SNPs were selected and applied in watermelon variety identification.They were also validated by the Kompetitive allele-specific PCR(KASPar)platform.The present study furthered our understanding of the genetic relationships and pedigree of watermelon varieties in China,and will help to manage the plant variety protection in watermelon.

Epidemiological Surveillance: Genetic Diversity of Rotavirus Group A in the Pearl River Delta, Guangdong, China in 2019

Objective This study aimed to understand the epidemic status and phylogenetic relationships of rotavirus group A(RVA)in the Pearl River Delta region of Guangdong Province,China.Methods This study included individuals aged 28 days–85 years.A total of 706 stool samples from patients with acute gastroenteritis collected between January 2019 and January 2020 were analyzed for 17 causative pathogens,including RVA,using a Gastrointestinal Pathogen Panel,followed by genotyping,virus isolation,and complete sequencing to assess the genetic diversity of RVA.Results The overall RVA infection rate was 14.59%(103/706),with an irregular epidemiological pattern.The proportion of co-infection with RVA and other pathogens was 39.81%(41/103).Acute gastroenteritis is highly prevalent in young children aged 0–1 year,and RVA is the key pathogen circulating in patients 6–10 months of age with diarrhea.G9P[8](58.25%,60/103)was found to be the predominant genotype in the RVA strains,and the 41 RVA-positive strains that were successfully sequenced belonged to three different RVA genotypes in the phylogenetic analysis.Recombination analysis showed that gene reassortment events,selection pressure,codon usage bias,gene polymorphism,and post-translational modifications(PTMs)occurred in the G9P[8]and G3P[8]strains.Conclusion This study provides molecular evidence of RVA prevalence in the Pearl River Delta region of China,further enriching the existing information on its genetics and evolutionary characteristics and suggesting the emergence of genetic diversity.Strengthening the surveillance of genotypic changes and gene reassortment in RVA strains is essential for further research and a better understanding of strain variations for further vaccine development.

Genome-wide SNP markers provided insights into the reproductive strategy and genetic diversity of the green tide causative species Ulva prolifera in China

Ulva prolifera is the causative species of the annually occurring large-scale green tides in China since 2007.Its specific biological features on reproductivity strategies,as well as intra-species genetic diversity,are still largely unknown,especially at the genome level,despite their importance in understanding the formation and outbreak of massive green tides.In the present study,the restriction site-associated DNA genotyping approach(2b-RAD)was adopted to identify the genome-wide single-nucleotide polymorphisms(SNPs)of 54 individual thalli including samples collected from Subei Shoal in 2019 and Qingdao coast from 2019 to 2021.SNPs genotype results revealed that most of the thalli in 2019 and 2020 were haploid gametophytes,while only half of the thalli were gametophytes in 2021,indicating flexibility in the reproductive strategies for the formation of the green tides among different years and the dominance of asexual and vegetative reproductive mode for the floating period.Besides,population analysis was conducted,and it revealed a very low genetic diversity among samples from Subei Shoal and the Qingdao coast in the same year and a higher divergence among samples in different years.The results showed the efficiency of 2b-RAD in the exploration of SNPs in U.prolifera and provided the first genome-wide scale evidence for the origin of the large-scale green tides on the Qingdao coast.This study improved our understanding of the reproductive strategy and genetic diversity of the green tide causative species and will help further reveal the biological causes of the green tide in China.

Impact of Genetic Diversity of Uropathogenic Escherichia coli and Klebsiella pneumoniae Strains on the Dissemination of Extended Spectrum Beta-Lactam Resistance Genes in Côte d’Ivoire

The increase and spread of bacterial resistance to extended-spectrum beta-lactam antibiotics are reported in many infections and are a real public health problem worldwide. Drug pressure is a factor that favors the emergence of a population of better adapted bacteria. However, there is no literature highlighting the genetic diversity and evolutionary structure of E. coli and K. pneumoniae in an environment with high selection pressure in Côte d’Ivoire. The objective of this study was to evaluate the genetic diversity of E. coli and K. pneumoniae strains circulating at the HKB Hospital in Abobo and at the Daloa Regional Hospital and its impact on the dissemination of extended spectrum beta-lactam resistance genes. A total of 39 strains isolated from the urinary tract of infected patients, including 30 strains of E. coli and 9 strains of K. pneumoniae were studied. A total of 39 strains isolated from the urinary tract of infected patients, including 30 strains of E. coli and 9 strains of K. pneumoniae were studied. From genomic DNA extracts, ESBL resistance genes were amplified by PCR and sequenced, in addition to genetic typing by ERIC-PCR. The data obtained were submitted to genetic and bioinformatics analyses. The results have shown a genetic diversity important in E. coli and K. pneumoniae with diversity indexs (SID) ranging from 0.5 to 0.77. The genetic structure of the bacterial species studied has shown a clonal distribution of strains with clones expressing TEM-9 and CTX-M-15 variants. Also, this clonal structure was correlated with the spread of resistance genes in E. coli and K. pneumoniae. The spread of resistant clones is a factor that might limit the fight against antibiotic resistance.

Genetic Relationships Among Four Minorities in Guangxi Revealed by Analysis of 15 STRs

The aim of this study is to investigate the genetic diversity in 15 STRs （short tandem repeats） loci of four minorities in Guangxi Province and to probe into the genetic variation and relationships among these ethnic groups. Allele frequencies of 15 STR loci were collected from 766 unrelated Mulao, Maonan, Miao, and Yao ethnic individuals by PCR-STR and sequencing, and their allele-frequency distribution were compared with each other. The genetic parameters and genetic distances were calculated, and the phylogenetic tree was constructed. Based on the results from this study, 135, 134, 148, and 145 alleles and 424, 432, 445, and 436 genotypes for 15 STR loci were observed in the Mulao, Maonan, Miao, and Yao minorities, respectively. The average heterozygosity of all ethnic groups analyzed was above 0.7; the cumulative power of discrimination （DP）, the probabilities of paternity exclusion （EPP）, and the polymorphic information content （PIC） were greater than 0.99999. Comparison of the allele-frequency distribution indicated that there were significant differences at most loci between Maonan vs. Miao, Yao vs. other groups, but no distinct differences between Mulao vs. Maonan, and Mulao vs. Miao minorities. The NJ tree based on the genetic distance showed that the four minorities were separated into two groups. Mulao and Maonan were clustered into one group, whereas Miao and Yao into the other. Our results revealed that 15 STR loci of the four minorities possessed high genetic diversities. Therefore, the combination of these 15 STRs is a powerful tool for forensic individual identification and paternity investigation, as well as anthropologic and genetic researches. The genetic variation and relationships among the 4 populations revealed by 15 STRs are basically consistent with their linguistic culture and ethical history.

ISSR Analysis of Genetic Relationship of Germplasm Resource in Prunus mume Sibe. et Zucc

Using ISSR technique to analyze the diversity and genetic relationship of germplasm resources in 39 Prunus mume Sibe. et Zucc., the result showed that 10 primers were screened with high resolution from 51 primers, 120 fragments were amplified, of which 98 were polymorphic loci, accounting for 81.67% of total. Tested materials were divided into 3 classes, as was fundamentally accorded with the traditional classification base on horticulture. There was no obvious difference in geographic relationship among the clustering results.

Genetic relationship of interspecies for eight birch species

Genetic relationships of eight species of genus Betula were evaluated using ISSR marks. A total of 236 loci were generated from 17 ISSR primers. Percentage of polymorphic bands (PPB) varied from 5.93 to 19.92. The highest and the lowest level of genetic differentiation were detected in B. ovalifolia and B. maximowicziana Regel respectively. In these eight species, genetic diversity of birch (HT) was 24.38 %, and the genetic variation (GST ) interspecies was accounting for 79.36% of total genetic variation. According to the cluster results of genetic distance, the eight species were classified into three groups as B. davurica, B. ovalifolia, B. platyphylla and B. pendula for one group; B. schmidtii, B. costata and B. ermanii Cham. var. communis for one group, and B. maximowicziana Regel for another group. The result of cluster is consistent with traditional morphological classification.

Analysis of Genetic Diversity of Dendrobium by RSAP Marker

[Objective] This study aimed to analyse the genetic diversity of and genet- ic relationship between 33 Dendrobium species by using RSAP （Restriction Site Amplification Polymorphism） marker technique. [Method] A PCR-reaction system was established, by which 33 pairs of primers screened from 45 pairs were used to con- duct the PCR amplification. [Results] The 33 pairs of primers produced 2 047 ampli- fied fragments, of which 2 044 were polymorphic, with a polymorphism rate of 99.8%, and each pair of primers produced 61.9 polymorphic fragments on average. The genetic similarity coefficients between species ranged from 0.081 to 0.442, sug- gesting that the experimental materials used in this study possess a wide genetic background. According to the result of RSAP, the 33 Dendrobium species were di- vided into 6 groups by the cluster analysis （UPGMA）. The result showed that the genetic relationship between D. acinaciforme and D. guangxiense was the closest, and that between D. sinense and either D. lituiflorum or D. hancockii was the fur- thest. [Conclusion] The result suggested that Dendrobium germplasms have a great genetic diversity. This study provides a molecular basis for the classification and breeding of Dendrobium plants, as well as the selection of hybridization parents in the future.

Analysis of Genetic Relationships in Prunus domestica L. in Xinjiang Using ISSR Markers

[Objective] This paper aimed to explore the genetic relationships among different types of Prunus domestica L. in Xinjiang. [Method] The inter-simple se- quence repeat （ISSR） markers were applied to analyze the genetic diversity and relationships among 30 individual plants from 5 types of P. domestica germpiasm resources in Xinjiang. [Result] A total of 317 bands were amplified by 16 selected IS- SR primers. Among the amplified bands, there were 246 polymorphic bands, accounting for 77.60% of the total. The Nei＇s gene diversity index （H） of individuals was 0.266 6. The average Shannon＇s information index （I） of individuals was 0.399 1. And most of the genetic similarity coefficients ranged from 0.555 2 to 0.996 8. It is indicated that the P. domestica germplasm resources have a certain genetic diversity in Xinjiang. The cluster analysis showed that, at the genetic similarity coefficient of 0.719, the 30 individuals were divided into 3 major groups, including a group of introduced European plum varieties, a group of Tacheng Smoked Plum and Tacheng Binzi and a group of Jiashi Smoked Plum and Wild European Plum. While at the genetic similarity coefficient of 0.949, Jiashi Smoked Plum and Wild European Plum were divided into two small groups. [Conclusion] There are very close genetic relationships between Jiashi Smoked Plum and Wild European Plum, and among the introduced European plum varieties, Tacheng Smoked Plum and Tacheng Binzi.

Investigating the genetic diversity of several varieties of Iranian tomato (Solanum lycopersicum) using RAPD and ISSR molecular markers

Background:Numerous studies have demonstrated the existence of approximately 7,500 genetic tomato varieties worldwide.Hence,it is crucial to assess the genetic diversity among tomato cultivars.This study aimed to investigate the genetic diversity of selected Iranian tomato cultivars(Solanum lycopersicum)using RAPD and ISSR molecular markers.Method:Ten RAPD primers and ten ISSR primers were employed to assess the genetic diversity among 10 tomato cultivars:Matin,RFT 112,Hirad,Golsar,Raha,Hengam,Hedah,Fasa,JS12,and Emerald.Data analysis involved the UPGMA algorithm and NTYSYSpc software.Results:RAPD analysis revealed close genetic proximity between Fasa and JS12,as well as between Raha and Hadieh.Conversely,the RFT 112,Hengam,Hirad,and Emerald cultivars exhibited significant genetic diversity within this group.ISSR primer analysis identified Hengam as the most diverse variety,while Matin,Emerald,and Vibrid,as well as Raha and JS12,displayed genetic similarities with minimal observed diversity.Furthermore,the overall analysis of the cultivars using RAPD and ISSR markers indicated that Hengam exhibited the highest diversity among all the varieties.Notably,Raha and JS12 demonstrated limited diversity in this analysis.Conclusion:This research demonstrates substantial genetic diversity among the investigated tomato varieties,with Hengam displaying the highest diversity within this group.Furthermore,ISSR markers proved more effective in determining genetic diversity in tomato plants.

Genetic Relationships Among Soluble Carbohydrates, Anthocyanins and Growth Characteristics in Leymus (Gramineae) Detected with Molecular Markers

Low-temperature soluble carbohydrate accumulations are commonly associated with anthocyanin coloration, attenuated growth and cold adaptation of cool-season grasses. The vrn-1 gene has potent effects on vernalization requirement, growth, and soluble carbohydrate accumulations of the winter-annual Triticeae species. Two hundred and four unmapped AFLP markers and genome-specific DNA markers genetically linked to the vrn-1 gene were used to detect QTL controlling soluble carbohydrate accumulations, anthocyanin coloration and growth characteristics in a segregating population derived from open pollinated Leymus cinereus x L. triticoides hybrids. These perennial Triticeae grasses are distinguished by adaptation and growth habit. As expected, positive trait correlations and pleiotropic gene effects were detected for soluble carbohydrate accumulations and anthocyanin coloration. Likewise, positive trait correlations and pleiotropic gene effects were detected for tillering, leaf development, leaf growth, regrowth and rhizome spread. However, soluble carbohydrate accumulations were not associated with attenuated growth. In fact, several DNA marker alleles, including one near vrn-Ns1, had positive effects on soluble leaf carbohydrate concentrations and low temperature growth. The corresponding DNA marker near vrn-Ns1 had more specific effects on tillering. We speculate that vrn-1 exerts quantitative effects on low-temperature soluble leaf carbohydrate accumulations and growth habit of the perennial Leymus. However, a number of other DNA markers displayed highly significant effects on soluble carbohydrate accumulations and various growth characteristics. Findings indicate that anthocyanin coloration may be a useful phenotypic marker for soluble carbohydrate accumulation. Although variation for soluble carbohydrates was not associated with attenuated growth in this population, this trait was under genetic control.

Relationship Between Hybrid Performance and Genetic Diversity Based on SSRs and ISSRs in Brassica napus L.

To investigate the relationship between genetic distance (GD) and hybrid performance, two types of molecular markers, microsatellites (simple sequence repeats, SSRs) and intro-simple sequence repeats (ISSRs), were employed to detect the genetic diversity of 3 double low self-incompatible lines and 22 male parental varieties of Brassica napus from different geographical origins. Hybrids were produced in a NCⅡ mating design by hand-pollination. The result indicated that 25 parental varieties (lines) could be divided into six groups by Un-weighted Pair Group Mathematics Average (UPGMA) clustering based on GDs. SI-1300 and SI-1320 could be singly clustered into one group, respectively. Varieties from China could be separated into another group, SI-1310 and varieties from foreign countries could be separated into other three groups. The grouping was generally consistent with parental pedigrees and geographical origins. Significant differences in yield, quality and phenological period traits were observed among these parent groups. Although hybrid yield/plant showed significantly positive correlation with genetic distance based on SSR and ISSR markers, but the determination coefficient was low. It appeared to be unsuitable for using the genetic distance based on SSR and ISSR markers to predict heterosis and hybrid performance in Brassica napus.

Genetic diversity and phylogenetic relationships between and within wild Pistacia species populations and implications for its conservation

Although cultivation and utilization of Pistacia are fully exploited, the evolutionary history of the Pistacia genus and the relationships among the species and accessions is still not well understood. The aim of this study was to analyze random amplified polymorphic DNA（RAPD） in a total of 50 accessions of wild pistachio species, which included five populations Pistacia vera, Pistacia khinjuk,Pistacia atlantica, Pistacia mutica, and Pistacia eurycarpa.High levels of genetic diversity were detected within wild pistachio accessions, as revealed by using the unweighted pair-group method with arithmetic averaging and supported via analysis of molecular variance. The objectives of this investigation were to estimate marker indices, polymorphic information contents（PICs）, and genetic similarities（GS）for RAPD markers; assess the genetic diversity of Pistacia species, using GS estimated from RAPD fingerprints and molecular characterization; and facilitate the use of markers in inter-specific introgression and cultivar improvement.Out of the 149 polymerase chain reaction fragments that were scored, 146（97.98 %） were polymorphic. Genetic similarities ranged from 0.3 to 0.86 %, marker indices ranged from 2.98 to 17.74 %, and PICs ranged from 0.80 to0.99 %. Our results provided great molecular identification of all assayed genotypes, which have shown that there is large quantity of genetic diversity among the pistachio accessions. This finding might render striking information in breeding management strategies for genetic conservation and cultivar development.

Analysis on genetic diversity of mangrove species of Sonneratia and relationship to plant introduction

RAPD markers were used to assess the relationships among 6 species of Sonneratia in the National Mangrove Nature Reserve of Dongzhai Harbor in Hainan. By using the 15 effective 10 -oligonucleotide arbitrary primers, a total of 512 DNA bands were amplified, among which 297 (58.01%) were polymorphic. Based on UPGMA cluster analysis of 512 DNA bands amplified by the thirty primers, a DNA molecular dendrogram was established, which divided 6 species of Sonneratia into three main groups. Group A included 4 species: Sonneratia apetala , S. hainanensis, S. abla, S. ovata, and Group B: S. paracaseolaris and Group C: S. caseolaris only contained one species respectively. Group A could be divided into two subgroups, A1; Sonneratia apetala , S. hainanensis, S. covata and A2: S. abla; Two populations of Sonneratia apetala, which were from Hainan and Fujian (introduced from Hainan) respectively, were compared by RAPDs. The phenotypic frequencies detected by the 15 primers were calculated and used to estimate diversity (H) within sub-populations. Fujian sub-population exhibited 0.669 and Hainan exhibited 0.671 variability. Shannon's index of phenotypic diversity was then used to partition the diversity within and between sub-populations components. An assessment of the proportion of diversity present within sub-populations, Hpop/Hsp = 0.933, compared with that between sub-populations, (Hsp- Hpop) /Hsp = 0.067, indicates that, on average, most of the diversity (93.3%) is detected within sub-populations; while only 6.7% between populations. The plant introduction of S. hainanensis and S. ovata, which have the nearer genetic distance with Sonneratia apetala , is also discussed.