Shannon's Information Index Research Articles

Genetic diversity between and within full-sib families of Jatropha using ISSR markers

The aim of this study was to evaluate the genetic diversity between and within of six full-sib families of Jatropha through ISSR molecular markers. Six genitors were selected based on oil and seed potentiality. A set of 20 ISSR markers was used. The genetic distances were estimated based on Jaccard similarity coefficient and the descriptive statistics of populations for estimation of genetic parameters were also performed. A total of 177 polymorphic bands were obtained. The polymorphism within full-sib families ranged from 22 to 51.6% for families 2 and 5, respectively. The similarity analysis between families presented an average distance of 61%. The effective number of alleles varied from 0.56 to 1.86. The lowest value for Nei’s gene diversity index was 0.34 and the largest was 0.46 and the Shannon information index ranged from 0.51 to 0.65. The genetic variability analysis, by ISSR molecular markers showed low genetic dissimilarity within of full-sib families of Jatropha. However, the evaluation between the full-sib families demonstrated that the accessions belonging to family 1 are the most divergent, and should be considered in future artificial hybridations strategies.

Exploring the genetic variations and population structure of Turkish pepper (Capsicum annuum L.) genotypes based on peroxidase gene markers.

Capsicum is thought as one of the most diverse and significant genera due to its varied uses in different parts of the world. In this study, we worked with a total of 71 pepper genotypes from different locations of Turkey to investigate the level of their diversity using the peroxidase gene polymorphism (POGP) markers to reveal their population structure. For this purpose, 14 peroxidase primer pairs were used. They produced 139 bands (mean = 9.9 bands/primer), of which ~ 85.6% were polymorphic in the all germplasm collection. Polymorphism information content (PIC) ranged between 0.48 and 0.97 with an average of 0.75. Range and mean values for gene diversity (h) were 0.09-0.22 and 0.17, respectively. Shannon's information index (I) per POGP marker ranged from 0.18 to 0.35 with a mean of 0.29. Using three clustering methods (unweighted pair-group method with arithmetic means, principal coordinate analysis, and STRUCTURE) revealed a clear separation of all the C. annuum accessions from C. frutescens and C. chinense accessions in our study. Clusters did not establish an association between the accessions and their geographical origin. This is the first study exploring the population structure through the genetic diversity of Turkish peppers from different regions of the country based on the peroxidase gene markers.

Interspecies and intraspecies genetic diversity of Ongole Grade cattle and Madura cattle based on microsatellite DNA markers

Sutarno, Kurnianingrum N, Herawati E, Setyawan AD. 2018. Interspecies and intraspecies genetic diversity of Ongole Grade cattle and Madura cattle based on microsatellite DNA markers. Biodiversitas 19: 1593-1600. DNA microsatellite has been extensively employed for estimating the degree of kinship between genotypes and improving the quality of cattle products. Microsatellite markers are short-patterned DNA sequences and repeated tandem (sequentially) with 2-5 nucleotide units scattering the entire genome. The purpose of this study was to investigate the genetic characteristics of inter and intraspecies of Ongole Grade cattle and Madura cattle using microsatellite DNA markers. Blood samples from 20 individuals of each species were extracted by the method referring to Wizard Genomic DNA Purification Kit (Promega, USA) and PCR amplification was performed using 5 microsatellite loci, i.e., BM1824, ETH225, INRA005, MM12, and TGLA227. Results of the genetic characteristics of both species were calculated using the POPGENE program version 1.31. The data suggest that there is a genetic diversity of inter and intraspecies of Ongole Grade cattle and Madura cattle. The average value of Shannon's Information Index (I) at all microsatellite loci for Ongole Grade cattle was 0.76 and for Madura cattle was 1.12. Meanwhile, the average interspecies I value was 1.03. The mean intraspecies Polymorphic Information Content (PIC) of Ongole Grade and Madura cattle was 0.43, and 0.63, respectively, and the mean interspecies PIC value was 0.57. The data altogether suggest that all loci meet the standards as being informative markers in the assessment of genetic population because it has a PIC value> 0.5 especially for intraspecies of Madura cattle.

Characterization and development of EST-SSR markers to study the genetic diversity and populations analysis of Jerusalem artichoke (Helianthus tuberosus L.)

In recent years, Jerusalem artichoke has received widespread attention as a novel source of sugar, biofuel, and animal feed. Currently, only few gDNA-SSRs derived from sunflower were verified in the Jerusalem artichoke; therefore, it is particularly important to develop SSR primer markers that belonged to Jerusalem artichoke resources. Using EST data to develop EST-SSR markers is simple and effective. In order to understand the general characteristics of SSR markers in Jerusalem artichoke EST sequences and accelerate the use of SSR markers in Jerusalem artichoke research. This study used 40,370 sequenced unigene fragments and MISA software to identify SSR loci. The 48 pairs of EST-SSR primers assessed for the identification of 45 varieties of Jerusalem artichoke. Cluster, genetic diversity parameters and AMOVA analysis was conducted using the genetic similarity coefficient, revealing genetic differences between 48 genetic material. A total of 1204 SSR loci were identified with 13 different types of repeats, distributed among 1020 EST sequences, of which trinucleotide repeats were the most common, accounting for 38.21% of the total SSR loci. Among the 44 repeat motifs, AG/CT, AAG/CTT, and ATC/ATG motifs had the highest frequencies, accounting for 22.45, 14.71, and 7.84% of all motifs, respectively. From these sequences, 48 pairs of EST-SSR primers were designed, and 22 primer pairs for loci with high polymorphism were selected to analyze the genetic diversity of 45 Jerusalem artichoke germplasm sources. The results indicated that the variation range of the effective number of alleles for 22 primers ranged between 1.7502 and 4.5660. The Shannon's information index ranged between 0.6200 and 1.6423. The variation range of PIC ranged between 0.3121 and 0.6662 with an average of 0.5184. Cluster analysis was conducted using the genetic similarity coefficient, revealing significant genetic differences between Asian and European genetic material. Cluster analysis revealed a relationship between the genotypes and geographic origins of the Jerusalem artichoke. The results of AMOVA as well as the genetic identity and genetic distance in the Jerusalem artichoke population showed that there presented certain genetic heterogeneity in Jerusalem artichoke genetic structure of 45 samples from seven different geographic populations. The Jerusalem artichoke EST-SSR marker system established in this study provides an effective molecular marker system for future research focused on Jerusalem artichoke genetic diversity and the breeding of new varieties.

The Genetic Diversity and Geographic Differentiation of the Wild Soybean in Northeast China Based on Nuclear Microsatellite Variation.

In this study, the genetic diversity and population structure of 205 wild soybean core collections in Northeast China from nine latitude populations and nine longitude populations were evaluated using SSR markers. A total of 973 alleles were detected by 43 SSR loci, and the average number of alleles per locus was 22.628. The mean Shannon information index (I) and the mean expected heterozygosity were 2.528 and 0.879, respectively. At the population level, the regions of 42°N and 124°E had the highest genetic diversity among all latitudes and longitudes. The greater the difference in latitude was, the greater the genetic distance was, whereas a similar trend was not found in longitude populations. Three main clusters (1N, <41°N-42°N; 2N, 43°N-44°N; and 3N, 45°N–>49°N) were assigned to populations. AMOVA analysis showed that the genetic differentiation among latitude and longitude populations was 0.088 and 0.058, respectively, and the majority of genetic variation occurred within populations. The Mantel test revealed that genetic distance was significantly correlated with geographical distance (r = 0.207, p < 0.05). Furthermore, spatial autocorrelation analysis showed that there was a spatial structure (ω = 119.58, p < 0.01) and the correlation coefficient (r) decreased as distance increased within a radius of 250 km.

Assessment of intra-specific variability in Saprolegnia parasitica populations of aquaculture facilities in British Columbia, Canada.

Among the Saprolegnia species found in aquaculture facilities, S. parasitica is recognized as the primary fish pathogen and remains an ongoing concern in fish health management. Until recently, these pathogens were kept in check by use of malachite green; due to its toxicity, this chemical has now been banned from use in many countries. It is difficult to predict and control S. parasitica outbreaks in freshwater systems and there is a need to understand the population genetic structure of this pathogen. Genetic characterization of this species in aquaculture systems would provide information to track introductions and determine possible sources of inoculum. Degenerate PCR primers containing short sequence repeats were used to create microsatellite-associated genetic markers (random amplified microsatellites) for the comparison of S. parasitica isolates collected primarily from commercial Atlantic salmon aquaculture systems in British Columbia, Canada, over a 15 mo period to describe their spatial and temporal variability. The frequencies of amplified products were compared and the population genetic diversity was measured using Nei's genetic distance and Shannon's information index, while the species population structure was evaluated by phylogenetic analysis. S. parasitica was detected in all facilities sampled. Genetic diversity was low but not clonal, most likely due to repeated introduction events and a low level of sexual recombination over time. A better understanding of pathogen population structure will assist the development of effective preventative measures and targeted treatments for disease outbreaks.

Molecular insights into genetic diversity and population dynamics of five medicinal Eulophia species: a threatened orchid taxa of Africa.

Genetic diversity existing amongst five Eulophia orchid species were assessed using start codon targeted polymorphism (SCoT) and inter-retrotransposon amplified polymorphism (IRAP) markers. A total of 12 SCoT and 5 IRAP markers revealed an average of 63% genetic variability [SCoT = 63.87; IRAP = 64.95%] amongst the five Eulophia species investigated. The genetic similarities were assessed using both UPGMA and Bayesian approaches which indicated identical clustering patterns at a genetic similarity level of 50%. Analysis of molecular variance (AMOVA) revealed the presence of a significant degree of genetic variability, mostly compartmentalized within the species level. Amongst the five assessed Eulophia species, E. parviflora was the most genetically diverse representative whereas E. welwitschii was found to be least diverse based on a comparative assessment of various population genetic parameters like Nei's gene diversity (h) and Shannon's information index (I) with an overall gene flow value greater than 1. In order to evaluate the comparative marker efficiency, SCoT and IRAP marker data were subjected to various benchmark analyses like marker index, resolving power, polymorphic index content, multiplex ratio and effective multiplex ratio which revealed the robustness of both the marker techniques in assessment of genetic diversity. The present report provides the first molecular insights into the aspects of inter and intra specific genetic variability in medicinally as well as horticulturally important Eulophia species along with addressing their conservation concerns. In a nutshell, the present approach is simple, rapid and cost effective and can be extended for analysis of genetic diversity of other related plant species.

AFLP-based genetic diversity of wild orchardgrass germplasm collections from Central Asia and Western China, and the relation to environmental factors.

Dactylis glomerata L. (orchardgrass) is an important perennial forage species in temperate areas of the world. It is usually used for silage, grazing and hay because of its high nutritional value and reproducibility. Central Asia, Xinjiang and Tibetan Plateau in China possess various special micro-environments that harbor many valuable resources, while different degrees of degradation of the grassland ecosystem occurred due to climatic changing and human activities. Investigating the genetic diversity of wild D. glomerat could provide basis for collection, protection, and utilization of some excellent germplasm resources. Totally 210 individuals from 14 populations—five from Xinjiang, two from Kangding (Tibetan Plateau), and seven from Central Asia were identified using AFLP technology. The average values of Nei’s genetic diversity (Hj) and Shannon information index (Ho) were 0.383 and 0.394 respectively. UPGMA tree, STRUCTURE analysis and principal coordinate analysis (PCoA) showed populations from same region clustered together. AMOVA revealed 35.10% of the genetic differentiation (Fst) occurred among populations. Gene flow (Nm) was limited among all populations. Genetic diversity of D. glomerata was high but limited under isolation-by-distance pattern, resulting in high genetic differentiation and low gene flow among populations. Adjacent regions also exhibited similar results because of the barriers of high mountains. The environmental factors, such as precipitation, elevation, latitude and longitude also had some impacts on genetic diversity and structure pattern of populations.

Unconstrained gene flow between populations of a widespread epiphytic lichen Usnea subfloridana (Parmeliaceae, Ascomycota) in Estonia

Few studies have investigated the genetic diversity of populations of common and widespread lichenized fungi using microsatellite markers, especially the relationships between different measures of genetic diversity and environmental heterogeneity. The main aim of our study was to investigate the population genetics of a widespread and mainly clonally reproducing Usnea subfloridana at the landscape scale, focusing on the comparison of lichen populations within hemiboreal forest stands. Particular attention has been paid to the genetic differentiation of lichen populations in two geographically distinct regions in Estonia and the relationships between forest characteristics and measures of genetic diversity. We genotyped 578 Usnea thalli from eleven lichen populations using seven specific fungal microsatellite markers. Measures of genetic diversity (allelic richness, Shannon's information index, Nei's unbiased genetic diversity, clonal diversity, the number of multilocus genotypes, the number of private alleles, and the minimum number of colonization events) were calculated and compared between Usnea populations. Shared haplotypes, gene flow and AMOVA analyses suggest that unconstrained gene flow and exchange of multilocus genotypes exist between the two geographically remote regions in Estonia. Stand age, mean circumference of the host tree, size of forest site and tree species composition did not show any significant influence on allelic richness, Shannon's information index, Nei's unbiased genetic diversity, clonal diversity, the number of private alleles, and the minimum number of colonization events of U. subfloridana populations. Therefore it was concluded that other factors of habitat heterogeneity could probably have a more significant effect on population genetics of U. subfloridana populations.

Genomewide identification and development of microsatellite markers for Marssonina brunnea and their applications in two populations

SummaryMarssonina brunnea is an important pathogen that causes Marssonina leaf spot disease of poplar (MLDP) in various poplar species. Resistance breeding is considered as the main method for preventing this disease and requires information on genetic diversity and population structure. However, molecular markers that may be utilized in the identification of this fungus are limited. This study investigated the distribution of microsatellites in the M. brunnea genome. A total of 15,356 microsatellite markers (excluding mononucleotide repeats) were isolated from 50.1 Mb of genomic sequence. Eight M. brunnea isolates were evaluated in terms of 102 loci, followed by the selection of markers that could be utilized in investigating the population structure of 47 M. brunnea isolates from two populations. Twenty‐four polymorphic microsatellite markers were developed for M. brunnea. The number of alleles per locus ranged from two to eight (average: 3.75). The polymorphism information content (PIC) of these loci ranged from 0.0408 to 0.6492. The average Shannon's information index of these loci in the two populations was 0.3819 and 0.5351, respectively. Using these markers, M. brunnea isolates were mainly divided into two distinct clusters based on the relatedness of the sampling sites. These results indicate that the selected markers could be effectively utilized in investigating the population genetic structure of M. brunnea. This is the first report on microsatellite markers in M. brunnea.

Association Mapping for Important Agronomic Traits in Safflower (Carthamus tinctorius L.) Core Collection Using Microsatellite Markers.

Carthamus tinctorius L. (safflower) is an important oilseed crop producing seed oil rich in unsaturated fatty acids. Scarcity of identified marker-trait associations is a major limitation toward development of successful marker-assisted breeding programs in safflower. In the present study, a safflower panel (CartAP) comprising 124 accessions derived from two core collections was assayed for its suitability for association mapping. Genotyping of CartAP using microsatellite markers revealed significant genetic diversity indicated by Shannon information index (H = 0.7537) and Nei's expected heterozygosity (I = 0.4432). In Principal Coordinate Analysis, the CartAP accessions were distributed homogeneously in all quadrants indicating their diverse nature. Distance-based Neighbor Joining analysis did not delineate the CartAP accessions in consonance with their geographical origin. Bayesian analysis of population structure of CartAP demonstrated the unstructured nature of the association panel. Kinship analysis at population (Gij) and individual level (Fij) revealed absence of or weak relatedness between the CartAP accessions. The above parameters established the suitability of CartAP for association mapping. We performed association mapping using phenotypic data for eight traits of agronomic value (viz., seed oil content, oleic acid, linoleic acid, plant height, number of primary branches, number of capitula per plant, 100-seed weight and days to 50% flowering) available for two growing seasons (2011–2012 and 2012–2013) through General Linear Model and Mixed Linear Model. Our study identified ninety-six significant marker-trait associations (MTAs; P < 0.05) of which, several MTAs with correlation coefficient (R2) > 10% were consistently represented in both models and in both seasons for traits viz., oil content, oleic acid content, linoleic acid content and number of primary branches. Several MTAs with high R2-values were detected either in a majority or in some environments (models and/or seasons). Many MTAs were also common between traits (viz., oleic/linoleic acid content; plant height/days to 50% flowering; number of primary branches/number of capitula per plant) that showed positive or negative correlation in their phenotypic values. The marker-trait associations identified in this study will facilitate marker-assisted breeding and identification of genetic determinants of trait variability.

Genetic Diversity and Population Structure of F3:6 Nebraska Winter Wheat Genotypes Using Genotyping-By-Sequencing.

The availability of information on the genetic diversity and population structure in wheat (Triticum aestivum L.) breeding lines will help wheat breeders to better use their genetic resources and manage genetic variation in their breeding program. The recent advances in sequencing technology provide the opportunity to identify tens or hundreds of thousands of single nucleotide polymorphism (SNPs) in large genome species (e.g., wheat). These SNPs can be utilized for understanding genetic diversity and performing genome wide association studies (GWAS) for complex traits. In this study, the genetic diversity and population structure were investigated in a set of 230 genotypes (F3:6) derived from various crosses as a prerequisite for GWAS and genomic selection. Genotyping-by-sequencing provided 25,566 high-quality SNPs. The polymorphism information content (PIC) across chromosomes ranged from 0.09 to 0.37 with an average of 0.23. The distribution of SNPs markers on the 21 chromosomes ranged from 319 on chromosome 3D to 2,370 on chromosome 3B. The analysis of population structure revealed three subpopulations (G1, G2, and G3). Analysis of molecular variance identified 8% variance among and 92% within subpopulations. Of the three subpopulations, G2 had the highest level of genetic diversity based on three genetic diversity indices: Shannon’s information index (I) = 0.494, diversity index (h) = 0.328 and unbiased diversity index (uh) = 0.331, while G3 had lowest level of genetic diversity (I = 0.348, h = 0.226 and uh = 0.236). This high genetic diversity identified among the subpopulations can be used to develop new wheat cultivars.

Genetic diversity and population structure of a protected species: Polygala tenuifolia Willd

Polygala tenuifolia Willd. is an important protected species used in traditional Chinese medicine. In the present study, amplified fragment length polymorphism (AFLP) markers were employed to characterize the genetic diversity in wild and cultivated P. tenuifolia populations. Twelve primer combinations of AFLP produced 310 unambiguous and repetitious bands. Among these bands, 261 (84.2%) were polymorphic. The genetic diversity was high at the species level: percentage of polymorphic loci (PPL)=84.2%, Nei's gene diversity (h)=0.3296 and Shannon's information index (I)=0.4822. Between the two populations, the genetic differentiation of 0.1250 was low and the gene flow was relatively high, at 3.4989. The wild population (PPL=81.9%, h=0.3154, I=0.4635) showed a higher genetic diversity level than the cultivated population (PPL=63.9%, h=0.2507, I=0.3688). The results suggest that the major factors threatening the persistence of P. tenuifolia resources are ecological and human factors rather than genetic. These results will assist with the design of conservation and management programs, such as in natural habitat conservation, setting the excavation time interval for resource regeneration and the substitution of cultivated for wild plants.

Analysis of population structure and genetic diversity in an exotic germplasm collection of Eleusine coracana (L.) Gaertn. using genic-SSR markers

Finger millet (Eleusine coracana (L.) Geartn.) is one of the important small millets serves as a food security crop because of its high nutritional values. The complex tetraploid genome of finger millet requires a large number of informative, functional DNA markers for different applications in genetics and breeding. Yet, less number of simple sequence repeat (SSR) markers have been developed from expressed sequence tags in finger millet. In the present study, 56 new genic SSR markers were developed from publicly available drought related ESTs. The 43 polymorphic markers were used to evaluate polymorphism, revealed a range of PIC value 0.41 to 0.79. Our results suggest that, analyzed genotypes have high genetic diversity with an average gene diversity (h) of 0.176 and Shannon's information index (I) of 0.315. We conclude that there was a higher gene exchange within populations, by the value of overall gene flow (Nm) of 0.7721. The unweighted pair group method with arithmetic mean and neighbor joining dendrogram generated three main clusters to differentiate genotypes and these results were also confirmed by PCA and PCoA analysis. The high genetic diversity (77%) was found within the populations in the analysis of molecular variance. A Bayesian model-based cluster analysis evidenced a high extent of admixture between the gene pools from the different geographical origins. Population based cluster analyses pointed out a strong pattern of ‘isolation by distance’. Overall, these results underscored that this study showed a significantly high level of polymorphism, adequate genetic diversity and population structure which expand the modern genetic resources and its utility in various applications in genetics and genomics including association mapping and breeding.

Genetic Diversity of Marrubium Species from Zagros Region (Iran), Using Inter Simple Sequence Repeat Molecular Marker

This study concerns the genetic diversity and taxonomic status of Marrubium species from central and south-west of Zagros region, Iran. It is investigated by Inter-Simple Sequence Repeat analysis. A total of 68 accessions from five Marrubium species were collected from their natural habitats. Molecular analysis was approved with 17 primers, of which 12 were carried out in the reaction mixture. Moreover, a data matrix was designed to estimate genetic parameters. To determine the genetic structure and taxonomic status, analysis of molecular variance, clustering analysis with UPGMA (Unweighted Pair Group Method Average) and the Jaccard similarity coefficient were estimated using NT-SYS-pc and Gene Alex software. Supplementary morphological evidences of calyx teeth features were also provided. The results of this study revealed that both sections Marrubium, Microdonta, and Ballota aucheri displayed a high percentage of polymorphism (PP=100%). In addition, their genetic diversity (Gst=0.99), number of effective alleles (Ne=1.53) and Shannon information index (I=0.51) showed a high percentage. Notably, all of the 12 primers produced reproducible bands. Analysis of molecular variance detected low quantities of gene variation among species (18%) from which high proportion of variation presented among populations within species (82%). Based on cluster analysis, M. cuneatum, M. vulgare and M. anisodon were definitely separated. Moreover, M. crassidens and M. vulgare were closely grouped. The calyx teeth features of M. cuneatum and M. crassidens revealed high variations which is consistent with molecular results. In conclusion, high genetic diversity in Marrubium species and accessions presents a valuable genetic resource in Zagros region, Iran.

Assessment of the Genetic Diversity, Breeds Structure and Genetic Relationships in Four Egyptian Camel Breeds using Microsatellite and Start Codon Targeted (SCoT) Markers

The genetic diversity, relationships and population structure of sixty Egyptian camels derived from four breeds (Baladi, Sudani, Somali, and Maghrabi) were investigated using 18 microsatellite (SSRs) loci. In addition, the four breeds were genotyped using 16 Start Codon Targeted (SCoT) primers. A total of 346 SSR alleles were detected across the four camel breeds with an overall mean of 9.3 ± 0.66 alleles / locus. The mean number of alleles (MNA) and effective number of alleles (Ne) ranged from 9.2 ± 1.45 in the Baladi to 9.5 ± 1.27 in the Maghrabi breeds and from 6.5 ± 0.82 in the Maghrabi to 7.1 ± 0.93 in the Somali breeds, respectively. The values of observed heterozygosity (HObs) and expected heterozygosity (HExp) per breed varied from 0.82 ± 0.07 in the Maghrabi to 0.87 ± 0.07 in the Sudani camel breeds, and from 0.75 ± 0.03 in the Sudani to 0.79 ± 0.03 in the Maghrabi breeds , respectively. The genetic diversity estimated as the Shannon's information index (I) revealed the highest value (1.88 ± 0.14) in the Maghrabi and the lowest value (1.78 ± 0.18) in the Sudani breed. The values for fixation indices (FIS, FST and FIT) were -0.07284, 0.12364 and 0.05981, respectively. Thus indicating a moderate level of differentiation among the four breeds and a random mating process within each breed. The genetic structure revealed that the three breeds (Baladi, Sudani and Maghrabi) were genetically distinct and look like pure breeds, while the Somali breed showed some degree of admixture. A total of 153 amplicons were generated by the 16 SCoT primers, with an average of 9.56 amplicon/ primer and a polymorphism rate of 49%. The phylogenetic tree based on microsatellite and SCoT markers revealed that Maghrabi was separated in one cluster while, the second cluster comprised two sub-clusters. Sudani and Somali formed one sub-cluster and Baladi was in the second sub-cluster. Thus, the closest phylogenetic relationship was between the Sudani and Somali breeds.

Genetic Diversity of Aromatic Rice Germplasm Revealed By SSR Markers.

Aromatic rice cultivars constitute a small but special group of rice and are considered the best in terms of quality and aroma. Aroma is one of the most significant quality traits of rice, and variety with aroma has a higher price in the market. This research was carried out to study the genetic diversity among the 50 aromatic rice accessions from three regions (Peninsular Malaysia, Sabah, and Sarawak) with 3 released varieties as a control using the 32 simple sequence repeat (SSR) markers. The objectives of this research were to quantify the genetic divergence of aromatic rice accessions using SSR markers and to identify the potential accessions for introgression into the existing rice breeding program. Genetic diversity index among the three populations such as Shannon information index (I) ranged from 0.25 in control to 0.98 in Sabah population. The mean numbers of effective alleles and Shannon's information index were 0.36 and 64.90%, respectively. Similarly, the allelic diversity was very high with mean expected heterozygosity (He) of 0.60 and mean Nei's gene diversity index of 0.36. The dendrogram based on UPGMA and Nei's genetic distance classified the 53 rice accessions into 10 clusters. Analysis of molecular variance (AMOVA) revealed that 89% of the total variation observed in this germplasm came from within the populations, while 11% of the variation emanated among the populations. These results reflect the high genetic differentiation existing in this aromatic rice germplasm. Using all these criteria and indices, seven accessions (Acc9993, Acc6288, Acc6893, Acc7580, Acc6009, Acc9956, and Acc11816) from three populations have been identified and selected for further evaluation before introgression into the existing breeding program and for future aromatic rice varietal development.

Phenotypic and Genetic Diversity of the Culinary-Medicinal Winter Mushroom Flammulina velutipes (Agaricomycetes) in China.

Flammulina velutipes is one of the mushrooms produced most widely in East Asia. In this study we investigated phenotypic variations of 7 agronomic traits in 37 F. velutipes strains from China, and we analyzed their genetic diversity with 70 simple sequence repeat markers. The Shannon information index and gene diversity were 0.894 and 0.478, respectively, demonstrating high genetic variation among the tested strains. Poor genetic variation was found among white strains, in contrast to yellow ones. Analysis of population structure resolved 2 unambiguous genetic groups in the tested F. velutipes strains, with little differentiation between them (FST = 0.016). Yellow cultivars possibly originated from indigenous wild strains in southwest China. Phenotypic correlations were identified among the 7 traits. In particular, stipe length (SL) was significantly positively correlated with yield, indicating that SL could be used as an index for breeding high-yield strains. The 2 genetic groups, and white strains and yellow ones, showed significant differences between SL, yield, and the time interval (days) from mycelial scratch to formation of the first fruiting body. These results indicate that these 3 traits were stratified by population structure. Detection of genetic and phenotypic variations would lay the groundwork for further breeding of elite F. velutipes strains.

Characterization of Gladiolus Germplasm Using Morphological, Physiological, and Molecular Markers.

Estimation of variability and genetic relationships among breeding materials is one of the important strategies in crop improvement programs. Morphological (plant height, spike length, a number of florets/spike), physiological (chlorophyll content, chlorophyll fluorescence, and rapid light curve parameters) and Directed amplification of minisatellite DNA (DAMD) markers were used to investigate the relationships among 50 Gladiolus cultivars. Cluster analysis based on morphological data, physiological characteristics, molecular markers, and cumulative data discriminated all cultivars into seven, five, seven, and six clusters in the unweighted pair-group method using arithmetic mean (UPGMA) dendrogram, respectively. The results of the principal coordinate analysis (PCoA) also supported UPGMA clustering. Variations among the Gladiolus cultivars at phenotypic level could be due to the changes in physiology, environmental conditions, and genetic variability. DAMD analysis using 10 primers produced 120 polymorphic bands with 80% polymorphism showing polymorphic information content (PIC=0.28), Marker index (MI=3.37), Nei's gene diversity (h=0.267), and Shannon's information index (I=0.407). Plant height showed a positive significant correlation with Spike length and Number of florets/spike (r=0.729, p<0.001 and r=0.448, p=0.001 respectively). Whereas, Spike length showed positive significant correlation with Number of florets/spike (r=0.688, p<0.001) and Chlorophyll content showed positive significant correlation with Electron transport rate (r=0.863, p<0.001). Based on significant morphological variations, high physiological performance, high genetic variability, and genetic distances between cultivars, we have been able to identify diverse cultivars of Gladiolus that could be the potential source as breeding material for further genetic improvement in this ornamental crop.

Genetic diversity and its implications in tlie conservation of threatened fish species Barilius bendelisis (Hamilton)

Genetic diversity in four populations of the hill stream teleost Barilius bendelisis, a threatened fish species in India, from Ramnagar (Kosi), Srinagar (Alal<nanda), Dehradun (Yamuna) and Bhimtal (Chanfee) Uttarakhand, was studied using Random Amplified Polymorphic DNA (RAPD) markers for the first time in India. Four selective primers provided distinct and consistent RAPD profiles in all the four populations. Upon screening 40 random decamer primers four primers giving reproducible results were selected and used for generating DNA fingerprints from a total of 48 fish samples collected from the above-mentioned streams. The bands in the range 666-4830 bp were scored for consistent results. A total of 30 loci were scored, 12 of which were found to be polymorphic in nature. The mean values of Nei's gene diversity and Shannon's information index were found 0.1899 and 0.2617 respectively indicating an average level of genetic diversity in the studied samples of the threatened species. The RAPD profiles generated by all the four primers revealed varying degrees of polymorphism, ranging from 25% (primer OPH03) to 45.45% (primer OPA09). The overall oroportion of polymorphic bands and genetic diversity (h) among the four populations was observed 40% and 0.1899.