Molecular Characterization of Genetic Diversity in Apricot Cultivars: Current Situation and Future Perspectives

In the recent years, an important renewal of apricot cultivars is taking place worldwide with the introduction of a large number of new releases, which are replacing traditional and local cultivars in many situations. To study the current genetic diversity, a group of 202 apricot accessions, including landraces and releases from breeding programs in several countries, has been characterized using 13 microsatellite markers. The diversity parameters showed higher diversity in modern releases than in landraces, but also suggested a loss of diversity associated with recent breeding. Two main clusters according to the pedigree origin of the accessions were clearly differentiated in the phylogenetic analysis based on Nei’s genetic distance. The first group comprised mostly European and North American traditional cultivars, and the second group included the majority of recent and commercial releases from breeding programs. Further population analyses showed the same clustering trend on the distribution of individuals and clusters, confirming the results obtained in the molecular phylogenetic analysis. These results provide a sight of the erosion and the decrease of the genetic diversity in the currently grown apricot and highlight the importance of preserve traditional cultivars and local germplasm to assure genetic resources for further breeding.

↵​Genetic Diversity and Population Structure of Two Faba Bean Mutant Populations Based on AFLP Markers

Background: Although induced mutagenesis can rapidly generate genetic diversity, every genotype responds differently to different mutagen treatments in induceing genetic diversity. This study assesses and compares the genetic diversity of two mutant faba bean populations. Methods: Two genotypes representing landrace (Hassawi 2) and inbred variety (ILB4347) were exposed to gamma radiation and diethyl sulfate (DES). Two hundred eighty-two samples derived from individual 140 M2 mutant plants of Hassawi 2 and ILB 4347 and two parental lines were characterized using 11 Amplified Fragment Length Polymorphism (AFLP) primer combinations. Result: 89,820 bands within 2,083 polymorphic alleles were generated from the samples. Genetic diversity comparison of the mutant populations revealed that each genotype had varying responses to different treatments. The two genotypes had a relatively similar response to gamma radiation, while different responses were recorded in DES-derived mutant plants. Based on the Nei’s genetic distance, the populations were separated based on the genotypic origin. The population structure analyses showed that the Hassawi 2 and ILB4347 mutant populations were clustered into three and two groups, respectively. The difference in the number of clusters between the two mutant populations explains their breeding history. The present diversity considered as a valuable material used for breeding and conservation purposes.

Genetic polymorphism and phylogenetic analysis of 15 autosomal STR markers in the Santal indigenous population of Bangladesh

Fifteen autosomal STR markers, namely D8S1179, D21S11, D7S820, CSF1PO, D3S1358, TH01, D13S317, D16S539, D2S1338, D19S433, vWA, TPOX, D18S51, D5S818, and FGA were typed using AmpFlSTR® Identifiler® Plus PCR amplification systems in 132 unrelated Santal individuals of Bangladesh. Forensic efficiency parameters like, matching probability (MP), power of discrimination (PD), polymorphism information content (PIC), power of exclusion (PE), typical paternity index (TPI), observed heterozygosity (Hobs), and expected heterozygosity (Hexp) were calculated for all the loci. No deviations from Hardy-Weinberg equilibrium were detected for the loci after Bonferroni correction. The combined matching probability (MP), combined power of discrimination (PD) and combined power of exclusion (PE) for the 15 tested STR markers were 8.38 x 10-17, 0.999999998 and 0.0.999993866, respectively. A comparison of the locus wise allele frequencies of autosomal STR data of the Santal population with the published geographically close population data based on Nei’s genetic distance revealed that the Santal population is closely related to Munda population from Jharkhand, India. Bioresearch Commu. 7(2): 1004-1009, 2021 (June)

Screening of Salinity Tolerance of Twenty Rice Genotypes at the Seedling Stage Through Hydroponic and Ssr Marker

Salinity is one of the major abiotic stresses which severely affect the production of crops across the world. In this experiment, we examined 20 rice genotypes of diverse origins and sources including few salt tolerant varieties (Binadhan-8, Binadhan-10, Pokkali and FL478) as check. The main objective of this study was to determine salt tolerance at seedling stage and to evaluate genetic variation using SSR markers. IRRI standard protocol was applied to screen out salinity among those varieties, at the glasshouse of Bangladesh Institute of Nuclear Agriculture, BAU campus, Mymensingh-2202. Shoot length, root length and total dry matter were recorded at 6dS/m, 8dS/m, 10dS/m and 12 dS/m salt stress levels. According to the morphological and molecular survey of 20 rice genotypes at the seedling stage it was evident that, Binadhan-8, Binadhan-10, Pokkali, FL478, IR64, IR4630, FR13A and Sadamota identified as salt tolerant whereas THDB, Moulata, MV-20, CPD-23, CPD-29, Pot-18, Pot-27 and Dudkalam those were found as susceptible, BRRI dhan67, Binadhan-17 and Binadhan-21 those were traced as highly susceptible. The highest Nei’s genetic distance value 1.0 was found in Moulata vs Sadamota and the lowest value 0.08 was observed in Binadhan-21 vs IR64. It will be used in future breeding program to develop a saline tolerant variety of rice. Res. Agric., Livest. Fish.8(1): 75-88, April 2021

Molecular Diversity Analysis of Somaclonal Variants of Potato (Solanum tuberosum L.) by Random Amplified Polymorphic DNA Markers

Aims: An experiment was conducted to analyze the DNA fingerprinting and genetic diversity of nine potato (Solanum tuberosum L.) somaclonal variants and three check varieties. Place and Duration of Study: The experiment was carried out at the Biotechnology laboratory of the Department of Biotechnology, Faculty of Agriculture, Sher-e-Bangla Agricultural University, Dhaka-1207, Bangladesh during November, 2013 to December, 2014. Methodology: The somaclonal variants investigated were SIP-3, SIP-5, SVP-6, SVP-18, SVP-19, SVP-25, SVP-55, SVP-56 and SVP-68, while the check varieties were Cardinal, Diamant and Asterix. Six RAPD primers were used to perform PCR reaction after genomic DNA was extracted from young leaves. Results: The selected 6 primers produced total 54 distinct and differential amplified DNA bands of size range 88 bp to 3265 bp, where 47 bands (~87%) were polymorphic and 7 bands (~13%) were monomorphic. The pair-wise inter-genotype similarity indices were ranged from 61.59% to 93.55% with an average of 74.31%. The Nei’s genetic distance among 12 potato genotypes was estimated from 0.0972 to 0.6217 whereas, genetic identity was between 0.5370 and 0.9074. Here, the distantly linked accessions among the somaclonal variations with check varieties were SVP-6 (to Cardinal and Diamant) and SVP-25 (to Asterix). In addition, the UPGMA dendrogram segregated the 12 potato genotypes into two broad clusters containing 8 and 4 genotypes, respectively. Furthermore, the dendrogram also displayed the highest genetic distance between SVP-6 vs SVP-68 genotype pair. Conclusion: Significant relationship and diversity were found among the studied 12 genotypes. This genetic diversity among the potato genotypes would be utilized for further potato improvement.

Genetic Diversity in Finger Millet Landraces revealed by RAPD and SSR Markers

Genetic diversity assessment is the preliminary work for development of variety and conservation of diversity. Finger millet is a very important crop in Nepal however, its genetic potential has not been fully utilized. Genetic diversity was assessed in forty landraces of finger millet using 9 RAPD and 5 SSR markers. These landraces were collected from Kaski and Dhading districts. None of single primers of these RAPD and SSR could separate all 40 landraces. The average number of bands were 6.33 and 7.8 per RAPD and SSR primers respectively. Mean polymorphism information content was of 0.314 for RAPD and 0.37 for SSR. Primer OPA-4 produced the highest number of bands and the lowest numbers of bands were produced by OPA-16. Among the SSR primers, SSR-06 produced the highest number of polymorphic bands and UGEP-53 produced the lowest bands. RAPD based dendrogram has generated four clusters and SSR based dendrogram has generated two clusters. In both dendrogram and principal component analyses, Purbeli landrace was found unique locating separately in the cluster and scatter plot. Nei's genetic distance produced by RAPD and SSR primers was similar that is 0.327 by RAPD and 0.296 by SSR markers. Genetic distance produced by SSR markers was higher than distance produced by RAPD marker. These landraces were from two districts and therefore have shown intermediate diversity. These molecular marker-based findings should would be more useful if we could link with agromorphological traits. Inclusion of large number of landraces collected from different areas are required to get higher level diversity in addition to associate genetic diversity with geographical sites. Groupings of these landraces could be useful for selecting landraces in breeding program as well as planning conservation program.

Genetic Diversity and Population Structure of Dromedary Camel-Types

The dromedary camel is a unique livestock for its adaptations to arid-hot environments and its ability to provide goods under extreme conditions. There are no registries or breed standards for camels. Thus, named camel populations (i.e., camel-types) were examined for genetic uniqueness and breed status. Camel populations are generally named based on shared phenotype, country or region of origin, tribal ownership, or the ecology of their habitat. A dataset of 10 Short-Tandem Repeat markers genotyped for 701 individual camels from 27 camel-types was used to quantify genetic diversity within camel-types, compare genetic diversity across camel-types, determine the population genetic structure of camel-types, and identify camel-types that may represent true breeds. Summary statistics (genotyping call rate, heterozygosity, inbreeding coefficient FIS, and allelic frequencies) were calculated and population-specific analyses (pairwise FST, neighbor-joining tree, relatedness, Nei’s genetic distance, principal coordinate analysis [PCoA], and STRUCTURE) were performed. The most notable findings were 1) little variation in genetic diversity was found across the camel-types, 2) the highest genetic diversity measure was detected in Targui and the lowest was in Awarik, 3) camel-types from Asia (especially the Arabian Peninsula) exhibited higher genetic diversity than their counterparts in Africa, 4) the highest DeltaK value of population structure separated camel-types based on geography (Asia vs. Africa), 5) the most distinct camel-types were the Omani, Awarik, and the Gabbra, 6) camel-types originating from the same country did not necessarily share high genetic similarity (e.g., camel-types from Oman), and 7) camel-type names were not consistently indicative of breed status.

Genetic Diversity and Ancestral Study for Korean Native Pigs Using 60K SNP Chip

The Korean native pig (KNP; Sus scrofa coreanus) is an indigenous porcine breed in South Korea considered as a valuable but dwindling genetic resource. Studies using diverse methodologies and genetic markers suggest that this population originated from the Manchu province of Northeastern China and migrated approximately 3000 years ago into the Korean peninsula. This study aimed to verify those findings by performing diversity and ancestral analyses using the 60K single-nucleotide polymorphism (SNP) BeadChip on 891 pigs of 47 breeds worldwide. We also performed principal component analysis (PCA), ancestry analyses, phylogenetic tree analysis using SNPhylo, and linkage disequilibrium analysis. Furthermore, we generated heatmap, obtained Nei’s genetic distance and FST values, and explored the heterozygosity of commercial and native Korean pigs. The results demonstrated that KNP pigs are more closely related to European breeds than to Chinese breeds. In addition, as previous studies have suggested, our admixture analyses indicated that KNP pigs showed distinguishable genetic structure.

Molecular genetic diversity and conservation priorities of Egyptian rabbit breeds

<p>The limited rabbit resources in Egypt are threatened by the danger of extinction, whereas genetic diversity studies of native breeds could play a vital role in conservation and improvement of these breeds. In this study, 3 native rabbit breeds: Gabali (G), Baladi Red (BR) and Baladi Black (BB), in addition to New Zealand White (NZW), were genotyped using 12 microsatellite markers. All the typed microsatellites were polymorphic by average number of alleles 5.25 per locus. Observed and expected heterozygosity per locus averaged 0.62 and 0.68, respectively. The average polymorphic information content was 0.71 and the highest polymorphic information content was recorded in locus SOL33 by 0.85. All the studied loci except SAT7 and SAT2 showed deviation from Hardy-Weinberg equilibrium with significant level. The inbreeding coefficient of the individuals relative to the total population was 0.07. The within-population heterozygote deficit averaged 0.07 and ranged from 0.141 in BR to 0.015 in BB breeds. The highest pairwise differentiation among the populations was recorded between BB and NZW (0.071), while the lowest value was recorded between BR and both of G (0.038) and BB (0.039). The lowest pairwise Nei’s genetic distance was recorded between BR and BB (0.190), while the highest was recorded between NZW and BB breeds (0.409). BR and G populations were clustered together forming an admixed mosaic cluster. BR recorded the highest contribution in the aggregate genetic diversity based on the three prioritisation methods used.</p>