Comparison of genetic variability and growth characteristics of naturally regenerated and planted Scots pine

The aim of this study was to analyze the genetic variability and population structure of the Landrace population by using 12 microsatellite markers. A total of 90 pigs representing one commercial breed (Landrace) were sampled. Twelve microsatellite loci (SW24, S0155, SW72, SW951, S0386, S0355, SW240, SW857, S0101, SW936 SW911 and S0228) were selected and belong to the list of microsatellite markers recommended by FAO/ISAG. GenAIEx software was used to calculate the allele frequencies, effective number of alleles (Ae), observed (Ho) and expected (He) heterozygosity, within-population inbreeding estimate (Fis), Shannon’s information index (ISh). Overall allele frequency values ranged from 0.006 to 0.9333 (at allele SW951120). The number of observed alleles (Na) detected ranged from 5 (S0155 and SW911) to 13 (SW72), with an overall mean of 9.00 ± 0.80 and a total of 108 alleles were observed at these loci. However, the effective number of alleles (Ae) ranged from 1.57 (SW951) to 5.49 (SW240) with a mean of 3.29 ± 0.33. Shannon’s information index (ISh) which measures the level of diversity, was sufficiently high – from 0.79 (for SW951) to 2.01 (for SW240) – with a mean of 1.43 ± 0.09. The overall means for observed (Ho) and expected (He) heterozygosities were 0.578 ± 0.009 and 0.662 ± 0.004, respectively, which ranged from 0.307 (SW951) to 0.814 (SW857) and 0.361 (SW951) to 0.818 (SW240), respectively. Of the 12 microsatellites analyzed using Fisher’s exact test, 50% were in Hardy-Weinberg equilibrium, and 6 were out of equilibrium (P < 0.05). Three mutation models namely, infinite allele model (I.A.M.), two phase model (T.P.M.), stepwise mutation model (S.M.M.) were estimated using the BOTTLENECK software. The results are indicated that the Landrace pig population is non-bottlenecked and remained at mutation-drift equilibrium. The study stands first in genetic characterization of the Ukrainian Landrace pig population through microsatellite markers. The various parameters and values used to quantify genetic variability, such as the high mean (and effective) number of alleles and the expected and observed heterozygosities, indicated high genetic variability in the Ukrainian Landrace pigs. The population has not undergone any recent and/or sudden reduction in the effective population size and remained at mutation-drift equilibrium.

The preservation of genetic variability of autochthonous poultry breeds is crucial in global biodiversity. A recent report revealed small breed size and potential risk of extinction of all native Italian poultry breeds; therefore, a correct assessment of their genetic diversity is necessary for a suitable management of their preservation. In this work, we provided an overview of the contribution to poultry biodiversity of some Italian autochthonous breeds reared in conservation centers devoted to local biodiversity preservation. The level of genetic diversity, molecular kinship, inbreeding, contribution to overall genetic diversity, and rate of extinction of each breed were analyzed with a set of 14 microsatellite loci in 17 autochthonous chicken breeds. To evaluate genetic variability, total number (Na), and effective number (Ne) of alleles, observed (Ho) and expected (He) heterozygosity, and F (Wright’s inbreeding coefficient) index were surveyed. The contribution of each analyzed breed to genetic diversity of the whole dataset was assessed using MolKin3.0; global genetic diversity and allelic richness contributions were evaluated. All the investigated loci were polymorphic; 209 alleles were identified (94 of which private alleles). The average number of alleles per locus was 3.62, and the effective number of alleles was 2.27. The Ne resulted lower in all breeds due to the presence of low-frequency alleles that can be easily lost by genetic drift, thus reducing the genetic variability of the breeds, and increasing their risk of extinction. The global molecular kinship was 27%, the average breed molecular kinship was 53%, and the mean inbreeding rate 43%, with a self-coancestry of 78%. Wright’s statistical analysis showed a 41% excess of homozygous due to breed genetic differences (34%) and to inbreeding within the breed (9%). Genetic variability analysis showed that 11 breeds were in endangered status. The contribution to Italian poultry genetic diversity, estimated as global genetic diversity, and ranged from 30.2 to 98.5%. In conclusion, the investigated breeds maintain a unique genetic pattern and play an important role in global Italian poultry biodiversity, providing a remarkable contribution to genetic variability.

Aims: To elucidate the genetic variability, correlation, and path analysis of various agronomic and morphological traits among fifty genotypes of bread wheat (Triticum aestivum (L.) em. Thell) to facilitate targeted breeding efforts. Study Design: The experiment was laid out in Randomized Complete Block Design (RCBD) in 2 replications. Place and Duration of Study: The study was conducted during the Rabi season of 2019 at Banaras Hindu University, India. Methodology: Fifty genotypes of bread wheat were evaluated for thirteen morphological traits. Analysis of variance (ANOVA), correlation analysis, direct and indirect effects on grain yield per plot through path coefficient analysis were calculated. Assessed traits included biomass, harvest index, germination percentage, tillers per meter, days to flowering, plant height, and spike length. Genetic variability and heritability parameters were calculated for these traits. Genetic variability parameters were also calculated to determine the extent of variability and heritability for these traits. Results: The analysis of variance revealed significant genotypic differences for all studied traits. Correlation analysis highlighted intricate interrelationships among traits, with biomass exhibiting the highest positive direct effect on grain yield, followed by harvest index and germination percentage. In contrast, tillers per meter, days to flowering, and plant height had negative direct effects on yield. Genetic variability parameters indicated substantial variability for traits like harvest index and grain yield per plot, with spike length showing the highest heritability. Conclusion: The study highlights the complexity of grain yield determination, which is affected by various genetic and environmental factors. The results offer deeper insights into the genetic basis of yield-related traits in wheat, stressing the importance of selecting genotypes with beneficial trait combinations to boost yield potential.

ABSTRACTDurum wheat (Triticum turgidum var. durum) is one of the most important cereal crops widely cultivated all over the world with high economic value. In the present study, genetic variation in a mini-core collection of durum wheat germplasm, including 25 breeding lines and 18 landraces, was evaluated using 15 inter-simple sequence repeat (ISSR) and six start codon targeted (SCoT) markers. High levels of polymorphism were observed; 98.70% (ISSR) and 100% (SCoT), which indicated that these markers are useful tools for detection of genetic variation in the collection. Analysis of molecular variance revealed that the major part of genetic variations (90% and 93% for ISSR and SCoT, respectively) occurred within genotypes set. Comparing the genetic variation of breeding lines and landraces based on genetic parameters showed that effective number of alleles (Ne), Nei's gene diversity (He) and Shannon's Information index (I) in landraces were higher than in breeding lines. Although cluster analysis, based on both markers, separated the genotypes in five groups, the dendrogram obtained from SCoT provided the best clustering pattern. Inter-population differentiation (Gst) estimated on the basis of two marker systems representing that a vast portion of the total genetic diversity refers to variation within two sets of genotypes. In conclusion, the results verified a high level of genetic variation among the durum wheat mini-core collection, particularly among landraces, which can be interesting for future breeding programmes.

The growth characteristics and the genetic variability of 23 population of Norway spruce tested in the largest international comparative experiments IPTNS-IUFRO 1964/68 in Krynica were analysed. The studied populations belong to early and late flushing provenances from Alpine, Carpathian and north-eastern range of occurrence of species. The height, diameter at breast height (DBH) and genetic diversity of 79 trees were examined using random amplified polymorphism DNA (RAPD) technique. The mean spruce height at the age of 45 years was 17.5 m and the DBH 20.4 cm. The average and the effective number of alleles per locus calculated for all studied populations was 0.90 and 1.20, respectively. The expected heterozygosity was 0.10. The obtained results show statistically significant relationship of the parameters of genetic variability of Norway spruces and the type of seed collection from which the IUFRO experience was established. It was found that the genetic variability of the studied population depends on the longitude and height above sea level of mother stands. No significant correlation was found between the type of seed collection and location of mother stands and height and DBH of Norway spruce. Also the growth characteristics (height and the DBH) of trees do not depend on their genetic variability.

Forest-management practices relying on natural and/or artificial regeneration and domestication can significantly affect genetic diversity. The aim of the present study was to determine and compare the genetic diversity of the pristine old-growth, naturally and artificially regenerated and phenotypically selected white spruce, and to determine the genetic-diversity impacts of silvicultural practices. Genetic diversity was determined and compared for 51 random amplified polymorphic DNA (RAPD) loci for the adjacent natural old-growth, naturally regenerated and planted white spruce stands at each of four sites, one oldest plantation and open-pollinated progeny of 30 phenotypic tree-improvement selections of white spruce from Saskatchewan. Each of the 420 white spruce individuals sampled was genetically unique. The old-growth stands had the highest, and the phenotypic selections the lowest, genetic diversity. The genetic diversity of the natural regeneration was comparable to that of the old-growth, whereas the genetic diversity of the plantations was comparable to that of the selections. On average, the genetic diversity of the old-growth and natural regeneration was significantly higher than that of the plantations and selections. The mean percent of loci polymorphic, the number of alleles per locus, the effective number of alleles per locus, heterozygosity, and Shannon’s index was 88.7, 83.8, 72.2 and 66.7; 1.89, 1.84, 1.72 and 1.67; 1.69, 1.62, 1.53 and 1.46; 0.381, 0.349, 0.297 and 0.259; and 0.548, 0.506, 0.431 and 0.381 for the old-growth stands; natural regeneration; plantations; and open-pollinated progeny of selections; respectively. Reduced genetic diversity in the plantations and selections suggest that their genetic base is relatively narrow, and should therefore be broadened in order to maintain genetic diversity, and sustainably manage and conserve white spruce genetic resources.

ABSTRACTGenetic diversity is a crucial component for plant survivability and fitness in terms of adaptation, genetic stability and variability. In this study, a total of 160 genotypes were investigated using 12 random amplified polymorphic DNA (RAPD) primers to understand the genetic structure and diversity of nine naturally distributed Ostrya carpinifolia populations in Turkey. Twelve RAPD primers yielded 111 clearly identifiable DNA bands, of which 71 bands were found to be polymorphic (64%). Observed number of alleles (Na), effective number of alleles (Ne) and Nei's gene diversity (h) were found as 2, 1.53 and 0.32, respectively. Total genetic variation (HT), within-population genetic variation (HS) and Nei's genetic differentiation coefficient (GST) were found as 0.32, 0.09 and 0.70, respectively. Genetic diversity analysis (AMOVA) revealed highly significant (P < 0.001) genetic variations among and within populations. 69.94% of total variation was observed among populations while 26.69% was within populations. Gene flow value was calculated as 0.21 (Nm < 0.5), which could homogenize the genetic structure of a population. Two geographically isolated populations demonstrated high gene diversity and polymorphic loci ratio, indicating a relationship between geographic distribution of populations and eco-geographic factors. The findings of this study will pave the way for understanding the genetic diversity between inter- and intra-populations of O. carpinifolia species, as well as they would provide valuable information for management, conservation and utilization of in situ and ex situ Ostrya germplasms.

Gymnema sylvestre (Retz.) R. Br. ex Schult is a highly demanded antidiabetic medicinal herb native to India. There are no improved varieties available and the plant is still collected from the wild and therefore it is important to estimate the genetic variability and heritability parameters for devising appropriate crop improvement strategy. The present study was undertaken to assess the genetic variability, heritability, character association and path analysis for growth, yield and bioactive traits in 35 accessions of G. sylvestre collected from Indian South Peninsular region. Genetic variability parameters: genotypic variance, phenotypic variance, genotypic coefficient of variation (GCV), phenotypic coefficient of variation (PCV), broad-sense heritability, genetic advance and genetic advance as per cent over mean of yield and quality related characters were computed to understand the extent of variability present. High levels of GCV and PCV (&gt;20%) were observed for most of the traits. Leaf length, leaf area, leaf yield and gymnemagenin content reported with high heritability (&gt;60%) and genetic advance over mean (&gt;30%) suggest that variation in these traits is influenced predominantly by the genetic factors making selection more effective in improving them. The correlation and path analysis studies highlighted the importance of selecting leaf length, leaf breadth, leaf area index, fresh leaf yield and gymnemagenin content for improving dry leaf yield of G. sylvestre. The study also identified promising morphotypes (IIHR-GS-27 and IIHR-GS-9) and chemotypes (IIHR-GS-44) which can be utilized for the commercial exploitation or can serve as pre-breeding materials in the crop improvement programmes.

We studied the genetic impact of natural regeneration practices, such as Single seed tree, Group seed tree, Patch clear cutting and Alternate strip clear cutting systems, by comparing the nuclear microsatellite(nSSR) variation of post-practice natural regeneration one-year old seedlings of Pinus densiflora to that of pre-practice mature trees. The levels of genetic diversity of seedlings (A=13.6, =4.3, =0.571, =0.597) were similar to those of mature trees (A=13.4, =4.3, =0.596, =0.598) and the differences in the level of genetic diversity between seedlings and mature trees for each of the practices were not statistically significant. The degree of genetic differentiation between seedlings and mature trees was very low (=0.002) and the pairwise values between seedlings and mature trees for all practices were less than 0.01. Overall, the natural regeneration practices appeared to have only minor impacts on the genetic diversity and the genetic composition in the studied P. densiflora stands. For a better understanding of the genetic effects of natural regeneration practices, subsequent studies such as temporal genetic variation of seedlings formed by crossing among post-practice mature trees should be considered.

Population genetics and gene flow of the seagrass, Syringodium isoetifolium based on Start codon targeted (SCoT) marker from Palk Bay and Chilika Lake, India

To improve the ecological and economic benefits of Korean pine (Pinus koraiensis), we analysed and evaluated its germplasm resources. This promotes in-depth research and utilisation of germplasm resources, providing excellent genetic resources for Korean pine breeding. We performed genetic analysis based on morphological and physiological traits and nuclear SSR molecular marker data was performed by collecting 314 clones (5 ramets of each clone) of Korean pine from eight (8) locations within the Korean pine range. The core collection underwent testing and evaluation for representativeness using variable rate (VR), coincidence rate (CR), variance difference percentage (VD), mean difference percentage (MD), Shannon index (I), and other indicators. The results indicated significant differences in morphological and physiological traits among the populations. All traits had a coefficient of variation (CV) greater than 10%, except for the water content of the needles (WC), which had an average CV of 17.636%. The populations showed high overall genetic diversity, with the HL (Helong) population exhibiting the highest genetic diversity, with an Ne (number of effective alleles), I, and He (expected heterozygosity) of 3.171, 1.103, and 0.528, respectively. Genetic variation mainly originated from individuals within populations, while the variation between populations was relatively small, at only 3%. The population did not exhibit any distinct subpopulation structures and was mainly derived from two admixed gene pools. Six core sets were obtained using different sampling strategies, and subset 6 was identified as the core collection, consisting of 114 individuals, representing a selection rate of 36.31%. In conclusion, the most appropriate method for constructing the core collection of Korean pines is the M-strategy (maximizing the number of alleles), based on both phenotypic and molecular data. The resulting core collection effectively represents the genetic diversity of the entire population effectively.

Ecuador es un país con una elevada biodiversidad de recursos genéticos animales de interés agroalimentario, aunque la información científica sobre ellos es escasa. En este trabajo se aborda el estudio de la diversidad genética de los cerdos Criollos de la Zona de Planificación Cinco de Ecuador, conformada por las provincias de Bolívar, Guayas, Los Ríos y Santa Elena, en donde este cerdo juega un papel fundamental en las comunidades campesinas como la principal fuente de proteína de la unidad familiar y, como una fuente de ingresos complementarios en sistemas de producción tradicionales. Se analizan 90 muestras con 25 microsatélites recomendados por la FAO para estudios de diversidad genética porcina y se calculan los parámetros básicos de variabilidad genética (número medio de alelos, número efectivo de alelos, heterocigosis, PIC y coeficiente FIS). Se calculan las distancias genéticas DSA y se construye un dendrograma de distancias entre individuos. Los cerdos Criollos de Ecuador estudiados presentan una elevada diversidad genética intra-racial, no se desvían significativamente del Equilibrio de Hardy-Weinberg. No se detecta diferenciación genética entre los cerdos muestreados en las diferentes provincias por lo que se podría gestionar como una sola población.

Effects of Nitrogen Fertilization on Growth and Physiological Characteristics of Populus Sibirica Seedlings in a Desertification Area, Mongolia

The quantity and quality of seedlings in the nursery has an impact on the success of re-establishment and later growth. High germination rates enable a sufficient number of seedlings, and their quality is assessed using a number of parameters, including seedling height and root collar diameter. These parameters are influenced in some species by seed size, but the correlation between them is species-specific. The model species in this research was sweet chestnut (Castaneasativa Mill.), and seeds from 12 populations from two distinct biogeographical regions of Croatia were collected. We examined the influence of seed size on four parameters: germination rate, seedling height, root collar diameter and sturdiness quotient. Seed size has been shown to have a positive influence on both seedling height and root collar diameter, whereas no such correlation was noted for germination rate and sturdiness quotient. Significant differences in nut size and seedling growth parameters were found between the Mediterranean and continental populations, with higher values observed in the coastal Mediterranean populations. We concluded that seed origin and seed size have a significant impact on seedling growth and are important factors to consider when choosing seed material. Further nursery operations should consider seed origin and local environmental conditions when choosing seedlings for reforestation efforts and general forest operations.

article i nfo Background: Genetic diversity and genetic variation of 10 populations and subpopulations of Magnolia wufengensis, a new and endangered endemic species, were examined by inter simple sequence repeat (ISSR) and sequence-related amplified polymorphism (SRAP) molecular markers. Compared with other endangered endemic Magnolia taxa, M. wufengensis holds a relatively high level of genetic variation. Result: Total genetic diversity was found to be 87.7% for ISSR and 88.0% for SRAP markers. For polymorphic loci (P), the effective mean number of alleles (Ae) was 1.414 for ISSR markers and 1.458 for SRAP markers, while the mean expected heterozygosity (H) was 0.256 using ISSR and 0.291 for SRAP markers. Within-population variation was estimated for P as 74.9% using ISSR and 74.6% with SRAP markers; the number of alleles Ae was 1.379 with ISSR and 1.397 for SRAP and H 0.235 with ISSR and 0.247 for SRAP markers. Conclusion:Theanalysisof molecularvariationofbothISSRandSRAPmarkersystemsindicatedthatmostgenetic variation iswithin populations, with valuesof 90.64%and 82.92%respectively. Mantel tests indicated a moderate association between the two marker systems and a low correlation between genetic and geographic distances. High levels of genetic diversity and low levels of population divergence suggest that genetic drift is not currently of great concern for this species. Severe habitat loss and fragmentation, predominantly ascribed to anthropogenic pressures, caused in-situ developing restriction of this species. Action for conserving this rare species for its long-term survival should be taken immediately.