Genetic Diversity Studies Research Articles

Genetic Variability and Character Association Studies in Wheat (Triticum aestivum L. em. Thell) for Seed Yield and Its Contributing Traits

This study investigated genetic variability, correlation and path analysis in wheat 54 genotypes, including 40 F1 hybrids, 14 parental lines, and a standard check variety (HD-3086). The parental lines consisted of 10 females and 4 males, with the hybrids evaluated using a randomized block design (RBD) during the 2020-21 and 2021-22 rabi season. Analysis of Variance (ANOVA) revealed significant differences among genotypes for most traits, indicating considerable genetic variability. Genotypic correlation analysis identified strong positive relationships between grain yield per plant (GYPP) and key agronomic traits, such as spike length, spikelets per spike, grains per spike, grain yield per spike, harvest index, and test weight. Conversely, negative correlations with days to 50% flowering and plant height suggested that early flowering and shorter plants are beneficial for yield enhancement. Path coefficient analysis revealed that harvest index and biological yield had the most substantial positive direct effects on GYPP, while traits like protein content and days to maturity showed negative direct effects. Thus, using such traits like harvest index and biological yield in wheat improvement program could increase wheat yield”.

Evaluation of Morpho-agronomic and Fruits Quality, genetic variability, and correlation studies in Tomatoes (Solanum lycopersicum L.) Genotypes

Evaluation of Morpho-agronomic and Fruits Quality, genetic variability, and correlation studies in Tomatoes (Solanum lycopersicum L.) Genotypes

Study on characters associations and path coefficient analysis for yield and quality traits of parthenocarpic cucumber genotypes in poly-net house conditions

Parthenocarpy in cucumber is a complex trait regulated by various genes and phytohormones. It is an important feature which helps to overcome the problem of poor fruit setting in cucumbers. The present research was conducted to estimate the variability, correlation and path analysis in 15 yield and quality traits using 30 advance breeding parthenocarpic lines including standard check ‘Punjab Kheera 1’. The genetic variability studies reported high estimates of phenotypic and genotypic coefficient of variation for number of fruits set per node and number of fruits per plant which signified the improvement of these traits with selection. High to moderate heritability and genetic gains were observed for fruit length, fruit diameter, fruit weight, internodal length, vine length, number of female flowers per node, number of fruits set per node, number of fruits per plant, fruit yield per plant, and vitamin C content of fruit. The correlation and path analyses provided a clear picture that there was direct and positive effect of fruit weight, number of fruits per plant, number of fruits set per node, fruit length, vitamin C, flesh to seed cavity ratio, and pistil length on fruit yield per plant.

Cowpea genetic diversity, population structure and genome-wide association studies in Malawi: insights for breeding programs.

This study focuses on cowpea, a vital crop for smallholder farmers in sub-Saharan Africa, particularly in Malawi. The research aimed to understand the genetic diversity and population structure of cowpea and to perform genome-wide association studies (GWAS) to identify marker-trait associations (MTAs) for yield and related traits. These insights are intended to support varietal development and address agricultural challenges in Malawi. A total of 306 cowpea genotypes were characterized using single nucleotide polymorphism (SNP) markers and morphological traits. The study assessed the effects of genotype, location, and their interactions on morphological traits. The Fixed and Random Model Circulating Probability Unification (FarmCPU) algorithm was used to identify significant MTAs. The morphological traits showed significant genotype, location, and interaction effects. Genotypes MWcp24, MWcp47, MWcp2232, and TVu-3524 yielded the highest values. Grain yield was positively correlated with peduncle length, seeds per pod, and pods per plant. Three distinct clusters were identified based on morphological traits. Genetic diversity analysis revealed an average minor allele frequency of 0.31, observed heterozygosity of 0.06, and gene diversity of 0.33. The average inbreeding coefficient was 0.82, indicating a high level of inbreeding. Most of the genetic variation (73.1%) was found among genotypes within populations. Nine groups and ancestral populations were identified, which did not entirely overlap with geographic origins. Sixteen significant MTAs were linked to six morphological traits. The validation of these identified MTAs, along with the observed genetic diversity, offers valuable opportunities for cowpea improvement through marker-assisted selection, to addresses the challenges faced by Malawian farmers. The identification of thirty cowpea lines as key founder lines for breeding programs in Malawi, Mozambique, and Tanzania is a significant outcome. These efforts aim to develop more productive cowpea lines for the region, enhancing food security and agricultural sustainability.

DNA barcoding and genetic diversity studies of Water lily aphid, Rhopalosiphum nymphaeae from India

Aim: In this study, DNA barcoding of Rhophalosiphum nymphaeae was conducted using a population collected from five different aquatic host plants, and the genetic diversity analysis was performed. Methodology: Genomic DNA from R. nymphaeae adults was extracted and the COI gene was amplified using PCR. The PCR products were sequenced, analyzed for identification using NCBI and BOLD databases, and the sequences were submitted to NCBI GenBank. Further genetic analysis were conducted to study the genetic diversity of the pest. Results: Two new aquatic weed hosts of water lily aphid was reported from India, i.e., Blue water lily, Nymphaea nouchali Burm. f., and Four leaf clover, Marsilea quardrifolia L. The genetic diversity analysis revealed the lesser diversity among the Indian and USA population of water lily aphid as compared to the populations from China, Canada and Lithuania. Interpretation: The genetic diversity analysis indicated no genetic variation in the Indian population, however, a moderate level of variation was observed in the rest of the world population. This work will facilitate the quick identification of R. nymphaeae independent of sex and stage, furthermore helping in either pest management or its use as bio-control agent. Key words: DNA barcoding, Marsilea quadrifolia, Nymphaea nouchali, Pest, Water lily aphid

Genetic Diversity and Genome-Wide Association Study for Shoot and Root Traits in Rice Grown Under Water Deficit at Early Vegetative Stage

Water deficit affects rice growth, development, and yield. Knowledge of genetic diversity for water deficit tolerance, as well as the genetic architecture that is responsible for this trait, can accelerate rice cultivars’ improvement. In this study, different tools were applied to assess genetic diversity and identify genome regions associated with shoot and root traits in rice germplasm grown under water deficit at an early vegetative stage. A panel of 177 rice genotypes grown under water deficit was evaluated for root length (RL), root dry weight (RDW), shoot length (SL), and shoot dry weight (SDW). Genetic diversity was investigated using means grouping and principal component analysis. For the genome-wide association study, a general linear model was applied, using RL, RDW, SL, and SDW phenotypic data converted into Best Linear Unbiased Prediction (BLUPs); genotypic data (1185 single nucleotide polymorphism—SNPs-loci); and population structure. Overall, little genetic diversity was observed, but genotypes with a higher water deficit tolerance were identified. Several significant SNPs were mapped, 81, 5, 53, and 41 for RL, RDW, SL, and SDW, respectively. Among the identified genes, there are those encoding kinases, proteins involved in phytohormone and cell wall metabolism, and Cytochrome P450. The obtained results provide insight into genetic diversity and the genetic architecture of water deficit tolerance, which will be useful in improving this trait in rice grown in Brazil.

Genetic Variability and Genetic Advance Studies for Bulb Yield and Its Components of Different Mutant Lines of Garlic (Allium sativum L.)

This study aims to study aims to evaluate the genetic variability and genetic advance for bulb yield and components of different mutant lines of Garlic (Allium sativum L.) under Chhattisgarh plains. The experiment was laid out in Randomized Block design with three replications 21 mutant lines viz., IG C-1, IG C-2, IG C-3, local check, IG M-2021-1, IG M-2021-2, IG M-2021-3, IG M-2021-4, IG M-2021-5, IG M-2021-6, IG M-2021-7, IG M-2021-8, IG M-2021-9, IG M-2021-10, IG M-2021-11, IG M-2021-12, IG M-2021-13, IG M-2021-14, IG M-2021-15, IG M-2021-16, IG M-2021-17. Data were analyzed to work out performance of mutant lines, to assess genetic variability, heritability, genetic advance. The character taken under study include plant height (cm), number of leaves, collar height (cm), collar thickness (cm), fourth leaf length (cm), fourth leaf width (cm), polar diameter (cm), equatorial diameter (cm), neck thickness (cm), number of cloves, average weight of bulb (g), TSS, days to maturity, weight of ten outer cloves (g), marketable yield (t ha-1), total yield (t ha-1). Estimates of genetic parameters for various character under study revealed that high genotypic co-efficient of variation was found in general compared to phenotypic co-efficient of variation. Heritability estimates under present investigation ranged from moderate to high. High heritability estimates recorded for collar height, weight of outer ten cloves, marketable yield, total yield. High heritability coupled with high genetic advance was recorded for collar height, marketable yield and bulb yield.

Genetic variability studies in maize under managed drought and normal conditions

Genetic variability studies in maize under managed drought and normal conditions

Monkeys Swimming Across Rivers Refine Questions About the Riverine Barrier Hypothesis.

The Riverine Barrier Hypothesis posits that species distributions are limited by large rivers acting as geographical barriers. Accordingly, large rivers have long been thought to be a major driver of the extensive speciation and high levels of biodiversity among platyrrhine primates in South and Central America. Direct observations of river crossings provide evidence that complements studies of genetic diversity that can together shed new light on this hypothesis. Here, we discuss recent video evidence of howler monkeys successfully swimming across the Rupununi River in Guyana and the Panama Canal. The footage clearly reveals that howler monkeys can and do cross such bodies of water. These video observations help to refine questions about the species and circumstances under which rivers are barriers to gene flow. We end by joining other scientists who call for increased collaborations with local people living near river crossing sites to improve our knowledge and understanding of the frequency, contexts, and traits of the rivers and animals that characterize river crossings. Local knowledge provides new answers and helps refine questions about the river barrier hypothesis.

Genetic diversity studies for yield attributing traits, oil content and late leaf spot disease in advanced backcross lines of groundnut (Arachis hypogea L.)

Genetic diversity studies for yield attributing traits, oil content and late leaf spot disease in advanced backcross lines of groundnut (Arachis hypogea L.)

Genetic diversity and character association studies for agro-morphological and quality traits of advanced breeding lines in field pea (Pisum sativum L.)

Abstract The present study analysed the trait associations and the genetic diversity for morphological and qualitative traits among the 23 field pea genotypes using multivariate analysis. The correlation analysis revealed that traits like primary branches per plant, pod length, seeds per pod, harvest index and biological seed yield per plant showed a note-worthy positive association at both genotypic and phenotypic levels. Path analysis revealed the correlation of pod length, harvest index and biological yield per plant was due to direct positive effects. The principal component analysis indicated that the fiseven PCs together accounted for 86.56% of the total diversity. The cluster analysis classified genotypes into five different clusters with cluster 1 comprising 18 genotypes, cluster 2 with 2 genotypes, and the remaining three mono-genotypic clusters. The selection of diverse genotypes superior in traits with positive influence on yield can result in greater genetic gains and aid in crop improvement. Keywords: Genetic diversity, correlation, path analysis, PCA

Genetic variability and association studies for yield and pre-harvest sprouting traits in greengram [Vigna radiata (L.) Wilczek

Abstract The present study investigates the genetic variability and associations of agronomic traits impacting pre-harvest sprouting (PHS) in 30 greengram genotypes. Significant variability was observed across multiple traits, with seed yield per plant ranging from 2.19 to 7.82 g. ​Key findings indicate that hard seed percentage and alpha-amylase activity at different germination intervals are having high heritability, demonstrating genetic heritability essential for breeding strategies.​ High phenotypic variability suggests environmental influence on trait expression, especially in traits such as days to maturity and pod diameter. Correlation analysis revealed robust positive associations between seed yield and days to maturity, while negative correlations were noted with epicuticular wax content and pod wall thickness. The path analysis identified that days to 50 % flowering, along with alpha-amylase activity, directly affects yield, emphasizing the intricacies of trait interrelationships. This research aims to contribute towards developing PHS-resistant mung bean varieties that enhance crop yield and quality. Keywords: Greengram, genetic variability, pre-harvest sprouting, correlation analysis, path analysis

Genetic diversity studies for yield and physiological traits using principal component analysis in little millet

Abstract Principal Component Analysis (PCA) was conducted to assess the genetic variability among 50 little millet genotypes based on yield and physiological traits. Results revealed six principal components with an Eigen value more than one, which accounted for 74.25% of the total variability. PC 1 contributed the most towards the total variability at 27.98%, while PC 2, PC 3, PC 4, PC 5, and PC 6 contributed 12.90%, 11.19%, 8.93%, 7.08%, and 6.14% respectively. Days to 50 per cent flowering, grain yield plot-1, harvest index, leaf area index at both panicle and 15 days after panicle initiation, specific leaf weight at 15 days after panicle initiation, and main panicle weight were the foremost contributors to genetic diversity among the studied genotypes. The biplot diagram revealed that WV-167, BL-6, TNPsu-174 and GPUL-2 were the most diverse genotypes, with high yield potential compared to other entries. GPUL-1 and DLM-186 are likely to be drought resistance due to lower relative membrane injury (%). Hybridization among these genotypes could result in transgressive segregants with desirable traits for yield and physiological characteristics. Keywords: Little millet, Principal Component Analysis, Physiological traits, Yield traits

Genetic variability and association studies in F2 populations of Groundnut (Arachis hypogaea L.)

Groundnut is an extensively self-pollinating crop with a narrow genetic base; therefore, it relies on the F2 generation for optimal segregation and recombination. The genetic variability resulting from segregation and re- combination is essential for effective selection in crop improvement pro- grammes. F2 populations derived from the crosses BSR 2 × GPBD 4 and BSR 2 × TMV 2 were assessed for examining genetic variation, and correla- tion coefficients along path coefficients. Twenty-four yield-attributing, physiological, as well as biochemical characteristics were covered in the research, in the Kharif season of 2024. The assessment of the PCV along with GCV revealed that a majority of yield-related traits, including the number of pods, kernels, and pod yield, demonstrated high PCV along with GCV in both crosses, indicating substantial genetic variation. Regarding yield-related characteristics, high GAM along with high heritability in a broad sense were noted for both the crosses, suggesting that a breeding approach based on simple selection can be successful in increasing groundnut yield. Correla- tion and path coefficients indicated that the number of mature kernels and pod yield calculated for each plant possessed a high positive direct effect on kernel yield. Transgressive segregants were identified over twice the stand- ard deviation of the better parent mean for various traits. These findings can serve as a foundation for future breeding programmes aimed at enhancing the yield and oil content.

Identifying molecular differences using ISSR markers on three quinoa genotypes (Chenopodiumm quinoa) under Sinai conditions, Egypt

This study aimed to evaluate the performance of three quinoa genotypes (Giza1, Danish KVL3704, and Misr1) under three irrigation intervals (every three, six, and nine days). Genetic diversity among nine quinoa accessions was assessed using eight ISSR primers, yielding robust amplification products and polymorphic fingerprint patterns. A total of 102 bands were generated, averaging 12.75 bands per primer. Among these, 52 fragments were polymorphic, resulting in an average of 6.5 polymorphic bands per primer and an overall polymorphism level of 40.9%. Primer ISSR-8 exhibited the highest polymorphic capacity with 17 polymorphic bands, while primer ISSR-15 displayed the highest frequency (0.9). In contrast, primers ISSR-8 and ISSR-10 exhibited the lowest frequency (0.5). The polymorphism percentage ranged from 20% for primer ISSR-15 to 88% for primer ISSR-10. The similarity index revealed a minimum value of 78% between treatments, clustering the nine accessions into eight groups across four similarity levels, from 80% to a maximum of 93%. Dendrogram analysis underscored the utility of ISSR-PCR in detecting genetic relationships among quinoa accessions. These findings highlight the potential of ISSR-PCR as a reliable tool for genetic diversity studies and its applicability in quinoa breeding programs.

Development of Intragenic InDel Markers From RNA‐Seq Data for Map‐Based Cloning and Marker‐Assisted Selection in Maize (Zea mays L.)

ABSTRACTMaize is one of the most extensively grown and produced crops in the world. Functional molecular markers (FMM) are essential tools for enhancing the efficiency of both breeding and basic research. The transcriptome obtained from high‐throughput sequencing is a valuable resource for developing FMM. In this study, we precisely identified high‐density and highly polymorphic RNA‐derived InDel markers from 368 high‐quality, high read depth maize RNA‐seq datasets using stringent criteria. The nonredundant marker dataset comprised 13,904 InDel markers with a Polymorphism Information Content (PIC) ≥ 0.5 and a principal allelic difference (length difference between the most and second most frequent alleles) ≥ 3 bp, covering 7749 genes. Subsequently, the polymorphism of InDel markers was verified experimentally. Fifty InDel markers were randomly selected, and their average PIC values in 20 maize inbred lines selected from 368 RNA‐seq samples and 20 newly selected maize inbred lines were 0.53 and 0.54, with range intervals of 0.18 to 0.77 and 0.22 to 0.74, respectively. The high density and polymorphism of RNA‐derived InDel markers identified in this study make them effective tools for maize gene cloning, genetic diversity studies, genome‐wide association analysis, and marker‐assisted selection.

Detection of Genetic Variations in Children with Tetralogy of Fallot Using Whole Exome Sequencing Technology Integrated Bioinformatics Analysis.

Background: Tetralogy of Fallot (TOF) is the most common cyanotic heart defect in newborns, with a complex etiology and genetic variation considered to be one of the main pathogenic factors. Identifying genetic variations associated with TOF has important clinical value for understanding its pathogenesis, patient susceptibility, and prognosis of patients with TOF. Therefore, this study aimed to identify potential pathogenic genes of TOF through comprehensive genetic analysis. Materials and Methods: In this study, we employed whole exome sequencing (WES) of the DNA of 47 Chinese children who received surgical TOF treatment at the Children's Hospital of Zhejiang University of Medicine and processed for DNA extraction and quantification of the DNA following WES using the Illumina NovaSeq platform. WES data undergo strict quality control and analysis processes including alignment, postprocessing, variant calling, annotation, and prioritization. Key tools, such as GATK's haplotype calling module and Annotate Variation, were used for variant annotation. In addition, by combining bioinformatics tools such as SIFT, Polyphen2, and Clin Pred, we evaluated the potential impact of nonsynonymous mutations on protein function and referred to relevant literature to support our prediction. Results: Comprehensive data analysis and quality assessment analysis corroborated the data generated from the WES dataset of 47 patients with TOF. Interpreting variants from the perspective of clinical pathogenicity results revealed a novel polymorphism and variant associated with TOF. The identified genetic results revealed evidence for a major contribution of MUTYH, RARB, GFM1, PDZD2, CEP57, DCPS, POMT2, BUB1B, CYP19A1, MAZ, USP10, and TCF3 and provided novel findings for functionally interacting proteins associated with the pathomechanism of TOF. Seven pathogenic variants related to TOF were detected, most of which were previously unreported in this cohort. Conclusions: The genetic variations discovered in this study emphasize the importance of genetic factors in the pathogenesis of TOF, revealing its complex molecular pathways and protein-protein interactions. The study of genetic diversity provides a new perspective for understanding the etiology of TOF and promotes an in-depth exploration of its pathological mechanisms. These findings lay the foundation for subsequent clinical research and the development of treatment strategies.

Assessment of Genetic Diversity in Green Gram [Vigna radiata (l.) Wilczek] for Quantitative and Qualitative Traits

The current study, "Assessment of genetic diversity in green gram [Vigna radiata (L.) Wilczek] for quantitative and qualitative traits" was carried out during the kharif of 2022 at the College of Agriculture, Dhule. The experimental materials consisted local collection of 42 mungbean genotypes which were evaluated in a randomized block design (RBD) with two replications, representing various eco-geographic regions for twelve different characters and studies of genetic divergence were carried out. The genetic diversity among landraces is determined by the range of D2 values which varied from 44.68 (MG-2022-15 and MG-2022-30) to 1678.53 (MG-2022-18 and MG-2022-31) for each genotype, showing adequate variance. Based on D2 levels, the 42 genotypes were split up into 16 groups with notable genetic differences. Cluster I and III were the largest, with 11 and 10 genotypes each. It was adjacent to Clusters II, which had eight genotypes. Based on inter-cluster means and per se performance, breeding programs may employ the following effective genotypes viz., MG-2022-31, MG-2022-42, MG-2022-21, MG-2022-40, MG-2022-39, MG-2022-14, MG-2022-11, MG-2022-18, MG-2022-02, MG-2022-25, and MG-2022-24 to further enhance grain yield and its contributing characters in mungbean.

Characterization and studies of genetic diversity of sweet potato from Paraguay

El objetivo fue caracterizar genotipos y obtener datos sobre la diversidad genética de batata. El diseño fue en BCA con 26 tratamientos y tres repeticiones. Fueron evaluadas productividad total, rendimiento comercial y no comercial de raíz (t ha-1), número de raíces por planta, biomasa aérea, forma y color de la raíz. La diversidad genética fue obtenida por la medida de disimilaridad media similares y para delimitación de grupos se utilizó el método de dendrograma UPGMA. Como medida de proximidad de distancias se utilizó la medida de disimilitud Euclidiana Cuadrática. La cantidad de clusters fue por el Criterio de Mojena. El mayor número de accesiones fue agrupado en el cluster III, con nueve accesiones, cluster II con seis accesiones, cluster IV, con seis accesiones, cluster VII con dos accesiones y cluster I, V y VII con una accesión cada una. La mayor distancia genética fue entre Morotí Guazú (6) e Ib-019 (23) con 40.443 y los más similares resultaron Morado (3) y Pyta guazú (9) con un valor de 1098. La productividad de raíces es la variable de mayor importancia para la distancia genética. El color predominante de la piel de la colección es crema y color de carne amarillo pálido.

Molecular Characterisation of Some Corn (Zea mays L.) Genotypes Growing in Iğdır Province

Inter-primer binding site markers based on retrotransposons or iPBS retrotransposon markers have been useful in determining genetic diversity in a large number of organisms. The CTAB technique was employed to isolate DNA, and iPBS molecular markers were employed to conduct genetic diversity studies. Based on the analyses' findings, the genotypes exhibited a significant degree of genetic diversity, with a 100% polymorphic locus percentage. A total of 154 polymorphic bands were generated as a consequence of molecular identification experiments conducted with 12 IPBS markers. The typical polymorphism rate was determined to be 100%. Additionally, the average polymorphism (PIC) value, which quantifies the gene diversity of all markers examined in the study, was 0.228, and the average H value was 0.274. The genotypes 1 and 14 exhibited the lowest similarity ratio, with a coefficient value of 0.1600, when the DICE similarity coefficients were compared. These results were derived by comparing the DICE similarity coefficients of the samples. The analysis determined that the greatest similarity value between genotypes 4 and 3 was 0.6747. Maize genotypes are classified into four distinct subpopulations. Genotypes can be developed for reproductive research in order to demonstrate the molecular diversity of a population. It was determined that IPBS molecular markers are appropriate genetic instruments for genetic and phylogenetic analyses in maize varieties. This conclusion was attained as a consequence of the aforementioned. The data that is gathered will serve as a scientific foundation and a valuable contribution to the field of maize genetics in the future.