Magnitude Of Genetic Diversity Research Articles

Evaluation of Genetic Divergence in Chickpea (Cicer arietinum L.) Germplasm

A field experiment was carried out to assess the nature and magnitude of genetic divergence in forty genotypes of desi chickpea using Mahalanobis’s D2 Statistics. High magnitude of heritability (bs) was recorded for plant height, days to 50% flowering, biological yield, harvest index, number of pods per plant, seed yield per plot, 100 seed weight and seed yield per plant. High heritability coupled with high genetic advance was observed for seed yield per plant, seed yield per plot, number of pods per plant, 100 seed weight, harvest index, biological yield and plant height suggesting that, the role of additive gene effect and possibilities of achieving high genetic progress through selection. The forty chickpea genotypes were grouped into seven clusters suggesting considerable amount of genetic diversity in the material. The cluster III has a total of 10 genotypes, followed by cluster II with nine, cluster VI with seven, cluster IV and V with four, and cluster I and VII with three genotypes, respectively. The intra-cluster D2 value ranged from 148.25 to 491.49 while, inter-cluster D2value ranged from 386.99 to 2141.49. The maximum intra cluster distance was found in cluster I followed by cluster VII and VI, indicating that cross combinations may occur through hybridization between genotypes from the same clusters. The highest inter-cluster distance was observed between cluster I and V (2141.49), followed by cluster I and IV (1590.64), cluster II and V (1271.17) and cluster I and VII (1184.91) suggesting that the genetic architecture of the genotypes in one cluster differ entirely from those included in other clusters. These lines may be utilized in further breeding programe for the exploitation of hybrid vigour and suggesting wide diversity between them and crossings between genetically diverse lines will result in heterotic segregants, genotypes in these clusters could be employed as parents in a hybridization program to develop desirable plant types. Among the ten traits studied, maximum contribution was made by harvest index (21.28 %) followed by number of pods per plant (19.36%), biological yield (15.13%), plant height (14.87%), days to 50% flowering (12.18%) and seed yield per plant (8.08%). The genotypes ICC15921, ICC15903, K1058 and ICC15926, ICC15226, ICC7549, ICC15855 were identified as genetically diverse parents, which can be utilized for future crop improvement programe in chickpea. The aforementioned findings show that these genotypes contain the greatest genetic diversity and are useful for creating a large number of segregants through a crossing program.

Genetic diversity studies in soybean (Glycine max L. Merrill) germplasm

Hundred soybean genotypes along with five checks were evaluated to study the nature and magnitude of genetic divergence using Mahalanobis’s D2 Statistics. The data was recorded on nine important quantitative traits from the genotypes grown in Augmented Block Design. The characters plant height, number of pods/plant, days to 50% flowering, days to maturity and 100 seed weight contributed maximum towards genetic diversity. The genotypes grouped into 6 clusters, cluster I was larger containing 60 genotypes whereas cluster V has smallest cluster containing only one genotype. On the basis of clusters formed genotypes were selected to be utilized as donor like NRC 105, JS 20-34 and JS 95-60 for earliness; Kalitur and AGS 25 for more number of pods and branches; Karune for bold seed and AMS 100-39 and AMS 48-7-3 for high seed yield. On the basis of average inter cluster distance the cross AMS 48-7-3 x Kalitur and AMS 100-39 x AMS 48-7-3 were suggested for getting more number of pods and branches with high yield. The cross combination Karune x Kalitur, AMS 48-7-3 x Karune and AMS 100-39 x Karune were suggested for getting extra bold seeded high yielding variety.

Genetic Diversity Studies and Fusarium Wilt Screening in Chickpea (Cicer arietinum L.) Germplasm

Background: The genetic base of chickpea has narrowed substantially during the domestication process (Thudi et al., 2016). Therefore, increasing the genetic divergence of chickpea has been a major goal for breeders. The assessment of genetic diversity of chickpea germplasm can provide a valuable information to the breeder for parental selection strategies in plant breeding programs. Method: Two hundred and eighty chickpea germplasm including two checks (JG-11 and SA-1) were tested with an objective to explore the genetic divergence by using Mahalanobis D2 statistics. The field experiment was carried out during Rabi 2021-22 at Zonal Agricultural Research Station (ZARS), Kalaburagi. The magnitude of genetic divergence was studied using data obtained from five quantitative traits. Results: The 280 genotypes including checks were divided into seventeen clusters based on their D2 values. Out of seventeen clusters, cluster II (89 genotypes) was the largest followed by cluster I (83 genotypes), cluster III (31 genotypes), cluster VIII (29 genotypes), cluster VII (24 genotypes), cluster VII (15 genotypes). Same set of germplasm were also screened for fusarium wilt in wilt sick plot, 30 germplasm lines showed resistant (10.71%), 83 moderately resistant (29.64%), 44 moderately susceptible (15.71%), 31 susceptible (11.07%) and 92 highly susceptible reaction to fusarium wilt. Clusters XIV and XVI had extreme genetic distance and the germplasm lines in these cluster also showed moderate resistance to fusarium wilt.

Study of Genetic Diversity in Greengram (Vigna radiata (L.) Wilczek) Germplasm in Prayagraj Region

The present study consists of 41 Greengram genotypes including one Check variety used to study the nature and magnitude of genetic divergence using Mahalanobsi’s D2 statistics. The data for 13 quantitative characters recorded from the genotypes raised in Randomized Block Design having three replications at Department of Genetics and Plant Breeding, SHUATS, Prayagraj, Uttar Pradesh, India during Kharif-2021. 13 quantitative characters viz., Days to 50% flowering, Days to 50% pod setting, Days to maturity, Number of clusters per plant, Number of primary branches, Plant height (cm), Number of pods per plant, pod length (cm), Biological yield per plant (g), Number of seeds per pod, Harvest index (%), Seed yield per plant(g), Seed index to estimate the variability, heritability, genetic advance, genetic diversity among yield. SML-668 (14.96 g) has the highest Seed yield followed by IPM-205-7 (13.48 g), IPM-410-03913.21 g) showed the higher yield over the SM-20-29 (Check). Maximum (GCV), (PCV), Heritability was recorded for Number of primary branches. High Heritability coupled with high Genetic advance was recorded for Plant height (cm). Divergence analysis followed by Mahalanobis [1] D2 analysis has revealed the presence of a substantial amount of diversity among the genotypes. Clusters I contain 19 genotypes followed by Clusters II contain 18 genotypes while Clusters III, IV, V, VI are mono genotypic. The maximum inter-cluster distance was observed between Cluster IV and VI (290.82) followed by Cluster IV and V (238.70). Thus, genotypes present in these clusters suggest that the genetic architecture of the genotypes in one cluster differ from another cluster which provides a broad spectrum of variability in segregation and may be used as parents in the future hybridization programme to develop desirable genotypes.

Genetic Diversity Analysis for Yield and Quality Traits in Rice Cultivars of Manipur and Assam

The North–Eastern region of India is blessed with wide variability in rice. The present investigation was carried out with 41 diverse cultivars of rice collected from the farmers’ fields of Manipur and Assam to estimate the nature and magnitude of genetic divergence among the genotypes using Mahalanobis D2 statistics. The germplasm consisted of the popular black rice and some glutinous and non-glutinous rice which are commonly grown in both regions. The experimental materials were evaluated during the Kharif season of 2020-2021, following a randomized block design with three replications at the experimental field of BN College of Agriculture, Biswanath Chariali, Assam. The genotypes exhibited significant differences for all 24 characters under study. The cluster analysis indicated that 41 genotypes were grouped under 12 different clusters and cluster IV was the largest comprising the maximum number of genotypes with 12 genotypes, followed by cluster V with eight genotypes, cluster X with five genotypes, clusters II and XII with four genotypes each, cluster I with two genotypes and clusters III, VI, VII, VIII, IX & XI with one genotype each. Among all the characters studied, grain length exhibited maximum contribution towards divergence followed by kernel length after cooking, grain breadth, 100-grain weight and kernel breadth after cooking. Clusters X and XII showed the maximum inter-cluster distance and the maximum intra-cluster distance was exhibited by cluster XII, indicating the existence of a significant amount of variability within the cluster. The intra-cluster distance ranged from zero (clusters III, VI, VII, VIII, IX, XI) as they consist of a single genotype each to 1146.89 (cluster XII). Hybridization among the genotypes of clusters X and XII is expected to produce better heterotic combinations.

Assessment of Genetic Divergence in Pea (Pisum sativum L.) Genotypes in Western U.P

The present investigation was carried out with 20 genotypes of pea (Pisum sativum L.) at Horticulture Research Centre (HRC) of SVPUAT, Meerut, U.P, during 2021-22 to identify the nature and magnitude of genetic divergence among genotypes based on phenotypical traits using the multivariate analysis. The experiment was laid down in randomized block design (RBD) with three replications. The experiment has ten observations based on five randomly selected plants from each replication. D2 analysis grouped all 20 varieties into five clusters revealing the presence of considerable amount of variation among genotypes. Cluster pattern revealed that, clusters I and II had the highest number of 5 genotypes succeeded by cluster III with 4 genotypes, cluster IV and cluster V containing three genotypes each. Maximum intra cluster distances were recorded in cluster I (D2 =2.264) indicating maximum difference among the genotypes within the cluster and minimum intra cluster distance was recorded in cluster V (D2=1.481) whereas, Maximum inter-cluster distance (D2=5.211) was observed between cluster II and IV and the minimum was observed (D2=2.373) was observed between cluster III and V. The cluster means revealed the cluster IV was the best cluster for various characters like plant height, number of pods per plant, pod length, days to maturity and pod yield, providing upon the aim of breeding. Hence the potential genotype can opt from different clusters as parents.

Genetic divergence in gladiolus (Gladiolus hybridus Hort.) genotypes

Genetic diversity is the first and important parameter in crop improvement programme. In the presentinvestigation forty gladiolus genotypes were assessed to know the nature and magnitude of geneticdivergence using Mahalanobis D2 statistics. The population was grouped into four clusters. The averageweight of cormels, daughter corm diameter, average weight of daughter corm, days to corm sprouting,floret diameter and number of cormels per plant components were found main parameters contributingtowards divergence and played dominant role in the improvement of gladiolus quality. Based onMahalanobis D2 analysis, forty gladiolus genotypes were grouped into four clusters with maximum of 36genotypes in Cluster I. Remaining three clusters II, III and IV are solitary indicating their independentidentity and importance due to various unique characters possessed by them. The highest inter cluster D2value was recorded between clusters III (Copperking) and IV (Arka Kesar). Cluster I showed maximumintra cluster diversity. Therefore selection for divergent parents based on these traits is recommended forgetting desirable hybrids or segregates in Gladiolus.

No Two Alike - The surprising variability of brothers and sisters

I know a family where neither parent could read music or play an instrument. But that didn’t stop them from buying a piano. “With eight kids, at least one person was going to be musical,” the mother predicted. She was right: The sixth child became an avid pianist. Most of us don’t have eight children, so we might not be confronted quite as starkly with the incredible range of traits and talents that can pop up in a single family. Shrinking families have shrunk our imaginations about the sheer magnitude of genetic diversity that is lurking within our bodies.

Assessment of genetic diversity in linseed (Linum usitatissimum L.) genotypes

An investigation was carried out to assess the nature and magnitude of genetic diversity in 36 genotypes of linseed using Mahalanobis D2 statistics. Presences of diversity pave way for exploitation of genotypes in breeding programmes which intended to improve the yield and yield attributing traits. The cluster analysis grouped 36 linseed genotypes into 12 distinct clusters. Clusters II and V were the largest containing eight genotypes each followed by cluster I with seven and cluster VII with five genotypes. The pattern of distribution of genotypes within different clusters was random and independent of geographical origin or region of adaptation. The maximum inter cluster distance was observed between cluster VII and XI (227.97) followed by cluster III and VII (207.29). The greater the distance between the two clusters, wider the genetic diversity between genotypes. The intra cluster distance was maximum in cluster VII (48.85) followed by cluster V (41.30) indicating hybridization involving genotypes within the same clusters might result in good cross combinations. On the basis of cluster mean value, genotypes in cluster VI, VII and IV deserve consideration for their direct use as parents in hybridization programs to develop high yielding linseed varieties. Key wordsGenetic diversity, Cluster analysis, D2 statistics, Inter and Intra cluster distance

Genetic Divergence Studies in Horse gram (Macrotyloma uniflorum Lam.Verdc) for Quantitative Traits using Mahalanobis D2 Analysis

The present study aimed to estimate the nature and magnitude of genetic divergence in 60 horse gram genotypes for ten characters using Mahalanobis D2 analysis. The genotypes were grouped into thirteen clusters. Concerning intracluster distance, the genotypes falling within cluster III (31.51) has maximum divergence. Maximum inter-cluster distance was observed between cluster VIII and XIII (184.05), followed by cluster XI and XIII (170.83). Cluster VIII exhibited a higher mean for hundred seed weight, grain yield per plot and Bhusa yld/plot and cluster VI contained genotypes with the higher mean value for pod length and the number of seeds per pod. Among the yield contributing characters, the traits viz.,grain yield per plot (28.30%) followed by the number of pods per plant (26.21 %) and the number of branches per plant (18.36%) contributes to major genetic divergence.The results indicated that from cluster IV the genotype HA 871-5-67/2 was selected for plant height, from cluster II the genotype Morappur-1 was chosen for the number of branches per plant, from cluster XII the accession HG 102 was selected for the trait number of pods per plant, from cluster VI the genotype T 45 was chosen for pod length and the number of seeds per pod. From cluster VIII the genotypes 12EB and IC 9606 were nominated for hundred seed weight, grain yield per plot and Bhusa yield per plot(g).

Pattern and magnitude of genetic diversity in Pinus gerardiana wall. Populations

Twelve populations of Pinus gerardiana in North- west Himalayas of India were analysed for isozyme variation based on the seven enzyme systems. In isozyme analysis, of the 16 gene loci identified for the assayed seven enzyme, six loci under six enzyme systems were polymorphic. Only one enzyme system i.e. GDH does not show any polymorphic loci. The mean number of alleles per locus was 1.48 and mean expected heterozygosity was 15%. The gene pool allelic differentiation among the populations varied from 38.2% to 45. 2% whereas gene pool genotypic differentiation varied from 52% to 60%. For all possible pairs of populations Nei’s genetic distance values averaged 0.0021.The value of differentiation observed in the study could be attributed to the adaptive mechanism to the microenvironment shows high level of polymorphism.

Genetic divergence studies among different genotypes of bitter gourd (Momordica charantia L.)

A study was conducted during kharif 2019, in Uttar Pradesh, India, to evaluate the nature and magnitude of genetic divergence in 15 bitter gourd genotypes. Results revealed the presence of wide genetic diversity. The genotypes were grouped into 4 clusters based on Mahalanobis D2 statistics using Torcher’s method. The clustering pattern of genotypes revealed that the genetic diversity was independent of the geographical diversity. Among the 4 clusters, maximum numbers of genotypes were found in cluster I, while clusters IV was found to be mono-genotypic. Among the 14 quantitative characters studied, number of fruits/plants constituted a maximum of 59.05% contribution to the divergence, followed by fruit yield (q/ha). Ranking of genotypes based on intra-cluster mean performance for these characters which are major contributors of genetic diversity revealed its usefulness in selecting parents for heterosis breeding.

Assessment of Genetic Divergence in Long Day Onion (Allium cepa L.) through Principal Component and Single Linkage Cluster Analysis

To assess the nature and magnitude of genetic diversity in long day onion germplasm by using the principal component analysis and single linkage cluster analysis an experiment was carried out with 34 onion genotypes. High coefficient of variation with wide range in traits indicated an appreciable variability in germplasm. Genotypes were classified into seven principal components having Eigen value > 1, cumulatively accounted for 83.87% of total variability. Principal Component - I contributed for 24.73% of total variation for followed by principal component-II (15.27%). PC-I had high positive loading for bulb weight (0.401), marketable yield (0.338), total bulb yield (0.401) and PC-II had high positive loading for plant height (0.412), PC-III for high T.S.S. (0.276) PC -IV for A grade bulbs (0.436), PC-V for polar diameter of bulbs (0.514), PC-IV negatively loaded with purple blotch (-0.461) and PC-VII for narrow neck thickness (-0 .515). Plotting PC-I aganist PC-II differenciated CITH-O-13, CITH-O-4, CITH-O-22, CITH-O-19, CITH-O-9, CITH-O-6 and CITH-O2 as most divergent genotype.On the basis of single linkage cluster means cluster-I was most importent for average bulb weight, minimum bolters, high marketble bulb percentage high marketable and total bulb yield whereas cluster -II was important for maximum nuber of leaves/plant and minimum neck thicknes. Highest inter-cluster distance was observed between cluter II and Cluster-I(873.5% ).Most divergent genotypes with high inter cluter distance could be the most appropriate parents for crop impovement in onion.

Assessment of Genetic Divergence in Long Day Onion (Allium cepa L.) through Principal Component and Single Linkage Cluster Analysis

To assess the nature and magnitude of genetic diversity in long day onion germplasm by using the principal component analysis and single linkage cluster analysis an experiment was carried out with 34 onion genotypes. High coefficient of variation with wide range in traits indicated an appreciable variability in germplasm. Genotypes were classified into seven principal components having Eigen value > 1, cumulatively accounted for 83.87% of total variability. Principal Component - I contributed for 24.73% of total variation for followed by principal component-II (15.27%). PC-I had high positive loading for bulb weight (0.401), marketable yield (0.338), total bulb yield (0.401) and PC-II had high positive loading for plant height (0.412), PC-III for high T.S.S. (0.276) PC -IV for A grade bulbs (0.436), PC-V for polar diameter of bulbs (0.514), PC-IV negatively loaded with purple blotch (-0.461) and PC-VII for narrow neck thickness (-0 .515). Plotting PC-I aganist PC-II differenciated CITH-O-13, CITH-O-4, CITH-O-22, CITH-O-19, CITH-O-9, CITH-O-6 and CITH-O2 as most divergent genotype.On the basis of single linkage cluster means cluster-I was most importent for average bulb weight, minimum bolters, high marketble bulb percentage high marketable and total bulb yield whereas cluster -II was important for maximum nuber of leaves/plant and minimum neck thicknes. Highest inter-cluster distance was observed between cluter II and Cluster-I(873.5% ).Most divergent genotypes with high inter cluter distance could be the most appropriate parents for crop impovement in onion.

Genetic variability and divergence studies in Finger millet [Eleusine coracana (L.) Gaertn] germplasm

A total 158 finger millet accessions were evaluated to study the genetic diversity with the nature and magnitude of genetic divergence using Mahalanobis (1936) D2 statistics. Genotypic and phenotypic variances, coefficient of variation, heritability and genetic advance were estimated and cluster analysis was performed. The data was recorded on fifteen traits. The one hundred fifty eight genotypes were grouped into XIII clusters. Clusters I was the largest with 58 genotypes. Maximum heritability was observed for iron content (99.8%) followed by calcium content (99.7%), days to maturity (98.6%), days to 50% flowering (97.2%), seed yield per plant (93.7%), finger number per panicle (92.7%) and flag leaf sheath width (91.8%). Genetic advance as per cent of mean ranged from 5.425 to 137.52. Since there is significant variability observed in all the finger millet genotypes, this could be used for genetic improvement through selection and hybridization.

Phenotypic Diversity of Pea Genotypes (Pisum sativum L.) Based on Multivariate Analysis

The present study was conducted to identify the nature and magnitude of genetic divergence among fifty five genotypes based on phenotypical traits using the multivariate analysis. Based on cluster analysis, the genotypes were best fitted into six clusters. The maximum and minimum genotypes grouped in cluster III (14) and minimum were in Cluster IV (4) respectively. The maximum intra-cluster distance was shown by cluster I (D2 2.543) indicating maximum difference among the genotypes within and the minimum value was shown by cluster II (D2 =1.827). Maximum value of inter-cluster distance (D2=6.471) was recorded between cluster I and cluster IV revealing that the genotypes of these clusters were highly diverse from others and can be used as divergent parents for hybridization and selection. Thus, for getting high heterosis for recovering transgressive segregants, genotypes from cluster I and IV can be used as distant parents in any breeding programme for successful pea improvement. The Optimum number of K-means clusters formed were four. The result of PCA revealed that all the four principal components (PC-I, PC-II, PC-III and PC-IV) contributed 86.7% of the total variability. The results of present study could be exploited in the future genetic improvement programme of pea genotypes in Uttar Pradesh region.

Genetic divergence among mutant genotypes of greengram [Vigna radiata (L.) Wilczek

The nature and magnitude of genetic divergence was estimated among forty five mutant lines of greengram variety OBGG-52, developed by single and combination treatments with gamma rays, Ethyl Methane Sulphonate (EMS), N-methyl-N¢-nitrosoguanidine (NG) and maleic hydrazide (MH) using multivariate analysis. These mutant genotypes were grouped in to 12 clusters based on D2 values using Tocher’s method. A large proportion of mutant lines showed divergence from the parent variety and also among themselves. No definite relationship of mutagenic origin and clustering of mutant lines were observed. The mutant lines developed from the same mutagenic treatments often grouped into different clusters indicating that each mutagenic treatment was effective in inducing diverse types of changes in the nine traits studied. Sixteen genotypes were grouped with their parents in cluster-I, while rest of 28 genotypes grouped in to another eleven divergent clusters. Cluster-IV had maximum intra-cluster distance (3.95), while inter-cluster distance was highest (8.27) between cluster-XI and cluster-XII. Genotype of Cluster-III was superior for yield per plant, seeds/pod where as Cluster- VIII was superior for 100-seed weight and pods per plant. Thus hybridization of genotype belonging to cluster-III with genotype in cluster-VIII is suggested for development of superior genotypes.

Assessment of genetic divergence among Indian genotypes of pomegranate for economic traits

The efficacy of pomegranate improvement for higher productivity as well as fruit quality can be achieved by selecting superior parental combinations made between divergent clones. The nature and magnitude of genetic divergence was assessed for 35 quantitative traits using Mahalanobis D2 analysis in 23 popular Indian pomegranate genotypes. Interestingly, peel weight followed by seed width had higher contribution to the diversity among the selected genotypes. Tocher's method of cluster analysis grouped all the cultivars into four distinct clusters. Genotypes falling in clusters II and III were highly diverse from each other. Mean value for most of the fruits and aril parameters were highest in cluster III, a solitary cluster comprising of the most popular cultivar Ganesh followed by cluster I consisting of a commercial pomegranate cultivars like Bhagwa and its clones. The wider variations for different traits among the clusters in the selected pomegranate cultivars shows that genotypes from desirable clusters could be directly used in breeding experiments for the desirable traits of interest depending upon the breeding objectives.

Genetic divergence of aromatic rice (Oryza sativa L.)

Thirty aromatic rice genotypes were studied to assess the nature and magnitude of genetic divergence among them for grain yield and yield contributing characters. Based on 23 characters the genotypes were grouped into 5 clusters. Inter-distances were higher than intra-cluster showing a wide range of genetic diversity among the genotypes of different groups. The highest level of inter-cluster distance (73.48) was found between cluster IV and V. The highest intra-cluster distance (3.364) was computed to cluster V and the lowest 1.851 was observed in cluster IV. Panicle length, days to initial flower opening, spikelet sterility, pollen fertility and harvest index had maximum contribution towards genetic divergence of 30 aromatic rice genotypes. Genotypes having these characters in the genetically distant cluster could, therefore, offer a significant scope for the development of high yielding variety through judicious selection.

Genetic diversity and stand structure of neighboring white willow (Salix alba L.) populations along fragmented riparian corridors: a case study

Abstract Remnant riparian woodlands have an important landscape function, due to their ability to act as ecological corridors. In this study we used molecular markers to assess the genetic variation occurring within and between spontaneous white willow (Salix alba L.) riparian woodlands. Our main goal was to evaluate the extent to which the fragmentation of a woodland corridor along a heavily impacted river in northeastern Italy and stand structural conditions may have affected the population genetics. Although having different structures, the three examined white willow stands showed high estimates of genetic similarity, as well as low genetic differentiation between them, indicating that they shared a similar gene pool and that the stands could result from a common set of individual genotypes, and should be regarded as metapopulations. The magnitude of genetic diversity within each of the stands and genetic differentiation between them, despite their high sexual reproductive capacity associated with a highly marked gene flow, suggest that these stands are dynamic and capable of adaptive responses to possible changes in their fluvial environment. However, the factors influencing genetic diversity should be interpreted from a long-term perspective. Fluvial geomorphic patterns in regulated rivers may be modified to a degree that could lead to changes in dispersal processes, sexu­al reproduction vs. asexual propagation, and hence genetic diversity.