Magnitude Of Genetic Diversity Research Articles

Genetic Divergence Analysis for Quantitative Traits in Rice (Oryza sativa L.)

The present investigation was conducted with 64 rice germplasm to investigate the nature and magnitude of genetic divergence during Rabi 2016. The analysis of variance showed significant differences for all the characters studied among the genotypes. Based on the analysis, the genotypes were grouped into 3 clusters. Maximum number of 58, 4 and 2 genotypes was grouped under cluster II, III and I respectively. Maximum inter cluster distance was observed between cluster II and III (45.279) followed by cluster II and I (37.703) indicates wider the genetic diversity between genotypes. Cluster I showed highest mean for seed yield per plant (26.60 g) followed by cluster III. Milling percentage, panicle length and panicle weight (0.05%), number of productive tillers per plant and number of grains per panicle were failed to contribute significantly towards genetic diversity. Plant height (39.51%), kernel breadth after cooking (14.48%), kernel length after cooking (7.59%) were found to be the most contributing traits towards genetic diversity. Hence these traits could be focused for selection while improving grain quality and yield.

Genetic divergence in rice germplasm collected from North east India

The nature and the magnitude of genetic divergence were estimated in 54 rice genotypes collected from Arunachal Pradesh and upper parts of Assam state using Mahalonobis’s D 2 statistics. The analysis of variance revealed significant differences among the genotypes for nine quantitative characters studied. The genotypes were grouped into 18 clusters showing fair degree of relationship between geographic distribution and genetic divergence. All the minimum and maximum cluster mean values were distributed in relatively distant clusters. Maximum numbers of genotypes were included in cluster I which has 26 genotypes. Traits contributing maximum to genetic divergence viz ., plant height, days to 50% flowering, 100 grain weight and leaf width may be utilized in selecting genetically diverse parents.

Genetic divergence in mung bean

The present study was undertaken to provide information on the nature and magnitude of genetic diversity among 30 mung bean genotypes for yield traits by using Mahalanobis’s D2 statistics. Thirty genotypes could be grouped in 6 clusters, cluster VI showed maximum intra-cluster distance while the highest inter-cluster distance was observed between cluster III and VI. Cluster II recorded highest means for seeds per pod, 100 seed weight, seed yield per plant and shelling %. The percent contribution towards genetic diversity was highest for shelling percentage (17.70) followed by seed yield per plant (16.55) and number of clusters per plant (14.71). From the divergence analysis, it may be concluded that the genotypes belonging to different clusters separated by high estimated statistical distance may be used in the hybridization programme for developing high yielding mung bean varieties. Five genotypes viz., PDM-11, TARM-2, TM-98-50, PDM 54 and Basanti could be identified as most useful in the future breeding programme.

Genotypic diversity in vegetable amaranth for antioxidant, nutrient and agronomic traits

In this investigation, magnitude of genetic divergence was studied in 25 vegetable amaranth using D2 statistics. The genotypes were grouped into 5 clusters with the highest number of genotypes (10) in cluster V. High inter-cluster distance indicated that genotypes of cluster III were far diverged from the genotypes in cluster I, II and IV, respectively. The PCA indicated prominent contribution of protein, foliage yield, leaf area and Zn content towards total divergence. Cluster I and Cluster III could be considered for excellent antioxidant and nutrients and high foliage yield. Cluster II for nutrients, cluster IV for antioxidant and nutrients and cluster V for antioxidant, nutrients, and foliage yield. Based on inter-cluster distance, intra-cluster and scatter diagram, the genotypes AA28, AA15, AA19, AA26, AA9 and AA17 would be potential genotypes for generating transgressive segregants.

Assessment of genetic variability and correlation analysis of seed and seed cotton yield attributing traits of tetraploid cotton genotypes (G. hirsutum L.)

The nature and magnitude of genetic divergence, variability and correlation were estimated in 110 extant varieties of cotton using Mahalanobis D 2 statistics by considering 20 quantitative characters to reveal a considerable amount of diversity in the material. The genotypes were grouped into ten clusters. Cluster I constituted a maximum number of accessions (80). The genotypes falling in cluster VIII (32.329) had the maximum divergence, which was closely followed by cluster IX (28.032), cluster X (23.674) and cluster I (15.717). The inter cluster distance was maximum between cluster VIII and IX (45.242) suggesting that the genotypes representing these clusters may be used as parents for future crop improvement programme. Traits like yield per plant, number of bolls per plant, sympodial length, number of sympodia per plant, dry matter of seedlings and plant height were the major contributors for genetic divergence. ANOVA revealed the presence of considerable amount of variability among the genotypes. High estimates of the genotypic coefficient of variation (GCV) and phenotypic coefficient of variation (PCV) were observed for yield per plant, number of bolls per plant, sympodial length, number of sympodia per plant, dry matter of seedlings and plant height. High heritability coupled with high genetic advance as per cent of mean was recorded for yield per plant, number of bolls per plant, dry matter of seedlings, sympodial length, number of sympodia per plant, plant height, speed of germination, shoot length, boll weight per plant, vigour index and fibre fineness. In correlation analysis, seed cotton yield was significant and positively correlated with number of bolls per plant followed by boll weight, plant height, seed index and fibre length. Hence, selections based on the above characters will result in genotypes with high seed cotton yield.

Genetic diversity assessment in European carrot genotypes

To assess the nature and magnitude of genetic diversity in carrot germplasm using the multivariate analysis, the experiment was carried out with 40 European carrot genotypes. The genotypes were classified for four principal components having the eigen values more than one. The first principal component largely accounted for total variation among the genotypes followed by second principal component. Component PC-I, had a high positive loading for root weight (0.420), root diameter (0.378), crown diameter (0.404), root weight and yield (q/ha), PC-II had the high positive loading for root: top ratio, PC-III for top length and PC-IV for flesh thickness. Plotting of PC-I against PC-II differentiated SH-C-12, SH-C-27, SH-C-136, SH-C-101, SHC-7-3-2, CITH-C-1 and SH-C-54 as the most divergent genotype. On the basis of single-linkage cluster analysis means, cluster-IV was the most important for number of leaf/plant, root weight, root length, crown diameter, flesh thickness and yield, whereas, cluster-I was important for minimum core thickness. Highest inter-cluster distance was observed between clusters II and IV (282.50). Most divergent accessions with high inter-cluster distance could be most appropriate parent for crop improvement.

Correlation path analysis and assessment of genetic diversity for yield attributing traits in rice (Oryza sativa L.) genotypes

The magnitude of genetic divergence and character association was estimated in 208 core germplasm accessions (landraces) of rice (Oryza sativa). A total of 10 quantitative traits were measured at suitable stage. Rice germplasm accessions were grouped into 8 clusters. The paramount inter-cluster distance varied from 9.778 to 1.867. Maximum inter-cluster distance was observed between cluster VIII and IV (9.778) suggesting maximum diversity among them. Cluster VIII (3.84gm) had highest mean value for 100 grain weight. Cluster II had highest mean value for panicle length (28.55 cm.), effective tillers/plant (8.65) and L/B ratio (3.79). Better genotypes could be selected for most of the characters on the basis of mean performance from different clusters. The cluster II showed highest grain yield/plant and effective tillers (9 tillers/plant). These clusters can be utilized in the hybridization programme for obtaining desirable transgressive segregents. Grain yield had positive and significant correlation (P<0.01) with days to 50% flowering (r=0.206), plant height (r=0.3998) and panicle length (r=0.2338).

Genetic divergence analysis in papaya (Carica papaya L.) Genotypes

The experiment on papaya (Carica papaya L.) consisting of fourteen genotypes from diversd gene pool was conducted at the Regional Agricultural Research Station, Ishurdi, Pabna during April 2013 to May 2014 to study the nature and magnitude of genetic divergence and eventually identification of suitable genotypes for use in breeding program. Multivariate analysis was subjected to assess the genetic diversity and Mahalanobis’ generalized distance (D2) was used to assess the divergence present among the genotypes. The fourteen genotypes were grouped into four clusters. The cluster IV had the maximum genotypes (5) followed by cluster I having 4 genotypes and cluster II having 3 genotypes. Cluster III had the minimum genotypes (2). The inter-cluster distances were greater than intra-cluster distances in all cases, suggesting wider genetic diversity among the genotypes of different groups. The highest intracluster distance was observed in cluster III and the lowest in cluster II. The maximum inter-cluster distance was estimated between clusters I and IV (11.3212), moderate distance between clusters II and IV (9.961) and clusters III and IV (7.568), and that of the lowest between clusters I and III. Cluster III recorded the highest mean values for fruit length, plant height at last harvest, number of fruits/plant, weight of fruits/plant and fruit yield, while cluster IV exhibited the maximum mean values for pulp thickness, plant height at 1st harvest and the second highest mean values for fruit length, fruit breadth and TSS. Therefore, more emphasis should be given on cluster III for selecting genotypes as parents for crossing with the genotypes of cluster IV which may produce new recombinants with desired traits.Bangladesh J. Agril. Res. 41(4): 647-656, December 2016

Stability by additive main multiplicative interaction (AMMI) model and genetic diversity studies in micro and macro-sperma Lentil (Lens culinaris L.) in mid hills of Jammu and Kashmir, India

The present investigation was aimed at ascertaining the nature and magnitude of genetic diversity among a set of 12 lentil genotypes through Mahalanobis D2 Method. The genotypes under study fall into four clusters. The cluster-I contained the highest number of genotypes (05) followed by cluster-III (03) and Cluster-II and IV each contained the lowest (02). Cluster-II produced the highest mean value for days to maturity and cluster-I exhibited minimum mean value for pod length (0.64). The inter-cluster distances were much higher than the intra-cluster distances. Members of cluster -III and IV were highly diverse from each other as these clusters showed maximum inter-cluster distance. Cluster-IV exhibited the highest intra-cluster distance while the lowest distance was observed in cluster-I. The highest inter-cluster distance was observed between cluster-III and IV while the lowest was between cluster-I and III. The trait pod length (33.33%) contributed maximum for genetic diversity followed by seed yield /plant (27.27%), 100 seed weight (21.21%) and days to maturity (10.61%). Therefore these characters contributed maximum for getting the genetic diversity.

Genetic diversity analysis in Gladiolus genotypes (Gladiolus hybridus Hort)

In the present investigation, thirty gladiolus (Gladiolus hybridus Hort) genotypes were assessed to know the nature and magnitude of genetic divergence using Mahalanobis D2 statistics. Genetic diversity study indicated that among the 17 characters, most of the flower characters contributed towards diversity. Floret diameter contributed maximum towards genetic divergence followed by number of florets per spike, vase life, spike length and plant height.Thirty genotypes were grouped into 8 clusters and among them, cluster I was the largest with 9 genotypes followed by cluster II having 7 genotypes, and IV cluster 6 and cluster III with 3 genotypes each. Clusters were of V, VII and VIII solitary type means they having only one genotype in their group. Divergence values (D2 value) ranged from zero to 7.97 indicating considerable amount of moderate variability in the material studied. Information generated from the present study would be useful in selection of parents for future breeding programme for flower quality improvement in gladiolus. It is desirable to select genotypes from clusters having high cluster means and also with high flower character like spike length as parents for future recombination breeding programmes.

Genetic diversity analysis in green gram based on morphological traits

Twenty three advanced breeding lines of green gram, developed at different centres under the All-India Coordinated Research Project on MULLARP, were evaluated by growing them during summer to characterize the genotypes and to assess the magnitude of genetic diversity in the genotypes. Genetic dissimilarities as revealed by Euclidean distances ranged from 2.891 to 10.494. Maximum distance was observed between ML 1354 and MH 721. Based on Euclidean distances four clusters were formed. Cluster II was the largest, and was further divided into two sub-clusters, IIA and IIB, comprising of four and nine genotypes, respectively. Genotypes MH 709 and KM 2272 belonging to cluster I were closely placed as they shared most of the characters. But they could be distinguished with the help of characters like days to 50% flowering, position of pods in the plant and growth habit. Similarly, GM 04-02 and NM 1 in sub-cluster IIA were closely grouped, and they could be distinguished based on the characters leaf size and pod length. Similarly other closely grouped genotypes were also distinguishable on the basis of some characters. It was observed from the average Euclidean distances that ML 1354, SG 1, MH 721, SG 63-14 and MH 709 were divergent genotypes. These genotypes were potential parents in green gram breeding programme.

Assessment of genetic diversity using morphological traits in pigeonpea [Cajanus cajan (L.) Millsp.

The nature and magnitude of genetic diversity was assessed among 120 genotypes of pigeonpea along with three checks in augmented design during Kharif, 2011-12. The Non-hierarchical Euclidean cluster analysis grouped all the genotypes into twelve distinct non-overlapping clusters indicated existence of high degree of genetic diversity in the materials. The crossings between the members of diverse clusters separated by high inter-cluster distances are likely to throw desirable segregants. In this context, very high inter cluster distances were recorded between cluster VI and XII, cluster V and XII, cluster II and IX, cluster VI and XI, cluster II and VI and cluster V and IX. Considering the mean performance for different characters of genotypes belonging to diverse clusters, the promising genotypes for exploitation as parents in breeding programme were NDAGC 2011-4, NDAGC 2011-42 and NDAGC 2011-2 of cluster II; NDAGC 2011-18, NDAGC 2011-58, NDAGC 2011-34 and NDAGC 2011-27 of cluster V; NDAGC 2011-16, NDAGC 2011-41, NDAGC 2011-88, NDAGC 2011-104 and NDAGC 2011-103 of cluster VI; IC 525504 and Pusa 33 of cluster IX and IC 525456, IC 525408 and IC 525463 of cluster XII. It may be concluded that crosses between diverse genotypes belonging to clusters separated by high inter-cluster distances with desired means are likely to produce transgressive segregants may be advocated for developing high yielding pigeonpea varieties.

Genetic divergence studies in foxtail millet (Setaria italica L.)

Present investigation was made to study the nature and magnitude of genetic divergence in 66 foxtail millet genotypes using multivariate analysis through Mahalanobis ‘D 2 statistics. The analysis suggested considerable genetic divergence among the material. D 2 statistics resulted in five clusters. Based on relative magnitude of D 2 , the genotypes were grouped into five different non-overlapping clusters. Cluster I, having 36 genotypes, emerged with highest number of entries; cluster II were constituted by 15 genotypes. Cluster III comprising 13 genotypes. Cluster IV and V having one genotype each. The maximum intra-cluster distance was observed for cluster II, followed by cluster III and cluster I. The highest inter-cluster distance was recorded between cluster IV and III followed by cluster IV and V, then cluster IV and I followed by cluster III and I. Among the 13 characters studied highest contribution in manifestation of genetic divergence was exhibited by grain iron content (ppm) followed by flag leaf length, grain zinc content (ppm), straw weight, flag leaf area, plant height, flag leaf width, panicle weight and grain yield.

Molecular analysis of genetic diversity among different groups of potato (Solanum tuberosumL.)

Twenty one simple sequence repeat (SSR) markers were used to develop SSR profile in 169 genotypes of potato belonging to Indian accessions, tuberosum group (Solanum tuberosum ssp. tuberosum), breeding lines, neotuberosum, andigena group and tuberosum × andigena derivatives. All the 21 SSR markers showed polymorphism and were able to discriminate the genotypes studied. Molecular markers viz., STM0037, STI0012, STM1052, STM 5127, STG0001 and STI0030 were useful due to their high polymorphic information content and differentiating power. A high magnitude of genetic diversity was observed in andigena group (Solanum tuberosum ssp. andigena). Andigena accessions were also diverse from other groups of accessions as most of them formed a clear separate and distinct cluster. Tuberosum group germplasm, breeding lines, neotuberosum and Indian accessions formed a separate cluster, whereas Indian accessions were distributed widely. The Shannon Weaver diversity index for Indian accessions was higher than that of breeding lines, tuberosum germplasm, neotuberosum and tuberosum × andigena accessions. These results show that comparative genetic diversity of Indian accessions is good in comparison to other tuberosum group accessions.

Genetic resources, diversity, characterization and utilization of agronomical traits in turmeric (Curcuma longa L.)

The nature and magnitude of genetic divergence were estimated among sixty-five turmeric (Curcuma longa L.) genotypes using Mahalanobis D2-statistics on thirteen agro-morphological quantitative traits. Mahalanobis’s D2 analysis revealed considerable amount of diversity among the Curcuma genotypes. The genotypes were grouped into seven clusters. Cluster I had maximum number of genotypes (37) followed by cluster II and III (9 genotypes each), IV (4), V (3), VI (2) and VII (1) in order. The genotypes falling under cluster I had the maximum divergence (430.90), which was closely followed by cluster II (332.99) and cluster IV (325.72). The highest inter-cluster distances were observed between cluster VI (959.96) and cluster VII (1020.64), suggesting that the genotypes included in these clusters may be used for future breeding programme. Traits like plant height, fresh weight of rhizome were the major contributors to genetic divergence.

Genetic diversity based on cluster and principal component analysis in wheat and triticale genotypes

The nature and degree of genetic diversity present in wheat collections from its principal areas of cultivation would help to select parents for evolving superior varieties. The present investigation was aimed at estimating the nature and magnitude of genetic divergence in a set of wheat germplasm including that from triticale showing cross compatibility with Triticum aestivum L. The experiment was conducted at Nadia district of West Bengal during rabi season in two consecutive years 2012–13 and 2013–14 following RBD design. Forty-nine genotypes were grouped into 10 clusters following Mahalanobis D2 analysis and maximum numbers of genotypes were found in cluster I followed by clusters V and VII. Maximum intra-cluster distance was observed in cluster I followed by cluster VI. Maximum inter-cluster distance was observed between clusters VIII and X followed by clusters VI and X. PCA and cluster analysis were found to be almost similar as D2 analysis except some variations. Six principal components PC 1 to PC 6 cumulatively contributed about 73% of the total variation.

AFLP markers and composition of alkaloids between populations of Annona crassiflora Mart. of Brazilian savanna

Annona crassiflora Mart. is a native tree from Brazilian savanna, widely spread throughout this biome. Isoquinoline alkaloids are an important characteristic of species of Annonaceae and several biological activities have been reported in the literature concerning these compounds [e.g. 1]. The present work aims to assess the magnitude of genetic diversity among different populations of A. crassiflora using AFLP markers, and verify the existence of any correlation between the AFLP data and the composition of alkaloids [2]. 106 samples of Annona crassiflora from eight populations from Brazilian savanna areas in the states of Sao Paulo, Goias, Minas Gerais and Distrito Federal were analyzed. Regarding the genetic diversity, the percentage of polymorphisms (P) ranged from 23.8% to 62.96%, the average expected heterozygosity (He) ranged from 0.077 to 0.215 and the Shannon's Index ranged from 0.119 to 0.323. These data suggest a low to moderate level of genetic diversity. The molecular analysis of variance (AMOVA) indicates that most of the genetic variation occurs within populations (70%), while interpopulation variation is lower (22%). The FST value was 0.401. The Mantel test (r = 0.107; p = 0.154) showed a weak correlation between geographic distance and genetic distance. No correlation between alkaloid profiles and genetic differentiation was observed (Mantel test, r =-0.084; p = 0.003). Our results may contribute to establishment of conservation strategies for Brazilian savanna, looking forward to avoid genetic losses and ensure the long-term viability of populations of A. crassiflora. Acknowledgements: FAPESP (Fundacao de Amparo a Pesquisa do estado de Sao Paulo) for financial support (2007/0651143 – 0). DYACS is a research fellow of CNPq. Keywords: Annona crassiflora, genetic diversity, AFLP, Isoquinoline alkaloids

Genetic Diversity and Interrelationship of Qualitative and Quantitative Traits in Sweet Potato

Understanding the nature and magnitude of genetic diversity and interrelationship among sweet potato genotypes for traits of economic importance is vital to effective crop improvement. Genetic variability, character association, path coefficient, and genetic diversity analysis for 17 qualitative and quantitative traits in 20 diverse sweet potato genotypes was undertaken. A wide range of genetic variation occurred for tuber yield per plant, carotene content, starch content, fresh weight of tubers per plant, and numbers of branch per plant. Fresh weight of tuber per plant had a positive phenotypic correlation with number of tubers per plant followed by days to maturity and vine internode length. Total carotene content had a positive significant association with vine length, number of leaves per plant, and number of branches per plant. Days to maturity had a positive phenotypic correlation with vine length, vine internode length, and number of leaves per plant. At the genotypic level the highest, positive, direct effect on fresh weight of tubers per plant was due to dry matter content and days to maturity followed by moisture content via numbers of tubers per plant and total sugar content. Cluster analysis divided genotypes into two main groups, indicating a genetic relationship among accessions. The genetic variability and traits relationship could provide new avenues to breed improved sweet potato.

Genetic divergence among micromutants in finger millet (Eleusina coracana)

The nature and magnitude of genetic divergence was estimated in 44 mutant lines of fingermillet variety VR708, developed by single and combination treatments with gamma rays, EMS and NG using three multivariate analysis. The mutant lines were grouped into ten genetically diverse clusters by D2 and canonical analysis and eight clusters by similarity coefficient (dendrogram) grouping. The clustering pattern in these three methods was almost similar. 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. Traits like days to 50% flowering, maturity duration and plant height were the major contributors to genetic divergence. The hybridization of two divergent mutant lines VE 3–3 and VE 2–4 would be expected to produce promising transgressive segregants for yield in subsequent generations.

Genetic Divergence Analysis in Rice under Irrigated Conditions

The nature and magnitude of genetic divergence were estimated in 134 rice germplasm accessions during kharif 2013 using Mahalanobis D2 statistics. The genotypes were grouped into five clusters based on Euclidean cluster analysis. The pattern of distribution of genotypes into various clusters was random and independent of geographical origin or region of adoption indicating geographical diversity and genetic diversity were not related. Cluster means indicated considerable differences in the mean values of different traits. The genotypes of cluster II and cluster III exhibited high seed yield. The highest intra-cluster distance was observed among the genotypes, in cluster IV (12.19) followed by cluster III (11.03) and cluster V (10.90) indicating existence of wide genetic divergence among genotypes. Number of filled grains/panicle contributed highest towards divergence. The relative divergence of each cluster from other clusters displaced higher order of divergence between cluster IV and V followed by clusters II and V. The hybridization involving genotypes belong to these clusters is expected to give desirable segregants in rice breeding programmes.