Tocher Method Research Articles

Identification of Superior Forage Pearl Millet (Pennisetum glaucum (L.) R.Br.) Inbred Lines

The experiment was conducted during kharif, (July–November, 2022) at ICAR–Indian Institute of Millet Research (IIMR), Rajendranagar, Hyderabad, India. In this experiment, 81 forage pearl millet (Pennisetum glaucum (L.) R.Br.) lines was evaluated for its genetic diversity and variability. For all variables examined, an analysis of variance revealed a considerable variation between lines. Leaf-to-stem ratio, first-cut and second-cut of green fodder yield, as well as dry fodder yield, all had high PCV and GCV values. For Plant height, Leaf length, Number of leaves tiller-1, Number of tillers plant-1, Stem thickness, and Regeneration ability however, moderate PCV and GCV values have been identified. Plant height, Number of leaves tiller-1, Leaf-to-stem ratio, Green fodder yield in first cut, the Green fodder in second cut, and the yield of dry fodder all showed high heritability and high genetic advance. On the basis of Mahalanobis D2 statistics for clustering, genetic diversity was examined. The Tocher method was used to grouping of genotype lines into 11 clusters. The most lines were found in cluster I (52), followed by cluster VI with 14 lines, cluster III with 6 lines, and cluster IX with 2 lines. Cluster VI has the greatest intra-cluster distance (86.59), followed by clusters I (54.11), III (52.99), and IX (52.30). Between cluster III and IX had observed greater inter-cluster distance of 594.54 followed by cluster III and X (471.67), cluster IX and XI (458.76) and cluster I and IX (410.82). Intercrossing of these clusters lines might be useful to develop better forage pearl millet hybrids.

Assessment of Genetic Diversity among Quantitative Traits of Chickpea Genotypes

Chickpea (Cicer arietinum L.) is the most important pulse crop providing the livelihood to farmers. India is one of the topmost countries in chickpea production followed by middle-east. Assessment of morphological traits and their genetic diversity will help in increasing production of chickpea. A comprehensive evaluation of 44 distinct chickpea genotypes was conducted during 2020-21 Rabi season at RLBCAU, Jhansi. Utilizing Tocher's method and D2 values, the studied genotypes were meticulously organized into nine non-overlapping clusters, with cluster (I) comprising the most, featuring 17 genotypes, followed by cluster (II) with 12 genotypes. Significant genetic diversity was evident, especially between clusters (IV) and (VI) (2710.13) followed by (V) and (VI) (2565.51), highlighting the diversity among these genotypes. Key contributors to this divergence were 100-seed weight (48.8%), number of secondary branches per plant (26.5%), and seed yield per plant (9%). Cluster (VIII) exhibited higher mean values for days to maturity (140.57), while cluster (VII) had elevated values for the number of pods per plant (84.61). Genotypes like Phule G 171105, RVSSG 81, RLBG 6, GL-16063, and RKG 19-2 emerged as potential contributors to future breeding programs, promising significant hybrid vigour and superior heterotic segregants to advance chickpea genetics.

Future-ready crops, genetic variability in lima bean seeds

Lima bean cultivation has not received proper national and regional attention by research agencies, impairing the knowledge of the agronomic characteristics and its potential, information that is essential for the selection and launching of superior genotypes. The objective of this work was to characterize the seeds of 17 lima bean genotypes produced by family farmers in Paraíba State. The characterization was based on the descriptors for Phaseolus lunatus. A completely randomized design was used with 15 replicates. Data were submitted to analysis of variance with a subsequent grouping of means by the Scott-Knott test at 1% of probability. For analysis of the genetic diversity, the Tocher method was used based on the generalized Mahalanobis distance. There is variability among the genotypes. According to the means test, genotype 10 has a higher seed length, width, and weight. Considering the diversity among the groups and aiming to select light-colored and higher means of the evaluated traits, the selection of genotypes 8, 13, 4, and 10 is recommended to establish a breeding program that satisfies both the consumer and the producer.

Assessment of selection criteria using multi-year study for effective breeding program of Zingiber officinale L.

Ginger has been an important cash crop with numerous applications since ancient times. As the demand for ginger is ever-growing and being a seasonal crop, a high-yielding variety of ginger would be economically profitable. In this study, 150 germplasm were collected from different regions of NE India and evaluated for three years in CRBD design with three replications. The present study thus focused on the variability, association, and diversity studies for the first time on 150 ginger germplasm from across North East India. The genotypic and phenotypic coefficient of variation, heritability, correlation, and path analysis were evaluated for the germplasm. Analysis of variance (ANOVA) revealed considerable differences among the studied germplasm for studied characters, revealing sufficient variability in the materials. The Mahalanobis D2 and Tocher methods grouped the 150 ginger germplasm into ten clusters. Based on the results of the path coefficient analysis determined for essential oil yield and rhizome yield per plant, it can be concluded that the characters' initial rhizome weight, the weight of mother rhizome, and weight of secondary rhizome were the most important and appeared promising in improving the overall yield potential of ginger rhizome and essential oil yield. Thus, selection based on the identified traits would lead to an effective ginger breeding program for higher rhizome and essential oil yield.

Enumeration of Genetic Parameters and Genetic Diversity of Morpho-Physiological Traits in CIMMYT Bread Wheat Accessions [Triticum aestivum (L.) em. Thell

Fifty genotypes of CIMMYT bread wheat were evaluated at Agricultural Research Farm, BHU, Varanasi during 2019-2020.The analysis of variance revealed significant differences among genotypes for all traits. High Phenotypic coefficient of variation was recorded compared to the genotypic coefficient of variation. However, high genotypic coefficients of variation were found particularly for: grain yield per plot (8.71), harvest index (9.22), test weight (8.9), normalized difference vegetative index (9.59) and chlorophyll content (9.79), suggesting that these traits are having ample genetic potential for selection amongst genotypes, in breeding programs. The highest broad sense heritability manifested for harvest index (91.61%); remaining traits showed moderate estimates of heritability. Low to moderate genetic advance as percent mean was estimated for all the traits studied. This suggests the existence of variability for agronomic traits in the studied wheat genotypes which, should be exploited during future breeding programmes. Fifty genotypes were divided into six non-overlapping distinct clusters using tocher's method based on Euclidean distances. Thirty-one genotypes were classified in the first cluster accounting 62% of total genotypes followed by 15 genotypes categorized in the second cluster. The remaining four clusters have one genotype each. Divergence and cluster mean show that, crossings between genotypes of clusters (II, III), and VI could lead to recovery of good transgressive segregants for maximum heterosis in wheat varietal improvement.

Multivariate analysis for evaluation of indigenous rice (Oryza sativa L.) accessions collected from Madhya Pradesh

Eighty indigenous rice genotypes were evaluated for twenty-nine quantitative and quality traits, planted in RCBD with three replications. The data on different characters were analyzed through Mahalanobis' generalized distance D2 (1936) and Principal Component Analysis for estimating genetic diversity and identification of superior rice genotypes. On the basis of genetic distance the 80 genotypes were grouped into 18 clusters following Tocher's method. Among them, five clusters contain more than one genotype, while thirteen clusters contain single genotype. The genotypes of cluster VIII and IX showed a higher (19816.1) inter cluster distance followed by cluster IV and VIII (12414.7). Cluster V has been discovered to have the largest intra-cluster distance. In order to increase the genetic diversity of rice, genotypes from these clusters may be crossed. On the basis of PCA findings, among all genotypes contributing their presence in more than one PC with high PC score only five genotypes viz., Biranjphool Shivram, Jeera Phool, Basmati Purani, Kardhana Baldev and Kailari Ram Madan confine with favourable yield as well as quality associated PCs, and had excellent remark for both the traits. These genotypes might be utilized in hybridization programme for the transfer of good yield as well as good quality traits in the recipient rice genotypes for the development of promising rice cultivars.

Technical feasibility of using a geotextile waste material as an alternative to agrofilm for mulching in lettuce

ABSTRACT In semiarid regions, water deficit can be a problem affecting agricultural production. Agrofilm mulches can be used to reduce soil water evaporation as well as to control weeds. The SoilTain DW® geotextile blanket, which is a solid waste material generated in water treatment plants, has the potential to be used for mulching in agriculture. The aim of this study was to evaluate the technical feasibility of using this geotextile waste material as an alternative to different agrofilms for mulching in lettuce under the semiarid conditions of the state of Alagoas, Brazil. Four experiments were carried out in 2020–2021, each with four mulching treatments (white and black polyethylene, geotextile blanket, uncovered soil). Soil surface temperature, plant density, weeds and biometric parameters of the lettuce were assessed and evaluated by univariate and multivariate statistical analyses. Significant treatments × experimental period interactions for all lettuce parameters were observed, except for root biomass. Experiment 2 (winter) presented the most favourable environmental conditions for plant development (mild temperatures) and resulted in an average yield of 25.0 Mg ha−1. In Experiment 1 (autumn/winter), high temperatures (47.9°C) under the black polyethylene reduced plant density (96,800 plants ha−1), though leaf length (16.2 cm) and yield (13.1 Mg ha−1) were not significantly affected. The two canonical variables explained 97.7% of the total variation, forming three similarity groups by Tocher method. All mulches effectively controlled the weeds. Application of the geotextile blanket was concluded to be technically feasible, but it was not recommended for use in the summer when temperatures are high.

Diversidade genotípica e parâmetros genéticos de lima ácida 'Tahiti' com uso de diferentes porta-enxertos

Abstract The objective of this work was to estimate the genetic parameters and to evaluate the genotypic diversity of 12 'Tahiti' acid lime (Citrus latifolia) genotypes grafted onto two rootstocks. The experiment was carried out from July 2017 to January 2019, in the municipality of São Mateus, in the state of Espírito Santo, Brazil. Vegetative (stem diameter, canopy projection diameter, and plant height), productive (yield and fruit number), and fruit quality (fruit diameter, soluble solids content, and juice yield) traits were determined. A mixed model was used to estimate heritability and repeatability coefficients, as well as to predict clonal values. Scion diversity was determined through the standardized mean difference of Euclidean distances, and genotypes were clustered by modified Tocher. Clustering quality and trait importance were evaluated using the principal component analysis (PCA). Genotypic variance was observed, which is indicative of the possibility of selection of superior genotypes. The Tocher method showed the presence of three clusters, which is in alignment with the PCA results. The multivariate analyses allows of the selection and the recommendation of superior 'Tahiti' acid lime genotypes.

The Study of Genetic Divergence in Rice (Oryza Sativa L.) Genotypes with Grain Yield and Different Morpho-Physiological Traits using Mahalanobis’ D2 Analysis

The current study attempted to study genetic divergence in rice (Oryza sativa L.) genotypes with grain yield and different morpho-physiological traits among 18 rice varieties using Mahalanobis' D2 analysis. Keeping this in mind, the performance of the studied genotypes, as well as the association between various morpho-physiological and yield contributing traits among the genotypes, were evaluated in the field. The experiments were conducted from July to December 2018 at the Agronomy Field, Department of Agronomy and Agricultural Extension, Faculty of Agriculture, Rajshahi University. In terms of grain yield and other morpho-physiological traits, the genotypes differed significantly. The genotypes were classified into five clusters using Mahalonobis' D2 statistics and Tocher's method (Table 3). Cluster IV was the smallest of the clusters. Cluster l is the largest, with six genotypes. Clusters II and lV each contained three and two genotypes. The pattern of genotype distribution among various clusters reflected the significant genetic variability present in the genotypes, which may be due to adaptation of these genotypes to specific environmental conditions. Genotypes from different clusters are expected (inter-cluster). The intra (bold) and inter-cluster distances from D2 analysis (Table 4). Cluster I has the greatest intra cluster distance (0.956), while Cluster IV has the smallest (0.3583). The greatest inter-cluster distance is observed between cluster IV and (8.190), while the smallest inter-cluster distance is observed between cluster II and IV (2.924). In both vectors, the average inter-cluster distances were greater than the average intra-cluster distances, indicating the presence of greater genetic diversity among genotypes from different clusters than those from the same cluster. These findings indicated that these five traits contributed the most to the divergence among the eighteen rice genotypes. The results revealed that the clusters were remarkably distinct for the majority of the traits, indicating proper clustering. The most effective tiller, grain panicle, effective grain panicle, and days to maturity were found in Cluster V. The intra-cluster mean for grain yield was the lowest in this cluster. Cluster III had the lowest grain yield per acre. This was the cluster with the lowest initial grain yield. The intra-cluster mean for effective tiller and days to maturity was highest in this cluster. Cluster II had the smallest grain yield and the second smallest thousand grain weight. Cluster V had the shortest panicle length intra-cluster.

DIVERGÊNCIA GENÉTICA E SELEÇÃO DE CULTIVARES DE FEIJÃO BASEADA EM ARQUITETURA DE PLANTA E PRODUTIVIDADE

ABSTRACT The characterization of genetic divergence in common bean cultivars for various traits related to plant architecture and grain yield is unprecedented. This study proposes to determine whether common bean cultivars of different grain types differ for 12 traits of plant architecture and grain yield; examine the correlations between these traits; analyze the genetic divergence of these cultivars; and select superior cultivars for these traits. A total of 22 common bean cultivars with the grains types most produced in Brazil were evaluated in two growing seasons. Plant architecture was analyzed based on 12 traits, and grain yield was determined at maturity. Significant genotype and genotype × environment interaction effects were obtained, indicating the existence of genetic variability for all evaluated traits. Several plant architecture traits were correlated, but none was highly correlated with grain yield. Firstand second-internode lengths are more important in differentiating common bean cultivars. Principal component and Tocher’s analyses resulted in the formation of four and seven groups of cultivars, respectively. Both methods are efficient in analyzing genetic divergence; however, Tocher's method is more informative. Cultivars BRS Campeiro, SCS 205 - Riqueza, BRS Esteio, IAC Imperador and Guapo Brilhante have a high grain yield potential, but only BRS Campeiro, BRS Esteio and Guapo Brilhante have upright plant architecture.

PARÂMETROS GENÉTICOS, DIVERSIDADE GENÉTICA E CORRELAÇÕES EM LINHAGENS DE CEBOLA

ABSTRACT Plant breeding programs have been investing in the development of high commercial standard onions; thus, they depend on the genetic resources available for obtaining commercial hybrids. The objective of this study was to evaluate genetic parameters and diversity, and phenotypic and genotypic correlations of characters related to onion production. The experiment was conducted in Uberlândia, Minas Gerais, Brazil. Fifty-three onion strains were evaluated, and a randomized block design was used. The number of plant and bulb characteristics evaluated was 13. The statistical analyses were performed using Genes and R software. A genetic variability among the genotypes was found for most of the characters at 1% level of significance in the F test. The heritability of most characters presented moderate to high values (≥ 70%) and high CVg/CVe ratio (≥ 1). The UPGMA method separated the genotypes into 20 groups, while the Tocher method separated them into 19 groups. The groups that stood out were V, XIV, XV, XV, XVI, XVII, XVIII, XIX, and XX. The results of t-test showed six significant phenotypic correlations with low to moderate degree of association, and the genotypic correlations, in most cases, were higher than the phenotypic ones and showed the same sign. From the genetic parameters studied, the possibility of gains in the selection is high. The separation of groups of divergent genitors was possible due to the wide genetic variability for the studied characters. Moreover, the phenotypic and genotypic correlations showed that indirect selection is not feasible.

Genetic Divergence Study in Bitter gourd (Momordica charantia L.)

The genetic divergence of forty bitter gourd genotypes was studied for sixteen different parameters by adopting Mahalanobis D2 statistics using Tocher's method. The genotypes were grouped into six clusters irrespective of geographic divergence, indicating no parallelism between geographic and genetic diversity. A maximum of 32 genotypes entered in cluster I, followed by 4 genotypes in cluster II. The cluster III, IV, V and VI had single genotypes each. The maximum inter-cluster distance was obtained between cluster II and VI (1620.05) while minimum distance was between III and V (103.32). Cluster V followed by cluster VI showed superiority for yield and other desirable traits, which indicate the potentiality of these diverse genotype collection for providing basic material for future breeding programmes.

Genetic variability in Capsicum spp. accessions through multicategorical traits

Capsicum peppers originate from the American continent. Their culinary and medicinal potential, first exploited by indigenous peoples over 7000 years ago is vast, however more studies are needed. Despite the existence of germplasm banks that house hundreds of accessions of the genus, only a little of this diversity is seen in large markets. In this respect, the morpho-agronomic characterization of the accessions allows not only the identification of the existing variability, but also the agronomic and commercial potential of the genotypes. Therefore, this study proposes to characterize and estimate genetic divergence between accessions of the Capsicum germplasm collection at the Universidade Federal Rural do Rio de Janeiro (UFRRJ) based on multicategorical traits. The species were identified and 29 accessions were characterized in a greenhouse, based on 31 multicategorical descriptors of the crop. The collected data were subjected to the Cole-Rodgers dissimilarity index and to hierarchical clustering (Nearest Neighbor) and optimization (Tocher’s) methods. Tocher's method was considered the most suitable to group the accessions of the germplasm bank. Results indicate that the multicategorical descriptors properly assess the diversity in the chosen method and display the existence of high variability in the collection, which can be used in Capsicum spp. breeding programs.

Assesment of divergence among soybean [Glycine max (L.) Merrill] genotypes based on phenological and physiological traits

A study was conducted to understand genetic divergence in Randomized complete block design accommodating 30 soybean [Glycine max (L.) Merrill] genotypes randomly in three replications. These genotypes were evaluated for twenty-seven traits: five phenological, nine agro-morphological, eight physiological traits (from field-trial) and five physiological traits (from laboratory experiment) recorded and subjected to PCA (Principal Component Analysis) and cluster analysis. Among all the studied cultivars, significant diversity, as well as analysis of dispersion, was recorded for different agro-morphological characters. D2-statistic (Tocher method) framed (generalized distance-based) nine clusters: largest with eight and five were oligo-genotypic. Harvest index>seed yield per plant>germination relative index>seedling dry weight contributed maximum towards total divergence. From the most divergent clusters, 21 crosses involving cluster v genotypes (PS-1347, RKS-18, PS-1092, NRC-142, VLS-94, NRC-136, and Shalimar Soybean-1) with monogenotypic cluster VII (AMS-2014), VIII (RSC-11-15) and III (RSC-10-71) suggested for future hybridization. Out of eighteen, only eight principal components revealed more than 1.00 eigen value and exhibited about 85.03% variability among the traits studied. The highest variability (25.41%) by PC1 followed by PC2 (15.60%), PC3 (12.35%), PC4 (10.13%), PC5 (7.20%), PC6 (5.43%), PC7 (4.80%) and PC8 (4.11%) for characters under study.

Genetic diversity among colored cotton genotypes to obtain potential parent plants

The objective of this study was to analyze the genetic diversity among colored cotton fiber genotypes using technological characteristics of the fiber, seed cotton yield and percentage of fiber, to identify potential parents with high performance. The experiment was conducted in the Brazilian city of Uberlândia, Minas Gerais, during the 2016/2017 harvest. Twelve colored fiber genotypes were used in a randomized block design. The characteristics that were evaluated included micronaire, maturation, fiber length, length uniformity, short fiber index, fiber resistance, elongation, seed cotton yield and percentage of fiber. Genetic divergence was estimated using the Mahalanobis generalized matrix with Unweighted Pair Group with Arithmetic Mean (UPGMA) and the Tocher method. The Singh method was used to evaluate the relative contributions of the characteristics in the divergence. In detecting divergence, fiber length and maturation were observed to have contributed the most. In order to obtain segregant populations with greater genetic variability and greater productive potential, hybridizations between UFUJP-17 and UFUJP-16 with commercial cultivars could be promising. Crossing UFUJP-16 with commercial controls would have a higher chance of success of producing superior fiber quality.

Genetic diversity and correlation between morphological traits of pequi fruits (Caryocar brasiliense Camb.) with and without thorns at the endocarp

Morphological characteristics of pequi fruits (Caryocar brasiliense) allows us to obtain information for the conservation, breeding, and detect genetic variability. Thus, the aims of this research were to characterize the genetic diversity of Caryocar brasiliense that produce fruits with and without thorn at the endocarp; determine the important characters in the study of genetic diversity, and to estimate phenotypic and genotypic correlations. 80 fruits with thorns and 90 fruits without thorns were evaluated. Data were used for analysis: Euclidian distance as a measure of dissimilarity and the Tocher method for delimitation of groups; Principal Component Analysis, and genotypic and phenotypic correlations. Genetic dissimilarity of C. brasiliense ranged from 0.066 (B6-D6) to 0.908 (A14-B3). Tocher method allowed dividing the matrices into three groups, the dendrogram into five groups, and the principal components allowed the distribution in 8 groups. We observed 15 significant correlations for characters of fruit with thorns and 31 correlations for characters of fruit without thorns. The weight of the fruit (with thorns) and the pyrene yield (without thorns) are relevant correlations for production. The groupings generated allowed the classification of the matrices into distinct sets. Allowed the identification of potential producers plants that could be used in breeding programs.

Genetic diversity of Peltophorum dubium (Spreng.) Taub. progenies from the states of Minas Gerais and Mato Grosso do Sul, Brazil.

There is little information regarding the genetic diversity of native species aimed at identifying the best viable progenies for in situ and ex situ conservation. Furthermore, there is a lack of future forest improvement programs. We aimed to know the genetic diversity of 64 Peltophorum dubium (Spreng.) Taub. (Fabaceae) progenies. We determined this species' dendrometric characteristics, and when using multivariate techniques and cluster analysis, we verified the differences between the progenies and groups with less heterogeneity. The progeny and provenance test was installed in Dourados (Mato Grosso do Sul - MS), with seeds collected in three MS regions (Vale do Ivinhema, Serra de Maracaju, and Serra da Bodoquena) and in the micro-region of Lavras (Minas Gerais - MG). The experiment was conducted in an alpha lattice 8 x 8 with four repetitions. We found genetic variability among and within P. dubium populations for all height, diameter, circumference at breast height, volume, and basal area characters. We suggest that P. dubium populations have high genetic variability, which indicates possible genetic improvement through best progeny selection. The UPGMA and Tocher methods grouped the progenies into three and nine groups, respectively, in which the most divergent individuals come from MG and the Bonito region in MS. Based on morphological characters, P. dubium progenies identified as 45, 47, 49, 50, 55, and 59 from MG are the most promising, while progenies 6 and 9 were the least promising.

Genetic Divergence Studies in Tomato Genotypes Grown under Low-Cost Polyhouse Conditions

Assessment of genetic diversity was made for sixteen yields and yield contributing traits in twenty-one tomato genotypes using D2 statistics. These genotypes were grouped into five clusters by the use of the Tocher method. Cluster I was the most significant, comprising 13 genotypes (Pusa Ruby, CLN2123A1 Red, PKM-1, IIHR-2042, Marglobe, EC 163605, Hawaii 7998, Palam Pink, EC 521038, Punjab Rakthak, EC 163383, Arka Abha and IIVR BT-10) followed by Cluster II with 5 genotypes (EC 163611, Punjab Sartaj, EC 160885, Punjab Barkha Bahar and Roma). Other Clusters (II, IV and V) were solitary ones (EC 249515, Kashi Chayan, DVRT-2). Cluster II recorded a maximum intra cluster distance of 3521.73 followed by cluster I (2796.45), whereas, cluster II, IV and V had zero intra cluster distance. The inter cluster D2 value also ranged widely, with a minimum value of 4082.34 between cluster I and IV, indicating a close relationship among the genotypes included. The maximum inter cluster D2 value (23102.20) between cluster II and V indicates high diversity among the genotypes in the clusters. Hence, maximum contribution towards divergence was observed by average fruit weight (14%) followed by fruit set percentage (12%), number of flowers per cluster (8%), fruit yield per plant (7%), number of fruits per truss (6 %) and total soluble solid content (6 %). Hence, due importance could be given to the selection of genotypes for further improvement based on these traits.

Genetic divergence for adaptability and stability in sugarcane: Proposal for a more accurate evaluation.

The best agro-industrial performance presented by a crop genotype in one environment may not be reproduced in another owing to complex edaphoclimatic variations. Therefore, breeding programs are constantly attempting to obtain, through artificial hybridization, novel genotypes with high adaptability and stability potential. The objective of this study was to analyze genetic divergence in sugarcane based on the genotypic values of adaptability and stability. A total of 11 sugarcane genotypes were analyzed for eight agro-industrial traits. The genotypic values of the traits were determined using mixed model methodology, and the genetic divergence based on phenotypic and genotypic values was measured using the Mahalanobis distance. The distance matrices were correlated using the Mantel test, and the genotypes were grouped using the Tocher method. Genetic divergence is more accurate when based on genotypic values free of genotype–environment interactions and will differ from genetic divergence based on phenotypic data, changing the genotype allocations in the groups. The above methodology can be applied to assess genetic divergence to obtain novel sugarcane genotypes with higher productivity that are adapted to intensive agricultural systems using diverse technologies. This methodology can also be tested in other crops to increase accuracy in selecting the parents to be crossed.

​​Genetic Divergence in Leafy Mustard (Brassica juncea var. rugosa) Germplasm Grown under Tarai Condition of Uttarakhand

Background: Mustard represents a rich diversity and widely cultivated in 23 states and union territories of India. However, much of this diversity is concentrated in the Indo-Gangetic plains and the sub-mountain Himalayas. Genetic diversity plays a significant role in plant improvement because a hybrid between the lines of diverse origin usually display a greater heterosis than those between closely related ones which permit the selection of genetically divergent plants to obtain the desirable recombination of segregating generation. Therefore, the present study was undertaken to assess “Genetic Divergence in Leafy Mustard (Brassica juncea. var. rugosa) germplasm grown under Tarai condition of Uttarakhand” and to identify divergent parents for hybridization program, which would provide superior transgressive segregants from collected germplasm. Methods: The present investigation consisted of thirty-two genotypes of leafy mustard and the research was carried out at Vegetable Research Centre (VRC), G.B. Pant University of Agriculture and Technology, Pantnagar, U.S. Nagar (Uttarakhand) in rabi season of 2015-2016. Mustard genotypes were sown in randomized block design with three replications in field and data were observed for seventeen quantitative and qualitative characters. The estimation of genetic divergence was done with the help of Mahalonobis D2 statistic as suggested by Rao (1952). Cluster analysis by Tocher method for all the traits was done. Result: Thirty two germplasm of leafy mustard for different characters and grouped them into six clusters using Mahalanobis D2 statistic. The analysis revealed the maximum inter cluster distance was (20534.12) between cluster V and cluster VI so, we can create variation by inter mating genotypes from these two clusters to each other and the maximum intra cluster distance in cluster III (441.91) with six germplasm. It means we can intermate genotypes of this cluster with each other (2014/MGVAR-2, FS-13-1, FS-13-4, 2014/MGVAR-4, PRHC-12-9-1, PRHC-12-7-2, FS-13-3 and Pusa Sag 1) to create variation in next generations. The clustering pattern could be utilized in selection of parents for crossing and deciding the best cross combinations which may generate the highest possible variability for various traits.