Magnitude Of Genetic Variation Research Articles

Studies on Variability Parameter and Character Association of Lentil Germplasms in West Bengal Condition

Background: Lentil is the major cultivated pulse crop in the state of West Bengal in terms of total area coverage under cultivation. Selection of high yielding and better quality genotype is the prime vital matter to increase productivity. Investigation and a better understanding of the variability existing in a population base of the crop are pivotal to crop improvement so that the plant breeders can exploit it. Methods: The current study has been carried out at the experimental farm of the University of Calcutta during 2016-2017 in a plot designed with the randomized block design. It was carried out to estimate the magnitude of genetic variability, heritability and genetic advance of fifty-four lentil germplasms. Result: Moderate to high heritability, GCV, PCV, GA and GA % of mean was obtained by days to1st flowering, days to 50% flowering, pods per plant and harvest index. The genotypic and phenotypic association of seed yield was significantly positive with traits like plant height, pods/plant, 100 seed weight and harvest index. Characters like days to 50% flowering, plant height, primary branches per plant, pods/plant, pod length, 100 seed weight and harvest index shows a positive direct effect on seed yield in path analysis suggesting select for such traits while exercising selection for seed yield per plant in lentil.

Genetic variability and divergence studies in mungbean (Vigna radiata) under rainfed conditions

Twenty three genotypes of moongbean were evaluated in two different environments for variability stability performance. The present investigation was conducted to provide information on the nature and magnitude of genetic variability and divergence among 23 genotypes of mungbean under different environments. It was measured by seed yield/plant under rainfed conditions during kharif 2016 and 2017. Seed yield/plant showed significant correlation with number of seeds/pod and negative correlation with days to maturity. These genotypes were divided into five clusters on the basis of D2 statistics. Maximum inter cluster distance was exhibited by cluster IV and intra-cluster distance by cluster I. Hence, the genotypes of cluster III & IV shall be utilized for the hybridization programme for the development of high yielding varieties (HYVs) of mungbean.

VARIABILITY AND HERITABILITY ESTIMATE OF 30 RICE LANDRACES OF LAMJUNG AND TANAHUN DISTRICTS, NEPAL

The variability in the rice landraces is the source of variation and offers substantial opportunity for the development of new varieties through the selection. Exploring diversity and variability of landraces is utmost for rice improvement. The objective of the study was to assess diversity indices, magnitude of genetic variability, heritability, genetic advance for the yield, and yield contributing traits. An experiment was carried out in alpha-lattice with 30 landraces, two replications in the Agronomy farm of IAAS, Lamjung Campus, during June-November, 2018. Shannon and Simpson's indices were calculated for 18 qualitative traits. The value of the Shannon and Simpson index ranged 0.15-1.41 and 0.07- 0.75, respectively. Landraces showed significant variations (p<0.001) for all 13 qualitative traits studied. The higher value of the phenotypic coefficient of variation (PCV) compared to the corresponding genotypic coefficient of variation (GCV) for all the studied traits indicated the influence of the environment. The filled-grain per panicle exhibited a high estimate of PCV and GCV, followed by the effective tiller and filled grain percentage. High heritability, along with high genetic advance was found in 10 traits, including 1000 grain weight, grain length, and filled grain per panicle indicated the presence of additive gene action. Direct selection of characters of these traits based on phenotypic expression by a selection method will be more reliable for yield improvement. The study suggests that the existence of diversity and estimated genetic parameters among landraces of rice that can be exploited in future rice breeding programs.

Genetic divergence analyses of lowland rice genotypes in North Western Ethiopia

Information on the nature and magnitude of genetic variability is one of the prerequisites for a successful breeding program in selecting genotypes with desirable characters. To estimate the level of genetic divergence of lowland rice genotypes, a field experiment was conducted using thirty-six genotypes during 2017 main cropping season. The experiment was laid out 6x6 simple lattice design. Analyses of variances showed significant differences among traits tested, except harvest index. Principal components PC1, PC2 and PC3 accounted for 64.16% of the total variation. The highest inter-cluster distance was exhibited between cluster I and IV (D2 = 769.77), cluster I and VI (D2=485.33), cluster I and III (D2=232.35), cluster III and IV (D2=312), cluster III and VI (D2=197), cluster IV and VI (D2=746.51), cluster VI and V (D2=259.51) and cluster VI and VII (D2=140.15). The crosses between genotypes selected from cluster I with clusters IV, VI and III; cluster IV with clusters III, VI and V are expected to produce better genetic recombination and segregation in their progenies. The cluster means for cluster VI and I were characterized by early heading and early maturity. While cluster I, II, III, and IV were characterized by high mean performance for grain yield for most of its components. Key words: Cluster analysis, divergence, genetic distance, principal component, rice.

Genetic Variability, Heritability, and Genetic Advance for Ethanol Yield and Yield Components in Sweet Sorghum (Sorghum Bicolor Var. Saccharatum (L.)

Sweet sorghum is a strong candidate for a cheap and renewable source of energy and play a vital role for the uplift of socio-economic status of the farmers of Turkey through the development of high yielding varieties along with a reasonable amount of fodder and biofuel production. The objective of this research was to evaluate the potential of sweet sorghum as a source for fodder and biofuel production, also the magnitude of genetic variability, heritability and genetic advance for yield and contributing characters of forty-nine sweet sorghum genotypes. The experiment was carried out in a randomized complete block design with four replications in Turkey. Analysis of variance revealed that there are highly significant differences among the genotypes in all investigated traits indicating the presence of variability. The genotypes Smith and Batem-3 with high juice, sugar and ethanol yield can be used for breeding of biofuel production in the Mediterranean region of Turkey. High heritability accompanied with high genetic advance was observed for the flowering day, fresh biomass weight, stem fresh weight, juice volume, estimated sugar yield, and estimated ethanol yield. Therefore, these characters could be used for the development of high yielding sorghum varieties through selection in a breeding program.

Family × environment interaction for sugarcane yield and its components in South Africa

AbstractIn sugarcane (Saccharum spp. hybrids) breeding, knowledge of progeny performance and adaptability increases crossing and selection efficiency. Family evaluation across environments uses progeny data to determine family genetic values and family × environment interactions. The objectives were to determine family × environment breeding parameters, family values across locations, and contribution of yield components to cane yield of families in different environments. Data were collected from the plant, first ratoon, and second ratoon crops of 44 families made from 18 female and 18 male parents and planted in the Midlands (24 mo harvest), coastal (12–18 mo), and irrigated (12 mo) environments. Cane yield was estimated from stalk number, stalk height, and stalk diameter, measured from the first 20 plants per family plot. Significant (P < .01) family variance for cane yield traits indicated genetic variability among the families. Significant (P < .01) family × location variance for cane yield, stalk number, and diameter indicated that the magnitude of genetic variability among families was influenced by location. The nonsignificant (P > .05) family × crop year and family × location × crop year variances indicated similar genetic variability across crop years. Therefore, testing families in multiple locations was more important than across crop years. Best linear unbiased predictor estimates showed that families TT1051, UU0332, and UU0312 had significantly higher cane yield across locations and, therefore, were broadly adapted. VV0701 (irrigated), VV0390 (Midlands), and UU0198 (Midlands) produced greater cane yield and showed location‐specific adaptability. The irrigated, coastal, and Midlands populations showed higher specific adaptability for cane yield and stalk height.

Genetic parameters and diversity studies of yield and yield contributing characters in Brassica genotypes

The potential of a crop to favorably respond to breeding programs depends on its existing nature and magnitude of genetic variability, heritability and genetic advance. An experiment was conducted with eighteen Brassica genotypes following Randomized complete block design (RCBD) with three replications at the field of the department of Genetics and Plant Breeding, Bangladesh Agricultural University, Mymensingh, Bangladesh to estimate genetic divergence, variability ranges and contribution of each trait towards genetic diversity. Analysis of variance showed significant variation among the genotypes for all the studied yield and yield contributing characters. The phenotypic co-efficient of variation (PCV) was higher than the genotypic co-efficient of variation (GCV) for all the characters measured, indicated that the traits were influenced by environment. All traits showed high heritability (61.54% to 98.64%) which indicated possible improvement through selection. High heritability values (>60%) along with high genetic advance and genetic advance in percentage of mean indicated prevalence of additive gene action, which provides good scope for further improvement by selection. The genotypes were grouped into four clusters, most of the genotypes were grouped into Custer I (8 genotypes), while cluster IV contained only one genotype. Considering the mean value, the cluster IV and Cluster II were ranked as the top groups in terms of yield and early maturity. High Heritability with high genetic advance in percentage of mean was observed for number of branches/plant, number of pod/plant, number of seeds/pod and yield/plant and selection focused on these traits could be useful for future breeding program of Brassica. The genotype BD-7114 was the best performer considering all the studied traits especially yield and days to maturity which could be used as an important breeding material for the improvement of Brassica.
 J Bangladesh Agril Univ 17(3): 295–300, 2019

Genetic variability and effective population size in Hymenaea stigonocarpa (Fabaceae) germplasm collection: tools for breeding programs and genetic conservation.

The conservation of plant genetic resources is essential for breeding programs. Regarding the native species of the Brazilian Cerrado biome, many studies have demonstrated their high potential for use in both medicines and foods. Hymenaea stigonocarpa, a tree with wide occurrence in the Cerrado, has economic importance, and due its extractive use, the establishment of a breeding program is relevant for sustainable use and conservation. Thus, the first germplasm collection of the species was installed at the Federal University of Goiás (UFG). To know the magnitude of genetic variability and how it was distributed in the collection, 353 individuals, distributed in 119 families from 24 subpopulations collected in the Cerrado biome, were genotyped using capillary electrophoresis. Nine pairs of microsatellite markers were genotyped. The UFG germplasm collection showed a high level of genetic diversity (mean [Formula: see text] = 0.554) at the evaluated loci. By Analysis of Molecular Variance (AMOVA), a significant genetic structure was detected (θP = 0.152, p < 0.01), which was expected since the subpopulations that originated the germplasm collection were collected in geographically distant locations. In addition, the germplasm collection had a population effective size of 54.9 and presented an allelic representation of 79.89% compared to 32 natural subpopulations. These results demonstrate that the germplasm collection preserves a high genetic diversity of H. stigonocarpa with a population effective size considered sufficient for the conduction of a breeding program.

Genetic Variability, Character Association and Path Analysis in Boro Rice (Oryza sativa L.) Germplasm from Bangladesh

The success of varietal development programmme largely depends on the nature and magnitude of genetic variability, heritability and characters association of the crop. The objective of the present study was to estimate the extent of genetic variability and relation between yield and related characters of rice. Forty Boro rice germplasm were evaluated in a randomised complete block design with three replications. Analysis of variance indicated significant differences among the genotypes for 14 quantitative characters. The presence of slightly higher phenotypic coefficient of variation than genotypic coefficient of variation indicated the negligible influence of environment on the expression of yield and its component traits. Leaf length, days to flowering, days to maturity and 1000 grain weight showed highly positive significant correlation present with yield hill-1. High heritability had been observed for yield contributing traits during the study, suggested that these traits would respond to selection owing to their high genetic variability and transmissibility. Therefore, a thorough understanding of the inheritance of traits, their heritability and relationship with other important characteristics is important for the choice of breeding and selection methods for crop improvement.&#x0D; Bangladesh Rice j. 2018, 22(1): 35-43

English

Inbred line development requires information on the nature and magnitude of genetic variability and transmissibility of desired trait in source populations. In this study, the level of genetic variability, heritability and genetic advance of thirteen agronomic and fresh yield traits among twelve shrunken-2 super-sweet corn populations were evaluated. Field experiments were conducted for two years in Ibadan, Nigeria using a randomised complete block design with three replicates. Estimates of genetic variability components, broad-sense heritability and genetic advance were computed for each trait. All the traits exhibited significant genotypic differences. Genotypic variance was significant for number of marketable cobs, yield of cobs, number of cobs, number of kernel rows, husk cover, ear height and days to anthesis, while environmental variance was significant for all the traits. Phenotypic coefficients of variation were higher than the corresponding genotypic coefficients of variation for all traits. Broad-sense heritability ranged from 22.2% for anthesis-silking interval to 85.1% for husk cover. The genetic advance was high (32.7%) for husk cover, medium (12.0%) for yield of cobs and low for other traits. Genetic variability was present among the shrunken-2 super-sweet corn populations. Opportunities abound for further improvement of the populations and extraction of lines for hybrid seed production. Key words: Broad-sense heritability, genotypic coefficient of variation, husk cover score, sweet corn, yield of marketable cobs. &nbsp

Variability parameters in okra (Abelmoschus esculentus L.)-A review

Okra is one of the most important vegetables member of Malvaceae family. It is thought to be originated from West African and Ethiopian regions. Generally the success of any crop improvement program largely depends on the magnitude of genetic variability, genetic advance, character association, direct and indirect effects on yield and yield attributes. Genetic diversity is important for selection of parents to recover transgressive segregants. Studies in this direction are very less and can not to be generalized for every climatic condition and with other genetic materials. Hence, the information in a collection of some genotypes of okra in order to formulate a sound breeding plan for its improvement has been reviewed here.

Genetic variability, heritability and genetic advance studies in marigold (Tagetes spp.) under the South Gujarat region

The success of crop improvement programme depends on the extent of genetic variability existing in the population of germplasm. The improvement and development of new varieties depends to a great extent upon the magnitude of genetic variability. The present investigation was carried out at three different locations during Rabi season (November 2014- April 2015) to evaluate 26 genotypes of marigold. The analysis of variance for all the traits revealed presence of considerable genetic variability in the material studied. The phenotypic coefficient of variation (PCV) was higher than genotypic coefficient of variation (GCV) for all the traits studied, which indicated appreciable influence of environment. The high magnitude for genotypic and phenotypic coefficient of variation as well as high magnitude of broad sense heritability coupled with genetic gain was observed for plant height, number of secondary branches per plant, leaf area, leaf biomass, photosynthetic rate, flower weight, number of flower per plant, flower yield per plant, seed yield per plant and carotenoid content, which indicated additive gene effects. Hence, these characters were less influenced by environment and direct selection for these traits would be effective for further improvement.

Genetic variability, heritability and correlation path analysis in mungbean (Vigna radiata L.wilczek)

The success of crop improvement program largely depends on the nature and magnitude of genetic variability, heritability and characters association. This experiment was undertaken to estimate the extent of genetic variability and relation between yield and related characters. Twenty eight mungbean genotypes were grown at Pulses Research Centre, Ishurdi, Pabna during kharif-I 2015 in a randomized complete block design with three replications to estimate the extent of genetic variability and association between yield and yield related traits. Analysis of variance revealed that all the traits showed highly significant difference among genotypes except seeds per pod. Pods per plant, plant height and 100 seed weight showed high genotypic coefficients of variation (GCV) and phenotypic coefficients of variation (PCV). High broadsense heritability coupled with moderate genetic advance as percent of mean was observed for 100 seed weight, days to flower and pods per plant suggesting preponderance of additive gene action for these characters and selection of such traits might be effective for the improvement of grain yield. Seeds per pod, plant height and pods per plant showed positive significant phenotypic and genotypic correlation with yield. The result of path analysis indicated that pods per plant had maximum direct effect on yield followed by plant height and 100 seed weight and they contribute 31% variation in yield.Bangladesh J. Agril. Res. 43(3): 407-416, September 2018

Assessment of genetic variability, its heritable components and character association in yield and yield contributing traits in apricot (Prunus armeniaca)

The nature and magnitude of genetic variability and correlation studies was assessed in 20 apricot (Prunus armeniaca L.) genotypes for fruit, yield and quality traits. The phenotypic and genotypic coefficients of variation were almost identical in expression for these traits. High heritability and high genetic gain were reported for fruit weight and yield per tree. High heritability with moderate genetic gain was obtained for titratable acidity, pulp/stone ratio, stone width, fruit breadth, firmness, fruit length, total sugars and TSS. Genotypic and phenotypic correlationsfor important component traits were also significant with each other. Maximum positive direct effect cited towards yield were contributed by fruit weight, followed by phenols, sugar/acid ratio, TSS, stone width, fruit breadth and non reducing sugars. Hence, selection can prove effective for improvement in fruit yield and other traits.

INTERAKSI FAMILI × LOKASI PADA UJI KETURUNAN GENERASI KEDUA Eucalyptus pellita

The interaction assessment of genotype and environment is necessary to find out an effective selection strategy in progeny trial, particularly in advanced generations. This study aims to observe the effect of family × site interaction in second generation progeny trial of Eucalyptus pellita planted at two locations: Wonogiri, Central Java and Pelaihari, South Kalimantan. The trials design were completely randomized block design (CRBD) with 49 families, 6-10 blocks, 5 tree-plot and 4 m × 1.5 m spacing. Data measurements included height, diameter at breast height, and stem volume at two and four years age. The study results showed that the families had significant differences (p<0.01) for all measured traits at two and four years age, but the family and site interaction was not statistically significant. Family heritability across the two sites were moderate to high for all traits with the type B genetic correlation ranged from 0.67 to 0.94. Heritability and genetic correlation tended to be higher as tree getting older. Less than 16% of families showed an interactive rank changes in the two locations based on multiple-traits selection index. In general, family selection by combining data from the two sites of progeny trial provided higher genetic gain than those by indirect selection, but it was varied to those direct selection on each site. Therefore, these results imply that, the strategy for family selection by combining data from the two sites of progeny trials should be practiced in appropriate combination and direction by considering the magnitude of genetic variation.

GENETIC VARIABILITY, CORRELATION AND CLUSTER ANALYSIS IN ELITE LINES OF RICE

Development of rice cultivars with appreciative performance is one of the prime objectives of rice breeding programs. In this regard, the current experiment was conducted during 2016 at Agricultural Research Institute, Dera Ismail Khan, Khyber Pakhtunkhwa, Pakistan. The aims of the study were to generate scientific information on nature and magnitude of genetic variability and relationship of yield and related attributes and to classify genotypes into distinct clusters on the basis of quantitative traits. Fourteen elite rice genotypes were evaluated following randomized complete block design with three replications. Analysis of variance manifested significant (P ≤ 0.01) differences among genotypes based on the studied triats viz., panicle emergence, flag leaf area, effective tillers plant-1, panicle length, primary branches and grains panicle-1, 1000 grain eight and paddy yield plot-1, except physiological maturity. The magnitudes of PCV and GCV were higher (&gt;20%) in all the studied traits, except physiological maturity, reflecting wide spectrum of variability and offering greater opportunities for selection. Similarly, the magnitude of broad-sense heritability and genetic advance as percent of mean was moderate to high for majority of traits, indicating additive gene action in their inheritance hence, amenable for simple selection. Correlation analysis revealed that paddy yield manifested significantly positive correlation with physiological maturity (r = 0.46**) and negative correlation with 1000-grain weight (r = -0.30*). The dendrogram grouped 14 rice genotypes into four clusters. Cluster IV incorporated the highest number of genotypes, which also had highest cluster mean for paddy yield. Therefore, prominence should be given to genotypes aggregated in cluster IV that having high yield potentiality. Based on mean performance, Irrigated-04, E-93, E-94 and E-107 showed superiority in respect of paddy yield and some other traits, hence these lines could be recommended for varietal development.

Genetic divergence in forage sorghum (Sorghum bicolor L. Moench)

Thirty genotypes of forage sorghum were studied for generating information on nature and magnitude of genetic variability and diversity for designing breeding programme. The experiment was conducted in randomized complete block design in three replications. The data were recorded on days to 50% flowering, plant height, leaf breadth, leaf length, leaf area, stem girth, leaves per plant, leaf stem ratio, total soluble solids, protein content and green fodder yield. Analysis of variance revealed a substantial amount of variability among the genotypes for all the characters under study, indicated a wide spectrum of variability among the genotypes. Highest estimates of the phenotypic coefficient of variation and genotypic coefficient of variation were observed for plant height, leaf breadth, leaves per plant, leaf stem ratio and green fodder yield. High heritability coupled with high genetic advance was observed for plant height, leaf area, stem girth, leaves per plant, leaf stem ratio and green fodder yield. Based on D2 – Statistics, 30 genotypes were grouped into six clusters. The highest inter-cluster distance was observed between cluster III and VI followed by IV and VI, indicating genotypes included in these clusters had wide genetic diversity. Genetic divergence and cluster mean indicates maximum heterosis and good recombinants may be achieved in crosses between genotypes of clusters III, IV and VI in varietal improvement programme. Thus, crossing between genetically diverse genotypes of cluster III with genotypes CSV 15, PC 1001, SPV 462, PC 3, SSV 84, PC 8 and cluster VI with genotype HJ 513 are expected to exhibit high heterosis and good recombinants with desired traits.

Estimation of genetic variability, GCA and SCA effects for development of early and high yielding bell pepper hybrids suitable for protected cultivation

The present investigation involves 29 diverse bell pepper genotypes for variability studies and 14 promising lines (11 lines and 3 testers), 33 F1 and 1 standard check for combining ability studies. The objective of the study was to assess the nature and magnitude of genetic variability among the bell pepper genotypes for yield and other horticultural traits and to identify the potential parental lines and cross combinations suitable for the protected environment based on the estimation of general combining ability and specific combining ability. A wide range of variability was observed for most of the characters studied. The genotypes viz., Kashmir Sel-1 (L2), DARL-10 (L9) and UHFSP(Y)-11 (L11) for marketable fruit yield per plant and Kashmir Sel-1 (L2), UHFSP(Y)-11 (L11) and DARL-01 (L5) for earliness were good general combiners and these may be included for exploiting hybrid vigour or development of purelines. On the basis of specific combining ability effects and per se performance, the crosses viz., ARCH-19 (L1) × Solan Bharpur (T1), DARL-10 (L9) × California Wonder (T2) and UHFSP(Y)-11 (L11) × Yolo Wonder (T3) were the best cross combinations for marketable fruit yield per plant and number of marketable fruits per plant under protected environment. The cross combinations viz., DARL-10 (L9) × California Wonder (T2), DARL-01 (L5) × California Wonder (T2), LC (L10) × Solan Bharpur (T1) and Kandaghat Sel-9 (L7) × Solan Bharpur (T1) shows significant negative SCA for earliness and could be used for development of early hybrids.

English

The experimental material comprised 68 diverse genotypes of finger millet (Eleusine coracana (L.) Gaertn). The data on 13 quantitative traits were recorded to assess the magnitude of genetic variability, heritability and genetic advance for yield and yield contributing traits. In the present investigation, values of phenotypic coefficients of variability were greater than genotypic coefficients of variability for all the traits studied. Highest PCV and GCV were recorded for grain yield per plant. The characters viz., straw yield per plant, number of productive tillers per plant, main ear head length and number of fingers per ear were expressed the moderate amount of variation indicated large extent of genetic variability for these traits in the material. High heritability along with high genetic advance (% of mean) observed for for grain yield per plant, number of productive tillers per plant, straw yield per plant and main ear head length, indicating involvement of additive gene action for these traits and phenotypic selection based on these traits in the segregating generations would likely to be more effective.

Genetic variability, correlation and cluster analysis in elite lines of rice

Development of rice cultivars with appreciative performance is one of the prime objectives of rice breeding programs. The aims of the study were to generate scientific information on nature and magnitude of genetic variability and relationship of yield and related attributes and to classify genotypes into distinct clusters on the basis of quantitative traits. Fourteen elite rice genotypes were evaluated under RCB. There was significant (P ≤ 0.01) differences for all studied traits, except physiological maturity. The magnitudes of PCV and GCV were higher (&gt;20%) in all the studied traits, except physiological maturity, reflecting wide spectrum of variability and offering greater opportunities for selection. Similarly, the magnitude of broad-sense heritability and genetic advance as percent of mean was moderate to high for majority of traits, indicating additive gene action in their inheritance hence, amenable for simple selection. Correlation analysis revealed that paddy yield manifested significantly positive correlation with physiological maturity (r = 0.46**) and negative correlation with 1000-grain weight (r = -0.30*). The dendrogram grouped 14 into four clusters. Cluster IV incorporated the highest number of genotypes, which also had highest cluster mean for paddy yield. Therefore, prominence should be given to genotypes aggregated in cluster IV that having high yield potentiality. Based on mean performance, Irrigated-04, E-93, E-94 and E-107 showed superiority in respect of paddy yield and some other traits, hence these lines could be recommended for varietal development