Phenotypic Path Analysis Research Articles

Study on Correlation and Path Analysis in Forage Sorghum [Sorghum bicolor (L.) Moench

This investigation is conducted to determine character association and path coefficient analysis using 35 genotypes of forage sorghum at the Crop Research Centre of the Sardar Vallabhbhai Patel University of Agriculture and Technology in Meerut. In Kharif 2022, testing of all 35 genotypes of forage sorghum was conducted using a randomized block design with three replications. Observations were recorded for days to 50% flowering, plant height (cm), leaf breadth (cm), leaf length (cm), number of leaves per plant, total soluble solids (%), leaf area (cm2), stem girth (mm), leaf stem ratio and green fodder yield per plant (g). Correlation coefficient studies indicated that green fodder yield per plant was found highly significant positive association with leaf breadth, stem girth, leaf area, leaf length, number of leaves per plant, plant height and leaf stem ratio at both genotypic and phenotypic level, indicated that selection of these attributes may be helpful to increase fodder yield in sorghum. The results of genotypic and phenotypic path analysis indicated that stem girth had a strong positive direct effect on green fodder yield per plant, followed by leaf breadth and number of leaves per plant at both genotypic and phenotypic levels. Improving these attributes can increase fodder yield. The character showing indirect effect like Leaf breadth, leaf length, leaf area, and leaf stem ratio via another component trait, indirect selection through such trait can lead to improvement in green fodder yield.

Correlation and Path Analysis for Yield and Yield Component Traits on Bread Wheat (Triticum aestivum L.) Genotypes

The research was conducted at Kulumsa Agricultural Research Center Main Station, during July–November, 2021 (Main cropping season) to study the association among traits and estimate the direct and indirect effects of various traits on grain yield of bread wheat genotypes. A total of 64 bread wheat genotypes were evaluated for 16 traits in 8×8 simple lattice design. Grain yields showed positive and highly significant at (p<0.01) genotypic and phenotypic correlation with plant height, number of seeds spike-1, head weight, yield head-1, biomass yield, hectoliter weight, test weight and harvest index. Genotypic correlation coefficients were greater for all significantly correlated with grain yield studied traits than the corresponding phenotypic correlation coefficients, indicating inherent association of the characters, therefore, selection for these characters could improve grain yield. Genotypic path analysis of the direct effects revealed that days to maturity, number of spikelets spike-1, head weight, yield head-1, biomass yield, hectoliter weight, test weight and harvest index exerted direct positive effect on grain yield. Phenotypic path analysis of the direct effects showed that days to maturity, plant height, number of tillers plant-1, number of seeds spike-1, head height, yield head-1, biomass yield, test weight and harvest index had direct positive effect on grain yield. Therefore, these traits should be considered for bread wheat breeding program for yield improvement.

Study on Correlation and Path coefficient analysis for yield related traits in Ricebean (Vigna umbellata)

Rice bean (Vigna umbellata) is a pulse crop, mainly grown in the kharif season. It is having potential to resist pest and diseases and also rich source of proteins and minerals. Twenty genotypes were evaluated to study the correlation and path analysis in the present research work. The experiment was conducted in crop research centre, ITM University, Gwalior, M.P. in kharif season 2022. Correlation analysis showed that seed yield per plot had positive and highly significant association between days to maturity, clusters per plant, number of pods per plant and hundred seed weight. The genotypic correlation results are slightly greater than the phenotypic path analysis. Path analysis of the present investigation revealed that the characters like number of seeds per pod exhibits positive and direct effect on the seed yield per plot at both genotypic and phenotypic level. Selection of these traits could be helpful in enhancing the seed yield.

Direct Selection Parameter Estimates and Path Coefficient Analysis for Grain Yield and Quantitative Traits in Maize (Zea mays L.)

The study was carried out at the Maize Research Institute “Zemun Polje”, Belgrade, Serbia during 2021 growing season in three location. Six inbred lines were crossed according to complete diallel method. In this way 15 hybrids and 15 reciprocal combinations were obtained. Hybrid and reciprocal combinations derived from these parental components were used in this paper. The present study was carried out to study the variability, broad-sense heritability (H2 bs), genetic advance (GA), correlation among traits, genotypic and phenotypic path analysis among grain yield and its components. The results indicated that the genotypes were significantly different for all traits. For all traits, the phenotypic coefficient of variation was higher than the genotypic coefficient of variation. The highest heritability was found in 1000 kernel weight, followed by grain yield, ear diameter and anthesis-silking interval (ASI). In our study Genetic Advance over Mean (GAM) for the traits ranged from lowest value (9.739%) for cob diameter to the highest value (90.579%) for anthesis-silking interval. According to results of path analysis, the trait 1000 kernel weight with the value of 0.365 has the strongest direct positive effect on grain yield. Positive direct effects on grain yield were also observed for ear length (0.202), ear diameter (0.248) and number of rows per ear (0.076), while negative direct effects were observed for cob diameter (-0.057). The trait 1000 kernel weight had the highest indirect positive effects on grain yield via ear diameter (0.232). The cob diameter had highest negative indirect effect on grain yield via ear diameter (-0.048). Coefficient of multiple determinations (R2) had a value of 0.428. This indicated the important role of additive gene effect in the inheritance of these traits and could be improved through simple selection.

Unravelling the Genetic Potential of Buckwheat Genotypes through Yield and Yield Attributing Parameters in Semi-tropical Climate of India

In this comprehensive study on buckwheat genotypes conducted in the semi-tropical region of Prayagraj, Uttar Pradesh, India during the rabi, 2021 growing season, a range of critical agronomic traits, including plant height, flowering time, days to maturity, test weight, and economic yield, were systematically analyzed. The analysis of variance highlighted the significance of both replicates and treatments in explaining variations across these traits. The genotypes exhibited remarkable diversity, with notable differences in plant height, with IC-26755 exhibiting the tallest plants at 99.75 cm, while IC-582972 displayed the shortest at 14.93 cm. Moreover, flowering time varied widely, with IC-582972 and IC-329201 being non-flowering genotypes. These variations in plant height and flowering time can have significant implications for crop management and breeding strategies. Assessment of genetic variability and genetic advancement underscored the substantial potential for improving traits such as economic yield and days to flowering through selective breeding efforts. Genetic coefficients of variation (GCV) and phenotypic coefficients of variation (PCV) were calculated, with "Economic yield" displaying the highest values, signifying significant inherent variability among genotypes for this trait.Phenotypic and genotypic correlation analyses unveiled intriguing relationships among traits, offering valuable insights for crop management and breeding strategies. There were strong positive correlations between days to 50% flowering and total weight, suggesting that genotypes taking more time to flower tend to produce greater total weight.Phenotypic and genotypic path analyses further elucidated the intricate interplay of traits, providing actionable insights for trait improvement through selective breeding. In the phenotypic path analysis, it was observed that total biomass fraction had a direct positive effect on days to 50% flowering and days to 80% maturity, suggesting that genotypes with higher biomass fractions tend to have later flowering and maturity.

Estimation of Correlation and Path Coefficient Analysis for Quantitative Characters in Okra (Abelmoschus esculentus L. Moench) Genotypes

The purpose of the present study was to evaluate the genetic variability and parameters such as genotypic coefficient of variation (GCV), phenotypic coefficient of variation (PCV), heritability, genetic advance, as well as perform correlation and path analyses on 20 different okra genotypes, including one check variety. The experiment was conducted during the kharif season of 2022 at the experimental farm of the Department of Genetics and Plant Breeding, Naini Agricultural Institute, Sam Higginbottom University of Agriculture, Technology and Sciences in Prayagraj, Uttar Pradesh. A randomized block design with three replications was employed for the study. Thirteen characteristics were observed and recorded, which includes: days to first flowering, days to 50% flowering, length of mature fruit (cm), diameter of fruit (cm), average fruit weight (gm), internodal length (cm), number of nodes on the main stem, number of primary branches, plant height (cm), number of fruits per plant, number of seeds per fruit, seed index (gm), and fruit yield per plant (gm). Azad Bhindi-1 exhibited the highest mean performance in terms of fruit yield per plant among all the genotypes. The PCV values were consistently higher than the corresponding GCV values for all traits, indicating the influence of environmental factors on trait expression. Fruit yield per plant and number of primary branches displayed the highest GCV and PCV values. The number of primary branches exhibited both high heritability and genetic advance. The correlation analysis revealed a positive and significant association between number of fruits per plant and fruit yield per plant at both the genotypic and phenotypic levels. The traits with the highest positive direct effects on fruit yield per plant were obsereved for average fruit weight and plant height, as determined through genotypic and phenotypic path analysis. These identified traits can serve as effective selection criteria for strategizing an efficient breeding programme to enhance fruit yield in okra.

Agronomic performance, yield stability and selection of doubled haploid rice lines in advanced yield trials

<abstract> <p>Anther culture is a widely utilized technique in rice breeding because of its simplicity and effectiveness in rapidly obtaining pure lines in the form of doubled haploid plants. The selection of doubled haploid (DH) rice lines derived from anther culture in advanced yield trials is an important step for obtaining superior DH lines. We aimed to determine agronomic performance, including yield and yield stability in order to select lowland DH rice lines that are high yield and have good agronomic performance based on the selection index method. The research was conducted in Indonesia at three locations, i.e., Bogor (West Java), Indramayu (West Java) and Malang (East Java) from July to December 2022. The genotypes tested were 29 DH lines and three check varieties (Inpari-42 Agritan GSR, Inpari-18 Agritan and Bioni63 Ciherang Agritan) using a randomized complete block design (RCBD) with genotypes as a single factor and three replications. High heritability values are found in all agronomic characters, except the percentage of filled grain/panicle, the percentage of empty grain/panicle and productivity. The yield stability based on the Kang method showed that 15 lines were stable and had high productivity. Phenotypic correlation analysis showed that the number of productive tillers, days to flowering, days to harvesting, number of filled grains/panicle and percentage of filled grains all had positive values and significantly correlated with productivity. Phenotypic path analysis showed that the character of days to harvesting, number of filled grains/panicle, number of productive tillers and percentage of filled grains/panicle directly affected the productivity. Based on the weighted selection index, 12 DH lines were selected due to having a positive and higher index (8.54 to 0.28) than the Bioni63 Agritan and Inpari 18 check varieties. Among those lines, 9 DH lines were also stable based on the Kang Method.</p> </abstract>

Characterization of wheat genotypes for terminal heat stress tolerance in Bangladesh

This study was aimed to determine the types and levels of variability, heritability, genetic progress, relationships between yield and the features that contribute to it, and some key indicators of terminal heat stress tolerance. Twenty different wheat genotypes were planted in the fields over the course of six different treatments spaced 10 days interval following a Randomized Complete Block Design (RCBD) with three replications. A high degree of significant variation was observed for all the characters studied. Estimates of the genotypic coefficient of variation (GCV) and phenotypic coefficient of variation (PCV) revealed that the phenotypic coefficient of variation was higher than the genotypic coefficient of variation, which indicates a large effect of environment on the expression of the characters studied. The highest estimates of PCV and GCV were observed for grain yield/plant followed by the number of tillers/plant. Heritability estimates revealed that characters like pollen fertility and sterility exhibited the highest heritability followed by days to maturity. The genetic advance was higher for grains/plants followed by plant height. Grain yield showed significant and positive phenotypic and genotypic correlations with grains/plant and 100-grain weight. Phenotypic path analysis revealed a significant direct positive effect of 100-grain weight on grain yield. Principal component analysis (PCA) revealed that the first five components having greater than one Eigenvalue contributed to 83.41% variability. The heat stress tolerance indices revealed that Bijoy and BARI Gom-25 had the lowest tolerance index (TOL), stress susceptibility index (SSI) values and highest yield susceptibility index (YSI) values which show more tolerance and less susceptibility to terminal heat stress and produce moderate grain yield under terminal heat stress. Balaka and Shughat had the highest mean productivity (MP), geometric mean productivity (GMP), and stress tolerance index (STI) values and produce high yields under terminal heat stress conditions.

Assessing Genetic Variability, Correlation, Direct and Indirect Effects of Yield Contributing Characters on Seed Yield in Finger Millet (Eleusine coracana L. Gaertn)

A field experiment was conducted aiming to study the Assessing genetic variability, correlation, direct and indirect effects of yield contributing characters on seed yield in 20 Finger millet lines in kharif season 2021 in Randomized Block Design (RBD) at Field Experimentation Station, Department of Genetics and Plant Breeding. Phenotypic and genotypic coefficient of variation was found highest in ear head length (25.37& 21.16) and lowest in plant height (3.49 & 1.76), heritability (%) in broad sense for 13 characters were range from (25.30%) to (78.70%). A perusal of genetic advance revealed that it was high for ear head length (40.43) and low for number of fingers (0.45). Phenotypic correlation coefficient analysis revealed that seed yield/plant showed highly significant and positive association with seed yield/plant (0.930) and plant height (0.769) and for genotypic correlation coefficient showed significant and positive association with harvest index (0.930) and plant height (0.769). The phenotypic path analysis showed positive and direct effects on grain yield was exhibited by biological yield and for genotypic path analysis positive and direct effects on grain yield was exhibited by plant height and biological yield.

Studies on Genetic Association and Path Coefficient Analysis for Yield and Yield Attributing Characters in Maize (Zea mays L.)

During kharif-2021, the present trial was carried out at the field experimentation centre of the Genetics and Plant Breeding, Naini Agricultural Institute, Sam Higginbottom University of Agriculture, Technology And Sciences, Allahabad to assess genetic association and path coefficient analysis in forty-five maize genotypes, including one check variety SHAKTIMAN-5 for eighteen quantitative traits. Based on mean performance of 45 genotypes of maize, grain yield per plant was highest in case of MGC-240 [67.07] and SHAKTIMAN-5 [64.87] genotypes. On the basis of Analysis of variance, significant difference was recorded for all the grain yield and its components indicating presence of large amount of variability in the genotypes. The magnitude of GCV and PCV recorded highest for Grain yield per plant and Ear height. High heritability recorded in 100 grain weight, Ear height, plant height. High genetic advance was recorded in Plant height, biological yield per plant. High genetic advance as percent mean was recorded in Ear height, Grain yield per plant. Correlation studies revealed that Grain yield per plant at genotypic and phenotypic level was positively and significantly correlated with Cob weight, biological yield plant per plant and Cob girth. Path analysis revealed that Days to 75% maturity, biological yield per plant registered high and positive direct effect on Grain yield per plant in genotypic path analysis. In phenotypic path analysis revealed that Cob weight, Days to 50% silking registered high and positive direct effect on Grain yield per plant. It indicates true relationship between these traits and direct selection for these traits will be rewarding for yield improvement.

Direct and indirect effect computed between different phenotypic and genotypic level of yield relatable traits in rice (Oryza sativa L.) under sodic soil

The present investigation consisting a set in a fashion of line x tester cross combinations were carried out to investigate the inter characters relationship for fifteen characters in In Rice (Oryza staiva L.). The experiments were conducted during Kharif, 2019-2020at Students Instructional Farm of Department of Genetics & Plant Breeding, Acharya Narendra Deva University of Agriculture and Technology, Narendra Nagar (Kumarganj), Ayodhya-224229 (U.P.) days to 50% flowering, day to maturity, plant hright (cm), productive tillers per plant, chlorophyll content, panicle length, flag leaf area (cm), number of spikelets per panicle, spikelets fertility, grains size (L:B ratio), 1000-grain weight (g), biological yield per plant (g), harvest-index (%), protein content and grain yield per plant (g), were studied in the LxT experiment. In this study, grain yield per plant exhibited highly significant and positive association at phenotypic level with harvest index, followed by panicle length and other traits at genotypic and phenotypic correlation analysis. Character harvest index has highest direct effect on seed yield followed by biological yield per plant and some other traits at both genotypic and phenotypic path analysis. Resultant direct selection for these traits would be effective for further yield improvement in given genotype of rice.

Genotypic and Phenotypic Correlation and Path Coefficient for Quantitative Traits in Field Pea (<i>Pisum sativum</i> L.) Genotypes at Arsi Highland of Ethiopia

In Ethiopia, field pea (<i>Pisum sativum</i> L.) is the main source of protein for resource poor growers. The improvement of varieties for yield and disease resistance is one of the important activities to support farmers and improve the productivity of the crop. Consequently, this study was showed to evaluate the genotypic correlations, phenotypic correlations and path coefficient analysis between the field pea genotypes for yield and yield associated traits. Forty-nine field pea genotypes were evaluated in simple lattice design at two locations Bekoji and Asasa in 2018/2019 cropping time of year. Grain yield per plot had positive and highly significant genotypic association through plant height whereas highly significant phenotypic correlation observed between grain yield and plant height and biomass yield. At Bekoji genotypic path analysis, days to 50% flowering, plant height, grain filling period, thousand seed weight, harvest index and total biomass showed strong positive direct effect on grain yield per plot. At Asasa the path analysis for grain yield at genotypic level showed that harvest index, thousand seed weight, plant height, days to 50% flowering and days to 95% physiological maturity and total biomass yield exerted positive direct effect on grain yield per plot. Path coefficient analysis at genotypic levels of the combined data exhibited that days to 50% flowering and total biomass per plot had strong positive direct effect on grain yield per plot. The phenotypic path analysis of the combined data revealed total biomass yield, thousand seed weight, plant height and days to maturity has strong positive direct effect on grain yield per plot. The study showed the existence of reasonable genetic variability between the field pea genotypes that can be exploited in breeding programs.

Estimation of path analysis of mutant lines of lentil (Lens culinaris Medik L.)

Seed of 9 induced mutant lines of lentil (Lens culinaris Medik. L.) were used for the experimental purpose. These mutants were isolated from variety K -75 with gamma ray and EMS treatment. The self-seeds of all mutants were sown in randomized block designed in three replications at Agricultural Research Farm, Institute of Agricultural sciences, B.H.U, Varanasi, during Rabi 2017-18.Distance between row to row and plant to plant was maintained 30cm and 5cm respectively. In genotypic path analysis, the secondary branches showed the highest positive direct effect (0.991) on grain yield followed by test weight (0.8706) and number of pods per plant (0.2640) in year 2017-18. In phenotypic path analysis, the number of pods per plant showed highest positive direct effect (1.054) followed by days to 50% flowering and test weight (0.0436) in year 2017-18. So that maximum importance of these characters might be given in selection program me.

Evaluation of wheat genotypes (Triticum aestivum L.) for assessment of character association, path coefficient and cluster analysis

Thirty wheat genotypes (Triticum aestivum L.) were evaluated for 11 morphological and yield trait for analysis of character association (phenotypic and genotypic correlation coefficient), path analysis and cluster analysis. The experiment was conducted during rabi seasons of 2014-2015 in a randomized block design with three replication. Days to 50% heading showed positive and significant correlation with flag leaf area and number of spiklet per ear; flag leaf area showed positive and significant correlation with 1000 grain weight; Plant height showed positive and significant correlation with spike length; spike length showed positive and significant correlation with 1000 grain weight. Phenotypic path analysis showed biological yield and number of grain per spike had highly positive and direct effect on grain yield. Direct and highly positive effect on grain yield was shown by number of productive tillers, plant height, spike length, number of spikelet per spike genotypic path coefficient. Biological yield and grains yield per plant show highly positive and direct effect on yield with number of productive tillers, plant height, number of spikelet per spike and spike length. In cluster analysis the intra cluster distance ranged from 1.61 (cluster II) to 2.37 (cluster III and VI ). Thus the member of cluster II were least divergent and similarly the member of cluster III and IV were most divergent The maximum inter cluster distance was between cluster II and III followed by cluster IV and V , cluster VI and III and cluster VI and V that order therefore the accessions grouped in the five pair of cluster may be considered as most divergent.

Genotypic and Phenotypic Path Analysis for Yield and Yield Components in Groundnut (Arachis hypogea)

Genotypic and Phenotypic Path Analysis for Yield and Yield Components in Groundnut (Arachis hypogea)

English

This study aims to identify the phenotypic effects of traits associated with soybean pods and their growth habit. The experiments were carried out during the 2012 - 2013 agricultural year. It was done in randomized blocks arranged in a 2×20 factorial design (environments × soybean cultivars) with three replications. Data were subjected to individual analysis of variance for each environment and growth habit to verify the homogeneity of variances. Phenotypic path analysis among agronomic traits was performed for each environment within the soybean growth habits. The results showed considerable influences of growth habit via traits associated with soybean pods. The traits number of pods with two, three, and four grains directly influenced the grain yield of genotypes with indeterminate growth habit regardless of the environment. The soybean genotypes with determinate growth habit contributed greatly to grain yield through the traits number of pods with one, two, and three grains and thousand grain weight via pods with two or four grains. Indirect selection of superior genotypes for pods per plant and grain weight could provide satisfactory results for soybean yield in relation to the growth habit. The interrelationships obtained between growth habits and environments, can be applied to superior genotypes selection strategies in breeding soybean programs. Key words: Agriculture science, biometric models, Glycine max L., indirect selection, grain yield, soybean breeding.

Character association and path analysis for fruit chromatic, physicochemical and yield attributes in mango (Mangifera indica)

The present investigation was conducted during the year of 2014 and 2015 to determine the genotypic and phenotypic correlation along with their direct and indirect effects through path coefficients analysis and to estimate the contribution of most important traits towards fruit quality and yield in mango. The genotypic correlation values were recorded higher than their corresponding phenotypic value in 60 diverse mango genotypes grown at ICARIARI, New Delhi. The result suggests that there were strong inherent relationship between the traits. The a* (r2 = 0.179, 0.178), fruit weight (r2 = 0.236, 0.234), fruit length (r2 = 0.371, 0.370), fruit diameter (r2 = 0.393. 0.391), fruit width (0.366, 0.361), titrable acidity (r2 = 0.273, 0.272), stone weight (0.329, 0.328), stone length (r2 = 0.351, 0.347), stone diameter (r2= 0.249, 0.248), stone width (r2 = 0.278, 0.272) and peel weight (r2 = 0.370, 0.365) showed positive association with yield both at genotypic and phenotypic levels, respectively. At genotypic level, the highest positive direct effect was exhibited via fruit weight (5.74) followed by b* (1.006), peel % (0.685), stone length (0.292), fruit diameter (0.259), titrable acidity (0.159), pulp: stone (0.143), fruit shape index and ascorbic acid (0.067), stone diameter and stone width (0.053) on yield. The residual effects of genetic and phenotypic path analysis were 0.24 and 0.32 on fruit yield was not much higher side and revealed higher genetic variability, supports lower degree of environmental influence on the selected traits. In combination with correlation coefficient and path analysis, it was found that fruit weight, fruit diameter, stone length, stone diameter and titrable acidity exhibited significant positive correlation coefficients with yield and also induced the high positive direct effect. Thus, results affirmed that fruit weight, fruit diameter, stone length, stone diameter and titrable acidity are the major components of fruit yield and to be considered in mango improvement programme.

Evaluation of chickpea genotypes for variability in seed protein content and yield components under restricted soil moisture condition

A study was conducted at IARI, Research Farm, New Delhi, during the winter (rabi) season of 2009–10 with 12 chickpea genotypes grown under restricted soil moisture condition. On the basis of results obtained, seed protein (%) was highest in Pusa 1103 (30.80), followed by BG 1101 (29.77), Pusa 362 (29.13) and BGD 112 (28.87); and therefore, Pusa 362 and Pusa 1103 can be used in breeding programme for improving protein content in seed under restricted soil moisture condition. Genotypic, phenotypic coefficient of variation, heritability, genetic advance, correlation coefficients and path coefficients analysis were performed for yield and its contributing parameters along with protein and cold tolerance index in chickpea genotypes. Analysis of variance for traits studied showed significant (P < 0.01) differences among the genotypes. Phenotypic coefficient variation values for most characters were closer to the corresponding genotypic coefficient variation values, showing little environment effect on the expression of various characters. The estimated values of broad-sense heritability were found between 7.86 % (Cold tolerance index) and 99 % (biomass per plant). High heritability coupled with high genetic advance as per cent of mean was observed for pods per plant and biomass per plant, suggesting that selection for these traits would give good response. Biological yield (r = 0.854) and harvest index (r = 0.766) had high positive association with grain yield. Phenotypic path analysis indicated that biological yield (0.792) and harvest index (0.407) contributed directly towards grain yield. It is suggested that these characters can be considered as selection criteria in improving the grain yield of chickpea genotypes.

Correlation and path coefficient analysis of mango (Mangifera indica L.)

Sixty diverse genotypes of mango were selected from the Germplasm Centre of BAU during December 2007–August 2009 to determine the genotypic and phenotypic correlation along with their direct and indirect effects through path coefficients analysis in mango as to estimate the contribution of most important characters towards yield. It appeared that in most of the cases, the genotypic correlation values were higher than their corresponding phenotypic values. This suggests that there were strong inherent relationship between the traits. Percent flowering shoot had significant positive correlation with inflorescence per shoot, percent perfect flower, percent initial fruit set, number of fruits per plant and fruit weight both at phenotypic and genotypic levels. Fruit yield is determined by some components. The residual effects of genetic and phenotypic path analysis were 0.209 and 0.385, respectively, revealed higher genetic variability and also proved lower percent of environmental influence on the selected ten characters. In genotypic path analysis, number of fruits per plant had the highest positive direct effect (0.899) on yield. Higher positive direct effects were also observed for the characters inflorescence per shoot (0.539), percent perfect flower (0.816), and percent initial fruit set (0.292), and fruit weight (0.324). Leaf area, percent flowering shoot, number of fruits per plant, and fruit length showed negative direct effects towards yield. In phenotypic path analysis, except percent flowering, shoot per plant and fruit length and other characters also exhibited similar trend on yield as genotypic path coefficient. In combination with correlation coefficient and path analysis, it was found that number of fruits per plant and percent perfect flower gave significant positive correlation coefficients with yield and also produce the high positive direct effect. Thus, it was clear that plant height, inflorescence per shoot, percent perfect flower, percent initial fruit set per inflorescence, and fruit weight are the major component of fruit yield in mango. Bangladesh J. Agril. Res. 37(3): 493-503, September 2012 DOI: http://dx.doi.org/10.3329/bjar.v37i3.12126

A Study of Variability, Associations, and Path Analysis in Poplar (Populus deltoides Bartr. ex Marsh)

Forty-two genotypes were evaluated for juvenile wood yield and its components at three locations in Bihar, India. A significant difference was observed among the genotypes for all the characters under study. The highest value of genotypic and phenotypic coefficients of variation was observed in juvenile wood volume followed by diameter at breast height (DBH). Characters like plant height, clear bole height, crown diameter number of branches, angle of branch, diameter of branch, and length of branch showed moderate values for genotypic and phenotypic coefficients of variation. Very high heritability was estimated for clear bole height, crown diameter, angle of branch, and length of branch. Diameter and plant height showed moderate to high heritability. Relatively genetic advance expressed in percentage of mean or genetic gain was observed the highest in volume (30.86%), DBH (18.96), clear bole height (17.19%), angle of branch (17.39), length of branch (19.53), and in plant height (11.87%). Juvenile wood volume per plant showed significant and positive correlation with height (0.619), diameter (DBH, 0.770), clear hole height (0.305), number of branch (0.372); and positive association with crown diameter (0.145), angle of branch (0.055), diameter of branch (0.251), length of branch (0.200), and survival (0.166); and significant negative correlation with taper (−0.499) at the phenotypic level. In phenotypic path analysis diameter (DBH, 0.702), plant height (0.169), crown diameter (0.121), taper (0.027), and survival (0.050) showed positive direct effect on juvenile wood volume. The direct impact of the same through clear bole height (−0.366), number of branch (−0.130), angle of branch (−0.228), and length of branch (−1.567) was negative. Hence it is suggested that due importance should be given to diameter (DBH), plant height, crown diameter, diameter of branch, taper, and survival for selection of superior plant with high juvenile wood yield potential in poplar.