High Genotypic Coefficient Of Variation Research Articles

Morphological characterization of maize (Zea mays L.) hybrids under excessive soil moisture stress

A critical assessment of 32 maize hybrids with two replications for excessive soil moisture stress (ESM) was carried out during Kharif 2019-20. The plants were exposed to waterlogging stress for 12 days at the flowering stage by maintaining a water level of 3-5 cm. High genotypic coefficient of variation (GCV) and phenotypic coefficient of variation (PCV) were attained for maize plants with adventitious roots and senescence percentage after stress. High heritability along with high genetic advance was determined for number of plants with adventitious roots, senescence percentage, plant height and 100 kernel weight. Plant yield depicted a highly significant positive genotypic and phenotypic correlation with plant height, ear height, number of plants with adventitious roots and number of kernels per row, along with a significant negative correlation with senescence percentage. Kernels per row and plant height manifested the highest positive direct effect on plant yield at phenotypic and genotypic levels, respectively, reflecting that the characters can be considered for plant selection under ESM stress.

Correlation and Path Coefficient Analysis for Grain Yield Components in Maize (Zea mays L.)

In the present study, "Correlation and path coefficient analysis for grain yield components in maize (Zea mays L.)," the aim was to estimate genetic variability, genetic advance, correlation, and direct and indirect effects of yield contributing traits on yield. According to the analysis of variance, all traits exist. Hence, the data on all the 16 traits which showed significant differences among the entries were subjected to further statistical analysis. GP-184 had the shortest grain yield per plant in comparison to other genotypes, whereas GP-87 had the highest grain yield. Grain yield per plant, ear height, plant height, and cob weight exhibited the highest genotypic coefficient of variation. Cob weight. Among the traits, grain yield per plant, ear height, plant height, cob weight, and cob length showed a higher phenotypic coefficient of variation. The traits ear height, grain yield per plant, plant height, number of cobs per plant, cob length, number of kernels per row, cob weight, number of kernels per row per cob, anthesis to silking interval, shank weight, and days to 50% silking exhibited the highest heritability. Plant height, grain yield per plant, ear height, and cob weight were traits that showed higher genetic advances. These traits included grain yield per plant, ear height, plant height, cob weight, cob length, number of cobs per plant, tassel length, number of kernels per row, number of kernel rows per cob, 100-kernel weight, anthesis to silking interval, cob girth, and shank weight that showed higher genetic advance as a percent mean. The correlation coefficient indicates there is a significant positive correlation between grain yield and cob weight, number of cobs per plant, number of kernels per row, number of kernel rows per cob, 100 kernel weight, cob length, cob girth, plant height, ear height, shank weight, and tassel length at the phenotypic level. Grain yield per plant significantly positive correlation with cob weight, number of cobs per plant, number of kernels per row, number of kernel row per cob, 100 kernel weight, cob length, cob girth, plant height, shank weight, ear height, tassel length at the genotypic level the phenotypic level, the traits cob weight, 100 kernel weight, and plant height had the greatest direct impact on grain yield per plant. The traits were cob weight, number of kernel row per cob, 100 kernel weight showed higher direct effect on grain yield per plant at genotypic level.

<p><strong>Variability and Traits Association Analyses in Bacterial Wilt Resistant Genotypes of Tomato </strong><strong>(<em>Solanum lycopersicum </em>L.) under Mid-Hill Conditions of Himachal Pradesh </strong></p>

18 bacterial wilt resistant F4 progenies of tomato were evaluated along with two bacterial wilt resistant checks at the Vegetable Research Farm of the Department of Vegetable Science and Floriculture, Chaudhary Sarwan Kumar Himachal Pradesh Krishi Vishvavidyalaya, Palampur during summer-rainy season’2016 to identify the most promising progenies on the basis of nature and extent of genetic variability and heritability coupled with genetic gain. To ascertain the variability source structure, computation of principal component analysis (PCA) was also done. Estimates for phenotypic coefficient of variation (PCV), genotypic coefficient of variation (GCV), heritability and genetic gain were found to be high for average fruit weight, total fruits per plant, marketable fruits per plant, marketable yield per plant, gross yield per plant and lycopene content. High PCV and GCV indicated the presence of sufficient variability ensuring ample scope for improvement through selection. High heritability allied with high genetic gain suggested the presence of additive gene action and thereby these traits could be considered as reliable indices for selection. For PCA studies, eigen values were calculated for 16 morphological traits of tomato. The results of PCA revealed that out of these 16 traits, initial eight traits exhibited more than 0.5 eigen values and showed more than 95 per cent of genetic variability. Among all, PC1 (days to 50 per cent flowering) has highest eigen value (4.927) and accounts for 30.793 per cent of genetic variability. As a result, these traits might be taken into consideration for effective selection to develop elite bacterial wilt resistant lines in tomato.

Genetic Variability of Gladiolus (Gladiolus grandiflorus) Cultivar under Prayagraj Agro-Climatic Conditions in Uttar Pradesh, India

An experiment to Study on genetic variability of Gladiolus (Gladiolus grandiflorus) cultivars under prayagraj agro-climatic conditions was carried out at Departmental research field of Horticulture, Naini Agriculture Institute during the Rabi season of 2021-2022 with Eight Cultivars in randomized block design with three replications. The viz. White prosperity, Mohini, Hunting song, Creamy green, Suchitra, Samara, Nova, Peterpears. Evaluated were out of twenty-five cultivars means estimated Genetic variability, heritability, phenotypic coefficient of variation (PCV) was higher than the genotypic coefficient of variation (GCV) and genotypic correlation. The characters, Plant height at (30, 60, 90 DAS), Number of leaves per plant at (30,60,90 DAS), No. of shoot per plant, Days taken for corm sprouting, Rachis length, Days taken to spike emergence, days taken colour break stage, No. of floret per spike, No. of spike per plant, No. of days taken for first floret open, No. of days taken for last floret open, spike length, floret diameter, vase life, Weight of daughter corm, Weight of mother corm, corm diameter, corm weight, No. of corm per hectare, No. of cormels per hectare and Corm yield/plant observed for all characters. Highest GCV and PCV were recorded for Weight of daughter corm (g) (33.6786 and 47.569), No. of cormels per hectare (37.743 and 37.97), No. of corm per hectare (27.961 and 32.13), No. of days taken for first floret open (30.0614 and 30.0889), Corm yield/plant (23.667 and 29.334), Weight of mother corm (25.6022 and 28.1499),Corm weight (21.75 and 25.49), Days taken for corm sprouting (23.7566 and 23.7566) and lowest GCV and PCV were recorded for No. of floret per spike (2.7578 and 3.3549). The genotypes Creamy green and White prosperity were found to produce the highest spike yields per plot and the highest numbers of corm per hectare, respectively. These genotypes may be sown for higher yields and showed a good response to selection due to their high heritability, variability, and genetic advance, which showed additive gene effect. These genotypes can be utilised to selectively increase yield and component attributes.

Assessing the phenotypic variation, heritability and genetic advance in bread wheat (Triticum aestivum L.) candidate lines grown under rainfed semi-arid region of Algeria

The genetic improvement of any breeding population largely depends upon the magnitude of genetic variability present. This study was carried out to estimate parameters of the genetic variation among 13 quantitative traits of bread wheat evaluated at INRAA-Setif institute (Algeria) during the 2020–2021 crop season in a rainfed environment. 34 genotypes including four control checks were planted in a randomized complete block design with three replications. Genotypes showed significant variations for almost all the studied traits. Proline content, spikes weight, and grain yield exhibited a high genotypic coefficient of variation along with moderate to high heritability coupled with a high genetic gain, suggesting the implication of additive gene action. The number of spikes, spikes weight, and thousand kernel weight were significantly and positively correlated with grain yield at both phenotypic and genotypic levels. Path analysis results showed that spikes weight is an important route through which most of the measured traits influenced indirectly grain yield. Lines L1, L20, L28, L16, and L18 exhibited a sizeable grain yield advantage, which suggests they are potential candidates for future release and could be incorporated into the wheat breeding programs as parents to improve yield in the rainfed environments of Algeria

Discrimination of Root System Architectural Traits, Morphometric Traits and Identification of Potential Genotypes in Response to Drought and Irrigated Conditions in Pearl Millet (Pennisetum glaucum (L.) R. Br.)

Aims: To identify the potential genotypes and the important traits for drought tolerance based on root system architectural traits and morphometric traits that can be used as a selection criteria in future crop improvement programs.
 Study Design: Completely randomized design for root system architectural traits and Randomized block design with two replications for morphometric traits.
 Place and Duration of Study: Department of Millets, Tamil Nadu Agricultural University, Coimbatore during Summer 2022.
 Methodology: The 33 elite genotypes were raised in polybags with two factors, one is genotype and other is treatment for observing root system architectural traits in completely randomized design. Also these genotypes were raised in the field in randomized block design with two treatments, irrigated and drought at early stage of the crop for observing morphometric traits.
 Results: Based on root system architectural traits, the significant traits were network perimeter, network surface area, network length and network volume. Under irrigated and drought condition, high phenotypic coefficient of variation and high genotypic coefficient of variation were observed for single plant yield, high heritability and high genetic advance for days to 50 per cent flowering, plant height, leaf blade length, spike length, 1000 seed weight and single plant yield. Correlation study revealed that all the characters except number of tillers and days to 50 per cent flowering had positive significant correlation with single plant yield. Path analysis showed that spike length had positive direct effect on single plant yield.
 Conclusion: The identified traits for drought tolerance were network perimeter, network surface area, network length, network volume, days to 50 per cent flowering, plant height, leaf blade length, spike length, 1000 seed weight and single plant yield. The identified drought tolerant genotypes were Nattu cumbu, ICMB 10444, 86M38 and PT 6752.

Genetic variability, correlation and path analysis of upland cotton (Gossypium hirsutum L.) germplasm for seed cotton yield

One hundred upland cotton germplasm accessions were evaluated for eight traits to evaluate the per se performance, genetic variability, heritability, genetic advance as a per cent of mean, correlation and path analysis. The estimation of variability indicated that the number of monopodia per plant had high GCV and PCV. High heritability along with high GAM was  found in plant height, internode length, the number of monopodia per plant, the number of sympodia per plant, the number of bolls per plant and seed cotton yield per plant which suggested that additive gene activity had a significant influence in the inheritance of these traits. Correlation analysis showed that the number of sympodia per plant, the number of bolls per plant and boll weight have a significant high positive correlation on the seed cotton yield. Path analysis showed that the number of bolls per plant and boll weight had the highest positive direct effect on seed cotton yield per plant. Keywords: Cotton, phenotypic coefficient of variation (PCV), genotypic coefficient of variation (GCV), heritability, genetic advance, correlation, path analysis.

Estimates of genetic variability, inter character association and path analysis in turmeric over environments

Pooled data of 27 traits, including quantitative and qualitative, from 15 turmeric varieties grown in three locations over two years were used to estimate the genetic parameters of variability and path analysis. High genotypic coefficient of variation (GCV) combined with high phenotypic coefficient of variation (PCV) was observed for collar girth, length of mother rhizome, number of mother rhizomes, weight of mother rhizome, weight of primary rhizome, number of secondary rhizomes, primary rhizome inter-nodal length, bisdemethoxycurcumin (BDMC), demethoxycurcumin (DMC), curcumin (CUR) and yield. High heritability coupled with high genetic advance as per cent mean (GAM) was recorded for plant height, number of shoots, leaf petiole length, leaf length, collar girth, length of mother rhizome, girth of mother rhizome, primary rhizome inter-nodal length, dry recovery, oleoresin, BDMC, DMC and curcumin. Correlation coefficients showed that yield was significantly associated with collar girth, weight of mother rhizome, number of primary rhizomes, weight of primary rhizome and number of secondary rhizomes. Path coefficient analysis at phenotypic level revealed that, positive direct effect was high for length of mother rhizome followed by number of mother rhizomes, weight of primary rhizome and curcumin content. The study confirmed that characters such as weight of mother rhizome, girth of mother rhizome, weight of primary rhizomes, number of primary rhizomes and curcumin content can be relayed upon to form selection criteria in turmeric.

Genetic Variability and Correlation Study in Determinate Type Progenies of Indian Bean [Lablab purpureus (L.) Sweet

Aims: In India, the Indian bean is a popular vegetable and legume crop. An attempt was made to analyze the variability, correlation as well as direct-indirect effects using path analysis for yield and its sub-characters.
 Place and Duration of Study: Navsari Agricultural University, Navsari, Gujarat. In Rabi 2019-20.
 Methodology: The investigation was conducted using 55 genotypes in a randomized block design using three replications. Total of eleven quantitative traits were studied and data was collected from ten random plants from each genotype.
 Results: ANOVA depicted sufficient variability present among the genotypes for all traits. Plant height, racemes per plant, pods per raceme, pod weight, pods per plant, pod width, and seed yield per plant showed moderate to high GCV (Genotypic coefficient of variation) and PCV (Phenotypic coefficient of variation), moderate to high heritability, and moderate to high genetic advance as a per cent of mean. Plant height, racemes per plant, pods per plant, pod weight, and pods per raceme were significantly and positively associated with seed yield per plant at the genotypic level. Pods per plant had the most favorable direct effects (0.736) on seed yield per plant, subsequently by pod weight, seeds per pod, pods per raceme, pod length, pod width, plant height and days to maturity.
 Conclusion: It is concluded that sufficient amount of variability is present within the material under study. The selection for pods per plant, pods per raceme, pod weight, pod length, pod width, plant height, seeds per pod and days to maturity would be easy and useful in bringing about improvement of seed yield in Indian bean.

Variability analysis in tomato (Solanum lycopersicum L.) crosses under drought stress

Climate change in recent years has affected crop production to a greater extent. To overcome these effects, climate-resilient varieties are needed. Tomato is a versatile crop. However, its growth is hindered when it is affected by drought stress. Hence, a variability analysis of tomatoes under drought stress was carried out at Horticulture College and Research Institute, Coimbatore. Variability studies revealed that all the crosses for all parameters exhibited higher phenotypic coefficient of variation (PCV) values than genotypic coefficient of variation (GCV), indicating the influence of environmental effects. For all the crosses, viz., EC169966 × LE118, EC177824 × LE27 and Arka Ashish × LE27, high PCV and high GCV were recorded for characteristics including fruit number per plant, yield per plant, lycopene content and peroxidase activity. Characteristics such as the number of flowers per cluster, fruit number per plant, individual weight of fruit, yield per plant, relative water content, proline content, peroxidase activity and ascorbic acid content recorded higher heritability coupled with high genetic advance as a percentage of the mean (GAM). Thus, direct selection of the above parameters improves drought-tolerant breeding programs in tomato.

Genetic Variability, GCV, PCV, Heritability and Genetic Advance Analysis in Fenugreek (Trigonella foenum- graecum L.)

An experiment was carried out using 55 (45 F1’S and 10 parents) genotypes of fenugreek to study the variability, heritability and genetic advance in percent of mean. The analysis of variance (ANOVA) revealed highly significant differences among the genotypes for the characters under study indicating presence of sufficient variability among the genotypes. Phenotypic coefficient of variation (PCV) was higher than the respective genotypic coefficient of variation (GCV) for all character that founded little effect on the characters on environment. The highest GCV and PCV were observed in the trait number of branches per plant followed by yield per plant. The high heritability coupled with moderate genetic advance in percent of mean were observed for number of branches per plant and yield per plant.

Genetic diversity, trait association and cause effect analysis in selected genotypes of finger millet [Eleusine coracana (L.) Gaertn.

Aim: The present investigation was planned to evaluate the finger millet genotypes for genetic variability, genotypic relatedness, an association between traits, and their direct effect on increasing grain and fodder yield. Methodology: The present investigation was planned to evaluate the finger millet genotypes for genetic variability, genotypic relatedness, an association between traits, and their direct effect on increasing grain and fodder yield. Results: Analysis revealed a high genotypic coefficient of variation (GCV) to the number of productive tillers per plant (57.98%), grain yield per plot (49.38%), number of heads per plot (49.27%) and number of fingers per head (45.54%). High heritability coupled with high genetic advance as percent of mean was observed for the number of heads per plot. Grain yield exhibited a significantly high positive correlation with fodder yield per plant (rg: 0.98), number of heads per plot (rg: 0.89) and harvest index (rg: 0.78). Fodder yield per plant, harvest index, single head weight, number of heads per plot and days to final harvest had a high direct positive effect on grain yield. The PCA separated total genetic variation into six components and covered almost 85.0% of genetic variation. Genotypes were grouped into four main groups and several subgroups based on Euclidean distances. Interpretation: The higher magnitude of GCV, heritability coupled with high genetic advance for a trait of interest; strong correlation between dependent and independent traits would be desirable for productivity enhancement in finger millet. The additive gene effect would also be rewarding by direct phenotypic selection.

Genetic variability, character association and path coefficient analysis in determinate F5 progenies of Indian bean [Lablab purpureus (L.) Sweet

The experiment was carried out to determine the genetic variability parameters and character associations for eleven quantitative traits in Indian bean genotypes. It revealed a significant amount of variability present among these genotypes. Seed yield per plant had high Genotypic coefficient of variation (GCV) and Phenotypic coefficient of variation (PCV) values, showing the potential for improvement by selection. Racemes per plant, pods per raceme, pods per plant, and pod weight had moderate GCV and PCV values. There was high heritability combined with a high genetic advance for pod weight and seed yield per plant. Plant height, pods per plant, and pod weight were significantly and positively associated with seed yield per plant. Pods per plant had the most positive direct effect on seed yield per plant, followed by racemes per plant, plant height, pod weight, pod length, and seeds per pod. Therefore, selection for such traits is advised to bring about improvement in Indian beans. Keywords: Variability, Heritability, Correlation, Path analysis, Dolichos bean, Indian bean

PHENOTYPIC AND GENETIC VARIABILITY AND GENETIC DIVERGENCE IN LENTIL (Lens culinaris Medik.) GERMPLASM

Lentil is a leguminous crop which plays important role in both human health and agriculture. Lack of genotypic and phenotypic variability limits the scope of breeding for developing high yielding lentil varieties. In order to know the genotypic and phenotypic variability and diversity in lentil, research was carried out with 30 lentil genotypes following a randomized complete block design using three replications. Highly significant variability was found for all of the traits among the genotypes under study. The genotype ILL 4127 showed superior performance whereas ILL 2894 showed poor performance. The environment had great impact on the genotypes as the PCV (phenotypic coefficient of variation) was greater than the GCV (genotypic coefficient of variation). High PCV coupled with high GCV, heritability, genetic advance and genetic advance in percentage of mean was found for number of pods plant-1 and number of seeds plant-1. Thirty genotypes were divided into 5 clusters where cluster I and cluster V had the maximum inter-cluster distance, specifying the existence of wider genetic diversity among the genotypes of these clusters. Hence, suitable transgressive segregants might be found from crosses between genotypes of those clusters. Genetic diversity at molecular level was found 0.861 to 1.112 which indicated the existence of genetic variation within the studied genotypes. Microsatellite profiling revealed that SSR19 was the highly informative and detectable polymorphic marker followed by SSR48, SSR156, SSR33, SSR13 and SSR130. The results showed the consistency both in molecular and morphological clustering. The genotypes ILL 2894, ILL 3823, ILL 2764, ILL 3201, BM 680, ILL 2083, ILL 5103, ILL 4355, ILL 4707 and ILL 5844 were found as stable considering genetic variability and diversity under study. Therefore, these genotypes might be used as suitable breeding materials for developing advanced lentil varieties.

EVALUATION OF GENETIC VARIABILITY, HERITABILITY AND GENETIC ADVANCES IN DAHLIA (DAHLIA VARIABILIS L.) GENOTYPES

The present investigation was carried out to know the genetic variability, heritability and geneticadvances in dahlia with thirty five genotypes. High genotypic coefficient of variation (GCV) and phenotypiccoefficient of variation (PCV) were observed for flower diameter, shelf life, individual weight of flower,number of flowers per plant, flower yield per hectare, tuber yield per plant. Whereas, high heritability (h2)coupled with genetic advance over mean (GAM) was registered highest in plant height, number ofsecondary branches per plant, leaf area, leaf area index number of days taken to first flowering, flowerdiameter, shelf life, individual flower weight number of flowers per plant, flower yield per hectare and tuberweight per plant.

Characterization of the Genetic Variability in Rice (Oryza sativa L.) and its Assessment Using Principal Component Analysis (PCA)

Present investigation was conducted to estimate genetic parameters such as Genotypic Coefficient of Variation (GCV), Phenotypic Coefficient of Variation (PCV), heritability and Genetic Advance (GA) along with correlations, path coefficients, Genetic divergence and Principal Component Analysis (PCA) from data collected on 21 rice genotypes. The results revealed highly significant mean squares due to genotypes for all traits studied, indicating the existence of sufficient variation among the genotypes and therefore an ample scope for effective selection. High PCV, GCV, heritability and genetic advance as per cent of mean was observed for 1000-grain weight, seed yield per plant, and harvest index, indicating the effectiveness of direct selection for improvement of these traits. Thousand grain weight and harvest index had recorded positive and significant association with seed yield per plant. The results on path analysis also revealed high and positive direct effect for harvest index followed by flag leaf width, days to 50% flowering, days to maturity, plant height, panicle length, number of filled grains/panicle, number of spikelets/panicle and hence, these traits were identified as the most effective selection criteria for improvement of seed yield per plant in rice genotypes. The results on divergence analysis revealed that the genotypes were grouped into five clusters. Cluster I constituted maximum number of (17) genotypes. Maximum differences among the genotypes within the same cluster (intra-cluster) were shown by cluster I (18.33) followed by cluster II, III, IV, V showed zero intra -cluster distance. Cluster III and V (37.41) showed maximum inter cluster distance, suggesting that the genotypes constituted in these clusters may be used as parents for future hybridization programme. Principal Component Analysis (PCA) was utilized to estimate the relative contribution of various traits for total variability. Five components were found to possess eigen value more than 1.00. The PC1, PC2, PC3, PC4 and PC5 contributed 31.2, 14.5, 12.6, 10.5 and 10.1 per cent of variability. Together, they accounted for 78.9% of the variability of the genotypes used in the study has revealed the traits contributing for the variation.

Assessment of Genetic Variability of Parameters for Yield and its Components in Soybean [ Glycine max (L.) Merrill

An experiment was conducted with 9 crosses of soybean in compact family block design for 14 quantitative traits during kharif 2019 at N. E. Borlaug Crop Research Centre, Govind Ballabh Pant University of Agriculture & Technology, Pantnagar, Udham Singh Nagar, Uttarakhand, India to assess genetic variability, heritability and genetic advance. Genetic variability were found among the experimental materials for all traits. Phenotypic coefficient of variation was higher than genotypic coefficient of variation for most of the traits. Seed yield per plant showed highest genotypic coefficient of variation (29.1%). The highest heritability was exhibited by plant height followed by number of pods per plant, seed yield per plant and harvesting index. The value of genetic advance ranged from 0.06 (number of seeds per pod) to 89.45 (seed yield per row). The highest value of heritability coupled with high genetic advance as per cent mean exhibited by seed yield per plant followed by dry matter weight per plant, seed yield per row, number of pods per plant, seed yield efficiency which ensured additive gene action.

Genetic analysis of introgression lines of Oryza rufipogon for improvement of low phosphorous tolerance in indica rice

Soil phosphorus (P) deficiency is one of the major challenges for rice cultivation. The present study was carried out under low soil P condition (available P, < 2 kg ha-1) to study the genetic variability, correlation, path and principal component analysis (PCA) in a set of 40 introgression lines derived from Samba Mahsuri (Oryza sativa ssp. indica) × Oryza rufipogon. High genotypic coefficient of variation and phenotypic coefficient of variation was recorded for productive tillers (PT), seed weight (SW), and grain yield (GY). High heritability coupled with high genetic advance was recorded for plant height (PH), PT, SW, number of spikelets/panicle (SPP), spikelet fertility, and GY. Correlation analysis revealed that grain yield had a significant positive association with PH, PT, panicle length, SPP, and SW. Regression analysis revealed that the grain yield was mainly influenced by PT and SW. This was confirmed by path analysis, wherein PT and SW exerted the highest direct positive effect on grain yield. The PCA revealed that the first two PCs contribute to maximum variability, which together accounted for 60% of the total variability. The traits PT and SW contributed the maximum to load/variance the total variability. Thus, the selection of introgression lines with a greater number of PT and higher SW would be the most appropriate strategy for yield improvement under low soil P condition in rice. Cluster analysis grouped introgression lines along with checks into three clusters. Overall, the study revealed the pattern genetic variability for low P tolerance in the introgression lines. This further helps in designing appropriate breeding strategies for the improvement of rice cultivars for low P tolerance.

Studies on Genetic Variability, Heritability, Correlation and Path Analysis in Chrysanthemum (Dendranthema grandiflora Tzvelev)

The studies were conducted in the Division of Flower and Medicinal Crops, ICAR-Indian Institute of Horticultural Research, Bengaluru to evaluate twenty genotypes of chrysanthemum under naturally ventilated polyhouse during 2019–21. The experiments were laid out in CRD with three replications for growth and flowering traits to determine the variability, heritability, genotypic and phenotypic coefficient of variation, correlation and path coefficient among 9 quantitative traits. Results revealed that magnitude of the genotypic coefficient of variation (GCV) was higher than phenotypic coefficient of variation (PCV) for all the traits. High (>20%) PCV and GCV was recorded for number of flowers per plant, plant height, number of branches plant-1, number of leaves plant-1, flower diameter and days to bud initiation. Heritability estimates ranged from 82% (number of branches plant-1) to 99% (plant height). High heritability coupled with high genetic gain as per cent of mean was recorded for all the traits studied. The number of flowers plant-1 exhibited positive and significant correlation with number of branches plant-1, number of leaves plant-1, days to bud initiation and days to optimum flowering. Path coefficient analysis using correlation coefficients revealed that days to optimum flowering, plant height and days to bud initiation contributed highest positive direct effect on number of flowers plant-1. Therefore, the selection on the basis of traits viz., number of branches plant-1, number of leaves plant-1, days to bud initiation and days to optimum flowering will be more effective for improvement of traits in breeding of chrysanthemum.

Pattern of genetic diversity in indigenous Ahu rice germplasm of Assam

The north-eastern part of India including Assam is one of the key centres of diversity of cultivated rice. Among the diverse varietal types, Ahu group of varieties with their evolutionary significance being intermediate between indica and japonica deserves attention for their detailed evaluation and utilisation in crop improvement programme. This work was attempted to elucidate the pattern of genetic variation and genetic diversity in a set of 147 indigenous Ahu rice genotypes of Assam grown under rainfed upland direct seeded condition. Among the 13 traits under study, the highest genotypic coefficient of variation was exhibited by primary branches per plant followed by secondary branches per plant and grain yield. Heritability in broad sense was the highest for grain L: B ratio followed by grain width and grain length. More than 90% heritability in broad sense was, observed for all the traits except effective tillers per plant, panicle length and grain yield. The highest genetic advance as per cent of mean was observed for primary branches per plant followed by secondary branches per plant and grain yield. Hence, selection for these traits would be most effective for further genetic improvement. At the intermediate linkage distance, four main and nine sub clusters were obtained by Euclidean cluster analysis. Cluster III b was the largest containing 35 entries, which was followed by cluster I c containing 32 entries. The variety Chidon Ahu remained distinct from all other entries and belonged to cluster I b. Based on per se performances of the genotypes and their inter se distance, promising genotypes were suggested for hybridization in order to obtain desirable segregants for further genetic improvement of Ahu rices. Keywords: Genetic variation, genetic divergence, Ahu rice, rainfed upland