Studies on Correlation and Path Coefficient for Yield and Its Contributing Traits in Rice (Oryza sativa L.)

The present investigation was carried out with five segregating populations in sorghum to assess the association between grain yield and its correlated traits. In correlation coefficients, three crosses viz., Cross 1, Cross 3 and Cross 5 showed significant positive association of grain yield with flag leaf length, flag leaf width, harvest index, plant height, number of leaves per plant, leaf chlorophyll index, stem girth, test weight (Cross 5), panicle weight, panicle length (except Cross 1) and biological yield and inter association of such traits were almost positive. Hence these three crosses could be exploited simultaneously for grain yield and other correlated traits by selection. From path coefficient analysis, it is concluded that the biological yield and harvest index had high positive direct effect on single plant yield in all crosses evaluated in the study. They also exhibited high indirect contribution on yield through yield components traits that could be used as yield determinants for further improvement in the population.

Submergence is the third most important abiotic stress hugely affecting yield and productivity in rice. There are many wild varieties and landraces available which are tolerant to submergence stress. These genotypes can be utilized as donors in different breeding programs. The population derived from such germplasms are subjected to genetic evaluation for yield and yield related attributes for development of lines that are high yielding as well as tolerant to submergence. The present investigation was executed in 120 Recombinant Inbred Lines (RIL) population (F10) derived from Swarna-Sub1 x AC 20431B along with four land races and Swarna-Sub1 to elucidate the association existing between yield and yield attributing characters. Apart from this, Correlation and path analysis was also employed to study direct and indirect effect on grain yield. Observations for agro-morphological traits such as days to 50% flowering, plant height, panicle length, total number of tillers, number of effective tillers per plant, number of filled grains and Spikelet fertility, test weight, grain yield per plant, biomass per plant and harvest index were recorded and analyzed for various variability parameters. Correlation and path coefficient analysis were also carried out. High heritability and genetic advance values were observed for days to 50% flowering, plant height, panicle length, total number of tillers per plant, effective tillers per plant, filled grains per panicle, spikelet fertility, test weight, grain yield and biomass per plant. Among all the characters; filled grains per panicle, biomass and harvest index per plant showed significant correlation with grain yield. Effective number of tillers per plant has the highest positive direct effect on grain yield.

Background: Foxtail millet cultivation inIndia’s North Eastern Hill regionholds promise due to its adaptation to diverse environments and high-quality grain. The objective of this study was to assess the amount of variability present among the genotypes, association of traits and find out foxtail millet genotypes that produce high yield in diverse environments. Methods: The investigation was carried out during July 2022 to May 2023 in four different dates of sowing. Two environments maintained under rainfed condition and the remaining two environments are maintained under irrigated condition. The experiment was conducted in randomized complete block design with three replications in all environments. Result: Analysis of variance revealed statistically significant differences (at 5%) among the 30 genotypes for all yield variables under evaluation. Genotype ‘G1’ exhibited superior performance for both yield and yield-related traits. The present study revealed considerable genetic variation among the yield traits, with all traits demonstrating high heritability except for harvest index.Traits such as fodder yield per plant, panicle length, biological yield, flag leaf width, peduncle length, panicle width and grain yield per plant show high heritability coupled with high genetic advance. A strong correlation was observed between grain yield per plant and several traits including days to 50% flowering, days to maturity, plant height, panicle length, flag leaf length, peduncle length, biological yield and fodder yield per plant. This correlation was consistent at both the genotypic and phenotypic levels. Biological yield exhibited the strongest direct influence on grain yield per plant, followed by harvest index, flag leaf width and number of base tillers on genotypic and phenotypic levels.

In winter (rabi) 2023–2024, at the Regional Agricultural Research Station, Nandyal, research on trait association and path analysis were carried out with an emphasis on 16 morpho-physiological and yield-attributing traits among 50 foxtail millet germplasm accessions. The results revealed that the majority of genotypic correlation coefficient estimations were higher than corresponding phenotypic correlations indicating the strong inherent associations among the traits. The yield-attributing traits viz., fodder yield plant-1, harvest index, plant height, panicle length, flag leaf length at flowering, 1000 grain weight, days to 50% flowering and flag leaf width at flowering had a significant and positive association with grain yield plant-1, whereas abortive grain rate and number of productive tillers had displayed negative association. Grain yield plant-1 was found to be significant and positively associated with physiological traits such as photosynthetic rate, stomatal conductance, transpiration rate, and relative water content, suggesting strong source and sink relationship. The strong and favorable direct impacts of fodder yield plant-1, harvest index, days to 50% flowering, flag leaf length and width at flowering, photosynthetic rate, relative water content, abortive grain rate and 1000 grain weight on grain yield plant-1 were found in the genotypic and phenotypic path analysis. Based on trait association and path analysis, the most important yield-attributing traits were the fodder yield plant-1, harvest index, flag leaf length and width, photosynthetic rate, relative water content and the 1000-grain weight. Therefore, these attributes should be given top priority when formulating the selection criteria for the foxtail millet grain yield improvement programme

This study aimed to estimate the genetic variability of 36 upland rice genotypes for yield and its components, and determine trait association among morphological traits. The field experiment was conducted using simple lattice design at two locations (Guraferda and Gojeb) during 2016 main cropping season. Analysis of variance for individual locations revealed significant differences (P≤0.05) among genotypes for most of the studied traits at Guraferda, however number of fertile tillers per plant, number of unfilled grains per panicle, non-fertile tillers per plant, panicle length, thousand grain weight and biological yield were found being non-significant. Similarly, the genotypes showed significant difference (P≤0.05) for plant height, number of filled grain per panicle, days to maturity, number of primary branches per panicle and grain yield however the remaining traits were showed non-significant difference among genotypes at Gojeb. Combined analysis of variance over the two locations revealed significant differences (P≤0.05) among the genotypes for most of the studied traits, while genotype x location interactions showed significant differences for the traits, total number of tillers per plant, plant height, days to 50% heading, days to maturity and grain yield. The mean over the two locations showed, wide ranges for number of filled grains per panicle (24-123), days to 50% heading (50-83) and grain yield (15-34 q/ha). The genotypic coefficient of variation ranged from 2.3% for plant height to 19.5% for number of filled grains per panicle, and phenotypic coefficient of variation (PCV) ranged from 4.0% for panicle length to 20.2% for filled grains per panicle. High broad sense heritability (H 2 B) estimates were obtained for number of filled grains per panicle (93.3%) and days to 50% heading (61.6%); while low H 2 B value was found for plant height (20.1%), number of primary branches per panicle (15.1%) and grain yield (14.4%). The estimates of genetic advance as the percentage of the mean (GAM) ranged from 2.1% for plant height to 38.8% for number of filled grains per panicle. High H 2 B coupled with high GAM were obtained for number of filled grains per panicle, which indicates that this trait can be effectively improved through selection. Grain yield showed significant and positive genotypic correlation with 1000-grain weight, days to 50% heading, days to maturity and harvest index. Similarly, it showed significant and positive phenotypic correlation with panicle length, number of filled grains per panicle, 1000-grain weight, fertile tillers per plant and number of primary branches per panicle. Path coefficient analysis at genotypic level revealed high and positive direct effect of days to heading (0.7), 1000-grain weight (0.6), days to maturity (0.3) and harvest index (0.2). The detected positive correlation indicated that, increases in the value of one trait results in increasing the correlated traits. Keywords: Broad sense heritability, Upland rice, Variability, DOI : 10.7176/JBAH/9-3-02

The present study was conducted for evaluating EMS induced mutants for sodicity tolerance in rice. A set of 402 Nagina 22 rice mutants along with three sodicity tolerant check varieties namely TRY2, TRY3 and TRY4 were screened at Anbil Dharmalingam Agricultural College and Research Institute, Trichy under sodic soil condition and also screened under hydroponics condition at the seedling stage. A total of 13 biometrical traits and salt injury scores were recorded development of better tolerant varieties.and subjected to association analysis and path analysis. Correlation analysis showed that there was a significant and positive correlation observed for flag leaf length, flag leaf breadth, the number of total tillers per plant, the number of productive tillers for the plant, tillering efficiency percentage, panicle length, panicle weight, panicle harvest index and hundred seed weight and also showed significant and negative correlation for salt injury index and vegetative vigour. Both the scores at the field (vegetative vigour) and salt injury score showed a negative correlation with single plant yield. Path analysis revealed a high positive direct effect on the number of productive tillers per plant, panicle weight, hundred seed weight and panicle length and the remaining traits showed negligible effects on single plant yield. As a result, enhancing the correlating trait as well as reducing the effect of negative correlating trait leads to the development of better tolerant varieties

An experimental trial on eight rice genotypes was designed at the field of Institute of Agriculture and Animal Science, Lamjung, Nepal under randomized complete block design with three replications from June-November 2017 to study the nature and extent of correlation among yield and yield attributing characters under reproductive heat stress. Grain yield was significantly correlated with 1000-grain weight (r=0.838**), SPAD reading (0.815*), relative water content (0.803*), harvest index (0.771**) and number of filled grains per panicle (0.719*) suggesting an instrumental role of these traits as “selection criteria” for yield improvement. The grain yield had negative non-significant association with the number of non-effective tillers per m2 (−1.05), sterility % (−0.378) and panicle length (−0.52). While the positive non-significant association with grain yield was exhibited by flag leaf area (0.161), the number of effective tillers per m2 (0.173), number of tillers per hill (0.634), plant height (0.110) and days to 50% anthesis (0.63*). The path coefficient analysis of different traits revealed highest positive direct effect of the number of tillers per hill (0.7220) followed by days to 50% flowering, SPAD reading, number of filled grains per panicle, 1000-grain weight, panicle length and harvest index upon yield. However, relative water content, sterility %, the number of effective, non-effective tillers per m2 and plant height expressed negative direct effect upon grain yield. Relative water content (pivotal drought parameter) had negative direct effect upon yield but its residual positive effect was justified via other traits such as tiller number, SPAD reading, days to 50% flowering and number of filled grains per panicle.

The discriminant-function technique was used to create selection indices for 29 wheat genotypes (Triticum aestivum L.) growing under late-sown condition. The discriminant function technique was used to create 31 selection indices based on grain yield (q/ha) and its four components. Increasing the amount of characters in the selection index improves selection efficiency. The selection index based on five characters, that is, grain yield (q/ha), harvest index (%), test weight (1000 kernel wt. in g), number of tillers per plant, and biological yield (q/ha), exhibited highest relative efficiency, with genetic advance of 2619.76% and 17.34, respectively. The correlation coefficient study demonstrated a substantial positive relationship between grain yield (q/ha) and key traits, including test weight (1000 kernel wt. in g), biological yield (q/ha), harvest index (%), flag leaf area (cm2), and number of tillers per plant. Path coefficient analysis further highlighted that harvest index (%), test weight (1000 kernel wt. in g), number of tillers per plant, and biological yield (q/ha) have a significant beneficial direct effect on grain yield.

During the kharif season of 2022, a set of 27 rice genotypes were evaluated for the study of "Correlation and path coefficient analysis for yield and grain yield contributing characters in rice (Oryza sativa L.) genotypes" using an RBD with three replications at the research field of Department of Genetics and Plant breeding, Sam Higginbottom University of Agriculture, Technology and Sciences, Naini Allahabad, U.P. Analysis of variance showed significant differences among genotypes for all 13 characters indicating that the material has adequate genetic variability to support the breeding programme for improving the grain yield of rice. Out of 27 rice genotypes evaluated for various characters, four genotypes were found superior for different characters. These four genotypes were found to be better for more than one character. Among the lines SIVA (26.83), KRISHNA (26.19g), RDR-8702 (25.79g) andSS-999 (24.48g) recorded high grain yield per hill. All these genotypes recorded significantly high yield as compared to the check NDR-359 (CHECK) (22.67g). High estimate of heritability coupled with high genetic advance as percent of mean was recorded for spikelets per panicle, biological yield, harvest index, test weight and grain yield per hill. These traits are governed by additive gene effects and therefore, may be improved through direct selection. Grain yield per hill correlated positively and significantly with flag leaf width, biological yield, harvest index, and test weight. Harvest index, biological yield, days to maturity, and number of panicles per hill all had a significant positive direct effect on grain yield per hill at both genotypic and phenotypic levels. Thus, selections for these characters will be proved efficient for the improvement of grain yield of rice.

The growth, yield and yield attributing characters of Tilki rice variety was evaluated under different age and number of seedlings hill -1 at Dang, Nepal during rainy season from June to September, 2019. The experiment was laid out into factorial design of two different age of seedlings as viz. 20 days and 30 days as main plot factor and four different number of seedlings hill -1 viz. 1, 2, 3 and 4 as sub-plot factor and replicated thrice. The results revealed that highest plant height (79.69cm) at the time of harvesting , LAI (0.17), panicle length (23.55cm), number of grains per panicle (101.82), effective tiller per hill (9.9), non-effective tiller per hill (1.03), total tiller per hill (10.94), test weight (29.22gm) ,economical yield (2.09ton/ha), biological yield (5.28ton/ha) and harvest index (39.34%) were recorded by 20 days of seedlings. Regarding the number of seedlings effective tiller per hill and harvest index were non-significant. Highest plant height (79.65cm), test weight (28.88gm) and LAI (0.17) were recorded in 1 seedling per hill. Longest panicle length (24.11cm) and more number of grains per panicle (100.48) were also recorded in 1 seedlings per hill. Highest number of non-effective tiller (1.66) and total tillers per hill (11.08) in four seedlings per hill were recorded. Highest economical yield (2.21ton/ha) and biological yield (5.43ton/ha) were recorded in 2 seedlings per hill. The interaction effect of age and number of seedlings per hill showed non-significant relation with all the growth, yield and yield attributing parameters except non-effective tiller per hill and LAI.

Genetic diversity within crop germplasm forms the foundation of plant breeding and crop improvement programs. A broad genetic base enhances the probability of identifying genotypes with superior adaptability, stress tolerance, and yield potential. The present study was carried out at Agriculture Research Station, Gangavati during late kharif 2020 to assess variability for yield and its components among 120 rice genotypes maintained at All India Coordinated Rice Improvement Programme, Agriculture Research Station, Gangavathi. ANOVA revealed significant difference for all the characters except panicle length, kernel length and length/breadth ratio. High phenotypic and genetic coefficient of variance was exhibited by plant height, total number of tillers per hill, number of productive tillers per hill, flag leaf length, panicle weight, test weight, total number of spikelets per panicle, number of filled grains per panicle, kernel breadth and yield per plant. High heritability coupled with genetic advance per cent mean was observed for plant height, total number of tillers per hill, number of productive tillers per hill, flag leaf length, panicle weight, test weight, total number of spikelets per panicle, number of filled grains per panicle, panicle fertility, kernel length, kernel breadth, length/breadth ratio and yield per plant.

Genetic variability is the prime and fundamental requirement for any crop breeding to develop superior varieties which yields more and fulfills the demanding requirements of increasing population.The current study investigates twenty genotypes of rice, including one check variety NDR-359, that were raised in the Field Experimentation Centre of the Department of Genetics and Plant Breeding, SHUATS, Prayagraj during Kharif 2022 using a Randomized Block Design with three replications.The best genotypes for grain yield per plant were chosen based on the mean performance of genotypes RNR – 1446, followed by MTU - 1121, JGL – 24423, and Rango Komal. All of the qualities under examination had significant differences, according to the analysis of variance. The characters viz., Biological yield, Grain yield per hill, Number of spikelets per panicle exhibited high Genotypic Coefficient of Variation (GCV) and Phenotypic Coefficient of Variation (PCV). For all the features under study, there were very slight variations between GCV and PCV, indicating that the environment had little to no impact on these individuals. High heritability recorded in Biological yield (95.92%), Grain yield per hill (91.89%), Panicle length (91.80%), Plant height (91.00%) and Days to 50% flowering (87.81%), whereas moderate heritability observed in Flag leaf width (47.08%). High heritability coupled with genetic advance as percent mean is recorded in Biological yield (77.10), Grain yield per hill (59.72), Panicle length (24.65) and Plant height (34.50) indicating that simple selection could be effective for improving these characters. Correlation results shown that grain yield per hill exhibited highly and significantly correlation with biological yield and Number of spikelets per panicle. The results of the Path coefficient analysis revealed that both phenotypic and genotypic levels, had positive direct effects on grain yield while compare with parameters like Biological yield, Harvest index %, Number of panicles per hill and Days to 50% flowering. Quality characters i.e., hulling (%), cooking and eating characters i.e., kernel length and breadth before and after cooking, elongation ratio was taken for 19 genotypes. As per mean performance highest maximum grain length was observed in Kasturi, DRRH2, highest elongation ratio observed in MTU - 1121 and NLR - 40024.

The study was conducted at the experimental farm of Rice and Wheat Research Centre, Malan during Kharif, 2021. Experimental material consist of 43 germplasm lines of red rice (Oryza sativa L.) sourced from various districts of Himachal Pradesh. Significant genotypic differences were existed among the genotypes. Correlation coefficients were computed for grain yield per plant (g), days to 50% flowering and days to 75% maturity, plant height (cm), flag leaf length (cm), flag leaf width (cm), total tillers per plant, effective tillers per plant, spikelets per panicle, 1000-seed weight (g), grain length [L] (mm), grain breadth [B] (mm), L:B ratio, biological yield per plant (g) and harvest index (%). The results revealed that grain yield per plant was positively and significantly correlated with days to 50 per cent flowering, days to 75 per cent maturity, plant height, flag leaf length, total tillers per plant, effective tillers per plant, spikelet per panicle, 1000 grain weight, grain length, L:B ratio, biological yield per plant and harvest index at phenotypic level as well as at genotypic level indicating that selection through these traits would be effective. At phenotypic level, biological yield per plant had the highest positive direct effect on grain yield per plant followed by harvest index, flag leaf length, spikelet per panicle, days to 50 per cent flowering, total tillers per plant, 1000 grain weight, grain breadth, plant height and L:B ratio. Thus they can be considered for direct selection for high grain yield.

Finger millet is important for providing food and nutritional security, especially among resource-poor farmers, due to its resistance to harsh climatic conditions and high amounts of calcium, iron, dietary fibre, and essential amino acids. Increasing economic output is a fundamental goal of all plant breeding initiatives; however, direct selection for yield is generally ineffective due to its poor heritability. As a result, understanding the relationship between yield-contributing features is critical since it determines the success of selection procedures. The present investigation was undertaken to assess the genetic divergence of thirty-seven finger millet (Eleusine coracana L.) genotypes using D2 analysis for fourteen characters, during kharif, 2024. The experiment was set up using a Randomised Block Design (RBD). The data were recorded from randomly selected five plants for each genotype for each replication for fourteen characters. The data was analysed with the technique of D2 statistics. Analysis of variance revealed significant differences with respect to all the characters viz, days to 50% flowering, plant height, flag leaf length, flag leaf width, number of tillers, fingers per head, fingers per plant, finger weight, finger length, biological yield per plant, grain yield per plant, harvest index and test weight under study at the 1% level except days to maturity, which is significant at the 5% level. This is an indication of the existence of sufficient variability for the traits. Following Tocher’s technique, the 37 genotypes were divided into five clusters. Cluster II was the largest one with thirteen genotypes. The maximum intra-cluster distance was exerted in cluster V. Inter-cluster distance was maximum between clusters I and V. The Cluster V exhibited the highest values for Days to 50% Flowering, Days to Maturity, Plant Height, Finger Width, Ear Head Width, and Biological Yield contributed more towards the genetic divergence. In Mahalanobis D2 analysis, three divergent genotypes, such as IE-190, IE-184, and IE-169, were identified as the most diverse genotypes in the population. Hence, these genotypes could be used in future breeding programmes to incorporate desirable features, such as high yield and high quality, into recipient finger millet genotypes, resulting in the creation of promising cultivars.

This study aimed to investigate the correlations among yield and yield component traits and estimate the direct and indirect effects of these traits on grain yield in rice. The experiment was conducted during kharif 2022. Correlation coefficients and path coefficients were analyzed to determine the relationships between these traits and seed yield. The results showed significant positive correlations between seed yield and traits such as effective tillers per plant, total tillers per plant, number of filled grains, spikelet fertility, biological yield, harvest index, and 100 seed weight. The genotypic correlations were slightly higher than the corresponding phenotypic correlations. Path coefficient analysis revealed that biological yield had the maximum direct effect on seed yield, followed by harvest index, panicle length, and number of filled grains per panicle, plant height, and effective tillers per plant, 100 seed weight, and days to 50% flowering. These findings provide valuable information for selecting superior cross combinations in hybrid rice breeding programs to improve grain yield.