Correlation and path coefficient studies for yield and yield attributes of rice (Oryza sativa L.) maintainer lines

Introduction

Rice (Oryza sativa L.) is one of the most important cereal crops and serves as the staple food for more than half of the world's population. In India, rice plays a vital role in food security, rural livelihoods and agricultural development. According to the Third Advance Estimates, India produced 154.02 million tonnes of rice during 2025-26, highlighting the continued importance of the crop in meeting the food requirements of a growing population (Ministry of Agriculture and Farmers Welfare, 2026). Therefore, the development of high-yielding and climate-resilient rice varieties remains a major objective of rice improvement programmes. Grain yield in rice is a complex quantitative trait influenced by several interrelated characters and environmental factors. Correlation analysis provides valuable information on the nature and extent of associations among traits, whereas path coefficient analysis helps partition these associations into direct and indirect effects, thereby identifying traits with the greatest influence on yield. Positive associations of grain yield with productive tillers per plant, panicle length, grains per panicle and spikelet fertility have been reported, indicating their importance in enhancing productivity (Kiran et al., 2023) [9] . Likewise, effective tillers, panicle length and filled grains per panicle were found to contribute significantly to grain yield and may serve as reliable selection criteria in breeding programmes (Paramanik et al., 2023) [14] . Direct positive effects of biological yield, harvest index and test weight on grain yield have also been reported, emphasizing their importance in improving rice productivity (Ratnam et al., 2024) [17] . three replications, and each plot was raised in 2 rows of 4 meters in length. Seeds of all 42 maintainer lines, along with 2 standard checks, were sown with a spacing of 20cm × 15cm 2 . Seedlings were transplanted in the main field at the age of twenty-eight days, and all the necessary package of practices were followed for raising a healthy crop. Observations on yield, yield-attributing features and quality traits were recorded on five randomly selected competing plants from each entry in each replication for characters viz., DFF: Days to 50% flowering, NET: Number of effective tillers per plant, PH: Plant height, PL: Plant length, NGP: Number of Grains per panicle, TW: 1000-grain weight, GYPP: Grain yield per plant, HRR: Head Rice Recovery, KL: Kernel Length, KL/KB: Kernel length/kernel breadth ratio. The analysis was done as per Singh and Chaudhary (1985) [20] for the correlation coefficient and Dewey and Lu (1959) [4] for path analysis, which were standard procedures used till today. Table 1: List of rice genotypes (Maintainer lines) utilised for the study.

Results and Discussions Association between yield, its attributing traits and floral traits

The study of the association between grain yield and its component traits helps to reveal their importance in rice breeding programs (Table 2). The genotypic and phenotypic correlations are nearly equal, indicating little or no effect of environment on the relationship of traits, strong genetic control, and stable trait expression.

Grain yield per plant

Phenotypic correlations revealed that grain yield per plant had significant and positive association with number of effective tillers per plant (0.61**), plant height (0.59**), panicle length (0.53**), number of grains per panicle (0.33**), head rice recovery (0.34**), and days to 50% flowering (0.23**), which indicated that all these characters were important for yield improvement. However, it had a negative and significant correlation with kernel length/breadth ratio (-0.48**), and kernel length Similar results were reported by Tiwari et al. (2026) [22] for panicle length, no of effective tillers per plant, Dinesh et al.

(2025), Das et al. (2024) [1] for no of effective tillers per plant, number of grains per panicle, Maneesha et al. (2024) [12] for plant height, panicle length, number of grains per panicle, Pathak et al. (2024) [16] for plant height, no of effective tillers per plant, Saketh et al. (2023) [18] for number of effective tillers per plant, plant height, panicle length, number of grains per panicle, and days to 50% flowering, Edukondalu et al. (2023) [6] for panicle length, number of effective tillers per plant, Devi et al. (2022) [3] number of effective tillers per plant, plant height, number of grains per panicle, Umarani et al. (2019) [23] for panicle length, number of grains per panicle.

Days to 50% flowering

The trait days to 50% flowering showed a significant positive correlation with plant height (0.48**), head rice recovery (0.46**), and number of effective tillers per plant (0.24**). Similar results were reported by Tiwari et al. (2026) [22] , Jasmine et al. (2022) [7] for the number of effective tillers per plant, Devi et al. (2022) [3] for head rice recovery, Das et al. (2024) [1] for plant height, Saketh et al. (2023) [18] for plant height and head rice recovery, Rukmini Devi et al.

(2019) [2] for plant height.

The trait plant height showed a significant positive correlation with number of effective tillers per plant (0.36**), panicle length (0.27**), head rice recovery (0.28**), number of grains per panicle (0.19*). It also has a significant negative correlation with kernal length (-0.20*) and kernel length/breadth ratio (-0.49**). Similar results were reported by Parimala et al. (2020) [15] , Umarani et al. (2019) [23] , for panicle length, Pathak et al.

(2024) [16] , Jasmine et al. (2022) [7] , for panicle length and number of effective tillers per plant, Saketh et al. (2023) [18] , for number of grains per panicle, panicle length, and head rice recovery.

Number of effective tillers per plant

The trait number of effective tillers per plant showed a significant positive correlation with panicle length (0.0.51**), number of grains per panicle (0.53**), head rice recovery (0.46**). it also has a significant negative correlation with test weight (-0.29**), kernel length (-0.34**), and kernel length/breadth ratio (-0.35**). Similar results were reported by Parimala et al. (2020) [15] and Edukondalu et al. (2023) [6] for panicle length.

Panicle length

The trait panicle length showed a significant positive correlation with number of grains per panicle (0.38**) and head rice recovery (0.21*). it has a significant negative correlation with kernel length (-0.17*). Similar results were reported by Devi et al. (2022) [3] for head rice recovery, Saketh et al. (2023) [18] for the number of grains per panicle and head rice recovery, and Rukmini Devi et al. (2019) [2] for the number of grains per panicle.

Number of grains per panicle

The trait number of grains per panicle showed a significant positive correlation with head rice recovery (0.41**). it has a significant negative correlation with test weight (-0.67**), kernel length (-0.68**), kernel length/breadth ratio (-0.32**). Similar results were reported by Saketh et al. (2023) [18] for head rice recovery, 1000 grain weight, and kernel length.

1000 grain weight

The trait test weight showed a significant positive correlation with kernel length (0.63**). It has a significant negative correlation with head rice recovery (-0.35**). Similar results were reported by Saketh et al. (2023) [18] for kernel length, head rice recovery.

Head rice recovery

The trait head rice recovery showed a significant negative correlation with kernel length (-0.23**). Similar results were reported by Maneesha et al. (2024) [12] and Rukmini Devi et al. (2019) [2] for kernel length.

Kernel length

The trait kernel length showed a significant positive correlation with kernel length/breadth ratio (0.57**). Similar results were reported by Singh et al. (2024) [19] , Devi et al. (2022) [3] , Kumar et al. (2020) [10] for the kernel length/breadth ratio.

Traits other than yield direct and indirect effects on the grain yield

Path coefficient analysis divides the correlations for a lucid understanding of the cause-and-effect relationship; correlation only assesses the relationship between two variables. Path coefficient analysis employs other attributes to describe the direct and indirect causes of association (Wright, 1921) [24] . The path coefficient analysis estimates for yield and its related traits are shown in Table 3).

Grain yield per plant

Path coefficient analysis revealed that 1000 grain weight showed the highest positive direct effect on the grain yield per plant fallowed by number of grains per panicle, plant height, number of effective tillers per plant, head rice recovery, and panicle length.

Days to 50% flowering

The trait days to 50% flowering had a direct negative phenotypic effect on grain yield per plant (-0.207). The correlation between days to 50% flowering and grain yield per plant is positive (0.235) and significant. The trait exhibited positive indirect effects through the traits, 1000-grain weight, and kernel length. Similar results are reported by Jasmine et al. (2022) [7] , Umarani et al. (2019) [23] , Maneesha et al. (2024) [12] for grain yield per plant, Devi et al. (2022) [3] for grain yield per plant,1000 grain weight, and kernel length, and Saketh et al. (2023) [18] for kernel length.

Plant height

The trait plant height had a direct positive phenotypic effect on grain yield per plant (0.274). Its association with the grain yield per plant is highly positive and significant (0.591) due to high direct positive indirect effect through days to 50% flowering (0.131), number of effective tillers per plant (0.100). The trait also surfaces negative indirect effects with the kernel length/ breadth ratio (-0.135) Similar results were reported by Tiwari et al. (2020) [22] for the direct effect of plant height on grain yield per plant, Edukondalu et al. (2023) [6] for the kernel length/breadth ratio, Saketh et al. (2023) [18] for grain yield per plant, and Days to 50% flowering.

Number of effective tillers per plant

The trait number of effective tillers per plant showed a direct positive phenotypic effect on grain yield per plant (0.261). The correlation between this trait and grain yield per plant is high and significant (0.610) due to positive indirect phenotypic effects through plant height (0.134), number of grains per plant (0.139), and head rice recovery (0.119). Similar results were reported by Edukondalu et al. (2023) [6] , Das et al. (2024) [1] , Rukmini Devi et al. (2019) [2] for the direct effect on grain yield, Parimal et al. (2019), Rukmini Devi et al. (2019) [2] for plant height, Saketh et al. (2023) [18] for grain yield, plant height, Number of grains per plant, and head rice recovery.

Panicle length

The trait panicle length had a direct positive effect on grain yield per plant (0.154). Its association with grain yield per plant is high positive. The trait also manifested with indirect positive and negative effects on other traits which are negligible Similar results were reported by Tiwari et al. (2020) [22] , Edukondalu et al. (2023) [6] , Maneesha et al. (2024) [12] , Lakshmi et al. (2020) [11] , Rukmini Devi et al. (2019) [2] for the direct effect of panicle length on grain yield per plant, Parimala et al. (2020) [15] for the indirect positive effect through plant height, Devi et al. (2022) [3] for head rice recovery, and Saketh et al. (2023) [18] for grain yield.

Number of grains per panicle

The trait number of grains per panicle had a direct positive effect on the grain yield per plant (0.346). This trait is also associated with grain yield per plant, which is positive mainly due to positive indirect contribution through number of effective tillers per plant (0.184), panicle length (0.131), and head rice recovery (0.142). The trait also revealed negative indirect effects through 1000 grain weight (-0.232), Kernel length (-0.234), and Kernel length/Kernel breadth ratio (-0.110). Similar results were reported by Edukondalu et al. (2023) [6] for panicle length, Saketh et al. (2023) [18] for grain yield per plant, and panicle length.

grain weight

The trait 1000 grain weight expressed a positive high direct effect on Grain yield per plant (0.388). The correlation between the trait and Grain yield per plant is positive but not significant, due to positive indirect effects through kernel length (2.44), and negative indirect effects through Number of grains per panicle (-0.261), Number of effective tillers per plant (-0.114), and Head rice recovery (-0.136). Similar results were reported by Das et al. (2024) [1] , Jasmine et al. (2022) [7] for the direct effect on grain yield, Parimala et al. (2020) [15] for grain yield, number of effective tillers per plant, Saketh et al. (2023) [18] for grain yield per plant, kernel length, number of grains per panicle, and head rice recovery.

Milling

The trait milling shows a negative direct effect on the grain yield per plant (-0.149). The association of this trait with grain yield per plant is positive but not significant due to negligible positive and negative indirect effects through other traits. Similar results were reported by Ratnam et al. (2024) [17] and Singh et al. (2020a) [21] for the negative direct effect of milling on grain yield per plant.

Head rice recovery

The trait head rice recovery had a positive direct phenotypic effect on grain yield per plant (0.213). Its correlation with the grain yield per plant is positive and significant due to a positive indirect contribution through milling (0.128) The trait also surfaced with positive and negative indirect effects through other traits, but those are negligible or insignificant. Similar results were reported by Edukondalu et al. (2023) [6] , Maneesha et al. (2024) [12] , Ratnam et al. (2024) [17] and Das et al. (2024) [1] for the direct effect on grain yield.

Kernel length

The trait kernel length had a positive direct effect on grain yield per plant (0.085). Its association with the grain yield per plant is negative, mainly due to the negative indirect effect through plant height (-0.170). Though this trait, together with other traits like days to 50% flowering, number of effective tillers per plant, number of grains per panicle, and panicle length, shows a negative indirect effect, it is negligible. Similar results were reported by Edukondalu et al. (2023) [6] for plant height, Saketh et al. (2023) [18] , and Maneesha et al. (2024) [12] for grain yield per plant.

Kernel length/kernel breadth ratio

The trait kernel length/kernel breadth ratio shows a positive direct effect on grain yield per plant (0.102). Where its correlation with the grain yield per plant is negative The trait materialised negative indirect effects through kernel length, and positive indirect effects with the remaining traits, but those are negligible Similar results were reported by Nanda et al. (2026) [13] and Lakshmi et al. (2020) [11] for grain yield per plant.

Residual effect

Residual effect was 0.52for phenotypic and 0.4620 for genotypic path coefficient analysis. High values of residual effect could be due to the influence of other traits, which were not included in this study.

Conclusion

The correlation and path coefficient analyses revealed that the number of effective tillers per plant, plant height, panicle length, number of grains per panicle, head rice recovery and days to 50% flowering were the important yieldcontributing traits due to their significant positive association with grain yield. Path coefficient study revealed that 1000-grain weight was the most influential variable, followed by number of grains per panicle, plant height, number of effective tillers per plant, head rice recovery and panicle length through their positive direct effects on grain yield. Therefore, these features should be given more importance in selection programs to improve grain yield in rice. Simultaneous enhancement of these traits is likely to create superior high-yielding genotypes.

Acknowledgement

AcknowledgementsThe work was conducted as a part of the research work of an M.Sc. student of the Professor Jayashankar Telangana Agricultural University. Research content:The research content in this manuscript is original and has not been published or submitted elsewhere for publication.

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