Unveiling the genetic variability, character association for yield and yield contributing traits in sesame (Sesamum indicum L.)

Introduction

Sesame (Sesamum indicum L.) (2n = 26), also known as Til or Gingelly, it is one of the most important oilseed crop of tropical and temperate regions. It is commonly known as "Queen of oilseeds". Because of its excellent nutritional content and resistance to oxidation and rancidity, it is a major industrial food crop (Swapna et al. 2024) [32] Sesame occupies an area of 21,000 ha with production and productivity of 15,000 tonnes and 714 kgha-1 respectively in Telangana [1] . It is grown as summer crop in Northern Telangana districts viz., Adilabad, Jagtial, Karimnagar and Nizamabad. However, the development of improved plant cultivars and increasing the production is restricted mainly due to narrow genetic pool, which results in limited possibility to restructure the sesame crop. Despite the economic importance for food, oil and medicine, the yield potential of sesame is not spectacular due to its cultivation in sub-marginal lands and non availability of superior high yielding varieties due to lack of an appropriate breeding program (Manjeet et al. 2020 and Pandey et al. 2015) [15,21] . Effective breeding programs depend on the amount of variability existing in the genetic stocks of the crop so that, it can be exploited for crop improvement by geneticist and crop breeders. Genetic variation is the inherent variation which remains unchanged by the environmental factors and this type of variation is more useful to a breeder for exploitation by selection or hybridization (Manjeet et al. 2020 and Bagheri et al., 2017) [15, 3] . Progress in any crop improvement project depends not only on the magnitude of genetic variability but also on the heritability and genetic advance under selection (Dutta et al. 2013) [8] . Heritability estimates the magnitude of variation present in a particular trait which is transmissible from the parent to the offspring which helps plant breeders for the selection of elite genotypes from diverse genetic populations (Patidar et al., 2018) [22] . Since heritability is also influenced by environment, the information on heritability alone may not help in selecting characters on the basis of their phenotype (Nahak et al., 2018) [18] . Therefore, the genetic advance is also considered important because high value of genetic advance is indicative of additive gene action which is the only genetic variance which response to the selection and it also provides information about the expected gain in a character from one cycle of selection (Dutta et al. 2013) [8] . Keeping in view of the above facts, the present study was carried out with the objective to assess genetic variability, heritability, genetic advance and character association among the seven morphological characters of sesame.

Materials and methods

The experiment was conducted in Randomised Block Design (RBD) with two replications at the Regional Agricultural Research Station in Polasa, Jagtial, during the summer, 2022. Each genotype was sown in eight rows of three meteres length, with inter-row spacing of 30 cm and intra row spacing of 15 cm. Sowing was done by dibbling the seed at 2-3 cm depth. All the standard package of practices were followed during crop growth period except spraying of insecticides. The experimental material used in the present investigation comprised of 14 advanced breeding lines of sesame including three checks i.e., two national checks (TKG 22 and GT 10), zonal check (Pragathi) and one local check (Swetha Til). The data were recorded on yield and yield attributing characters viz., days to 50% flowering (days), days to maturity (days), plant height (cm), number of branches per plant, number of capsules per plant, 1000 seed weight (g), seed yield (kg/ha) from five randomly selected plants in each replication and the collected mean data was subjected to Statistical analysis was performed as per the standard methods. Analysis of variance was used to assess genotypic variability following Federer (1956), with significance tested using F-values (Fisher and Yates, 1963) [9] . GCV and PCV were calculated as per Burton and de Vane (1953) [5] , heritability (broad sense) as per Allard (1960) [1] and genetic advance and GAM according to Johnson et al. (1955) [12] . The GCV and PCV estimates were taken as low, medium and high as per the classification of Singh and Chaudhary, (1977) [30] while the heritability and genetic advance as percent of mean estimates were taken as low, medium and high as per the classification of Johnson et al., (1955) [12] . The calculations were performed through computer generated programme WINDOSTAT, a statistical package at Computer Centre, PJTAU, Rajendranagar, Hyderabad, Telangana, India.

Results and Discussion

The presence of sufficient variability indicated that the materials of sesame under study were good enough for further study. The phenotypic coefficient of variation (PCV) was greater than the genotypic coefficient of variation (GCV) for all the characters studied, which reflected the role of the environment in the expression of the observed traits. Similar results were also reported by Revathi et al. (2012) [26] , Wide variability was observed for seed yield (813-1045 Kg/ha) and other characters also. PCV showed higher values than GCV suggesting less impact of environmental factors on the studied traits. Genotypic and phenotypic coefficients of variation were observed as low for Days to 50% flowering and days to maturity which were similar to the findings of Saxena and Bisen (2017) [27] and Divya et al. (2018) [7] . Variation in days to maturity is essential in selection of early and late duration varieties which is important for further improvement. Plant height and number of productive branches per plant showed a moderate extent of variation for both phenotypic and genotypic coefficients, which was on par with the results observed by Gayathri et al., (2025) [24] Thouseem et al. (2022) [33] and Vamshi et al. (2021) [34] for plant height and Ashfaq et al. (2025) [2] reported for number of capsules per plant. Low PCV and GCV values were recorded for days to 50% flowering, days to maturity, test weight and seed yield which were in agreement with the results reported by Padmaja et al. (2022) [20] for 1000 seed weight, Gayathri et al. (2025) [24] for days to maturity and days to 50% flowering and test weight. Pavani et al. (2020) [23] reported for seed yield. Number of branches per plant recorded high PCV and GCV, which was on par with the findings reported by Swapna et al. (2024) [32] . The traits number of branches per plant recorded both high PCV and GCV. Similar observations were recorded by Divya et al. (2018) [7] and Swapna et al. (2024) [32] In contrast, when both heritability and genetic advance are low, it suggests a strong environmental influence on the trait, and selection in such cases would likely be ineffective. Heritability values in the present investigation ranged from 27.7 % to 96.20%, while GAM (genetic advance as percent of mean) spanned from 2.6% to 36.88 %. Traits such as number of branches per plant and number of capsules per plant exhibited high heritability along with a high genetic advance as a percent of the mean. Similar findings for number of capsules per plant and number of branches per plant were reported by Divya et al. (2018) [7] and Gayathri et al. 2025 [24] . Results indicate that the trait was controlled by additive gene action and selection can be effective. Moderate heritability coupled with moderate genetic advance as percent of mean was observed for plant height. Similar findings reported by Rajitha et al. (2021) [25] and Nisha et al. (2024) [19] .

High heritability along with moderate GAM was observed for 1000 seed weight. Similar results were obtained by Mitkari et al. (2023) [20] and Gayathri et al. 2025 [24] . It indicates that this trait was less influenced by environment and selection may be effective. High heritability coupled with low GAM was observed for days to 50% flowering and days to maturity which align with the findings observed by Gayatri et al. 2025 [24] . High heritability and low genetic advance as percent of mean of this trait indicates that this trait is governed by non additive gene effects play an important role in the expression of this trait. Therefore, the results indicated a little scope for further improvement through individual plant selection. Seed yield recorded low heritability coupled with low GAM. These results are similar with the findings of Padmaja et al., 2022 [20] . [2] for days to 50% flowering and Rajitha (2025) [25] and Madhu et al., 2023 [14] number of capsules per plant. This type of character association indicates the improvement in seed yield can be achieved by improving the characters like number of capsules per plant. Some characters viz., days to maturity (0.268), plant height (0.029), number of primary branches per plant (0.162) found to have positive and nonsignificant association with seed yield per plant. The results were similar to the findings of Bharathi et al. (2015) [4] , Saxena and Bisen (2016) [28] for days to maturity, Madhu et al., 2023 [14] for plant height and number of branches per plant. While one character viz., 1000 seed weight (-0.273) exhibited non significant negative correlation with seed yield per plant. These results were in confirmation with Iqbal et al. (2016) [11] Laghari et al. (2016) [13] . Days to maturity exhibited significant positive association with days to 50% flowering (0.666). These results are similar with the findings of Madhu et al., 2023 [14] . 1000 seed weight was negative significant correlation with days to maturity (-0.423) and plant height (-0.423). These results are in agreement with the findings of Ashfaq et al. (2025) [2] and for plant height by Singh et al. (2018) [29] .

Conclusion

The present experiment revealed substantial genetic variability in the studied sesame genotypes. Traits such as Number of Productive Branches and plant number of capsules, seed yield per plant exhibited substantial heritability coupled with considerable genetic advance as percent of mean, indicating the predominance of additive genetic effects and the potential for effective improvement through selection. These traits should be prioritized in breeding programmes aimed at yield enhancement improvement in sesame.

Acknowledgement

AcknowledgementThe authors would like to acknowledge the PJTSAU University, RARS, Polasa, Jagtial staff for their extended support, PC Unit, AICRP on Sesame and Niger,Jabalpur and ICAR-IIOR Oilseeds.

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