Estimation of genetic variability, heritability, and genetic advance for quantitative traits in elite urd bean (Vigna mungo L.) genotypes under agro-climatic conditions of Chhattisgarh

Introduction

Urdbean (Vigna mungo L. Hepper), a crucial self-pollinated diploid legume with a chromosome number of 2n=22 belongs to the family Fabaceae and sub-family Papilionoideae (Dana, 1980) [2] . This pulse crop thrives across diverse soil and climatic conditions, playing a significant role in enhancing soil fertility through atmospheric nitrogen fixation (Gowda et al., 2013) [6] . As the fourth most important pulse crop in India, following chickpea, pigeon pea, and green gram, urdbean is cultivated across 40.02 lakh hectares, yielding 26.31 lakh tonnes with an average productivity of 657 kg/ha (Directorate of Pulses Development, 2023). In Chhattisgarh, the crop covers 136.31 thousand hectares, producing 55.77 metric tonnes at a productivity of 409 kg/ha (Directorate of Extension Services, 2024; Krishi Darshika, 2024) [4] . Urdbean is recognized as a vital source of dietary protein, containing approximately 24-25% protein, alongside essential minerals such as phosphorus (983 mg/100g), calcium (138 mg/100g), and iron (7.57 mg/100g), and vitamins like niacin (1.447 mg/100g) and thiamine (0.273 mg/100g) (Sakila and Pandiyan, 2018) [10] . The availability of sufficient genetic variability is paramount for any crop improvement program, necessitating the assessment of parameters like phenotypic and genotypic coefficients of variance, heritability and genetic advance to develop high-yielding varieties. The availability of sufficient genetic variability is paramount for any crop improvement program, necessitating the assessment of parameters like phenotypic and genotypic coefficients of variance, heritability, and genetic advance to develop high-yielding varieties (Deepalakshmi and Kumar, 2004) [3] .

Material and Methods

The present investigation was carried out during Kharif 2024 at the Research-cum-Instructional Farm, Department of Genetics and Plant Breeding, College of Agriculture, IGKV, Raipur, Chhattisgarh. The experimental material comprised 21 elite urdbean genotypes including three checks, from various research institutes across India (Table .1). The genotypes were evaluated for genetic variability and divergence. The experiment was laid out in a Randomized Complete Block Design (RCBD) with three replications.

Each plot consisted of six rows, with spacing of 30 cm × 10 cm, and measured 4 × 1.8 m². Seeds were treated with SAAF, PSB, ZSB, and Rhizobium before sowing. Standard agronomic practices were followed throughout the crop season. Pest control was managed using Rocket and Indoxacarb. Data were recorded on 12 quantitative traits including days to 50% flowering, days to maturity, plant height (cm), number of primary branches per plant, number of clusters per plant, pod length (cm), number of pods per plant, number of seeds per pod, 100-seed weight (g), biological yield per plant (g), harvest index (%), and seed yield per plant (g).

Results and Discussion

Analysis of variance revealed highly significant differences among 21 urdbean genotypes for all 12 quantitative traits, indicating the presence of considerable genetic variability (Table .2). These findings are in agreement with earlier reports by Kumar et al. (2020) [8] and Aman et al. (2022) [1] , suggesting ample scope for selection and improvement. Wide ranges were observed in several traits, such as days to 50% flowering (41.33-52.67 days), days to maturity (75.33-83.67 days), and seed yield per plant (3.5-6.2 g), reflecting inherent variability among the genotypes.

Estimates of genotypic and phenotypic coefficients of variation indicated that PCV was higher than GCV for all traits, suggesting environmental influence on trait expression. According to the classification proposed by Sivasubramanian and Madhavamenon (1973) [11] which categorizes variation as low (<10%), moderate (10-20%), and high (>20% (2022) [13] . Low GCV and PCV were recorded in pod length (2.69%, 3.69%), days to maturity (2.62%, 2.87%) and number of seeds per pod (3.06%, 4.50%) (Fig. 1), indicating limited variability as reported by Toppo et al. (2019) [12] and Jyothsna et al. (2016) [7] . High heritability was observed in days to 50% flowering (90.18%), 100-seed weight (85.59%), and days to maturity (83.15%), plant height (76.33%), and clusters per plant (69.92%), suggesting that these traits are less influenced by the environment and governed by additive gene effects, consistent with Aman et al., (2022) [1] . Moderate heritability was found for harvest index (55.42%), pod length (53.30%), number of seeds per pod (46.16%), number of pods per plant (42.07%), and biological yield (37.57%), seed yield per plant (35.09%) and number of branches per plant (31.30%) indicating partial environmental influence. Genetic advance as percent of mean was highest for number of clusters per plant (31.79%), followed by plant height (24.66%) and harvest index (21.69%), suggesting that these traits could be effectively improved through selection, as also reported by Rajwade et al. (2025) [9] . Moderate genetic advance was noted in number of pods per plant (16.05%), biological yield (14.62%), seed yield (14.57%), 100-seed weight (11.40%), and days to flowering (13.64%), indicating moderate gain from selection. Low GA as percent of mean was recorded in number of branches per plant (7.96%), days to maturity (4.92%), number of seeds per pod (4.28%) and pod length (4.05%), limited scope for improvement in these traits. Traits such as number of clusters per plant (69.81%, 31.79%), plant height (76.26%, 24.66%), and 100-seed weight (85.59%, 11.40%) exhibited high heritability coupled with high to moderate genetic advance, indicating predominance of additive gene action (Fig. 2). These traits can be effectively improved through direct selection (Table .3).

Overall, traits such as clusters per plant, plant height, and harvest index exhibit high genetic variability, heritability, and genetic advance, making them promising selection indices for yield improvement in urdbean.

Conclusion

The phenotypic coefficient of variation exceeded the genotypic coefficient for all traits, indicating notable environmental influence. High heritability coupled with high genetic advance as percent of mean was observed for number of clusters per plant, plant height, and harvest index, suggesting additive gene action. These traits are genetically stable and responsive to selection. Overall, they play a crucial role in enhancing seed yield in urdbean genotypes.

Acknowledgement

AcknowledgmentI sincerely thank Indian Institute of Pulse Research (IIPR) Kanpur, for providing the seed material and timely support, which were instrumental in the smooth execution of field experiments and overall progress of this research.

References

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