Deciphering genetic diversity and trait interrelationships in pigeonpea (Cajanus cajan (L.) Millsp.)

Introduction

Pulses are one of the major sources of protein in vegetarian diets. Due to their high protein content and balanced amino acid profile, they form an important part of the daily human diet. Among pulse crops, pigeonpea (Cajanus cajan (L). Millsp) is an important grain legume cultivated mainly under rainfed conditions in the semi-arid tropics. Pigeonpea belongs to the genus Cajanus, sub tribe Cajaninae, tribe Phaseoleae, subfamily Papilionaceae and family Fabaceae. It is a diploid species having 11 pairs of chromosomes ( 2𝑛 = 2𝑥 = 22) with an estimated genome size of 858 Mbp. Out of the 32 species present in the genus Cajanus, 18 species are reported from India (Van der Maesen, 1980). Pigeonpea is commonly known as "Arhar" or "Tur" and is widely consumed as dal, a highly preferred dish among Indian vegetarians. The crop contains about 24-25 per cent protein along with valuable minerals (Sodavadiya et al., 2009) [1] . In India, a large vegetarian population depends on pigeonpea as a major source of dietary protein. The per capita protein availability in the country is estimated to be only 63.4 g per day, which is much lower than the 80 g per day recommended by WHO (Prasad et al., 2013) [2] . Seed yield in pigeonpea is a complex quantitative character greatly influenced by environmental factors. For a systematic breeding programme, it is essential to understand the magnitude and nature of variability present in the population due to both genetic and environmental causes. Therefore, estimation of parameters such as genotypic coefficient of variation, heritability in broad sense and genetic advance becomes important for assessing variability among traits. Information on genetic variability and heritability is highly useful for selecting elite genotypes and planning heterosis breeding programmes (Anuradha et al., 2019) [3] .

Materials and methods

The research was carried out at the Agricultural Research Station, Badnapur, during the Kharif season of 2025-26, thirty eight genotypes of pigeonpea, along with two check varieties viz. BDN-711 and Godawari, were planted in a Randomized Block Design with two replications for nine quantitative characters viz. Days to 50% flowering, days to maturity, plant height, number of primary branches per plant, number of secondary branches per plant, number of pods per plant, number seeds per pod, 100 seed weight and seed yield per plant. Phenotypic coefficient correlations were computed using the formula suggested by Falconer (1960). The Path coefficient analysis was conducted as described by Dewey et al. (1959) [4] . The list of genotypes presented in Table 1. Each genotype was sown in single row with 4 m in length, with a spacing of 90 cm between rows and 20 cm between plants. The data collected for individual traits were analyzed using the analysis of variance (ANOVA) method, which is typically applied to a randomized block design. This statistical technique helps to determine the significance of differences among the genotypes in the study (Panse et al., 1967) [5] . Divergence analysis was performed using the D 2 statistic, as proposed by Mahalanobis (1936) [6] and described by Rao (1952) [7] . Godawari

Results and discussion

Analysis of variance for genetic variability

The analysis of variance indicated significant differences among the genotypes for all the characters studied, suggesting the existence of substantial genetic variability in the experimental material evaluated in the present investigation in Table 2

Variability and genetic parameters

The estimates of variability (genotypic and phenotypic coefficient of variation), heritability (broad sense), genetic advance as percent of mean for seed yield and its component characters in forty genotypes of pigeonpea were presented in

Correlation studies

The genotypic and phenotypic correlations for yield and its components characters studied are presented in

Phenotypic and genotypic path coefficient analysis

Path coefficient analysis was done to determine direct and indirect contribution of different traits towards seed yield per plant with phenotypic and genotypic level. The result were presented in Table 6 and Table 7.

In the present investigation it was found that number of pods per plant (P = 0.5047) recorded the highest positive direct effect on seed yield per plant followed by number of primary branches per plant (P = 0.4083), number of seeds per pod (P = 0.1152), days to maturity (P = 0.0945) , plant height (P = 0.0797), and number of secondary branches per plant (P = 0.0527). The character days to 50% flowering (P=-0.1686) and 100-seed weight (P=-0.1035) exhibited negative direct effects.

At the genotypic level, number of pods per plant (G = 1.1168) also exhibited the highest positive direct effect on seed yield per plant, followed by number of primary branches per plant (G = 0.5297), 100seed weight (G = 0.3529), days to 50% flowering (G = 0.0895), days to maturity (G = 0.). The character days to maturity (G=-0.0390), plant height (G=-0.0476), number of secondary branches per plant (G=-0.2637), and number of seeds per pod (G=-0.1051), exhibited a negative direct effect at the genotypic level.

Conclusion

Significant genotype-related variations for the majority of the traits show a wide range of genetic diversity, which may be useful in the selection of superior germplasm. The environment may have an influence on these character because the phenotypic coefficients of variation were marginally larger than the genotypic coefficients of variation. The character viz. seed yield per plant, number of secondary branches per plant, number of primary branches per plant, number of pods per plant, 100 seed weight and days to 50% flowering showed moderate to high magnitudes of GCV and PCV. Suggested that choosing desirable genotypes for these character could be beneficial for enhancing seed yield in next breeding programme. The characters viz. 100 seed weight, number of pods per plant, seed yield per plant, days to maturity and number of pods per plant to show high heritability. Seed yield per plant exhibited the greatest genetic advance as a percentage of mean, followed by number of pods per plant, number of secondary branches, 100 seed weight, number of primary branches per plant, plant height, days to 50% flowering and days to maturity. The characters days to flowering, days to maturity, plant height, number of primary and secondary branches, number of pods per plant, number of seeds per pod, 100 seed weight and seed yield per plant showed more diversity among the studied pigeonpea germplasm and greatest emphasis should be more to these traits for selection of diverse parameters in pigeonpea improvement programme.

References

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7. Falconer DS. Correlated character, introduction to quantitative genetics, 312. London: Longman Group Ltd; 1989. How to cite this article: Patil U, Patil D, Gite V, Sontakke P. Deciphering genetic diversity and trait interrelationships in pigeonpea (Cajanus cajan (L.) Millsp.). International Journal of Advanced Biochemistry Research. 2026;SP-10(10):865-869. doi: https://www.doi.org/10.33545/26174693.2026.v10.i10Sk.10389