Journal of Advances in Biology & Biotechnology

Background: Seed germination and seed vigour are critical determinants of crop establishment and productivity in pigeonpea (Cajanus cajan L.). Understanding the genetic variability and the association of germination-related traits with seed yield is essential for identifying superior genotypes and developing efficient selection strategies in breeding programmes. The present study was undertaken to assess the genetic variability, diversity, and relationships between seed germination characteristics and yield-related traits in pigeonpea genotypes.

Methods: The experiment was conducted at the Regional Research and Technology Transfer Station (RRTTS), Odisha University of Agriculture and Technology (OUAT), Bhawanipatna, Odisha, using 40 pigeonpea genotypes comprising 36 advanced breeding lines and four check varieties. The field experiment was laid out in a randomised block design with three replications. Observations were recorded on eight seed germination and quality traits, namely seed vigour index-I (SVI-I), seed vigour index-II (SVI-II), germination rate index (GRI), coefficient of velocity of germination (CVG), germination index (GI), mean germination time (MGT), viability percentage and seed protein content, along with eight agro-morphological traits including plant height, days to 50% flowering, days to maturity, number of branches per plant, number of pods per plant, number of seeds per pod, seed index and seed yield per plant. Statistical analyses included analysis of variance (ANOVA), genotypic and phenotypic coefficients of variation (GCV and PCV), broad-sense heritability, genetic advance as a percentage of the mean (GAM), Mahalanobis D² cluster analysis, correlation and path coefficient analysis.

Results: Analysis of variance revealed significant genetic variability among the genotypes for all sixteen characters studied. The PCV values were marginally higher than the corresponding GCV values, indicating minimal environmental influence on trait expression. High broad-sense heritability coupled with high genetic advance as a percentage of the mean was observed for most germination-related traits, particularly SVI-I, SVI-II, GRI, CVG, GI, MGT and viability percentage, suggesting the predominance of additive gene action and the effectiveness of phenotypic selection. Mahalanobis D² analysis grouped the forty genotypes into seven distinct clusters, indicating substantial genetic diversity among the breeding materials. Correlation and path coefficient analyses revealed that SVI-I, SVI-II, GRI, CVG, GI and viability percentage exhibited positive associations with seed yield per plant, whereas mean germination time showed a negative association, indicating that rapid and vigorous germination contributes to improved productivity.

Conclusion: The study demonstrated the existence of considerable genetic variability and diversity among pigeonpea genotypes for seed germination, vigour and yield-related traits. High heritability coupled with additive gene action for major germination parameters suggests that these traits can be effectively exploited through direct selection. Seed vigour indices, germination rate index, coefficient of velocity of germination, germination index and viability percentage emerged as reliable selection criteria for improving seed yield, while genetically divergent clusters identified through D² analysis provide valuable parental combinations for future pigeonpea breeding programmes.