Analysis of variance revealed that a vast range of variability was recorded for all the traits in greengram lines (Table 1). The results on variability parameters are given in Table 2. Mean performance of all inter sub-specific lines exhibited a wide range of variation for all the biometrical traits
viz., days to 50 per cent flowering (38-44), plant height (37.22-59.92 cm), number of branches per plant (5.33-8.33), number of clusters per plant (8.50-19.83), number of pods per cluster (3.18-6.42), number of pods per plant (24.80-89.50), pod length (6.37-8.85 cm), number of seeds per pod (9.33-13.59), hundred seed weight (2.03-4.21 g) and single plant yield (3.32-10.84 g). The number of lines that exhibited more than the general mean values for yield attributing traits was: 97 lines for the number of pods per cluster, 95 lines for the number of pods per plant, 100 lines for the number of seeds per pod, 102 lines for hundred seed weight and 87 lines for single plant yield. More number of seeds (upto 13) per pod was observed in many lines and was due to small seeds, which were inherited from the
Vigna radiata var.
sublobata. The study showed that a significant amount of variation was observed for all the traits.
Rao et al., (2006) and
Reddy et al., (2011) also reported significant variations for all the characters studied.
The GCV for various traits ranged from 4.00 per cent (days to 50 per cent flowering) to 30.18 per cent (single plant yield). Moderate GCV was found for the characters
viz., number of clusters per plant (17.59%) and the number of pods per cluster (12.38%). The low GCV values were found for hundred seed weight (9.35%), plant height (9.09%), number of branches per plant (8.62%), pod length (5.07%), number of seeds per pod (4.86%) and days to 50 per cent flowering (4.00%). The high GCV values were found for single plant yield (30.18%) and the number of pods per plant (26.80%).
The PCV for various traits ranged from 4.26 per cent (days to 50 per cent flowering) to 31.89 per cent (single plant yield). The moderate PCV was found for hundred seed weight (15.50%), number of pods per cluster (13.90%), plant height (12.53%) and the number of branches per plant (11.47%). The low PCV was found for number of seeds per pod (8.97%), pod length (7.94%) and days to 50 per cent flowering (4.26%). The high PCV was found for single plant yield (31.89%), the number of pods per plant (28.22%) and the number of clusters per plant (21.11%).
High GCV and PCV estimates for the number of pods per plant and single plant yield were reported by
Raturi et al., (2015), Susmitha and Jayamani (2018),
Parimala et al., (2020) and
Salman et al., (2023) in greengram. High GCV and PCV for the number of pods per plant was observed by
Talukdar et al., (2020) in greengram. Moderate PCV for plant height, the number of branches per plant and hundred seed weight were observed by
Salman et al., (2023) in greengram. Moderate PCV for the number of branches per plant was observed by
Mehta et al., (2019) in greengram. Low PCV for days to 50 per cent flowering and pod length were observed by
Zuge et al., (2019) and
Salman et al., (2023) in greengram. Low PCV for days to 50 per cent flowering was observed by
Asari et al., (2019) in greengram.
The GCV was found to be lower than the PCV for all the traits studied. This showed that these characters are not only expressed through genotype but also influenced by environmental factors. The difference between PCV and GCV ranged from 0.26 per cent (days to 50 per cent flowering) to 6.16 per cent (hundred seed weight). The lowest difference is exhibited by plant height indicating the highest contribution of genotypic value to the phenotype and low influence of environmental factors suggesting a genetic gain for this trait through selection.
The heritability ranged from 29.34 per cent (number of seeds per pod) to 90.19 per cent (number of pods per plant). High heritability was found for the number of pods per plant (90.19%), single plant yield (89.58%), days to 50 per cent flowering (88.14%), number of pods per cluster (79.28%) and number of clusters per plant (69.50%). Moderate heritability was found for the number of branches per plant (56.48%), plant height (52.68%), pod length (40.83%) and hundred seed weight (36.35%). Low heritability was found for number of seeds per pod (29.34%) (Table 2). High heritability helps in the identification of traits that are transmissible from one generation to another generation and have environmental influence at a minimal level. High heritability was reported by
Asari et al., (2019) and
Salman et al., (2023) for the number of pods per plant, single plant yield, number of clusters per plant and number of pods per cluster. High heritability for plant height and number of pods per plant was reported by
Zuge et al., (2019) in greengram. Moderate heritability for pod length was reported by
Zuge et al., (2019).
The genetic advance as the per cent of mean ranged from 5.42 (number of seeds per pod) to 58.84 (single plant yield). High genetic advance as per cent of mean was observed for single plant yield (58.84), number of pods per plant (52.43), number of clusters per plant (30.22) and number of pods per cluster (22.70). Moderate genetic advance as per cent of mean was observed for plant height (13.60), the number of branches per plant (13.34) and hundred seed weight (11.61). Low genetic advance as per cent of mean was observed for days to 50 per cent flowering (7.74), pod length (6.68) and the number of seeds per pod (5.42) (Table 2). High genetic advance as the per cent of mean was reported by
Asari et al., (2019) and
Salman et al., (2023) for the number of pods per plant, single plant yield and number of clusters per plant.
High heritability combined with high genetic advance as per cent of mean was observed for the number of pods per plant (90.19, 52.43), single plant yield (89.58, 58.84), the number of pods per cluster (79.28, 22.70) and the number of clusters per plant (69.50, 30.22) which indicates additive gene effects which would be improved by simple selection. High heritability along with low genetic advance as per cent of mean was observed for days to 50 per cent flowering (88.14, 7.74) indicates the presence of non-additive gene action. Similar results were reported by
Muthuswamy et al., (2019), Mehta et al., (2019), Asari et al., (2019) and
Salman et al., (2023) for the number of pods per plant and single plant yield.
The frequency distribution for ten biometrical traits was represented in Fig 1. The traits number of branches per plant and the single plant yield showed positive skewness. The normal distribution was observed for days to 50 per cent flowering, plant height, the number of clusters per plant, the number of pods per cluster, the number of pods per plant, pod length, the number of seeds per pod and hundred seed weight which indicates the presence of adequate variability for the traits.
Correlation analysis helps find out the relationship among two or more variables. The genotypic correlation was indicated in Table 3. The traits
viz., plant height, number of branches per plant, number of clusters per plant, number of pods per cluster, number of pods per plant, pod length, number of seeds per pod, hundred seed weight were positively correlated with single plant yield. The number of cluster per plant showed a significant and positive association with plant height and number of branches per plant. The number of pods per plant showed significant and positive inter-correlation with plant height, number of branches per plant, number of clusters per plant and number of pods per cluster. Hundred seed weight showed positive significant inter-correlation with the number of clusters per plant, the number of pods per cluster and pod length.
Dhunde et al., (2021) observed that the number of branches per plant, number of clusters per plant, number of pods per cluster, number of pods per plant, plant height, number of seeds per pod and hundred seed weight had a positive significant correlation with single plant yield.
Mohammed et al., (2020) observed that the plant height, number of branches per plant, number of clusters per plant, pod length, number of seeds per pod, number of pods per plant and hundred seed weight had a positive significant correlation with single plant yield in greengram.
Path analysis helps to determine the direct and indirect contributions of other traits towards the yield. In the present study, the number of pods per plant had a high positive direct effect on single plant yield (Table 4). Similar results were reported by
Dhunde et al., (2021) where, the number of pods per plant had a high positive direct effect on single plant yield in greengram.
Number of branches per plant, the number of clusters per plant and the number of pods per cluster had a high indirect effect on seed yield through the number of pods per plant. The number of branches per plant, number of clusters per plant, number of pods per cluster, number of pods per plant, pod length and number of seeds per pod were found to be the yield attributing traits. Based on the direct effects of traits on a single plant yield, the number of pods per plant should be prioritized to execute the selection for genetic enhancement of seed yield in greengram. The residual effect in the present study was 0.331, which indicates that the characters contribute 68 per cent towards the expression of the trait single plant yield.