Anova, GCV and PCV
The analysis of variance (ANOVA) for all 11 morpho-agronomic traits in late-sown field pea revealed highly significant differences among genotypes (both parents and half-diallel crosses), demonstrating substantial genetic variation within the experimental material (Table 1). When comparing parents versus hybrids, significant differences were observed for all traits except seed per pod, indicating that hybridization effectively enhanced most agronomic characteristics. This genetic diversity provides a solid foundation for effective selection and breeding programs. The inference drawn from Table 2 showed that PCV were higher than the GCV for all traits, showing environmental influence on the trait expression. Secondary branches/plant (27.838%) and primary branches/plant (21.005%) displayed the maximum values of PCV, trailed by seed yield plant
-1 (20.42%).
Similarly, the highest GCV values were found for secondary branches/plant at 23.85%, trailed by seed yield/plant at (19.51%) and biological yield/plant (18.52%). Days to maturity has the lowest GCV (5.198%) and PCV (7.440%,) values, respectively. Consistent with
Jeberson et al., (2016),
Afreen et al., (2017) and
Meena et al., (2017). The narrow gap between GCV and PCV values for traits such as biological yield per plant and plant height suggests these characteristics are less influenced by environmental fluctuations and are primarily under genetic control. Conversely, traits showing wider GCV-PCV gaps, such as harvest index, indicate greater environmental sensitivity and may require more careful management during selection.
Heritability and genetic advance
Heritability for all traits ranges from 37.9% to 92.8%, suggesting low to high heritability. The largest heritability trait is biological yield per plant (92.8%), followed by plant height (91.6%), seed yield per plant (91.22%), pod per plant (89.4%), seed per pod (76.5%), secondary branches per plant (73.4%) and 100-seed weight (62.2%). Days to 50% flowering (55.4%) has shown moderate heritability, followed by days to maturity (48.8%) and primary branches per plant (41.04%), while harvest index (37.9%) has the lowest heritability. Higher heritability estimates suggest that genetic factors influenced these traits. Biological yield/plant had the largest genetic advance (GA), at 35.10%, followed by plant height (29.40%) and seed yield per plant (13.25%). The range of genetic advance was 0.50% to 35.10%. These results are in agreement with the findings of
Afreen et al., (2017) and
Pratap et al., (2024) who reported significant variability for all traits including 100-seed weight, plant height, pods per plant and primary branches per plant in pea. Similarly,
Singh et al., (2019) and
Gebre et al., (2024) concluded that traits with high heritability and high genetic advance are most amenable to breeding improvement. The present study confirms that biological yield per plant, seed yield per plant and plant height possess the most favorable genetic parameters for effective selection and breeding improvement in field pea under late-sown conditions.Traits exhibiting high heritability but low genetic advance may be governed by non-additive gene effects, while traits with low heritability and low genetic advance are highly influenced by environmental factors and are difficult to improve through direct selection. For such traits, indirect selection through correlated characters or selection in controlled environments would be more effective.
Correlation coefficient and path analysis
The perusal of Table 3 and 4 showed a wide similarity among the traits. This pattern is consistent with the findings of
Singh et al., (2017) and
Iqbal et al., (2020). The higher genotypic correlations suggest that the true genetic relationships between traits are stronger than what appears phenotypically, emphasizing the importance of considering genetic correlations in breeding decisions. Positive correlation was found among seed yield/plant and all traits except days to 50% flowering and days to maturity. Days to 50% flowering and days to maturity were significantly negatively correlated with seed yield plant
-1. This relationship can be attributed to the fact that early maturing genotypes escape terminal heat stress and moisture stress commonly encountered in late-sown conditions, thereby maintaining higher productivity. Similar observations were reported by
Katoch et al., (2016),
Tasnim et al., (2022) and
Yadav et al., (2024). Primary branches plant
-1 were significantly positively associated with seed yield per plant, harvest index, plant height and 100-seed weight, showing that more primary branches increase the components of seed yield and overall yields. Secondary branches/plant were significantly positively associated with pod/plant, biological yield/plant, 100-seed weight and seed yield/plant. In the trait plant height, there is a positive and significant relationship with seeds/pod, seed yield per plant, harvest index and primary branches per plant, showing that taller plants typically produce more seeds and produce a more yield. A significant positively correlation between pods/plant and 100-seed weight, secondary branches/plant, biological yield/plant, primary branch/plant and seed yield/plant, signifying that pods/plant plays an important role in improving seed yield and overall yield.
The seed pod
-1 was significantly correlated with plant height, biological yield/plant, seed yield/plant and harvest index, suggesting that increase in seed/pod positively affect overall seed yield. A positive correlation was found between 100-seed weight and biological yield/plant, pods/plant, primary branches/plant, number of secondary branches/plants, harvest index and seed yield plant
-1, indicating that increase in this trait can result in increased yield. Biological yield/plant is correlated positively with its seed yield, pod/plant, secondary branches/plant, seed pod
-1 and 100-seed weight demonstrating that biomass enhancement can increase overall yield. Seed yield/plant, seed pod
-1, primary branches/plant, plant height and 100-seed weight all have positive correlations with harvest index, indicating that a higher harvest index leads to a higher total yield component. These trait associations are in agreement with the results of
Ali et al., (2019) and
Jeberson et al., (2016),
Katoch et al., (2021) who reported similar correlation patterns in field pea. The consistent positive correlations observed across studies indicate the reliability of these relationships and their potential exploitation for indirect selection to improve seed yield, particularly focusing on pods per plant and 100-seed weight, as suggested by
Srivastava et al., (2018),
Georgieva et al., (2015) and
Sharma et al., (2023). Seed yield was strongly and significantly positively correlated with pods/plant (r » 0.83) and 100-seed weight (r » 0.74) and negatively with days to flowering/maturity. By concentrating on these traits, breeders can increase field pea production, particularly in light of changing climates.
Bhuvaneswari et al., (2017) and
Lal et al., (2018) had similar findings. Fig 1 demonstrate correlation heatmap of 11 traits in field pea showing relationship among variables. Correlation coefficients reveal trait relationships, without demonstrating causation. Phenotypic path coefficient analysis partitions correlation coefficients into direct and indirect effects with seed yield as the dependent variable. Table 5 shows that biological yield (0.8698) has the highest direct positive effects on seed yield, suggesting that it is a primary driver of seed yield, indicating importance selecting high biomass. Pods/plant (0.7649), 100-seed weight (0.6169), secondary branches/plant (0.6084), harvest index (0.3731), seed/pod (0.3197), primary branches/plant (0.2711) and plant height (0.2253) were the next most positive direct effects on seed yield. These findings were also reported
Tiwari and Lavanya, (2012),
Basaiwala et al., (2013) and
Kumar et al., (2013). Characters’ indirect contributions to seed yield were extremely minimal and detrimental. Days to 50% flowering (-0.1842) and days to maturity (-0.3148) showed a significant negative direct effect. By biological yield per plant, strong indirect impacts were observed in the no. of pods/plant (0.5968), secondary branches plant
-1 (0.5491), 100-seed weight (0.4366) and seeds per pod (0.1273). This indicates that these traits influence seed yield through two pathways: directly through their own effects and indirectly by enhancing total biomass production, which subsequently translates to higher seed yields. The substantial indirect effects through biological yield demonstrate that traits contributing to vegetative vigor ultimately benefit seed production. This finding aligns with
Tofiq et al., (2015), who demonstrated that biomass increase is strongly associated with higher seed yield.