In the present study, yield was significantly positively correlated with number of pods/plant, number of pod clusters/plant, days to first harvest and number of branches. So, when selection is done for these characters, it would simultaneously improves yield. This is in confirmation with the results of
Anandhi and Sunny (2006);
Lakshmanan and Vahab (2011);
Boghara et al., (2016); Muthuselvi et al., (2017); Gowd et al. (2020) and
Sharma et al. (2021).
Plant height was significantly, positively correlated with number of pods/cluster and number of seeds/pod, it did mean that when we select accessions with more plant height, it would also result in more number of pods/cluster and number of seeds/pod. Similar results on plant height and number of pods/cluster were reported by
Manivannan et al. (2015) and
Muthuselvi et al. (2017) and
Sharma et al. (2021). Plant height was negatively correlated with number of branches, days to 50% flowering, days to first fruit set and number of pod clusters/plant. Therefore it can be inferred that, accessions with more height will be having less number of branches, few pod clusters/plant and will be early in flowering and fruit set. These results were in agreement with the findings of
Manivannan et al. (2015) and
Muthuselvi et al. (2017) for number of branches and days to 50% flowering.
Number of branches were significantly and positively correlated with days to first harvest, number of pod clusters /plant and number of pods/plant. Therefore it can be inferred that selection of accessions with more number of branches would also result in more number of pod clusters/plant, number of pods/plant and delayed harvest. So it implies that accessions with more number of branches were late in harvest however, they were high yielders. These results were in agreement with
Singh et al. (2009);
Anandhi and Sunny (2006);
Lakshmanan and Vahab (2011);
Gowd et al. (2020) and
Sharma et al. (2021).
Days to 50% flowering was significantly and positively correlated with days to first fruit set. Both days to 50% flowering and days to first fruit set was found significantly and negatively correlated with number of pods/cluster. Therefore it was inferred that accessions with more days to 50% flowering had less number of pods/cluster. Similar results were reported by
Manivannan et al., (2015). Days to first harvest was positively and significantly correlated with number of pod clusters/plant, number of pods/plant and number of seeds/pod. Therefore it can be inferred that those accessions which are late for first harvest have more number of pod cluster/plant, number of pods/plant and consequently higher pod yield/plant. However, days to first harvest was also significantly negatively correlated with number of pods/cluster, pod girth and pod weight.
Number of pod clusters/plant was significantly, positively correlated with number of pods/plant, and pod yield/plant. It was inferred that selection of accessions with more number of pod clusters/plant would also have more number of pods /plant and more yield. Hence, accessions with more number of pod clusters/plant would be high yielders .Similar findings were reported by
Anandhi and Sunny (2006);
Lakshmanan and Vahab (2011);
Boghara et al., (2016) and
Sharma et al. (2021) for number of pods/cluster and number of pods/plant.
Number of pods/plant was significantly negatively correlated with pod length, pod girth and pod weight hence, those accessions with more number of pods will have shorter and small pods. This finding is in agreement with
Boghara et al., (2016). Pod length was significantly and positively correlated with pod girth and pod weight. It does mean that when pod length increases it would also result in an increase in pod girth. This result is similar to the findings of
Lakshmanan and Vahab (2011);
Kumar et al., (2015). Hence, when selection is done for longer pods, it would also improve pod weight and pod girth.
Correlation alone cannot give a real picture of inter character association, so it becomes necessary to study the path coefficient analysis, which takes into account the cause effect relationship apart from the degree of relationship. Path analysis will indicate whether, the association of the yield related traits with yield is due to their direct effect, where direct selection can be made for improvement or is a consequence of their indirect effect via some other traits in such cases a breeder has to select the trait by considering the indirect effect. In the present study the yield contributing characters like number of pods/plant, had highest positive direct effect (0.902) on yield followed by number of branches (0.607) and plant height (0.287). Correlation was also positive for these characters. Hence, direct selection can be employed for these traits for yield improvement because direct positive effect implies the true relationship between traits. Positive direct effect with number of pods/plant and plant height was reported by
Lakshmanan and Vahab (2018).
Gowd et al. (2020) and
Sharma et al. (2021) also reported positive direct effect of number of pods/plant on pod yield in cluster bean. Number of pod clusters/plant had positive significant correlation with pod yield/plant (0.493) but it has a negative direct effect (-0.307). This negative direct effect is counter balanced by indirect positive effect through number of pods/plant (0.482) and number of branches (0.463) making the association between number of pod clusters/plant and pod yield positive. These results are in line with the findings of
Anandhi and Sunny (2006). Number of branches have a positive indirect effect on pod yield through number of pods/plant (0.231). Days to first harvest have significant positive correlation with yield (0.422), but path analysis revealed that it has a negative direct effect (-0.161) on pod yield/plant. This negative direct effect is compensated by the positive indirect effect on pod yield through number of branches (0.216) and number of pods/plant (0.444).
There is a high positive association between pod yield/plant and number of pods/ plant, number of pod clusters/plant, number of branches, days to first harvest and plant height and the path analysis reveals that chief contributing characters towards pod yield/plant is number of pods/plant, number of branches and plant height. Hence, those accessions which grow taller with more number of branches and more number of pods have to be selected from the collected accessions. These accessions can be used as parents in the crop improvement programme for developing promising varieties or hybrids of cluster bean with high pod yield.